Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| identification of the tolfenamic acid binding pocket in prbp from liberibacter asiaticus. | in liberibacter asiaticus, prbp is an important transcriptional accessory protein that was found to regulate gene expression through interactions with the rna polymerase β-subunit and a specific sequence on the promoter region. it was found that inactivation of prbp, using the inhibitor tolfenamic acid, resulted in a significant decrease in the overall transcriptional activity of l. asiaticus, and the suppression of l. asiaticus infection in hlb symptomatic citrus seedlings. the molecular intera ... | 2017 | 28878750 |
| analyses of mitogenome sequences revealed that asian citrus psyllids (diaphorina citri) from california were related to those from florida. | asian citrus psyllid (acp, diaphorina citri kuwayama) transmits "candidatus liberibacter asiaticus" (clas), an unculturable alpha-proteobacterium associated with citrus huanglongbing (hlb). clas has recently been found in california. understanding acp population diversity is necessary for hlb regulatory practices aimed at reducing clas spread. in this study, two circular acp mitogenome sequences from california (mt-capsy, ~15,027 bp) and florida (mt-flpsy, ~15,012 bp), usa, were acquired. each m ... | 2017 | 28860662 |
| rapid, sensitive, and carryover contamination-free loop-mediated isothermal amplification-coupled visual detection method for 'candidatus liberibacter asiaticus'. | huanglongbing is a devastating citrus disease, and 'candidatus liberibacter asiaticus' (las) is the most prevalent huanglongbing-associated bacterium. its field detection remains challenging. in this work, a visual, rapid, sensitive, and carryover contamination-free method was developed for field detection of las. leaf samples were treated with 500 μl of 0.5 m sodium hydroxide solution for 3 min, and 50-fold dilutions were directly amplified by loop-mediated isothermal amplification. then, a nov ... | 2017 | 28858491 |
| huanglongbing impairs the rhizosphere-to-rhizoplane enrichment process of the citrus root-associated microbiome. | roots are the primary site for plant-microbe interactions. among the three root-associated layers (i.e., rhizosphere, rhizoplane, and endorhiza), the rhizoplane is a key component serving a critical gating role that controls microbial entry into plant roots. the microbial communities colonizing the three layers are believed to be gradually enriched from the bulk soil inoculum. however, it is unknown how this enrichment process, particularly the rhizosphere to rhizoplane step, is affected by biot ... | 2017 | 28797279 |
| bacterial phytopathogen infection disrupts belowground plant indirect defense mediated by tritrophic cascade. | plants can defend themselves against herbivores through activation of defensive pathways and attraction of third-trophic-level predators and parasites. trophic cascades that mediate interactions in the phytobiome are part of a larger dynamic including the pathogens of the plant itself, which are known to greatly influence plant defenses. as such, we investigated the impact of a phloem-limited bacterial pathogen, candidatus liberibacter asiaticus (clas), in cultivated citrus rootstock on a well-s ... | 2017 | 28690813 |
| combining 'omics and microscopy to visualize interactions between the asian citrus psyllid vector and the huanglongbing pathogen candidatus liberibacter asiaticus in the insect gut. | huanglongbing, or citrus greening disease, is an economically devastating bacterial disease of citrus. it is associated with infection by the gram-negative bacterium candidatus liberibacter asiaticus (clas). clas is transmitted by diaphorina citri, the asian citrus psyllid (acp). for insect transmission to occur, clas must be ingested during feeding on infected phloem sap and cross the gut barrier to gain entry into the insect vector. to investigate the effects of clas exposure at the gut-pathog ... | 2017 | 28632769 |
| innate immune system capabilities of the asian citrus psyllid, diaphorina citri. | citrus production worldwide is currently threatened by huanglongbing, or citrus greening disease. the associated pathogen, candidatus liberibacter asiaticus (clas), is transmitted by the asian citrus psyllid, diaphorina citri. annotation of the d. citri genome revealed a reduced innate immune system lacking a number of antimicrobial peptides and the imd pathway associated with defense against gram-negative bacteria. we characterized this apparent immune reduction in survival assays in which d. c ... | 2017 | 28624621 |
| psyllids, it's what's on the inside that counts: community cross talk facilitates prophage interactions. | despite the availability of massive microbial community data sets (e.g., metagenomes), there is still a lack of knowledge on what molecular mechanisms facilitate cross talk between microbes and prophage within a community context. a study published in msphere by jain and colleagues (m. jain, l. a. fleites, and d. w. gabriel, msphere 2:e00171-17, 2017, https://doi.org/10.1128/mspheredirect.00171-17) reports on an intriguing new twist of how a prophage of the bacterium "candidatus liberibacter asi ... | 2017 | 28612849 |
