| pcr detection of the two 'candidatus' liberobacter species associated with greening disease of citrus. | greening is a severe and widespread disease of citrus in two main citrus growing areas of the world, asia and africa. it is caused by an uncultured phloem restricted bacterium that we have recently characterized from the sequence of its 16s ribosomal dna. the bacterium is a new "candidatus' genus, liberobacter, in the alpha subdivision of the proteobacteria, and two 'candidatus species' have been recognized: liberobacter asiaticum and liberobacter africanum. in this paper we describe a pcr metho ... | 1996 | 8684375 |
| comparison of the 16s/23s ribosomal intergenic regions of "candidatus liberobacter asiaticum" and "candidatus liberobacter africanum," the two species associated with citrus huanglongbing (greening) disease. | 16s/23s intergenic spacer regions from the rrna operons of two strains of "candidatus liberobacter asiaticum" and one strain of "candidatus liberobacter africanum" were cloned and sequenced. the intergenic spacers of the two "candidatus l. asiaticum" strains studied are identical and contain the genes for isoleucine trna (trna(ile)) and alanine trna (trna(ala)) separated by 11 nucleotides. the intergenic spacer of the "candidatus l. africanum" strain contains only one trna gene (trna(ala)). the ... | 1997 | 8995827 |
| effect of sucrose octanoate on survival of nymphal and adult diaphorina citri (homoptera: psyllidae). | asian citrus psylla, diaphorina citri kuwayama (homoptera: psyllidae) was detected for the first time in the united states near delray beach, fl, on 2 june 1998 and is continuing to spread and multiply throughout southern florida. this psyllid is the vector of liberobacter asiaticum, a phloem-limited bacterium that causes citrus greening disease. this pathogen has not been found in the western hemisphere to date. furthermore, high infestation levels of d. citri can impact citrus plant health, fr ... | 2004 | 15279280 |
| citrus huanglongbing in são paulo state, brazil: pcr detection of the 'candidatus' liberibacter species associated with the disease. | symptoms of huanglongbing (hlb), one of the most serious diseases of citrus in asia and africa, have been noticed in march 2004 in the araraquara region of são paulo state, brazil. hlb has not been reported previously from america. the causal hlb bacteria, candidatus liberibacter africanus in africa and candidatus liberibacter asiaticus in asia, can be detected in symptomatic citrus leaves by pcr amplification of their 16s rdna with previously described primers. when this technique was applied t ... | 2005 | 15797817 |
| rapid, specific and quantitative assays for the detection of the endophytic bacterium methylobacterium mesophilicum in plants. | xylella fastidiosa is a xylem-limited bacterium that causes citrus variegated chlorosis disease in sweet orange. there is evidence that x. fastidiosa interacts with endophytic bacteria present in the xylem of sweet orange, and that these interactions, particularly with methylobacterium mesophilicum, may affect disease progress. however, these interactions cannot be evaluated in detail until efficient methods for detection and enumeration of these bacteria in planta are developed. we have previou ... | 2006 | 16266765 |
| diversity of "candidatus liberibacter asiaticus," based on the omp gene sequence. | huanglongbing (yellow dragon disease) is a destructive disease of citrus. the etiological agent is a noncultured, phloem-restricted alpha-proteobacterium, "candidatus liberibacter africanus" in africa and "candidatus liberibacter asiaticus" in asia. in this study, we used an omp-based pcr-restriction fragment length polymorphism (rflp) approach to analyze the genetic variability of "ca. liberibacter asiaticus" isolates. by using five different enzymes, each the 10 isolates tested could be associ ... | 2005 | 16269671 |
| quantitative real-time pcr for detection and identification of candidatus liberibacter species associated with citrus huanglongbing. | citrus huanglongbing (hlb, ex greening) is one of the most serious diseases of citrus. different forms of the disease are caused by different candidatus liberobacter species, candidatus liberibacter asiaticus (las), ca. l. africanus (laf) and ca. l. americanus (lam). the pathogen is transmitted by psyllid insects and by budding with contaminated plant materials. the vector psyllid diaphorina citri can transmit both las and lam. establishment of this vector into florida, reports of lam and las in ... | 2006 | 16414133 |
| rate, placement and timing of aldicarb applications to control asian citrus psyllid, diaphorina citri kuwayama (hemiptera: psyllidae), in oranges. | the asian citrus psyllid (acp), diaphorina citri kuwayama (hemiptera: psyllidae), is a cosmopolitan insect pest of citrus and vectors the bacterium candidatus liberibacter asiaticus, a suspected causal organism of citrus greening or 'huanglongbing' disease. aldicarb 150 g kg(-1) gr (temik((r)) 15 g) was evaluated at three rates, two placements and three timings for acp control in orange trees. | 2008 | 18537108 |
| bacterial diversity analysis of huanglongbing pathogen-infected citrus, using phylochip arrays and 16s rrna gene clone library sequencing. | the bacterial diversity associated with citrus leaf midribs was characterized for citrus groves that contained the huanglongbing (hlb) pathogen, which has yet to be cultivated in vitro. we employed a combination of high-density phylogenetic 16s rrna gene microarrays and 16s rrna gene clone library sequencing to determine the microbial community composition for symptomatic and asymptomatic citrus midribs. our results revealed that citrus leaf midribs can support a diversity of microbes. phylochip ... | 2009 | 19151177 |
| incidence of invasive diaphorina citri (hemiptera: psyllidae) and its introduced parasitoid tamarixia radiata (hymenoptera: eulophidae) in florida citrus. | diaphorina citri kuwayama (hemiptera: psyllidae), vectors the bacterium candidatus liberibacter asiaticus, one of the causal organisms of the devastating citrus disease "huanglongbing" or citrus greening. in the united states, d. citri was first discovered in florida, in 1998. tamarixia radiata waterston (hymenoptera: eulophidae) was imported from asia and released in florida in 1999-2001 to improve biological control of d. citri before citrus greening was detected in florida in 2005. florida ci ... | 2009 | 19253643 |
| characterization of copy numbers of 16s rdna and 16s rrna of candidatus liberibacter asiaticus and the implication in detection in planta using quantitative pcr. | citrus huanglongbing (hlb) is one of the most devastating diseases on citrus and is associated with candidatus liberibacter spp.. the pathogens are phloem limited and have not been cultured in vitro. the current management strategy of hlb is to remove infected citrus trees and reduce psyllid populations with insecticides to prevent the spreading. this strategy requires sensitive and reliable diagnostic methods for early detection. | 2009 | 19284534 |
| establishment of asian citrus psyllid (diaphorina citri) primary cultures. | the asian citrus psyllid (ascp), diaphorina citri kuwayama (hemiptera: psyllidae), is a highly competent vector of the phloem-inhabiting bacterium candidatus liberibacter asiaticus associated with the citrus disease huanglongbing (hlb). commonly referred to as citrus greening disease in the usa, hlb causes reduced fruit yields, quality, and ultimately tree death and is considered the most serious citrus disease. hlb has become a major limiting factor to the production of citrus worldwide. studie ... | 2009 | 19440802 |
| huanglongbing, a systemic disease, restructures the bacterial community associated with citrus roots. | to examine the effect of pathogens on the diversity and structure of plant-associated bacterial communities, we carried out a molecular analysis using citrus and huanglongbing as a host-disease model. 16s rrna gene clone library analysis of citrus roots revealed shifts in microbial diversity in response to pathogen infection. the clone library of the uninfected root samples has a majority of phylotypes showing similarity to well-known plant growth-promoting bacteria, including caulobacter, burkh ... | 2010 | 20382817 |
