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a plant pathogenic bacterium exploits the tricarboxylic acid cycle metabolic pathway of its insect vector.huanglongbing in citrus is caused by a phloem-limited, uncultivable, gram-negative α-proteobacterium, candidatus liberibacter asiaticus (clas). clas is transmitted by the phloem-sucking insect, diaphorina citri (hemiptera: liviidae), in a persistent, circulative, and propagative manner. in this study, we investigated the metabolomic and respiration rates changes in d. citri upon infection with clas using gas chromatography-mass spectrometry (gc-ms) and gas exchange analysis. the level of glycine ...028594267
occurrence of free fatty acids in the phloem sap of different citrus varieties.candidatus liberibacter asiaticus is a phloem restricted bacterium causes citrus greening disease or huanglongbing (hlb), a major treat to commercial citrus production in florida. it is transmitted by the asian citrus psyllid, a phloem sap-feeding insect. studies conducted on the composition of citrus phloem sap revealed the presence amino acids, organic acids and sugars and of low amounts of free fatty acids. in the present study, the phloem sap of twelve citrus varieties with different degrees ...028532234
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 ...19968684375
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 ...19978995827
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 ...199910508559
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 ...200415279280
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 ...200515797817
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 ...200516269671
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 ...200616414133
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 ...200616266765
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 ...200717505974
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 ...200817689920
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 ...200817955244
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.200818537108
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.200818755041
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 ...200818943228
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 ...200818955129
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 ...200919151177
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 ...200919253643
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.200919284534
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 ...200919440802
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 ...201019948801
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 ...201020096734
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 ...201020382817
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 ...201020546425
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.201020960465
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 ...201020960471
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 ...201021061950
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 ...201021111145
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 ...201021309215
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 ...201121360139
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 ...201121784907
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 ...201121684161
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 ...201121838733
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 ...201121874517
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 ...201122110747
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 ...201121876745
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 ...201121919983
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 ...201123450073
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. ...201122325873
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 ...201122216209
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.201121239554
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 ...201120609277
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 ...201222655039
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 ...201222807026
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 ...201222496839
'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 ...201222761700
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 ...201223166822
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 ...201222815919
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 ...201222703844
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 ...201222672649
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 ...201222347455
[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.201222799214
messa: meta-server for protein sequence analysis.computational sequence analysis, that is, prediction of local sequence properties, homologs, spatial structure and function from the sequence of a protein, offers an efficient way to obtain needed information about proteins under study. since reliable prediction is usually based on the consensus of many computer programs, meta-severs have been developed to fit such needs. most meta-servers focus on one aspect of sequence analysis, while others incorporate more information, such as predictprotein ...201223031578
sensitive and robust detection of citrus greening (huanglongbing) bacterium "candidatus liberibacter asiaticus" by dna amplification with new 16s rdna-specific primers.citrus greening disease is caused by "candidatus liberibacter spp.," including "candidatus liberibacter asiaticus (las)." for detecting this disease, we designed new primers from the las 16s rdna and used a very small dna template for pcr. more las-infected tissues were detected with our primers than with the common primers.201222728344
