| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| amino acids implicated in plant defense are higher in candidatus liberibacter asiaticus-tolerant citrus varieties. | citrus huanglongbing (hlb), also known as citrus greening, has been threatening the citrus industry since the early 1900's and up to this date there are no effective cures for this disease. field observations and greenhouse controlled studies demonstrated that some citrus genotypes are more tolerant to candidatus liberibacter asiaticus (clas) pathogen than others. however, the mechanisms underpinning tolerance has not been determined yet. the phloem sap composition of clas-tolerant and sensitive ... | 2016 | 27057814 |
| repertoire of novel sequence signatures for the detection of candidatus liberibacter asiaticus by quantitative real-time pcr. | huanglongbing (hlb) or citrus greening is a devastating disease of citrus. the gram-negative bacterium candidatus liberibacter asiaticus (las) belonging to the α-proteobacteria is responsible for hlb in north america as well as in asia. currently, there is no cure for this disease. early detection and quarantine of las-infected trees are important management strategies used to prevent hlb from invading hlb-free citrus producing regions. quantitative real-time pcr (qrt-pcr) based molecular diagno ... | 2014 | 24533511 |
| overexpression of a modified plant thionin enhances disease resistance to citrus canker and huanglongbing (hlb). | huanglongbing (hlb or citrus greening disease) caused by candidatus liberibacter asiaticus (las) is a great threat to the us citrus industry. there are no proven strategies to eliminate hlb disease and no cultivar has been identified with strong hlb resistance. citrus canker is also an economically important disease associated with a bacterial pathogen (xanthomonas citri). in this study, we characterized endogenous citrus thionins and investigated their expression in different citrus tissues. si ... | 2016 | 27499757 |
| development of a microemulsion formulation for antimicrobial seca inhibitors. | in our previous study, we have identified five antimicrobial small molecules via structure based design, which inhibit seca of candidatus liberibacter asiaticus (las). seca is a critical protein translocase atpase subunit and is involved in pre-protein translocation across and integration into the cellular membrane in bacteria. in this study, eleven compounds were identified using similarity search method based on the five lead seca inhibitors identified previously. the identified seca inhibitor ... | 2016 | 26963811 |
| possible role of plant volatiles in tolerance against huanglongbing in citrus. | volatile organic compounds (voc) play an important role in protecting plants from insect and pathogen attack. in this study, we investigated the leaf volatile profiles of 14 citrus varieties. the voc in citrus leaves were extracted with n-hexane and analyzed using gas chromatography-mass spectrometry (gc-ms). overall, 4six volatile compounds were identified in the n-hexane extract from citrus leaves. most of the detected compounds belonged to 3 main groups (monoterpenes, sesquiterpenes, and alip ... | 2016 | 26829496 |
| conservation of gene order and content in the circular chromosomes of 'candidatus liberibacter asiaticus' and other rhizobiales. | 'ca. liberibacter asiaticus,' an insect-vectored, obligate intracellular bacterium associated with citrus-greening disease, also called "hlb," is a member of the rhizobiales along with nitrogen-fixing microsymbionts sinorhizobium meliloti and bradyrhizobium japonicum, plant pathogen agrobacterium tumefaciens and facultative intracellular mammalian pathogen bartonella henselae. comparative analyses of their circular chromosomes identified 514 orthologous genes shared among all five species. share ... | 2012 | 22496839 |
| 'ca. liberibacter asiaticus' proteins orthologous with psyma-encoded proteins of sinorhizobium meliloti: hypothetical roles in plant host interaction. | sinorhizobium meliloti strain 1021, a nitrogen-fixing, root-nodulating bacterial microsymbiont of alfalfa, has a 3.5 mbp circular chromosome and two megaplasmids including 1.3 mbp psyma carrying nonessential 'accessory' genes for nitrogen fixation (nif), nodulation and host specificity (nod). a related bacterium, psyllid-vectored 'ca. liberibacter asiaticus,' is an obligate phytopathogen with a reduced genome that was previously analyzed for genes orthologous to genes on the s. meliloti circular ... | 2012 | 22761700 |
| identification of a ligand binding pocket in ldtr from liberibacter asiaticus. | ldtr is a transcriptional activator involved in the regulation of a putative l,d transpeptidase in liberibacter asiaticus, an unculturable pathogen and one of the causative agents of huanglongbing disease. using small molecule screens we identified benzbromarone as an inhibitor of ldtr activity, which was confirmed using in vivo and in vitro assays. based on these previous results, the objective of this work was to identify the ldtr ligand binding pocket and characterize its interactions with be ... | 2015 | 26635775 |
| 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 |
| 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 |
| 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 |
