Yadav Rajiv Kumar, Shukla Rakesh Kumar, Chattopadhyay Debasis
National Institute of Plant Genome Research, Aruna Asaf Ali Marg, JNU Campus, New Delhi 110067, India.
Virus Res. 2009 Sep;144(1-2):89-95. doi: 10.1016/j.virusres.2009.04.011. Epub 2009 Apr 24.
Yellow mosaic disease caused by whitefly-transmitted bipartite Geminiviruses is one of the major constraints on productivity of a number of pulse crops. We have cloned the bipartite genome of Mungbean Yellow Mosaic India Virus isolated from infected Soybean. We report here that agroinfection of Soybean seedlings with a single uncut recombinant binary plasmid containing tandem dimers of both DNA A and DNA B resulted in 100% infectivity in susceptible varieties. To understand the mechanism of natural resistance in a Soybean variety, we compared the abundance of the viral RNAs in a resistant and a susceptible variety at the early time points after agroinfection. Whilst the resistant variety displayed synthesis but rapid degradation of the early viral RNAs; the degradation in the susceptible variety was delayed resulting in accumulation of those transcripts later in infection. Accumulation of the late viral transcripts and DNA replication were detectable only in the susceptible variety. This indicates that rapid degradation of the early viral transcripts, possibly through siRNA mechanism, is one of the probable mechanisms of natural resistance against geminivirus.
由粉虱传播的双分体双生病毒引起的黄花叶病是多种豆类作物生产力的主要限制因素之一。我们克隆了从受感染大豆中分离出的绿豆黄花叶印度病毒的双分体基因组。我们在此报告，用含有DNA A和DNA B串联二聚体的单个未切割重组二元质粒对大豆幼苗进行农杆菌介导的感染，在易感品种中产生了100%的感染率。为了了解大豆品种中天然抗性的机制，我们比较了农杆菌介导的感染后早期时间点抗性品种和易感品种中病毒RNA的丰度。抗性品种表现出早期病毒RNA的合成但快速降解；易感品种中的降解延迟，导致这些转录本在感染后期积累。晚期病毒转录本的积累和DNA复制仅在易感品种中可检测到。这表明早期病毒转录本可能通过siRNA机制快速降解是对双生病毒天然抗性的可能机制之一。
