2013-2014年云南主要稻区病毒病调查及RSV的分子变异

于2013-2014连续两年对云南主要水稻种植区的水稻病毒病进行了调查,发现当前为害云南水稻的病毒病主要有水稻条纹叶枯病、南方水稻黑条矮缩病、水稻矮缩病和水稻齿叶矮缩病。其中,条纹叶枯病是当前为害云南水稻最严重的病毒病,部分田块最高发病率可达15.0%;其次是水稻矮缩病,调查田块最高发病率达10.0%;南方水稻黑条矮缩病的平均发病率达5.3%;水稻齿叶矮缩病只在局部地区发生且发病率都不高。对云南当前发生较普遍的RSV不同分离物RNA3基因间隔区(IR3)及RNA4基因间隔区(IR4)开展了分子变异分析。根据不同RSV分离物IR3、IR4核苷酸序列构建系统进化树,所分析的RSV分离物均可被划分为两个组,部分云南分离物和云南以外的中国、日本、韩国分离物聚在Ⅰ组,其余绝大多数云南分离物单独聚在Ⅱ组。不同RSV分离物的IR3和IR4长度差异较大,按每10个核苷酸的长度差异进行划分,均可划分为A、B、C三种不同的类型。部分RSV云南分离物IR3、IR4中有17-21nt的序列与其水稻、小麦和大麦等寄主的部分序列相同,这可能是病毒在进化过程中与寄主植物发生了重组。云南RSV分离物的IR3、IR4分子变异较大,可能与其特殊的地理、生态条件有一定的相关性。

Investigation of Rice Virus Diseases and Analysis of the Molecular Variation of RSV Isolates in the Main Rice-growing Areas of Yunnan Province from 2013 to 2014

Viral disease investigation in main rice planting areas in Yunnan Province from 2013 to 2014 showed that rice stripe disease, southern rice black-streaked dwarf disease, rice dwarf disease and rice ragged stunt disease were the four major viral diseases threaten rice production in Yunnan Province. Among them, rice stripe disease remained widely distributed in Yunnan with the incidence up to 15.0% in some fields followed by rice dwarf disease occurred in some areas with the highest incidence of 10.0%; and the average incidence of southern rice black-streaked dwarf disease was 5.3%; rice ragged stunt disease occurred with a low incidence. Molecular variation in rice stripe virus (RSV) isolates was analyzed based on the nucleotide sequence of intergenic region (IR) of RNA3 and RNA4. Phylogenetic analysis showed that all of Yunnan RSV isolates could be divided into two distinct clusters. The isolates from Japan, Korea and other provinces of China belonged to groupⅠ, whereas Yunnan isolates fell into both of the two groups and most of them form a distinct Yunnan population of group Ⅱ. The length of IR3 and IR4 varied with RSV isolates,which could be divided into three types of A, B and C according to the difference in the length per 10 nucleotides. Recombination might be occurred during the evolutionary process of RSV since 17 to 21 nucleotides of IR3 and IR4 of some Yunnan isolates shared some identical sequence with their host plants, rice, wheat or barley. We supposed that the high molecular variation of IR3 and IR4 in Yunnan isolates might result from the special geographical and ecological conditions in Yunnan Province.