| identification of small molecule inhibitors against seca of candidatus liberibacter asiaticus by structure based design. | huanglongbing is the most devastating disease of citrus caused by candidatus liberibacter asiaticus (las). in the present study, we report the discovery of novel small molecule inhibitors against seca atpase of las by using structure based design methods. we built the homology model of seca protein structure of las based on the seca of escherichia coli. the model was used for in-silico screening of commercially available compounds from zinc database. using the glide flexible molecular docking me ... | 2012 | 22703844 |
| 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 |
| reference genes for accurate transcript normalization in citrus genotypes under different experimental conditions. | real-time reverse transcription pcr (rt-qpcr) has emerged as an accurate and widely used technique for expression profiling of selected genes. however, obtaining reliable measurements depends on the selection of appropriate reference genes for gene expression normalization. the aim of this work was to assess the expression stability of 15 candidate genes to determine which set of reference genes is best suited for transcript normalization in citrus in different tissues and organs and leaves chal ... | 2012 | 22347455 |
| [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 |
| the enemy within: phloem-limited pathogens. | the growing impact of phloem-limited pathogens on high-value crops has led to a renewed interest in understanding how they cause disease. although these pathogens cause substantial crop losses, many are poorly characterized. in this review, we present examples of phloem-limited pathogens that include intracellular bacteria with and without cell walls, and viruses. phloem-limited pathogens have small genomes and lack many genes required for core metabolic processes, which is, in part, an adaptati ... | 2016 | 27997761 |
| development of multiplex polymerase chain reaction assay for simultaneous detection of clostero-, badna- and mandari-viruses along with huanglongbing bacterium in citrus trees. | citrus trees harbor a large number of viral and bacterial pathogens. citrus yellow vein clearing virus (cyvcv), indian citrus ringspot virus (icrsv), citrus yellow mosaic virus (cymv), citrus tristeza virus (ctv) and a bacterium, candidatus liberibacter asiaticus (cla) associated with huanglongbing (hlb) disease, the most prevalent pathogens in citrus orchards of different regions in india and are responsible for debilitating citriculture. for detection of these viral and bacterial pathogens a q ... | 2016 | 27208471 |
| 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 |
| sec-translocon dependent extracytoplasmic proteins of candidatus liberibacter asiaticus. | citrus huanglongbing (hlb) is the most destructive citrus disease worldwide. hlb is associated with three species of the phloem-limited, gram-negative, fastidious α-proteobacteria: candidatus liberibacter asiaticus (las), ca. l. americanus (lam), and ca. l. africanus (laf) with las being the most widespread species. las has not been cultured in artificial media, which has greatly hampered our efforts to understand its virulence mechanisms. las contains a complete sec-translocon, which has been s ... | 2016 | 28066334 |
| "candidatus liberibacter asiaticus" prophage late genes may limit host range and culturability. | "candidatus liberibacter asiaticus" is an uncultured alphaproteobacterium that systemically colonizes its insect host both inter- and intracellularly and also causes a severe, crop-destroying disease of citrus called huanglongbing, or citrus "greening." in planta, "ca. liberibacter asiaticus" is also systemic but phloem limited. "ca. liberibacter asiaticus" strain uf506 carries two predicted prophages, sc1 and sc2. bacteriophage particles have been observed in experimentally "ca. liberibacter as ... | 2014 | 25063651 |
| high incidence of preharvest colonization of huanglongbing-symptomatic citrus sinensis fruit by lasiodiplodia theobromae (diplodia natalensis) and exacerbation of postharvest fruit decay by that fungus. | huanglongbing (hlb), presumably caused by the bacterium "candidatus liberibacter asiaticus," is a devastating citrus disease associated with excessive preharvest fruit drop. lasiodiplodia theobromae (diplodia) is the causal organism of citrus stem end rot (ser). the pathogen infects citrus fruit under the calyx abscission zone (az-c) and is associated with cell wall hydrolytic enzymes similar to plant enzymes involved in abscission. by means of dna sequencing, diplodia was found in "ca. liberiba ... | 2015 | 25344245 |
| 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 |
| collection and chemical composition of phloem sap from citrus sinensis l. osbeck (sweet orange). | through utilizing the nutrient-rich phloem sap, sap feeding insects such as psyllids, leafhoppers, and aphids can transmit many phloem-restricted pathogens. on the other hand, multiplication of phloem-limited, uncultivated bacteria such as candidatus liberibacter asiaticus (clas) inside the phloem of citrus indicates that the sap contains all the essential nutrients needed for the pathogen growth. the phloem sap composition of many plants has been studied; however, to our knowledge, there is no ... | 2014 | 25014027 |