| a small wolbachia protein directly represses phage lytic cycle genes in "candidatus liberibacter asiaticus" within psyllids. | huanglongbing (hlb) is a severe disease of citrus caused by an uncultured alphaproteobacterium "candidatus liberibacter asiaticus" and transmitted by asian citrus psyllids (diaphorina citri). two prophage genomes, sc1 and sc2, integrated in "ca. liberibacter asiaticus" strain uf506 were described previously, and very similar prophages are found resident in the majority of "ca. liberibacter asiaticus" strains described worldwide. the sc1 lytic cycle is marked by upregulation of prophage late gene ... | 2017 | 28608866 |
| 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 ... | 0 | 28594267 |
| 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 ... | 0 | 28532234 |
| ldtr is a master regulator of gene expression in liberibacter asiaticus. | huanglongbing or citrus greening disease is causing devastation to the citrus industry. liberibacter asiaticus, an obligate intracellular pathogen of citrus, is one the causative agents of the disease. most of the knowledge about this bacterium has been deduced from the in silico exploration of its genomic sequence. l. asiaticus differentially expresses genes during its transmission from the psyllid vector, diaphorina citri, to the plant. however, the regulatory mechanisms for the adaptation of ... | 2017 | 28503858 |
| immune tissue print and immune capture-pcr for diagnosis and detection of candidatus liberibacter asiaticus. | 'candidatus liberibacter asiaticus' (calas), associated with citrus huanglongbing (hlb), is a non culturable member of the α-proteobacteria. in this study serologically based methods for the detection of calas were developed. an anti-outer membrane protein a (ompa) polyclonal antibody previously produced (in our laboratory) was highly effective for the detection of calas from citrus tissues in a simple tissue printing format. the antibody was also used to capture bacteria from periwinkle extract ... | 2017 | 28418002 |
| draft whole-genome sequence of "candidatus liberibacter asiaticus" strain tx2351 isolated from asian citrus psyllids in texas, usa. | we report here the draft genome sequence of "candidatus liberibacter asiaticus" strain tx2351, collected from asian citrus psyllids in south texas, usa. the tx2351 genome has a size of 1,252,043 bp, a g+c content of 36.5%, 1,184 predicted open reading frames, and 52 rna genes. | 2017 | 28408682 |
| 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 |
| defining the core citrus leaf- and root-associated microbiota: factors associated with community structure and implications for managing huanglongbing (citrus greening) disease. | stable associations between plants and microbes are critical to promoting host health and productivity. the objective of this work was to test the hypothesis that restructuring of the core microbiota may be associated with the progression of huanglongbing (hlb), the devastating citrus disease caused by liberibacter asiaticus, liberibacter americanus, and liberibacter africanus the microbial communities of leaves (n = 94) and roots (n = 79) from citrus trees that varied by hlb symptom severity, c ... | 2017 | 28341678 |
| oral delivery of double-stranded rnas induces mortality in nymphs and adults of the asian citrus psyllid, diaphorina citri. | the asian citrus psyllid (acp), diaphorina citri kuwayama, is one of the most important citrus pests. acp is the vector of the phloem-limited bacteria candidatus liberibacter americanus and candidatus liberibacter asiaticus, the causal agents of the devastating citrus disease huanglongbing (hlb). the management of hlb is based on the use of healthy young plants, eradication of infected plants and chemical control of the vector. rna interference (rnai) has proven to be a promising tool to control ... | 2017 | 28282380 |
| sclerenchymatous ring as a barrier to phloem feeding by asian citrus psyllid: evidence from electrical penetration graph and visualization of stylet pathways. | asian citrus psyllid (diaphorina citri) feeding behaviors play a significant role in the transmission of the phloem-limited candidatus liberibacter asiaticus (clas) bacterium that causes the economically devastating citrus greening disease. sustained phloem ingestion by d. citri on clas infected plants is required for pathogen acquisition and transmission. recent studies have shown a fibrous ring of thick-walled sclerenchyma around the phloem in mature, fully expanded citrus leaves that is more ... | 2017 | 28278248 |