| sulfur volatiles from allium spp. affect asian citrus psyllid, diaphorina citri kuwayama (hemiptera: psyllidae), response to citrus volatiles. | the asian citrus psyllid, diaphorina citri kuwayama, vectors candidatus liberibacter asiaticus (las) and candidatus liberibacter americanus (lam), the presumed causal agents of huanglongbing. d. citri generally rely on olfaction and vision for detection of host cues. plant volatiles from allium spp. (alliaceae) are known to repel several arthropod species. we examined the effect of garlic chive (a. tuberosum rottl.) and wild onion (a. canadense l.) volatiles on d. citri behaviour in a two-port d ... | 2011 | 20609277 |
| effects of pymetrozine, an antifeedant of hemiptera, on asian citrus psyllid, diaphorina citri, feeding behavior, survival and transmission of candidatus liberibacter asiaticus. | vector-borne plant disease management can be enhanced by deployment of antifeedants in addition to the use of broad-spectrum neurotoxic insecticides. the effects of pymetrozine on asian citrus psyllid (acp), diaphorina citri kuwayama, feeding behaviour, survival and transmission of candidatus liberibacter asiaticus (las), the presumed causal pathogen of huanglongbing, were investigated. | 2010 | 20960465 |
| effect of candidatus liberibacter asiaticus infection on susceptibility of asian citrus psyllid, diaphorina citri, to selected insecticides. | in the present investigation, the effect of candidatus liberibacter asiaticus (las), a bacterium considered to be responsible for causing huanglongbing (hlb) disease in citrus, on the physiology of its vector, the asian citrus psyllid (acp) diaphorina citri kuwayama, was determined. specifically, the effects of las infection on the susceptibility of acp to selected insecticides were determined. furthermore, total protein content and general esterase activity were quantified in las-infected and u ... | 2010 | 20960471 |
| transmission parameters for candidatus liberibacter asiaticus by asian citrus psyllid (hemiptera: psyllidae). | the purpose of this investigation was to evaluate acquisition and inoculation (together, transmission) efficiency of candidatus liberibacter asiaticus (las), the pathogen associated with citrus huanglongbing (hlb) by the asian citrus psyllid, diaphorina citri (kuwayama) (hemiptera: psyllidae). in laboratory studies, nymphs reared on las infected plants were more likely to acquire the bacterium than adults. acquisition by nymphs ranged from 60 to 100%, whereas acquisition by adults only reached 4 ... | 2010 | 21061950 |
| incidence of candidatus liberibacter asiaticus infection in abandoned citrus occurring in proximity to commercially managed groves. | huanglongbing is one of the most devastating diseases of citrus (citrus spp.). one management tactic against huanglongbing is aggressive management of the vector, the asian citrus psyllid (diaphorina citri kuwayama), with insecticide applications. however, d. citri in abandoned groves are not controlled and therefore pose a risk of reinfestation for nearby commercial citrus. these abandoned groves could serve as a reservoir for the vector, as well as a source of the presumed causal agent for hua ... | 2010 | 21309215 |
| isolation and characterization of beneficial bacteria associated with citrus roots in florida. | cultivable diversity of bacteria associated with citrus was investigated as part of a larger study to understand the roles of beneficial bacteria and utilize them to increase the productive capacity and sustainability of agro-ecosystems. citrus roots from huanglongbing (hlb) diseased symptomatic and asymptomatic citrus were used in this study. a total of 227 and 125 morphologically distinct colonies were isolated and characterized from hlb asymptomatic and symptomatic trees, respectively. we obs ... | 2011 | 21360139 |
| diversity and plasticity of the intracellular plant pathogen and insect symbiont, 'candidatus liberibacter asiaticus', revealed by hyper variable prophage genes with intragenic tandem repeats. | 'candidatus liberibacter asiaticus' (las) is a psyllid-transmitted, phloem-limited alpha proteobacterium, and the most prevalent species of liberibacter associated with a devastating worldwide citrus disease known as huanglongbing (hlb). two related and hyper variable genes (hyvi and hyvii) were identified in the prophage regions of the psy62 las genome. sequence analyses of the hyvi/hyvii genes in 35 las dna isolates collected globally revealed hyvi gene contains up to12 nearly identical tandem ... | 2011 | 21784907 |
| oral delivery of double-stranded rnas and sirnas induces rnai effects in the potato/tomato psyllid, bactericerca cockerelli. | the potato/tomato psyllid, bactericerca cockerelli (b. cockerelli), and the asian citrus psyllid, diaphorina citri (d. citri), are very important plant pests, but they are also vectors of phloem-limited bacteria that are associated with two devastating plant diseases. b. cockerelli is the vector of candidatus liberibacter psyllaurous (solanacearum), which is associated with zebra chip disease of potatoes, and d. citri is the vector of ca. liberibacter asiaticus, which is associated with the huan ... | 2011 | 22110747 |
| Characterization of five CYP4 genes from Asian citrus psyllid and their expression levels in Candidatus Liberibacter asiaticus-infected and uninfected psyllids. | Previously, we reported that Candidatus Liberibacter asiaticus (Las)-infected Diaphorina citri are characterized by lower levels of cytochrome P450 monooxygenases than uninfected counterparts. In the present study, we investigated expression levels of family 4 cytochrome P450 (CYP4) genes in Las-infected and uninfected D.citri adults. Five novel CYP4 genes (CYP4C67, CYP4DA1, CYP4C68, CYP4DB1 and CYP4G70) were identified. Four of the five CYP4 genes were expressed at significantly higher levels i ... | 2011 | 21919983 |
| sexual transmission of a plant pathogenic bacterium, candidatus liberibacter asiaticus, between conspecific insect vectors during mating. | candidatus liberibacter asiaticus is a fastidious, phloem-inhabiting, gram-negative bacterium transmitted by asian citrus psyllid, diaphorina citri kuwayama (hemiptera: psyllidae). the bacterium is the presumed causal agent of huanglongbing (hlb), one of the most destructive and economically important diseases of citrus. we investigated whether las is transmitted between infected and uninfected d. citri adults during courtship. our results indicate that las was sexually transmitted from las-infe ... | 2011 | 22216209 |
| drug repurposing: tolfenamic acid inactivates prbp, a transcriptional accessory protein in liberibacter asiaticus. | clibasia_01510, prbp, is a predicted rna polymerase binding protein in liberibacter asiaticus. prbp was found to regulate expression of a small subset of ribosomal genes through interactions with the β-subunit of the rna polymerase and a short, specific sequence on the promoter region. molecular screening assays were performed to identify small molecules that interact with prbp in vitro. chemical hits were analyzed for therapeutic efficacy against l. asiaticus via an infected leaf assay, where t ... | 2016 | 27803694 |
| annotation of the asian citrus psyllid genome reveals a reduced innate immune system. | citrus production worldwide is currently facing significant losses due to citrus greening disease, also known as huanglongbing. the citrus greening bacteria, candidatus liberibacter asiaticus (clas), is a persistent propagative pathogen transmitted by the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: liviidae). hemipterans characterized to date lack a number of insect immune genes, including those associated with the imd pathway targeting gram-negative bacteria. the d. citri draft ... | 2016 | 27965582 |