transcriptome profiling of citrus fruit response to huanglongbing disease.huanglongbing (hlb) or "citrus greening" is the most destructive citrus disease worldwide. in this work, we studied host responses of citrus to infection with candidatus liberibacter asiaticus (calas) using next-generation sequencing technologies. a deep mrna profile was obtained from peel of healthy and hlb-affected fruit. it was followed by pathway and protein-protein network analysis and quantitative real time pcr analysis of highly regulated genes. we identified differentially regulated path ...201222675433
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 ...201222407645
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 ...201223156142
effects of buprofezin and diflubenzuron on various developmental stages of asian citrus psyllid, diaphorina citri.diaphorina citri populations in florida are developing resistance to commonly used neurotoxic insecticides. alternatives to neurotoxins, such as insect growth regulators, are needed to control this season-long subtropical pest to prevent or delay development of insecticide resistance. in the present investigation, two insect growth regulators (igrs), buprofezin and diflubenzuron, were evaluated against various developmental stages of d. citri.201222653617
characterization of the relative abundance of the citrus pathogen ca. liberibacter asiaticus in the microbiome of its insect vector, diaphorina citri, using high throughput 16s rrna sequencing.the relationship between the causal agent of huanglongbing (hlb), ca. liberibacter asiaticus(las), and the naturally occurring endosymbiotic community of its insect vector, the asian citrus psyllid (acp), diaphorina citri, was studied. variation was observed in the titer of las within an acp population feeding on the same material. the cause of this disparity is unknown, and has implications for las transmission and the spread of hlb. this study utilizes culture independent methods to establish ...201222529882
induced release of a plant-defense volatile 'deceptively' attracts insect vectors to plants infected with a bacterial pathogen.transmission of plant pathogens by insect vectors is a complex biological process involving interactions between the plant, insect, and pathogen. pathogen-induced plant responses can include changes in volatile and nonvolatile secondary metabolites as well as major plant nutrients. experiments were conducted to understand how a plant pathogenic bacterium, candidatus liberibacter asiaticus (las), affects host preference behavior of its psyllid (diaphorina citri kuwayama) vector. d. citri were att ...201222457628
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 ...201323955888
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 ...201323857364
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 ...201323734251
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 ...201323660656
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 ...201323555830
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 ...201323336388
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 ...201323317046
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 ...201323448011
gene regulatory networks elucidating huanglongbing disease mechanisms.next-generation sequencing was exploited to gain deeper insight into the response to infection by candidatus liberibacter asiaticus (calas), especially the immune disregulation and metabolic dysfunction caused by source-sink disruption. previous fruit transcriptome data were compared with additional rna-seq data in three tissues: immature fruit, and young and mature leaves. four categories of orchard trees were studied: symptomatic, asymptomatic, apparently healthy, and healthy. principal compon ...201324086326
transcriptional and microscopic analyses of citrus stem and root responses to candidatus liberibacter asiaticus infection.huanglongbing (hlb) is the most destructive disease that affects citrus worldwide. the disease has been associated with candidatus liberibacter. hlb diseased citrus plants develop a multitude of symptoms including zinc and copper deficiencies, blotchy mottle, corky veins, stunting, and twig dieback. ca. l. asiaticus infection also seriously affects the roots. previous study focused on gene expression of leaves and fruit to ca. l. asiaticus infection. in this study, we compared the gene expressio ...201324058486
extraction of dna from orange juice, and detection of bacterium candidatus liberibacter asiaticus by real-time pcr.orange juice processed from huanglongbing (hlb) affected fruit is often associated with bitter taste and/or off-flavor. hlb disease in florida is associated with candidatus liberibacter asiaticus (clas), a phloem-limited bacterium. the current standard to confirm clas for citrus trees is to take samples from midribs of leaves, which are rich in phloem tissues, and use a quantitative real-time polymerase chain reaction (qpcr) test to detect the 16s rdna gene of clas. it is extremely difficult to ...201324047134
characterization of the microbial community structure in candidatus liberibacter asiaticus-infected citrus plants treated with antibiotics in the field.huanglongbing (hlb) is a worldwide devastating disease of citrus. there are no effective control measures for this newly emerging but century-old disease. previously, we reported a combination of penicillin g and streptomycin was effective in eliminating or suppressing the associated bacterium, 'candidatus liberibacter asiaticus' (las).201323701743