| rna interference of carboxyesterases causes nymph mortality in the asian citrus psyllid, diaphorina citri. | asian citrus psyllid, diaphorina citri kuwayama (hemiptera: liviidae), is an important pest of citrus. in addition, d. citri is the vector of huanglongbing, a destructive disease in citrus, also known as citrus greening disease caused by candidatus liberibacter asiaticus. huanglongbing causes huge losses for citrus industries. insecticide application for d. citri is the major strategy to prevent disease spread. the heavy use of insecticides causes development of insecticide resistance. we used r ... | 2017 | 28195667 |
| double-stranded rna delivery through soaking mediates silencing of the muscle protein 20 and increases mortality to the asian citrus psyllid, diaphorina citri. | asian citrus psyllid, diaphorina citri kuwayama, is the most important economic pest of citrus because it transmits candidatus liberibacter asiaticus (clas), the causal agent of huanglongbing (hlb). silencing genes by rna interference (rnai) is a promising approach for controlling d. citri. rnai-based insect management strategies depend on the selection of suitable target genes. | 2017 | 28195429 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| characterization of a bacterioferritin comigratory protein family 1-cys peroxiredoxin from candidatus liberibacter asiaticus. | to defend against the lethality of the reactive oxygen species (ros), nature has armed microorganisms with a range of antioxidant proteins. these include peroxiredoxin (prx) super family proteins which are ubiquitous cysteine-based non-heme peroxidases. the phytopathogenic bacterium candidatus liberibacter asiaticus (cla), an etiological agent of citrus plants diseases, posses many genes for defense against oxidative stress. the bacterioferritin comigratory protein (bcp), a member of prxs, is pa ... | 2017 | 27987036 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| crystal structure analysis in zn(2+)-bound state and biophysical characterization of clas-znua2. | a periplasmic solute binding protein from second of the two gene clusters of znu system in cla (clas-znua2) belong to cluster a1 family of solute binding proteins (sbps). the crystal structures in metal-free, intermediate and metal-bound states, in the previous study, revealed the unusual mechanism of metal binding and release for clas-znua2. although clas-znua2 showed maximum sequence identity to the mn/fe-specific sbps, the mechanistic resemblance seems to be closer to zn-specific sbps of clus ... | 2016 | 27570147 |
| 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 |
| transient expression of candidatus liberibacter asiaticus effector induces cell death in nicotiana benthamiana. | candidatus liberibacter asiaticus "las" is a phloem-limited bacterial plant pathogen, and the most prevalent species of liberibacter associated with citrus huanglongbing (hlb), a devastating disease of citrus worldwide. although, the complete sequence of the las genome provides the basis for studying functional genomics of las and molecular mechanisms of las-plant interactions, the functional characterization of las effectors remains a slow process since remains to be cultured. like other plant ... | 2016 | 27458468 |
| 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 |
| 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 |
| 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 |
| better together: association with 'candidatus liberibacter asiaticus' increases the reproductive fitness of its insect vector, diaphorina citri (hemiptera: liviidae). | the duration of the evolutionary association between a pathogen and vector can be inferred based on the strength of their mutualistic interactions. a well-adapted pathogen is likely to confer some benefit or, at a minimum, exhibit low pathogenicity toward its host vector. coevolution of the two toward a mutually beneficial association appears to have occurred between the citrus greening disease pathogen, candidatus liberibacter asiaticus (las), and its insect vector, the asian citrus psyllid, di ... | 2016 | 27418697 |
| 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 |
| 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 |
| 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 |
| disruption of vector host preference with plant volatiles may reduce spread of insect-transmitted plant pathogens. | plant pathogens can manipulate the odor of their host; the odor of an infected plant is often attractive to the plant pathogen vector. it has been suggested that this odor-mediated manipulation attracts vectors and may contribute to spread of disease; however, this requires further broad demonstration among vector-pathogen systems. in addition, disruption of this indirect chemical communication between the pathogen and the vector has not been attempted. we present a model that demonstrates how a ... | 2016 | 27193763 |
| 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 |