| an hplc-ms characterization of the changes in sweet orange leaf metabolite profile following infection by the bacterial pathogen candidatus liberibacter asiaticus. | huanglongbing (hlb) presumably caused by candidatus liberibacter asiaticus (clas) threatens the commercial u.s. citrus crop of an annual value of $3 billion. the earliest shift in metabolite profiles of leaves from greenhouse-grown sweet orange trees infected with clas, and of healthy leaves, was characterized by hplc-ms concurrently with pcr testing for the presence of clas bacteria and observation of disease symptoms. twenty, 8-month-old 'valencia' and 'hamlin' trees were grafted with budwood ... | 2013 | 24223954 |
| two plant bacteria, s. meliloti and ca. liberibacter asiaticus, share functional znuabc homologues that encode for a high affinity zinc uptake system. | the znu system, encoded for by znuabc, can be found in multiple genera of bacteria and has been shown to be responsible for the import of zinc under low zinc conditions. although this high-affinity uptake system is known to be important for both growth and/or pathogenesis in bacteria, it has not been functionally characterized in a plant-associated bacterium. a single homologue of this system has been identified in the plant endosymbiont, sinorhizobium meliloti, while two homologous systems were ... | 2012 | 22655039 |
| transcriptional response of susceptible and tolerant citrus to infection with candidatus liberibacter asiaticus. | candidatus liberibacter asiaticus (las), a non-culturable phloem-limited bacterium, is the suspected causal agent of huanglongbing (hlb) in florida. hlb is one of the most devastating diseases of citrus and no resistant cultivars have been identified to date, though tolerance has been observed in the genus poncirus and some of its hybrids. this study compares transcriptional changes in tolerant us-897 (citrus reticulata blanco×poncirus trifoliata l. raf.) and susceptible 'cleopatra' mandarin (c. ... | 2011 | 22325873 |
| sequence analysis and comparison of 16s rrna, 23s rrna and 16s/23s intergenic spacer region of greening bacterium associated with yellowing disease (huanglongbing) of kinnow mandarin. | high incidence (up to 40%) of symptoms of yellowing and yellow mottling was observed in 5-8 years old orchards of kinnow mandarin {citrus reticulate balanco ('king' × 'willow mandarin')} in the punjab state of india during a survey in january 2007. these symptoms are often confused with nutrient deficiency and other stress related disorders. however, a greening bacterium has been attributed to cause the disease. the disease was graft transmissible and sequencing of 16s rrna, 16s/23s intergenic s ... | 2011 | 23450073 |
| comparison of the 'ca. liberibacter asiaticus' genome adapted for an intracellular lifestyle with other members of the rhizobiales. | an intracellular plant pathogen 'candidatus liberibacter asiaticus,' a member of the rhizobiales, is related to sinorhizobium meliloti, bradyrhizobium japonicum, nitrogen fixing endosymbionts, agrobacterium tumefaciens, a plant pathogen, and bartonella henselae, an intracellular mammalian pathogen. whole chromosome comparisons identified at least 50 clusters of conserved orthologous genes found on the chromosomes of all five metabolically diverse species. the intracellular pathogens 'ca. liberib ... | 2011 | 21876745 |
| Callose deposition in the phloem plasmodesmata and inhibition of phloem transport in citrus leaves infected with "Candidatus Liberibacter asiaticus" | Huanglongbing (HLB) is a destructive disease of citrus trees caused by phloem-limited bacteria, Candidatus Liberibacter spp. One of the early microscopic manifestations of HLB is excessive starch accumulation in leaf chloroplasts. We hypothesize that the causative bacteria in the phloem may intervene photoassimilate export, causing the starch to over-accumulate. We examined citrus leaf phloem cells by microscopy methods to characterize plant responses to Liberibacter infection and the contributi ... | 2011 | 21874517 |
| comparative itraq proteome and transcriptome analyses of sweet orange infected by candidatus liberibacter asiaticus. | citrus huanglongbing (hlb) has been threatening citrus production worldwide. in this study, a comparative proteomic approach was applied to understand the pathogenic process of hlb in affected sweet orange leaves. using the isobaric tags for relative and absolute quantification (itraq) technique, we identified 686 unique proteins in the mature leaves of both mock-inoculated and diseased 'madam vinous' sweet orange plants. of the identified proteins, 20 and 10 were differentially expressed in lea ... | 2011 | 21838733 |
| discovery of novel seca inhibitors of candidatus liberibacter asiaticus by structure based design. | candidatus liberibacter asiaticus is the causal agent of huanglongbing (hlb) disease of citrus. current management practices have not been able to control hlb and stop the spread of hlb. the current study is focused on screening small molecule inhibitors against seca protein of ca. l. asiaticus. homology modeling, structure based virtual screening and molecular docking methods have been used to find the novel inhibitory compounds against seca activity at atp binding region. at 20++m 17 compounds ... | 2011 | 21684161 |
| differentiation of "candidatus liberibacter asiaticus" isolates by variable-number tandem-repeat analysis. | four highly polymorphic simple sequence repeat (ssr) loci were selected and used to differentiate 84 japanese isolates of "candidatus liberibacter asiaticus." the nei's measure of genetic diversity values for these four ssrs ranged from 0.60 to 0.86. the four ssr loci were also highly polymorphic in four isolates from taiwan and 12 isolates from indonesia. | 2011 | 21239554 |
| evaluation of the effects of candidatus liberibacter asiaticus on inoculated citrus plants using laser-induced breakdown spectroscopy (libs) and chemometrics tools. | this study investigated the organic and inorganic constituents of healthy leaves and candidatus liberibacter asiaticus (clas)-inoculated leaves of citrus plants. the bacteria clas are one of the causal agents of citrus greening (or huanglongbing) and its effect on citrus leaves was investigated using laser-induced breakdown spectroscopy (libs) combined with chemometrics. the information obtained from the libs spectra profiles with chemometrics analysis was promising for the construction of predi ... | 2010 | 21111145 |
| effect of liberibacter infection (huanglongbing or "greening" disease) of citrus on orange juice flavor quality by sensory evaluation. | some anecdotal reports suggest that infection of citrus trees with candidatus liberibacter asiaticus (las), the suspected causal agent of huanglongbing (hlb) disease, imparts off flavor to orange juice. it is of interest to the industry to know how las infection affects juice quality with respect to cultivar, maturity, or processing method. hamlin, midsweet, and valencia oranges were harvested over 2 y from trees that tested negative (las-) or positive (las+) for las from different groves and in ... | 2010 | 20546425 |
| a new diagnostic system for ultra-sensitive and specific detection and quantification of candidatus liberibacter asiaticus, the bacterium associated with citrus huanglongbing. | an ultra-sensitive and quantitative diagnostic system by combining nested pcr and taqman pcr in a single tube was developed for detection of "candidatus liberibacter asiaticus". the procedure involves two pcr steps using the species-specific outer and inner primer pairs. different annealing temperatures allow both the first and the second rounds of pcr to be performed sequentially in the same closed tube. the first pcr with outer primers was performed at a higher annealing temperature and with l ... | 2010 | 20096734 |
