Project description:‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid (ACP). We used quantitative mass spectrometry to compare the proteomes of CLas(+) and CLas(-) populations of D. citri. This experiment used adult mixed sex whole insect samples as starting material for protein extraction. DNA extracted from CLas(+) ACP was tested by qPCR to confirm presence of CLas.
Project description:‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid (ACP). This dataset was obtained from analysis of CLas(-) whole adult ACP samples.
Project description:‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid (ACP). This dataset was obtained from analysis of CLas(+) whole nymph ACP samples.
Project description:‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid (ACP). This dataset was obtained from analysis of CLas(+) whole adult ACP samples.
Project description:‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid (ACP). This dataset was obtained from analysis of peptides from CLas(-) nymph ACP samples.
Project description:‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid (ACP). Percoll gradient density centrifugation was used to fractionate an ACP homogenate to generate a sample enriched for intact microbial cells (CLas and insect endosymbionts) and associated ACP cells. Proteins were extracted from Percoll gradient fractions prepared in triplicate from CLas(-) ACP samples and CLas(+) ACP samples.
Project description:The Asian citrus psyllid (Diaphorina citri) is a pest of citrus and the primary insect vector of the bacterial pathogen, ‘Candidatus Liberibacter asiaticus’ (CLas), which is associated with citrus greening disease. Variability in CLas titer in insects collected from infected plants has been attributed in part to the host plant from which the insects were collected. CLas accumulates to high titers in infected Citrus macrophylla, and in D. citri feeding on the infected plants of this species. In contrast, in the citrus relative Murraya paniculata, CLas titers remain low in infected plants and in D. citri exposed to infected plants. In this study, top-down and bottom-up proteomics methods were used to investigate the impact of these different host plants on D. citri protein expression. Difference in gel electrophoresis (DIGE) was used to identify protein spots on two-dimensional gels that were larger in one of three insect sample classes compared to the other two: D. citri continuously reared on C. macrophylla, D. citri reared continuously on M. paniculata, and D. citri transferred to M. paniculata for five days feeding after continuous rearing on C. macrophylla. Peptide mass spectrometry was used to identify and quantify proteins in target spots upregulated in each sample class. Shotgun proteomics was used to identify and quantify proteins from analysis of tryptic peptide samples prepared from whole insects from four sample classes: the reciprocal host switch condition (D. citri transferred to C. macrophylla for five days feeding after continuous rearing on M. paniculata) in addition to the three sample classes used in DIGE analysis. Integration of the results of both analyses reveals proteins identified by separate experimental workflows to be upregulated in insects adapted to each host plant, and in insects adapting to a novel host plant. A peptidoglycan-degrading protein involved in the immune response to bacterial pathogens was found to be upregulated in M. paniculata-reared D. citri. In the absence of CLas infection, host plant factors specific to M. paniculata may prime the antibacterial immune response in D. citri. Understanding the insect proteins involved in the adaptation of D. citri to host plants with variation in their susceptibility to CLas will inform the development of control strategies aimed at stopping the spread of citrus greening disease.
Project description:Candidatus Liberibacter asiaticus (Las) is an emergent bacterial pathogen associated with the devastating citrus Huanglongbing (HLB), also known as the greening disease. Vectored by the Asian Citrus Psyllid (Diaphorina citri), Las colonizes the phloem tissue of citrus. So far, efforts of cultivating Las in vitro have not been successful and dual-transcriptome analyses could only detect ~100 Las genes due to the low abundance of bacterial RNA in infected citrus/psyllid tissues. Therefore, the biology of this pathogen is poorly understood. Here, we established a procedure to enrich Las RNA for transcriptome analysis in order to obtain insights into the interactions of Las with its two hosts. We were able to confidently determine the expression profiles of >400 Las genes, including 106 that were differentially expressed between citrus and psyllids. Genes related to transcription/translation and defense were found to be upregulated in citrus; whereas genes upregulated in psyllids are involved in metabolic pathways related to tricarboxylic acid (TCA) cycle. Genes encoding the succinate dehydrogenase and NADH quinone oxidoreductase complexes, as well as the flagellar system are also expressed to higher levels in psyllids. We also analyzed the relative expression levels of Sec-delivered effectors, which are considered key virulence factors of Las. This work advances our understanding of the HLB biology and offers novel insight into the HLB pathogenesis.
Project description:The aim of this study was to develop methods for the extraction of endogenous peptides from the Asian citrus psyllid, vector of the bacteria that cause the major citrus disease Huanglongbing. In addition, the native peptidome of the Asian citrus psyllid is described, with an emphasis on candidate neuropeptides.
Project description:Huanglongbing, or citrus greening disease, has devastated the citrus industry. It is associated with the gram negative bacterium Candidatus Liberibacter asiaticus (CLas) that can be transmitted by Diaphorina citri, the Asian citrus psyllid. For transmission to occur, CLas must cross the gut of the ACP to circulate through the insect body. The insect gut is the first site of widespread interactions between the CLas and the ACP and forms a barrier to transmission. To investigate the effect of CLas exposure on this dynamic interface, we performed RNAseq and mass spectrometry-based proteomics to analyze the transcriptome and proteome respectively of dissected ACP guts. We found changes in iron metabolism, insecticide resistance, immune system, and apoptosis. We identified 83 long non-coding RNAs that are responsive to CLas, two of which have no homology to other organisms in NCBI. We also determined that Wolbachia, a symbiont of the ACP, undergoes protein regulation when CLas is present. Fluorescent in situ hybridization (FISH) confirmed that Wolbachia and CLas can inhabit the same ACP gut cell, but do not co-localize. These data provide a snapshot of the ACP gut under normal and CLas-exposed conditions, and provide tools to better understand the insect vector of the citrus greening pathosystem.