| identification of the genes required for the culture of liberibacter crescens, the closest cultured relative of the liberibacter plant pathogens. | here tn5 random transposon mutagenesis was used to identify the essential elements for culturing liberibacter crescens bt-1 that can serve as antimicrobial targets for the closely related pathogens of citrus, candidatus liberibacter asiaticus (las) and tomato and potato, candidatus liberibacter solanacearum (lso). in order to gain insight on the virulence, metabolism, and culturability of the pathogens within the genus liberibacter, a mini-tn5 transposon derivative system consisting of a gene sp ... | 2016 | 27148230 |
| 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 |
| 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 |
| 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 |
| zinc treatment increases the titre of 'candidatus liberibacter asiaticus' in huanglongbing-affected citrus plants while affecting the bacterial microbiomes. | huanglongbing (hlb)-affected citrus often display zinc deficiency symptoms. in this study, supplemental zinc was applied to citrus to determine its effect on candidatus liberibacter asiaticus (las) titre, hlb symptoms, and leaf microbiome. | 2016 | 26909469 |
| inter-population variability of endosymbiont densities in the asian citrus psyllid (diaphorina citri kuwayama). | the asian citrus psyllid (diaphorina citri kuwayama) is an insect pest capable of transmitting candidatus liberibacter asiaticus (clas), the causal agent of citrus greening in north america. d. citri also harbors three endosymbionts, wolbachia, candidatus carsonella ruddii, and candidatus profftella armatura, which may influence d. citri physiology and fitness. although genomic researches on these bacteria have been conducted, much remains unclear regarding their ecology and inter-population var ... | 2016 | 26846216 |
| 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 |
| predominance of single prophage carrying a crispr/cas system in "candidatus liberibacter asiaticus" strains in southern china. | "candidatus liberibacter asiaticus" (clas) is an uncultureable α-proteobacterium associated with citrus huanglongbing (hlb, yellow shoot disease), a highly destructive disease affecting citrus production worldwide. hlb was observed in guangdong province of china over a hundred years ago and remains endemic there. little is known about clas biology due to its uncultureable nature. this study began with the genome sequence analysis of clas strain a4 from guangdong in the prophage region. within th ... | 2016 | 26741827 |
| characterization of a recombinant cathepsin b-like cysteine peptidase from diaphorina citri kuwayama (hemiptera: liviidae): a putative target for control of citrus huanglongbing. | huanglonbing (hlb) is one of the most destructive disease affecting citrus plants. the causal agent is associated with the phloem-limited bacterium candidatus liberibacter asiaticus (clas) and the psyllid diaphorina citri, vector of disease, that transmits the bacterium associated with hlb. the control of disease can be achieved by suppressing either the bacterium or the vector. among the control strategies for hlb disease, one of the widely used consists in controlling the enzymes of the diseas ... | 2015 | 26717484 |
| draft genome sequence of "candidatus liberibacter asiaticus" from a citrus tree in san gabriel, california. | the draft genome sequence of "candidatus liberibacter asiaticus" strain sgca5 from an orange citrus tree in san gabriel, california, is reported here. sgca5 has a genome size of 1,201,445 bp, a g+c content of 36.4%, 1,152 predicted open reading frames (orfs), and 42 rna genes. | 2015 | 26701083 |
| 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 |
| 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 |
| draft genome sequence of "candidatus liberibacter asiaticus" from diaphorina citri in guangdong, china. | the draft genome sequence of "candidatus liberibacter asiaticus" strain ycpsy from an asian citrus psyllid (diaphorina citri) in guangdong, china, is reported here. the ycpsy strain has a genome size of 1,233,647 bp, 36.5% g+c content, 1,171 open reading frames (orfs), and 53 rnas. | 2015 | 26543132 |
| characterization of the voltage-gated sodium channel of the asian citrus psyllid, diaphorina citri. | the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: liviidae), is an important insect pest of citrus. it is the vector of 'candidatus' liberibacter asiaticus, a phloem-limited bacterium that infects citrus, resulting in the disease huanglongbing (hlb). disease management relies heavily on suppression of d. citri populations with insecticides, including pyrethroids. in recent annual surveys to monitor insecticide resistance, reduced susceptibility to fenpropathrin was identified in se ... | 2017 | 26537022 |
