中文摘要：RNA沉默是宿主抵抗入侵病毒的一种适应性强、可诱导的抗病毒防御机制。这种适应性抗病毒功能是以病毒感染过程中由病毒衍生的小干扰RNAs（siRNAs）的形成为特征。作为反防御策略，很多植物病毒进化出病毒抑制基因以抑制抗病毒沉默。棉花曲叶病（CLCuD）是一种具有灾难性的较为复杂的病害，由目前所知的5种不同的单组分菜豆金黄花叶病毒属病毒与病害特有的β卫星（DNAβ）引起，β卫星是诱导病害症状必不可少的因素。β卫星是一种圆形的单链DNA分子，依赖辅助病毒进行复制、衣壳化以及昆虫在植物中的传播与运动。它们除了复制所必须的发夹结构外，对于各自的辅助病毒并没有明显的序列一致性。本研究将siRNA介导的策略运用到生成抵抗CLCuD侵染的转基因棉花中。研究结果表明，基于RNAi介导的抗性策略的βC1基因具有使CLCuMuB（在CLCuD症状诱导中会涉及到）沉默的潜力。
外文摘要：RNA silencing is an adaptive, inducible antiviral defence mechanism in the host against invading viruses. The adaptive antiviral function is characterized by the formation of virus-derived small interfering RNAs (siRNAs) during viral infection. As a counter defense strategy, a number of plant viruses evolve viral suppressors to target antiviral silencing. Cotton leaf curl disease (CLCuD) is a disastrous complex disease caused by presently known five distinct monopartite begomovirus species in association with disease specific betasatellite (DNA-beta), which is essential for induction of disease symptoms. Betasatellites are circular, ssDNA molecules that depend on helper viruses for their replication, encapsidation, insect transmission and movement in plants. They possess no appreciable sequence identity to their respective helper viruses except for a conserved hairpin structure necessary for their replication. In this study, siRNA-mediated strategy was applied to generate transgenic tobacco (Nicotiana tabacum) against CLCuD infection. A hairpin (hp) RNAi construct capable of expressing dsRNA homologous to the beta C1 gene of Cotton leaf curl Multan betasatellite (CLCuMuB) was designed and developed. A total of eighteen (T-0) and seven (T-1) independent lines of transformed N. tabacum plants were developed following Agrobacterium tumefaciens-mediated transformation with the beta C1 gene-derived intron-(i)hpRNAi construct. Presence of the potential stretch of beta C1 was confirmed by PCR coupled with Southern hybridization. The copy numbers of transgene varied between one and three. The transgenic N. tabacum plants of both T-0 and T-1 lines showed high level of resistance following inoculation with viruliferous whiteflies (Bemisia tabaci). No symptoms were developed on the five (T-0) and two (T-1) transgenic lines, and remained symptoms free even 90 d post inoculation. The present study has demonstrated that beta C1 gene based RNAi-mediated resistance strategy possesses potential to silence CLCuMuB implicated in the induction of CLCuD symptoms.
外文关键词：Silencing suppressor gene; betasatellite; begomovirus; siRNA; cotton leaf curl disease
作者：Akhtar, Sadia; Akmal, Mohd; Khan, Jawaid A.
作者单位：印度国立伊斯兰大学
期刊名称：INDIAN JOURNAL OF BIOTECHNOLOGY
期刊影响因子：0.289
出版年份：2017
出版刊次：1
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