| characterization of an atp translocase identified in the destructive plant pathogen "candidatus liberibacter asiaticus". | atp/adp translocases transport atp across a lipid bilayer, which is normally impermeable to this molecule due to its size and charge. these transport proteins appear to be unique to mitochondria, plant plastids, and obligate intracellular bacteria. all bacterial atp/adp translocases characterized thus far have been found in endosymbionts of protozoa or pathogens of higher-order animals, including humans. a putative atp/adp translocase was uncovered during the genomic sequencing of the intracellu ... | 2010 | 19948801 |
| survey of endosymbionts in the diaphorina citri metagenome and assembly of a wolbachia wdi draft genome. | diaphorina citri (hemiptera: psyllidae), the asian citrus psyllid, is the insect vector of ca. liberibacter asiaticus, the causal agent of citrus greening disease. sequencing of the d. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. to corroborate candidate endosymbionts previously identified by rdna amplification, raw reads from the d. citri metagenome sequence were mapped to reference genom ... | 2012 | 23166822 |
| predictive sequence analysis of the candidatus liberibacter asiaticus proteome. | candidatus liberibacter asiaticus (ca. l. asiaticus) is a parasitic gram-negative bacterium that is closely associated with huanglongbing (hlb), a worldwide citrus disease. given the difficulty in culturing the bacterium and thus in its experimental characterization, computational analyses of the whole ca. l. asiaticus proteome can provide much needed insights into the mechanisms of the disease and guide the development of treatment strategies. in this study, we applied state-of-the-art sequence ... | 2012 | 22815919 |
| morphological abnormalities and cell death in the asian citrus psyllid (diaphorina citri) midgut associated with candidatus liberibacter asiaticus. | candidatus liberibacter asiaticus (clas) is a phloem-limited, gram-negative, fastidious bacterium that is associated with the development of citrus greening disease, also known as huanglongbing (hlb). clas is transmitted by the asian citrus psyllid (acp) diaphorina citri, in a circulative manner. two major barriers to transmission within the insect are the midgut and the salivary glands. we performed a thorough microscopic analysis within the insect midgut following exposure to clas-infected cit ... | 2016 | 27630042 |
| asian citrus psyllid expression profiles suggest candidatus liberibacter asiaticus-mediated alteration of adult nutrition and metabolism, and of nymphal development and immunity. | the asian citrus psyllid (acp) diaphorina citri kuwayama (hemiptera: psyllidae) is the insect vector of the fastidious bacterium candidatus liberibacter asiaticus (clas), the causal agent of citrus greening disease, or huanglongbing (hlb). the widespread invasiveness of the psyllid vector and hlb in citrus trees worldwide has underscored the need for non-traditional approaches to manage the disease. one tenable solution is through the deployment of rna interference technology to silence protein- ... | 2015 | 26091106 |
| acquisition, replication and inoculation of candidatus liberibacter asiaticus following various acquisition periods on huanglongbing-infected citrus by nymphs and adults of the asian citrus psyllid. | the asian citrus psyllid, diaphorina citri (hemiptera: liviidae), is the primary vector of candidatus liberibacter asiaticus (las) implicated as causative agent of citrus huanglongbing (citrus greening), currently the most serious citrus disease worldwide. las is transmitted by d. citri in a persistent-circulative manner, but the question of replication of this bacterium in its psyllid vector has not been resolved. thus, we studied the effects of the acquisition access period (aap) by nymphs and ... | 2016 | 27441694 |
| infection of an insect vector with a bacterial plant pathogen increases its propensity for dispersal. | the spread of vector-transmitted pathogens relies on complex interactions between host, vector and pathogen. in sessile plant pathosystems, the spread of a pathogen highly depends on the movement and mobility of the vector. however, questions remain as to whether and how pathogen-induced vector manipulations may affect the spread of a plant pathogen. here we report for the first time that infection with a bacterial plant pathogen increases the probability of vector dispersal, and that such movem ... | 2015 | 26083763 |
| sequestering from host and characterization of sequence of a ribosomal rna operon (rrn) from "candidatus liberibacter asiaticus". | a 5005bp rrn dna sequence of "candidatus liberibacter asiaticus" was obtained by pcr using primers conserved to rhizobiaceae of alpha-proteobacteria. the rrn locus consisted of a 16s rrna gene (rrs), an intergenic transcribed spacer (its) containing two genes of trna(ile) and trna(ala), a 23s rrna gene (rrl), an its without trna gene and a 5s rrna gene (rrf). like rrs, rrl and rrf were also related (89-90%) to those of the members of rhizobiaceae. interestingly, the genes of trna(ile) and trna(a ... | 2008 | 18955129 |
| top 10 plant pathogenic bacteria in molecular plant pathology. | many plant bacteriologists, if not all, feel that their particular microbe should appear in any list of the most important bacterial plant pathogens. however, to our knowledge, no such list exists. the aim of this review was to survey all bacterial pathologists with an association with the journal molecular plant pathology and ask them to nominate the bacterial pathogens they would place in a 'top 10' based on scientific/economic importance. the survey generated 458 votes from the international ... | 2012 | 22672649 |
| in planta distribution of 'candidatus liberibacter asiaticus' as revealed by polymerase chain reaction (pcr) and real-time pcr. | huanglongbing (hlb) is one of the most devastating diseases of citrus worldwide, and is caused by a phloem-limited fastidious prokaryotic alpha-proteobacterium that is yet to be cultured. in this study, a combination of traditional polymerase chain reaction (pcr) and real-time pcr targeting the putative dna polymerase and 16s rdna sequence of 'candidatus liberibacter asiaticus,' respectively, were used to examine the distribution and movement of the hlb pathogen in the infected citrus tree. we f ... | 2008 | 18943228 |
| [endophytic bacterial community analysis of catharanthus roseus and its association with huanglongbing pathogen]. | to analyze the microbial diversity in healthy and hlb-affected catharanthus roseus under manual-grafting conditions and to find the association between the endophytic bacteria and the hlb pathogen. | 2012 | 22799214 |
| antimicrobial nanoemulsion formulation with improved penetration of foliar spray through citrus leaf cuticles to control citrus huanglongbing. | huanglongbing (hlb) is the most serious disease affecting the citrus industry worldwide to date. the causal agent, candidatus liberibacter asiaticus (las), resides in citrus phloem, which makes it difficult to effectively treat with chemical compounds. in this study, a transcuticular nanoemulsion formulation was developed to enhance the permeation of an effective antimicrobial compound (ampicillin; amp) against hlb disease through the citrus cuticle into the phloem via a foliar spray. the result ... | 2015 | 26207823 |
| comparative phylogenomics and multi-gene cluster analyses of the citrus huanglongbing (hlb)-associated bacterium candidatus liberibacter. | huanglongbing (hlb, previously known as citrus greening), is associated with candidatus liberibacter species and is a serious threat to citrus production world-wide. the pathogen is a gram negative, unculturable, phloem-limited bacterium with limited known genomic information. expanding the genetic knowledge of this organism may provide better understanding of the pathogen and possibly develop effective strategies for control and management of hlb. | 2008 | 18755041 |