| diaphorina citri (hemiptera: liviidae) vector competence for the citrus greening pathogen 'candidatus liberibacter asiaticus'. | characterizing the vector competence of diaphorina citri kuwayama for 'candidatus liberibacter asiaticus,' the pathogen causing citrus greening, is essential for understanding the epidemiology of this disease that is threatening the u.s. citrus industry. vector competence studies have been difficult because of the biology of d. citri, the inability to culture the pathogen, and the available diagnostic methods used to detect the bacteria in plant and insect tissues. the methods employed in many s ... | 2015 | 26470202 |
| effect of cyantraniliprole, a novel insecticide, on the inoculation of candidatus liberibacter asiaticus associated with citrus huanglongbing by the asian citrus psyllid (hemiptera: liviidae). | the asian citrus psyllid (diaphorina citri kuwayama) is the principal vector of 'candidatus liberibacter asiaticus' (clas) associated with huanglongbing (hlb), the most serious citrus disease worldwide. new control measures including pesticides are urgently needed to combat hlb, especially to protect young or newly planted citrus trees from clas-inoculation by vector psyllids. here, we tested clas-inoculation by d. citri adults (clas-exposed, reared on infected plants) by feeding them for 7 d on ... | 2015 | 26470150 |
| seasonal movement patterns and long-range dispersal of asian citrus psyllid in florida citrus. | the asian citrus psyllid, diaphorina citri kuwayama, is the vector of the bacterial pathogen, candidatus liberibacter asiaticus, which is the causal agent of huanglongbing (hlb) in the united states. both short-range and long-range dispersal of d. citri adults affect the spread of hlb; however, little is known about the long-range dispersal capabilities of d. citri in the field or the seasonality of flight behavior. in the present study, an in situ protein marking technique was used to determine ... | 2015 | 26470097 |
| comprehensive meta-analysis, co-expression, and mirna nested network analysis identifies gene candidates in citrus against huanglongbing disease. | huanglongbing (hlb), the most devastating disease of citrus, is associated with infection by candidatus liberibacter asiaticus (calas) and is vectored by the asian citrus psyllid (acp). recently, the molecular basis of citrus-hlb interactions has been examined using transcriptome analyses, and these analyses have identified many probe sets and pathways modulated by calas infection among different citrus cultivars. however, lack of consistency among reported findings indicates that an integrative ... | 2015 | 26215595 |
| 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 |
| 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 |
| 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 |
| 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 |
| asymptomatic spread of huanglongbing and implications for disease control. | huanglongbing (hlb) is a bacterial infection of citrus trees transmitted by the asian citrus psyllid diaphorina citri. mitigation of hlb has focused on spraying of insecticides to reduce the psyllid population and removal of trees when they first show symptoms of the disease. these interventions have been only marginally effective, because symptoms of hlb do not appear on leaves for months to years after initial infection. limited knowledge about disease spread during the asymptomatic phase is e ... | 2015 | 26034273 |
| infection density dynamics of the citrus greening bacterium "candidatus liberibacter asiaticus" in field populations of the psyllid diaphorina citri and its relevance to the efficiency of pathogen transmission to citrus plants. | huanglongbing, or citrus greening, is a devastating disease of citrus plants recently spreading worldwide, which is caused by an uncultivable bacterial pathogen, "candidatus liberibacter asiaticus," and vectored by a phloem-sucking insect, diaphorina citri. we investigated the infection density dynamics of "ca. liberibacter asiaticus" in field populations of d. citri with experiments using field-collected insects to address how "ca. liberibacter asiaticus" infection density in the vector insect ... | 2015 | 25819961 |
| whole-genome sequence of "candidatus liberibacter asiaticus" from a huanglongbing-affected citrus tree in central florida. | here, we report the draft genome sequence of "candidatus liberibacter asiaticus" strain fl17, isolated from a huanglongbing (hlb)-affected citrus tree in central florida. the fl17 genome comprised 1,227,253 bp, with a g+c content of 36.5%, 1,175 predicted open reading frames, and 53 rna genes. | 2015 | 25792067 |
| crystal structure of a periplasmic solute binding protein in metal-free, intermediate and metal-bound states from candidatus liberibacter asiaticus. | the znu system, a member of abc transporter family, is critical for survival and pathogenesis of candidatus liberibacter asiaticus (cla). two homologues of this system have been identified in cla. here, we report high resolution crystal structure of a periplasmic solute binding protein from second of the two gene clusters of znu system in cla (clas-znua2) in metal-free, intermediate and metal-bound states. clas-znua2 showed maximum sequence identity to the mn/fe-specific solute binding proteins ... | 2015 | 25641618 |
