中文摘要：RNA沉默机制是抵御入侵病毒的主要防御机制。对于RNA沉默机制需要注意的是效应物小干扰RNAs（siRNAs）可作用于任何序列RNA转录而不论目标源。本文对来源于番茄斑萎病毒（TSWV）基因组的高表达病毒小干扰RNAs（vsiRNAs）下调番茄转录组的倾向性进行了分析。本研究表明了vsiRNA诱导的宿主转录组RNA沉默的流行，并且是首次报道番茄斑萎病毒基因组衍生的siRNAs和番茄转录产物之间的交互作用，并提供了对vsiRNAs在致病性和干扰宿主机制中作用的更深入理解。
外文摘要：RNA silencing mechanism functions as a major defense against invading viruses. The caveat in the RNA silencing mechanism is that the effector small interfering RNAs (siRNAs) act on any RNA transcripts with sequence complementarity irrespective of target’s origin. A subset of highly expressed viral small interfering RNAs (vsiRNAs) derived from the tomato spotted wilt virus (TSWV; Tospovirus : Bunyaviridae ) genome was analyzed for their propensity to downregulate the tomato transcriptome. A total of 11898 putative target sites on tomato transcripts were found to exhibit a propensity for down regulation by TSWV-derived vsiRNAs. In total, 2450 unique vsiRNAs were found to have potential cross-reacting capability with the tomato transcriptome. VsiRNAs were found to potentially target a gamut of host genes involved in basal cellular activities including enzymes, transcription factors, membrane transporters, and cytoskeletal proteins. KEGG pathway annotation of targets revealed that the vsiRNAs were mapped to secondary metabolite biosynthesis, amino acids, starch and sucrose metabolism, and carbon and purine metabolism. Transcripts for protein processing, hormone signalling, and plant-pathogen interactions were the most likely targets from the genetic, environmental information processing, and organismal systems, respectively. qRT-PCR validation of target gene expression showed that none of the selected transcripts from tomato cv. Marglobe showed up regulation, and all were down regulated even upto 20 folds (high affinity glucose transporter). However, the expression levels of transcripts from cv. Red Defender revealed differential regulation as three among the target transcripts showed up regulation (Cc-nbs-lrr, resistance protein, AP2-like ethylene-responsive transcription factor, and heat stress transcription factor A3). Accumulation of tomato target mRNAs of corresponding length was proved in both tomato cultivars using 5’RACE analysis. The TSWV-tomato interaction at the sRNA interface points to the ability of tomato cultivars to overcome vsiRNA-mediated targeting of NBS-LRR class R genes. These results suggest the prevalence of vsiRNA-induced RNA silencing of host transcriptome, and the interactome scenario is the first report on the interaction between tospovirus genome-derived siRNAs and tomato transcripts, and provide a deeper understanding of the role of vsiRNAs in pathogenicity and in perturbing host machinery.
外文关键词：Gene regulation；Off–targets；Plant-virus interactions；RNA silencing；vsiRNAs； 期刊名称：Virus Research
作者：SV Ramesh， S Williams， M Kappagantu， N Mitter， HR Pappu
作者单位：华盛顿州立大学
期刊名称：Virus Research
期刊影响因子：2.628
出版年份：2017
出版刊次：5
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