| vitrification-cryopreservation, an efficient method for eliminating candidatus liberobacter asiaticus, the citrus huanglongbing pathogen, from in vitro adult shoot tips. | huanglongbing disease (hlb), caused by candidatus liberobacter asiaticus, constitutes a most serious problem for the chinese citrus industry. in this work, the use of vitrification-cryopreservation for eliminating ca. l. asiaticus from naturally infected plants of several citrus species was investigated. proliferating meristems were produced in vitro and excised tissue clumps were cryopreserved through vitrification using a plant vitrification solution 2. the health status of regenerated in vitr ... | 2008 | 17955244 |
| citrus tristeza virus-based rnai in citrus plants induces gene silencing in diaphorina citri, a phloem-sap sucking insect vector of citrus greening disease (huanglongbing). | a transient expression vector based on citrus tristeza virus (ctv) is unusually stable. because of its stability it is being considered for use in the field to control huanglongbing (hlb), which is caused by candidatus liberibacter asiaticus (clas) and vectored by asian citrus psyllid, diaphorina citri. in the absence of effective control strategies for clas, emphasis has been on control of d. citri. coincident cohabitation in phloem tissue by clas, d. citri and ctv was exploited to develop a no ... | 2014 | 24572372 |
| functional characterization of lotp from liberibacter asiaticus. | liberibacter asiaticus is an unculturable parasitic bacterium of the alphaproteobacteria group hosted by both citrus plants and a psyllid insect vector (diaphorina citri). in the citrus tree, the bacteria thrive only inside the phloem, causing a systemically incurable and deadly plant disease named citrus greening or huanglongbing. currently, all commercial citrus cultivars in production are susceptible to l. asiaticus, representing a serious threat to the citrus industry worldwide. the technica ... | 2017 | 28378385 |
| acquisition of uncharacterized sequences from candidatus liberibacter, an unculturable bacterium, using an improved genomic walking method. | an effective pcr-based genomic walking approach is described to discover previously unknown flanking genomic dna sequences from candidatus liberibacter asiaticus, an unculturable, phloem-limited bacterium. using this technique, 8564bp of new dna sequences were obtained from three genomic loci; tufb-sece-nusg-rplkajl-rpobc gene cluster, omp gene (outer membrane protein, omp) and 16/23s rrna gene in ca. l. asiaticus. these, together with publicly available ca. liberibacter sequences, are clustered ... | 2008 | 17689920 |
| etiology of three recent diseases of citrus in são paulo state: sudden death, variegated chlorosis and huanglongbing. | the state of são paulo (ssp) is the first sweet orange growing region in the world. yet, the ssp citrus industry has been, and still is, under constant attack from various diseases. in the 1940s, tristeza-quick decline (t-qd) was responsible for the death of 9 million trees in ssp. the causal agent was a new virus, citrus tristeza virus (ctv). the virus was efficiently spread by aphid vectors, and killed most of the trees grafted on sour orange rootstock. control of the disease resided in replac ... | 2007 | 17505974 |
| detection and identification of the two candidatus liberobacter species associated with citrus huanglongbing by pcr amplification of ribosomal protein genes of the beta operon. | huanglongbing, previously called greening, is a destructive disease of citrus in asia and africa. it is caused by an uncultured, phloem-restricted bacterium for which two species candidatus liberobacter asiaticum and candidatus liberobacter africanum have been characterized. in 1996, a polymerase chain reaction (pcr) detection method based on the amplification of the 16s ribosomal operon was developed and proved to be efficient for the detection of both liberobacter species. however, in order to ... | 1999 | 10508559 |
| nucleotides, micro- and macro-nutrients, limonoids, flavonoids, and hydroxycinnamates composition in the phloem sap of sweet orange. | currently, the global citrus production is declining due to the spread of huanglongbing (hlb). hlb, otherwise known as citrus greening, is caused by candidatus liberibacter asiaticus (clas) and is transmitted by the asian citrus psyllids (acp), diaphorina citri kuwayama. acp transmits clas bacterium while feeding on the citrus phloem sap. multiplication of clas in the phloem of citrus indicates that the sap contains all the essential nutrients needed for clas. in this study, we investigated the ... | 2016 | 27171979 |
| detection and characterization of miniature inverted-repeat transposable elements in “candidatus liberibacter asiaticus”. | miniature inverted-repeat transposable elements (mites) are nonautonomous transposons (devoid of the transposase gene tps) that affect gene functions through insertion/deletion events. no transposon has yet been reported to occur in “candidatus liberibacter asiaticus,” an alphaproteobacterium associated with citrus huanglongbing (hlb, yellow shoot disease). in this study, two mites, mclas-a and mclas-b, in “ca. liberibacter asiaticus” were detected, and the genome was characterized using 326 iso ... | 2013 | 23813735 |
| unusual five copies and dual forms of nrdb in "candidatus liberibacter asiaticus": biological implications and pcr detection application. | "candidatus liberibacter asiaticus" (clas), a non-culturable α-proteobacterium, is associated with citrus huanglongbing (hlb, yellow shoot disease) currently threatening citrus production worldwide. here, the whole genome sequence of clas strain a4 from guangdong of china was analyzed. five copies of nrdb, encoding β-subunit of ribonucleotide reductase (rnr), a critical enzyme involving bacterial proliferation, were found. three nrdb copies were in long form (nrdb(l), 1,059 bp) and two were in s ... | 2016 | 27958354 |
| comparative genomics of cultured and uncultured strains suggests genes essential for free-living growth of liberibacter. | the full genomes of two uncultured plant pathogenic liberibacter, ca. liberibacter asiaticus and ca. liberibacter solanacearum, are publicly available. recently, the larger genome of a closely related cultured strain, liberibacter crescens bt-1, was described. to gain insights into our current inability to culture most liberibacter, a comparative genomics analysis was done based on the rast, kegg, and manual annotations of these three organisms. in addition, pathogenicity genes were examined in ... | 2014 | 24416233 |
| genetic diversity of candidatus liberibacter asiaticus based on two hypervariable effector genes in thailand. | huanglongbing (hlb), also known as citrus greening, is one of the most destructive diseases of citrus worldwide. hlb is associated with three species of 'candidatus liberibacter' with 'ca. l. asiaticus' (las) being the most widely distributed around the world, and the only species detected in thailand. to understand the genetic diversity of las bacteria in thailand, we evaluated two closely-related effector genes, lasai and lasaii, found within the las prophages from 239 infected citrus and 55 i ... | 2014 | 25437428 |
| the abc transporters in candidatus liberibacter asiaticus. | candidatus liberibacter asiaticus (ca. l. asiaticus) is a gram-negative bacterium and the pathogen of citrus greening disease (huanglongbing, hlb). as a parasitic bacterium, ca. l. asiaticus harbors abc transporters that play important roles in exchanging chemical compounds between ca. l. asiaticus and its host. here, we analyzed all the abc transporter-related proteins in ca. l. asiaticus. we identified 14 abc transporter systems and predicted their structures and substrate specificities. in-de ... | 2012 | 22807026 |
| crystal structures and kinetic properties of enoyl-acyl carrier protein reductase i from candidatus liberibacter asiaticus. | huanglongbing (hlb) is a destructive citrus disease. the leading cause of hlb is candidatus liberibacter asiaticus. fatty acid biosynthesis is essential for bacterial viability and has been validated as a target for the discovery of novel antibacterial agents. enoyl-acyl carrier protein reductase (also called enr or fabi and a product of the fabi gene) is an enzyme required in a critical step of bacterial fatty acid biosynthesis and has attracted attention as a target of novel antimicrobial agen ... | 2014 | 24407918 |