| 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 |
| 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 ... | 2014 | 25372135 |
| 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 |
| 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. | 2014 | 25278540 |
| the push-pull strategy for citrus psyllid control. | the asian citrus psyllid (acp), diaphorina citri kuwayama (hemiptera: psyllidae), is the only natural vector of candidatus liberibacter asiaticus that causes citrus huanglongbing (hlb), a most destructive disease of citrus. currently, no remedial therapy exists for the disease, and so effective control of acp is very important in curbing the transmission of the disease. the push-pull strategy should be thoroughly explored as an approach to acp management. this mini-review summarises the current ... | 2015 | 25256398 |
| 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 |
| "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 |
| 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 |
| 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 ... | 2014 | 24959841 |
| 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 ... | 2014 | 24912994 |
| nested-quantitative pcr approach with improved sensitivity for the detection of low titer levels of candidatus liberibacter asiaticus in the asian citrus psyllid, diaphorina citri kuwayama. | candidatus liberibacter asiaticus (clas) is a phloem-limited bacterium transmitted by the asian citrus psyllid, diaphorina citri, and the presumptive causal agent of citrus greening disease. the current method of detection for clas within plant and insect samples is by a presence/absence qpcr assay using the clas 16s rdna gene target. although qpcr is highly sensitive, low bacterial titers or suboptimal qpcr conditions can result in false-negatives. using a nested qpcr assay, we determined the f ... | 2014 | 24769405 |
| 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. | 2014 | 24723715 |
| 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 |
| 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 |
| 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 |
| 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 ... | 2014 | 24420564 |
| 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 |
| 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 |
| 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 |
| 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 ... | 2013 | 24086326 |
| 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 ... | 2013 | 24058486 |
| 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 ... | 2013 | 24047134 |
| chemical and behavioral analysis of the cuticular hydrocarbons from asian citrus psyllid, diaphorina citri. | huanglongbing (hlb) is the most destructive disease of citrus worldwide. the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: psyllidae), is the vector of the phloem-inhabiting bacterium, candidatus liberibacter asiaticus, which is presumed to cause hlb in florida citrus. laboratory and field studies were conducted to examine the behavioral responses of male and female d. citri to their cuticular extracts. in olfactometer assays, more male d. citri were attracted to one, five, or 10 f ... | 2013 | 23955888 |
| herbivory by the insect diaphorina citri induces greater change in citrus plant volatile profile than does infection by the bacterium, candidatus liberibacter asiaticus. | the volatile organic compound (voc) profile in plant leaves often changes after biotic and abiotic stresses. monitoring changes in vocs in plant leaves could provide valuable information about multitrophic interactions. in the current study, we investigated the effect of asian citrus psyllid (acp) infestation, citrus greening pathogen (candidatus liberibacter asiaticus [clas]) infection, and simultaneous attack by acp and clas on the voc content of citrus leaves. leaf volatiles were extracted us ... | 2013 | 23857364 |
| 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 |
| silencing abnormal wing disc gene of the asian citrus psyllid, diaphorina citri disrupts adult wing development and increases nymph mortality. | huanglongbing (hlb) causes considerable economic losses to citrus industries worldwide. its management depends on controlling of the asian citrus psyllid (acp), the vector of the bacterium, candidatus liberibacter asiaticus (clas), the causal agent of hlb. silencing genes by rna interference (rnai) is a promising tool to explore gene functions as well as control pests. in the current study, abnormal wing disc (awd) gene associated with wing development in insects is used to interfere with the fl ... | 2013 | 23734251 |