| transgenic citrus expressing synthesized cecropin b genes in the phloem exhibits decreased susceptibility to huanglongbing. | expression of synthesized cecropin b genes in the citrus phloem, where candidatus liberibacter asiaticus resides, significantly decreased host susceptibility to huanglongbing. huanglongbing (hlb), associated with candidatus liberibacter asiaticus bacteria, is the most destructive disease of citrus worldwide. all of the commercial sweet orange cultivars lack resistance to this disease. the cationic lytic peptide cecropin b, isolated from the chinese tasar moth (antheraea pernyi), has been shown t ... | 2017 | 27866312 |
| serological detection of 'candidatus liberibacter asiaticus' in citrus, and identification by gelc-ms/ms of a chaperone protein responding to cellular pathogens. | we describe experiments with antibodies against 'candidatus liberibacter asiaticus used to detect the pathogen in infected plants. we used scfv selected to bind epitopes exposed on the surface of the bacterium in tissue prints, with secondary monoclonal antibodies directed at a flag epitope included at the carboxyl end of the scfv. unexpectedly, the anti-flag secondary antibody produced positive results with calas diseased samples when the primary scfv were not used. the anti-flag monoclonal ant ... | 2016 | 27381064 |
| generous hosts: what makes madagascar periwinkle (catharanthus roseus) the perfect experimental host plant for fastidious bacteria? | although much attention has been paid to the metabolism and biosynthesis of monoterpene alkaloids in catharanthus roseus, its value as an experimental host for a variety of agriculturally and economically important phytopathogenic bacteria warrants further study. in the present study, we evaluated the chemical composition of the phloem and xylem saps of c. roseus to infer the nutritional requirements of phloem- and xylem-limited phytopathogens. periwinkle phloem sap consisted of a rich mixture o ... | 2016 | 27620272 |
| raman spectroscopy an option for the early detection of citrus huanglongbing. | this research describes the application of portable field raman spectroscopy combined with a statistical analysis of the resulting spectra, employing principal component analysis (pca) and linear discriminant analysis (lda), in which we determine that this method provides a high degree of reliability in the early detection of huanglongbing (hlb) on sweet orange, disease caused by the bacteria candidatus liberibacter asiaticus. symptomatic and asymptomatic plant samples of sweet orange (citrus si ... | 2016 | 26988658 |
| metabolic variations in different citrus rootstock cultivars associated with different responses to huanglongbing. | huanglongbing (hlb) is one of the most destructive bacterial diseases of citrus. no resistant cultivars have been identified, although tolerance has been observed in the genus poncirus and some of its hybrids with citrus that are commonly used as rootstocks. in this study we exploited this tolerance by comparing five different tolerant hybrids with a cultivar that shows pronounced hlb sensitivity to discern potential contributing metabolic factors. whole leaves of infected and non-infected green ... | 2016 | 27236226 |
| coupling a branch enclosure with differential mobility spectrometry to isolate and measure plant volatiles in contained greenhouse settings. | volatile organic compounds (vocs) are off-gassed from all living organisms and represent end products of metabolic pathways within the system. in agricultural systems, these vocs can provide important information on plant health and can ordinarily be measured non-invasively without harvesting tissue from the plants. previously we reported a portable gas chromatography/differential mobility spectrometry (gc/dms) system that could distinguish voc profiles of pathogen-infected citrus from healthy t ... | 2016 | 26695246 |
| leaf-disc grafting for the transmission of candidatus liberibacter asiaticus in citrus (citrus sinensis; rutaceae) seedlings. | the search for resistance/tolerance to the devastating citrus huanglongbing disease (syn. hlb or citrus greening) is generating an increasing number of new plants of diverse genetic makeup. as the increasing number of new plants require more space, resources, and time, the need for faster and more efficient hlb screening tests becomes crucial. | 2017 | 28090406 |
| 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 |
| gene expression in citrus sinensis fruit tissues harvested from huanglongbing-infected trees: comparison with girdled fruit. | distribution of viable candidatus liberibacter asiaticus (calas) in sweet orange fruit and leaves ('hamlin' and 'valencia') and transcriptomic changes associated with huanglongbing (hlb) infection in fruit tissues are reported. viable calas was present in most fruit tissues tested in hlb trees, with the highest titre detected in vascular tissue near the calyx abscission zone. transcriptomic changes associated with hlb infection were analysed in flavedo (ff), vascular tissue (vt), and juice vesic ... | 2012 | 22407645 |
| 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 |