| overexpression of a citrus ndr1 ortholog increases disease resistance in arabidopsis. | emerging devastating diseases, such as huanglongbing (hlb) and citrus canker, have caused tremendous losses to the citrus industry worldwide. genetic engineering is a powerful approach that could allow us to increase citrus resistance against these diseases. the key to the success of this approach relies on a thorough understanding of defense mechanisms of citrus. studies of arabidopsis and other plants have provided a framework for us to better understand defense mechanisms of citrus. salicylic ... | 2013 | 23761797 |
| rapid and sensitive detection of candidatus liberibacter asiaticus by loop mediated isothermal amplification combined with a lateral flow dipstick. | citrus huanglongbing (hlb) is the most devastating bacterial citrus disease worldwide. three candidatus liberibacter species are associated with different forms of the disease: candidatus liberibacter asiaticus, candidatus liberibacter americanus and candidatus liberibacter africanus. amongst them, candidatus liberibacter asiaticus is the most widespread and economically important. these gram-negative bacterial plant pathogens are phloem-limited and vectored by citrus psyllids. the current manag ... | 2014 | 24708539 |
| metabolomic comparative analysis of the phloem sap of curry leaf tree (bergera koenegii), orange jasmine (murraya paniculata), and valencia sweet orange (citrus sinensis) supports their differential responses to huanglongbing. | orange jasmine, murraya paniculata and curry leaf tree, bergera koenegii are alternative hosts for diaphorina citri, the vector of candidatus liberibacter asiaticus (clas), the pathogen of huanglongbing (hlb) in citrus. d. citri feeds on the phloem sap where clas grows. it has been shown that orange jasmine was a better host than curry leaf tree to d. citri. in addition, clas can infect orange jasmine but not curry leaf tree. here, we compared the phloem sap composition of these 2 plants to the ... | 2016 | 27763819 |
| enhanced acquisition rates of 'candidatus liberibacter asiaticus' by the asian citrus psyllid (hemiptera: liviidae) in the presence of vegetative flush growth in citrus. | the asian citrus psyllid preferentially feeds and exclusively reproduces on young, newly emerged flush shoots of citrus. asian citrus psyllid nymphs feed and complete their life stages on these flush shoots. recent studies conducted under greenhouse conditions have shown that the transmission rates of 'candidatus liberibacter asiaticus' (clas), the putative causal agent of huanglongbing disease of citrus, are enhanced when flush shoots are present. however, it is unclear if clas acquisition by m ... | 2016 | 27451998 |
| costs and benefits of insecticide and foliar nutrient applications to huanglongbing-infected citrus trees. | the asian citrus psyllid (acp), diaphorina citri kuwayama (hemiptera: psyllidae), vectors candidatus liberibacter asiaticus, which causes huanglongbing (hlb). in florida, hlb incidence is approaching 100% statewide. yields have decreased and production costs have increased since 2005. despite this, some growers are maintaining a level of production and attribute this in part to aggressive psyllid control and foliar nutrition sprays. however, the value of these practices is debated. a replicated ... | 2017 | 27427170 |
| phenology of asian citrus psyllid (hemiptera: liviidae) and associated parasitoids on two species of citrus, kinnow mandarin and sweet orange, in punjab pakistan. | the population phenology of asian citrus psyllid, diaphorina citri kuwayama, was monitored weekly for 110 wk on two species of citrus, kinnow mandarin and sweet orange, at two different research sites in faisalabad, punjab pakistan. citrus flush growth patterns were monitored and natural enemy surveys were conducted weekly. flush patterns were similar for kinnow and sweet orange. however, flush on sweet orange was consistently more heavily infested with asian citrus psyllid than kinnow flush; de ... | 2014 | 25198345 |
| new excised-leaf assay method to test inoculativity of asian citrus psyllid (hemiptera: psyllidae) with candidatus liberibacter asiaticus associated with citrus huanglongbing disease. | the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: psyllidae), is the primary vector of candidatus liberibacter asiaticus (las) associated with huanglongbing, or citrus greening, the most devastating citrus (citrus spp.) disease worldwide. here, we developed a new "excised-leaf assay" that can speed up las-inoculativity tests on asian citrus psyllid from the current 3-12 mo (when using whole citrus seedlings for inoculation) to only 2-3 wk. young adults of asian citrus psyllid that ... | 2013 | 23448011 |
| comparative transcriptome and itraq proteome analyses of citrus root responses to candidatus liberibacter asiaticus infection. | root samples of 'sanhu' red tangerine trees infected with and without candidatus liberibacter asiaticus (clas) were collected at 50 days post inoculation and subjected to rna-sequencing and isobaric tags for relative and absolute quantification (itraq) to profile the differentially expressed genes (degs) and proteins (deps), respectively. quantitative real-time pcr was subsequently used to confirm the expression of 16 selected degs. results showed that a total of 3956 genes and 78 proteins were ... | 2015 | 26046530 |
| oral delivery of double-stranded rnas induces mortality in nymphs and adults of the asian citrus psyllid, diaphorina citri. | the asian citrus psyllid (acp), diaphorina citri kuwayama, is one of the most important citrus pests. acp is the vector of the phloem-limited bacteria candidatus liberibacter americanus and candidatus liberibacter asiaticus, the causal agents of the devastating citrus disease huanglongbing (hlb). the management of hlb is based on the use of healthy young plants, eradication of infected plants and chemical control of the vector. rna interference (rnai) has proven to be a promising tool to control ... | 2017 | 28282380 |
| sclerenchymatous ring as a barrier to phloem feeding by asian citrus psyllid: evidence from electrical penetration graph and visualization of stylet pathways. | asian citrus psyllid (diaphorina citri) feeding behaviors play a significant role in the transmission of the phloem-limited candidatus liberibacter asiaticus (clas) bacterium that causes the economically devastating citrus greening disease. sustained phloem ingestion by d. citri on clas infected plants is required for pathogen acquisition and transmission. recent studies have shown a fibrous ring of thick-walled sclerenchyma around the phloem in mature, fully expanded citrus leaves that is more ... | 2017 | 28278248 |
| rna interference of carboxyesterases causes nymph mortality in the asian citrus psyllid, diaphorina citri. | asian citrus psyllid, diaphorina citri kuwayama (hemiptera: liviidae), is an important pest of citrus. in addition, d. citri is the vector of huanglongbing, a destructive disease in citrus, also known as citrus greening disease caused by candidatus liberibacter asiaticus. huanglongbing causes huge losses for citrus industries. insecticide application for d. citri is the major strategy to prevent disease spread. the heavy use of insecticides causes development of insecticide resistance. we used r ... | 2017 | 28195667 |
| double-stranded rna delivery through soaking mediates silencing of the muscle protein 20 and increases mortality to the asian citrus psyllid, diaphorina citri. | asian citrus psyllid, diaphorina citri kuwayama, is the most important economic pest of citrus because it transmits candidatus liberibacter asiaticus (clas), the causal agent of huanglongbing (hlb). silencing genes by rna interference (rnai) is a promising approach for controlling d. citri. rnai-based insect management strategies depend on the selection of suitable target genes. | 2017 | 28195429 |
