Genetic identity of yellow mosaic viruses infecting legumes and their phylogenetic relationship.

摘要

Among all diseases that contribute to depression in yield, yellow mosaic disease (YMD) caused by whitefly transmitted geminiviruses (WTGs) pose a serious threat to the cultivation of pulses in India. All the viruses associated with YMD, infecting different leguminous crops produce characteristic symptoms of yellow and/or golden mosaic on leaves. Symptoms scattered small specks or yellow spots in the leaf lamina, which enlarge to irregular yellow and green patches alternating with each other on matured leaves. The yellow area increase and coalesce resulting in complete yellowing of leaves. The affected plants produce fewer flowers and pods, and the size of pods and seeds are reduced considerably. The symptoms in French bean are however different from other legumes. Instead of yellow mosaic, affected plants show downward leaf curling and corrugated leaf lamina and plants are extremely stunted. All the causal agents of YMD are transmitted by whitefly, Bemisia tabaci, in a persistent circulatory manner. The causal virus, molecular characterization, nomenclature and taxonomy, genome organization, genetic divergence, infectivity of cloned components, phylogenetic relationships and future prospects are discussed.