Project description:Purpose: We obtained RNA-seq-based differential expression profile of Valencia sweet orange plants challenged against healthy and CLas-infected psyllid infection at 1 dpi and 5 dpi. The goals of this study are to reveal the interaction between citrus and psyllid/CaLas during the early phase of infection and understand the molecular mechanisms underlying the host-pathogen interactions and the susceptibility of most citrus varieties. Methods: leaf mRNA profiles of in vitro cultured Valencia sweet orange (VAL) budwood (WT) and of VAL fed by healthy and CLas-infected psyllid were generated by RNA-seq, in triplicate (one sample is duplicate), using Illumina HiSeq platform. The sequence reads that passed quality filters were used for gene expression and DEG detection analysis by EBseq algorithms. qRT–PCR validation was performed using SYBR Green assays Results: Using the RNA-seq data analysis workflow, we mapped about 136.80M sequence reads per sample to the reference Citrus clementina v1.0 genome and a total of 32,677 genes were detected. The average total mapping of each library was 71.98%. RNA-seq data were validated with qRT–PCR. Conclusions: Our study obtained the transcriptional profiles of citrus host by feeding of psyllid transmitting Candidatus Liberibacter asiaticus at early stages of infection, with biologic replicates, generated by RNA-seq technology. The RNA-seq data analysis workflows reported here should provide a framework for comparative investigations of expression profiles. We conclude that RNA-seq based transcriptome characterization would expedite genetic network analyses and permit the dissection of complex biologic functions.
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 (HLB) is a devastating disease of citrus plants caused by the non-culturable phloem-inhabiting bacterium Candidatus Liberibacter asiaticus (CLas). Bacteria are vectored by the psyllid Diaphorina citri and introduced into sieve cells, evading plant immunity and establishing a successful infection in citrus plants. Although no resistance has been reported in Citrus species, complete or partial resistance has been documented in the distant relatives Murraya paniculate and Bergera koenigii, providing excellent systems to investigate molecular mechanisms leading to either resistance or susceptibility. The first weeks after bacterial release into the phloem are critical for the establishment of the bacteria. In this study, a thorough transcriptomic analysis of young flushes exposed to CLas-positive or negative psyllid has been performed in Citrus x sinensis, as well as in these resistant species along the first eight weeks after exposure. Our results suggest that the resistant genotypes do not deploy a classical immunity response. Instead, transcriptome changes are scarce and only a few genes are differentially expressed. Functional analysis suggest that primary metabolism and other basic cellular functions could be rewired in the resistant genotypes to limit infection. Transcriptomes of young flushes of the three species are very different, supporting the existence of distinct biochemical landscapes. These findings suggest that both intrinsic metabolic inadequacies to CLas survival, as well as inducible reprogramming of physiological functions upon CLas recognition, could orchestrate together to restrict bacteria multiplication in these resistant hosts.