| diaphorina citri induces huanglongbing-infected citrus plant volatiles to repel and reduce the performance of propylaea japonica. | transmission of plant pathogens through insect vectors is a complex biological process involving interactions between the host plants, insects, and pathogens. simultaneous impact of the insect damage and pathogenic bacteria in infected host plants induce volatiles that modify not only the behavior of its insect vector but also of their natural enemies, such as parasitoid wasps. therefore, it is essential to understand how insects such as the predator ladybird beetle responds to volatiles emitted ... | 2016 | 28083006 |
| a plant bacterial pathogen manipulates its insect vector's energy metabolism. | insect-transmitted plant-pathogenic bacteria may alter their vectors' fitness, survival, behavior, and metabolism. because these pathogens interact with their vectors on the cellular and organismal levels, potential changes at the biochemical level might occur. "candidatus liberibacter asiaticus" (clas) is transmitted in a persistent, circulative, and propagative manner. the genome of clas revealed the presence of an atp translocase that mediates the uptake of atp and other nucleotides from medi ... | 2017 | 28039132 |
| comparative proteomic analysis of hemolymph from uninfected and candidatus liberibacter asiaticus-infected diaphorina citri. | hemolymph was characterized from diaphorina citri adults infected with the phytopathogen, candidatus liberibacter asiaticus (clas), and compared with that from uninfected psyllids. this study identified 5531 and 3220 peptides within infected and uninfected hemolymph using nano-lc-ms/ms. a reduced number of proteins were detected for d. citri and all known endosymbionts within infected hemolymph as compared to uninfected hemolymph. a large number of immune defense proteins were absent from d. cit ... | 2017 | 27990558 |
| effects of candidatus liberibacter asiaticus on the fitness of the vector diaphorina citri. | the asian citrus psyllid (acp), diaphorina citri kuwayama transmits the bacterium 'candidatus liberibacter asiaticus' (las), which causes citrus huanglongbing (hlb) disease. although many studies have been conducted on the biology of acp on different host plants, few have taken the plant, las bacteria and the vector insect within one context to evaluate the effects of las on the fitness of acp under field conditions. understanding the relationship between las and acp is critical for both acp and ... | 2016 | 27667799 |
| better together: association with 'candidatus liberibacter asiaticus' increases the reproductive fitness of its insect vector, diaphorina citri (hemiptera: liviidae). | the duration of the evolutionary association between a pathogen and vector can be inferred based on the strength of their mutualistic interactions. a well-adapted pathogen is likely to confer some benefit or, at a minimum, exhibit low pathogenicity toward its host vector. coevolution of the two toward a mutually beneficial association appears to have occurred between the citrus greening disease pathogen, candidatus liberibacter asiaticus (las), and its insect vector, the asian citrus psyllid, di ... | 2016 | 27418697 |
| disruption of vector host preference with plant volatiles may reduce spread of insect-transmitted plant pathogens. | plant pathogens can manipulate the odor of their host; the odor of an infected plant is often attractive to the plant pathogen vector. it has been suggested that this odor-mediated manipulation attracts vectors and may contribute to spread of disease; however, this requires further broad demonstration among vector-pathogen systems. in addition, disruption of this indirect chemical communication between the pathogen and the vector has not been attempted. we present a model that demonstrates how a ... | 2016 | 27193763 |
| inter-population variability of endosymbiont densities in the asian citrus psyllid (diaphorina citri kuwayama). | the asian citrus psyllid (diaphorina citri kuwayama) is an insect pest capable of transmitting candidatus liberibacter asiaticus (clas), the causal agent of citrus greening in north america. d. citri also harbors three endosymbionts, wolbachia, candidatus carsonella ruddii, and candidatus profftella armatura, which may influence d. citri physiology and fitness. although genomic researches on these bacteria have been conducted, much remains unclear regarding their ecology and inter-population var ... | 2016 | 26846216 |
| characterization of a recombinant cathepsin b-like cysteine peptidase from diaphorina citri kuwayama (hemiptera: liviidae): a putative target for control of citrus huanglongbing. | huanglonbing (hlb) is one of the most destructive disease affecting citrus plants. the causal agent is associated with the phloem-limited bacterium candidatus liberibacter asiaticus (clas) and the psyllid diaphorina citri, vector of disease, that transmits the bacterium associated with hlb. the control of disease can be achieved by suppressing either the bacterium or the vector. among the control strategies for hlb disease, one of the widely used consists in controlling the enzymes of the diseas ... | 2015 | 26717484 |
| draft genome sequence of "candidatus liberibacter asiaticus" from diaphorina citri in guangdong, china. | the draft genome sequence of "candidatus liberibacter asiaticus" strain ycpsy from an asian citrus psyllid (diaphorina citri) in guangdong, china, is reported here. the ycpsy strain has a genome size of 1,233,647 bp, 36.5% g+c content, 1,171 open reading frames (orfs), and 53 rnas. | 2015 | 26543132 |
| characterization of the voltage-gated sodium channel of the asian citrus psyllid, diaphorina citri. | the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: liviidae), is an important insect pest of citrus. it is the vector of 'candidatus' liberibacter asiaticus, a phloem-limited bacterium that infects citrus, resulting in the disease huanglongbing (hlb). disease management relies heavily on suppression of d. citri populations with insecticides, including pyrethroids. in recent annual surveys to monitor insecticide resistance, reduced susceptibility to fenpropathrin was identified in se ... | 2017 | 26537022 |
| diaphorina citri (hemiptera: liviidae) vector competence for the citrus greening pathogen 'candidatus liberibacter asiaticus'. | characterizing the vector competence of diaphorina citri kuwayama for 'candidatus liberibacter asiaticus,' the pathogen causing citrus greening, is essential for understanding the epidemiology of this disease that is threatening the u.s. citrus industry. vector competence studies have been difficult because of the biology of d. citri, the inability to culture the pathogen, and the available diagnostic methods used to detect the bacteria in plant and insect tissues. the methods employed in many s ... | 2015 | 26470202 |
| effect of cyantraniliprole, a novel insecticide, on the inoculation of candidatus liberibacter asiaticus associated with citrus huanglongbing by the asian citrus psyllid (hemiptera: liviidae). | the asian citrus psyllid (diaphorina citri kuwayama) is the principal vector of 'candidatus liberibacter asiaticus' (clas) associated with huanglongbing (hlb), the most serious citrus disease worldwide. new control measures including pesticides are urgently needed to combat hlb, especially to protect young or newly planted citrus trees from clas-inoculation by vector psyllids. here, we tested clas-inoculation by d. citri adults (clas-exposed, reared on infected plants) by feeding them for 7 d on ... | 2015 | 26470150 |
| seasonal movement patterns and long-range dispersal of asian citrus psyllid in florida citrus. | the asian citrus psyllid, diaphorina citri kuwayama, is the vector of the bacterial pathogen, candidatus liberibacter asiaticus, which is the causal agent of huanglongbing (hlb) in the united states. both short-range and long-range dispersal of d. citri adults affect the spread of hlb; however, little is known about the long-range dispersal capabilities of d. citri in the field or the seasonality of flight behavior. in the present study, an in situ protein marking technique was used to determine ... | 2015 | 26470097 |
