云南辣椒双生病毒种类及致病性研究

Whitefly-transmitted geminiviruses（WTGs; genus Begomovirus ; family Geminiviridae）are significant groups of plant pathogenic DNA viruses responsible for economically devastating diseases of many crops throughout the tropics and subtropics regions of the world. Yunnan province is one of the major concentrated distribution areas of WTGs in China. Bgomoviruses cause destructive diseases in several solanaceous crops in Yunnan. The preliminary research showed that begomoviruses were found to be one of the major pathogeny infecting pepper plants in the low altitude region of Yunnan province, and the species diversity was complicated. Based on our previous results, this project will focus on the species, the distribution, the natural population structure and the mutation types of the pepper isolates of begomoviruses in Yunnan. We will distinguish their pathogenicity differences in various hosts including pepper, tomato etc. We will also dissect the characteristics of DNA-A and β satellite nucleotide sequences of high pathogenicity isolates and the efficiency of wthitefly(Bemisia tabaci) transmitting begomoviruses amongst the various plants infected by the different infectious clones. The above results obtained in this study will provide scientific basis of preventing and controlling the begomoviruses' diseases of the peppers.

粉虱传双生病毒（Whitefly-transmitted geminiviruses，WTGs）是一类对全球范围内热带及亚热带地区多种作物危害严重的植物DNA病毒。云南是我国WTGs的主要集中分布区之一，该病害在茄科作物上暴发流行，造成严重危害。前期调查研究发现，在云南低海拔地区双生病毒是辣椒的主要病原之一，其种类多样性复杂。本项目拟在前期研究基础上，以云南辣椒WTGs为研究对象，系统研究为害云南辣椒的WTGs的种类、分布、自然条件下的病毒种群结构及病毒的变异特征；探索WTGs辣椒分离物对辣椒、番茄等系列寄主的致病性差异；了解高致病性病毒分离物和beta卫星分子的核苷酸序列特征；明确不同分离物接种病株的烟粉虱传毒效率。从而为该类病害的防控提供科学依据。

本项目针对云南粉虱传双生病毒严重危害辣椒的问题，对其病毒种类、发生流行开展了系统的研究。从云南辣椒寄主作物上分离鉴定菜豆金色花叶病毒属病毒（begomoviruses）10种（新种1个），确定了不同地理区域的优势种为TYLCCNV、TbCSV、PepLCYnV、THYLCTHV。对10种病毒云南辣椒分离物核苷酸多态性指数其发生分布范围有一定的相关性。致病性相关beta卫星分子的突变频率显著高于其辅助病毒。其中上述9种病毒碱基以C/T替换类型最高，与病毒基因组甲基化引起的致病性变化相关。发现病毒或株系之间的重组主要位于AC2、AC4和IR区域。云南辣椒begomoviruses不同病毒DNA-A与不同beta卫星分子重配较普遍，一种病毒可与1至3种不同beta卫星分子重配。应用TYLCTHV和PepLCYnV与不同beta卫星分子接种本氏烟和番茄表明，重配复合体增强了致病性。明确了云南粉虱传双生病毒发生区域的烟粉虱优势种为入侵烟粉虱隐种MEAM 1、MED隐种，土著烟粉虱隐种Asia I。3种烟粉虱优势种对PaLCuCNV获毒能力无显著差异。.本项目系统开展了对云南主要WTGs发生区辣椒中begomoviruses种类、病毒变异特征以及优势病毒的致病性差异的研究，并为监测与防控提供了理论指导。本项目已发表接受论文6篇，其中SCI论文2篇。