complete genome sequence of a chinese strain of "candidatus liberibacter asiaticus".we report here the complete genome sequence of "candidatus liberibacter asiaticus" (strain guangxi-1). the 1,268,237-bp genome with a 36.5% g+c content comprises 1,141 open reading frames, 44 trnas, and 3 complete rrnas in a circular chromosome.201323640196
transcriptome comparison and gene coexpression network analysis provide a systems view of citrus response to 'candidatus liberibacter asiaticus' infection.huanglongbing (hlb) is arguably the most destructive disease for the citrus industry. hlb is caused by infection of the bacterium, candidatus liberibacter spp. several citrus genechip studies have revealed thousands of genes that are up- or down-regulated by infection with ca. liberibacter asiaticus. however, whether and how these host genes act to protect against hlb remains poorly understood.201323324561
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 ...201324223954
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 ...201323813735
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 ...201323761797
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 ...201424708539
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 ...201425437428
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 ...201424416233
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 ...201424533511
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 ...201424407918
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 ...201424572372
"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 ...201425063651
effective antibiotics against 'candidatus liberibacter asiaticus' in hlb-affected citrus plants identified via the graft-based evaluation.citrus huanglongbing (hlb), caused by three species of fastidious, phloem-limited 'candidatus liberibacter', is one of the most destructive diseases of citrus worldwide. to date, there is no established cure for this century-old and yet, newly emerging disease. as a potential control strategy for citrus hlb, 31 antibiotics were screened for effectiveness and phytotoxicity using the optimized graft-based screening system with 'candidatus liberibacter asiaticus' (las)-infected citrus scions. actid ...201425372135
draft genome sequence of "candidatus liberibacter asiaticus" from california.we report here the draft genome sequence of "candidatus liberibacter asiaticus" strain hhca, collected from a lemon tree in california. the hhca strain has a genome size of 1,150,620 bp, 36.5% g+c content, 1,119 predicted open reading frames, and 51 rna genes.201425278540
metabolite signature of candidatus liberibacter asiaticus infection in two citrus varieties.huanglongbing (hlb), also known as citrus greening disease, is caused by the bacterium 'candidatus liberibacter asiaticus' (clas) and is a serious threat to the citrus industry. to understand the effect of clas infection on the citrus metabolome, juice from healthy (n = 18), hlb-asymptomatic (n = 18), and hlb-symptomatic hamlin (n = 18), as well as from healthy (n = 18) and hlb-symptomatic (n = 18) valencia sweet oranges (from southern and eastern florida) were evaluated using (1)h nmr-based met ...201424959841
characterization of "candidatus liberibacter asiaticus" populations by double-locus analyses."candidatus liberibacter asiaticus" (calas) is associated with citrus huanglongbing (hlb, yellow shoot disease), which is highly destructive to world citrus production. understanding the relationships of calas isolates from different geographical regions is important for hlb research and development of disease management strategies. in this study, 301 calas isolates [85 brazil, 132 china, and 84 u.s. (83 florida and 1 california)] were collected, and genomic variations among them were evaluated ...201424912994
whole-genome sequence of "candidatus liberibacter asiaticus" from guangdong, china.the draft genome sequence of "candidatus liberibacter asiaticus" strain a4, isolated from a mandarin citrus in guangdong, people's republic of china, is reported. the a4 strain has a genome size of 1,208,625 bp, g+c content of 36.4%, 1,107 predicted open reading frames, and 53 rna genes.201424723715
spatial imaging of zn and other elements in huanglongbing-affected grapefruit by synchrotron-based micro x-ray fluorescence investigation.huanglongbing (hlb) is a highly destructive, fast-spreading disease of citrus, causing substantial economic losses to the citrus industry worldwide. nutrient levels and their cellular distribution patterns in stems and leaves of grapefruit were analysed after graft-inoculation with lemon scions containing 'candidatus liberibacter asiaticus' (las), the heat-tolerant asian type of the hlb bacterium. after 12 months, affected plants showed typical hlb symptoms and significantly reduced zn concentra ...201424420564
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 ...201424769405
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 ...201425014027
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 ...201425198345
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 ...201526717484
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.201526543132
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 ...201526470202
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 ...201526470150
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 ...201526470097
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 ...201526034273
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