| asymptomatic spread of huanglongbing and implications for disease control. | huanglongbing (hlb) is a bacterial infection of citrus trees transmitted by the asian citrus psyllid diaphorina citri. mitigation of hlb has focused on spraying of insecticides to reduce the psyllid population and removal of trees when they first show symptoms of the disease. these interventions have been only marginally effective, because symptoms of hlb do not appear on leaves for months to years after initial infection. limited knowledge about disease spread during the asymptomatic phase is e ... | 2015 | 26034273 |
| infection density dynamics of the citrus greening bacterium "candidatus liberibacter asiaticus" in field populations of the psyllid diaphorina citri and its relevance to the efficiency of pathogen transmission to citrus plants. | huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, "candidatus liberibacter asiaticus," and vectored by a phloem-sucking insect, diaphorina citri. we investigated the infection density dynamics of "ca. liberibacter asiaticus" in field populations of d. citri with experiments using field-collected insects to address how "ca. liberibacter asiaticus" infection density in the vector insect ... | 2015 | 25819961 |
| the push-pull strategy for citrus psyllid control. | the asian citrus psyllid (acp), diaphorina citri kuwayama (hemiptera: psyllidae), is the only natural vector of candidatus liberibacter asiaticus that causes citrus huanglongbing (hlb), a most destructive disease of citrus. currently, no remedial therapy exists for the disease, and so effective control of acp is very important in curbing the transmission of the disease. the push-pull strategy should be thoroughly explored as an approach to acp management. this mini-review summarises the current ... | 2015 | 25256398 |
| nested-quantitative pcr approach with improved sensitivity for the detection of low titer levels of candidatus liberibacter asiaticus in the asian citrus psyllid, diaphorina citri kuwayama. | candidatus liberibacter asiaticus (clas) is a phloem-limited bacterium transmitted by the asian citrus psyllid, diaphorina citri, and the presumptive causal agent of citrus greening disease. the current method of detection for clas within plant and insect samples is by a presence/absence qpcr assay using the clas 16s rdna gene target. although qpcr is highly sensitive, low bacterial titers or suboptimal qpcr conditions can result in false-negatives. using a nested qpcr assay, we determined the f ... | 2014 | 24769405 |
| chemical and behavioral analysis of the cuticular hydrocarbons from asian citrus psyllid, diaphorina citri. | huanglongbing (hlb) is the most destructive disease of citrus worldwide. the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: psyllidae), is the vector of the phloem-inhabiting bacterium, candidatus liberibacter asiaticus, which is presumed to cause hlb in florida citrus. laboratory and field studies were conducted to examine the behavioral responses of male and female d. citri to their cuticular extracts. in olfactometer assays, more male d. citri were attracted to one, five, or 10 f ... | 2013 | 23955888 |
| herbivory by the insect diaphorina citri induces greater change in citrus plant volatile profile than does infection by the bacterium, candidatus liberibacter asiaticus. | the volatile organic compound (voc) profile in plant leaves often changes after biotic and abiotic stresses. monitoring changes in vocs in plant leaves could provide valuable information about multitrophic interactions. in the current study, we investigated the effect of asian citrus psyllid (acp) infestation, citrus greening pathogen (candidatus liberibacter asiaticus [clas]) infection, and simultaneous attack by acp and clas on the voc content of citrus leaves. leaf volatiles were extracted us ... | 2013 | 23857364 |
| silencing abnormal wing disc gene of the asian citrus psyllid, diaphorina citri disrupts adult wing development and increases nymph mortality. | huanglongbing (hlb) causes considerable economic losses to citrus industries worldwide. its management depends on controlling of the asian citrus psyllid (acp), the vector of the bacterium, candidatus liberibacter asiaticus (clas), the causal agent of hlb. silencing genes by rna interference (rnai) is a promising tool to explore gene functions as well as control pests. in the current study, abnormal wing disc (awd) gene associated with wing development in insects is used to interfere with the fl ... | 2013 | 23734251 |
| candidate gene markers for candidatus liberibacter asiaticus for detecting citrus greening disease. | citrus huanglongbing (hlb) also known as citrus greening is one of the most devastating diseases of citrus worldwide. the disease is caused by candidatus liberibacter bacterium, vectored by the psyllid diaphorina citri kuwayama and trioza erytreae del guercio. citrus plants infected by the hlb bacterium may not show visible symptoms sometimes for years following infection. the aim of this study was to develop effective gene-specific primer pairs for polymerase chain reaction based method for qui ... | 2013 | 23660656 |
| stylet morphometrics and citrus leaf vein structure in relation to feeding behavior of the asian citrus psyllid diaphorina citri, vector of citrus huanglongbing bacterium. | the asian citrus psyllid (acp), diaphorina citri (hemiptera: psyllidae), is the primary vector of the phloem-limited bacterium candidatus liberibacter asiaticus (las) associated with huanglongbing (hlb, citrus greening), considered the world's most serious disease of citrus. stylet morphometrics of acp nymphs and adults were studied in relation to citrus vein structure and to their putative (histologically verified) feeding sites on valencia orange leaves. acp nymphs preferred to settle and feed ... | 2013 | 23555830 |
| global gene expression changes in candidatus liberibacter asiaticus during the transmission in distinct hosts between plant and insect. | huanglongbing (hlb) or citrus greening disease is a destructive disease of citrus worldwide, which is associated with candidatus liberibacter asiaticus. this phloem-limited fastidious pathogen is transmitted by the asian citrus psyllid, diaphorina citri, and appears to be an intracellular pathogen that maintains an intimate association with the psyllid or the plant throughout its life cycle. the molecular basis of the interaction of this pathogen with its hosts is not well understood. we hypothe ... | 2013 | 23336388 |
| biology and management of asian citrus psyllid, vector of the huanglongbing pathogens. | the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: psyllidae), is the most important pest of citrus worldwide because it serves as a vector of "candidatus liberibacter" species (alphaproteobacteria) that cause huanglongbing (citrus greening disease). all commercially cultivated citrus is susceptible and varieties tolerant to disease expression are not yet available. onset of disease occurs following a long latent period after inoculation, and thus the pathogen can spread widely prio ... | 2013 | 23317046 |
| effects of soil-applied imidacloprid on asian citrus psyllid (hemiptera: psyllidae) feeding behavior. | the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: psyllidae), is one of the most important pests of citrus (citrus spp.) because of its status as a vector of candidatus liberibacter asiaticus (las), the bacterium associated with citrus greening disease. the use of insecticides for vector control is the primary method of managing the spread of this pathogen. imidacloprid is an insecticide commonly applied to the root zone of young citrus trees to provide systemic protection from pes ... | 2012 | 23156142 |