黄瓜花叶病毒小青菜分离物RNA3全长序列分析

对侵染十字花科小青菜的黄瓜花叶病毒YN分离物（CMV-YN）RNA3进行全长克隆和序列分析．CMV-YNRNA3全长2220nt，分别编码279个氨基酸的3a蛋白和218个氨基酸的CP．序列同源性比较结果如下；CMV-YNRNA3核苷酸及其编码蛋白的氨基酸序列与亚组IA株系CMV-Fny、亚组IB株系CMV-Nt9、亚组Ⅱ株系CMV-Q的同源性，RNA3序列分别为92．7％、96．7％、74．2％，3a蛋白氨基酸序列分别为96．4％、98．6％、83．2％，CP氨基酸序列分别为97．7％、98．2％、83．1％．该结果表明CMV-YN与亚组IB株系CMV-Nt9的同源关系更密切．对CP核苷酸序列的系统进化树分析表明：CMV-YN归属于亚组IB，本研究为首次报道侵染我国十字花科植物的CMV基因组序列．

Full-length sequence analyses of CMV-YN genomic RNA 3 isolated from Brassica compestris ssp.chinensis(L.) Makino

The full-length cDNA clone of genomic RNA 3 of a Cucumber mosaic virus(CMV) isolate,named CMV-YN,obtained from Brassica compestris ssp.chinensis(L.) Makino,family Cruciferae was created by RT-PCR,and its sequence data were analyzed.The full length of YN RNA 3 was composed of 2 220 nt with two ORFs,encoding 3a protein and CP,respectively.The 3a protein consisted of 279 amino acids,and CP was found consisting of 218 amino acids.The sequence similarities of CMV-YN RNA 3 with the corresponding RNA 3 of CMV-Fny,CMV-Nt9,CMV-Q,from subgroup IA,IB,II,respectively,were listed as follows: 92.7%,96.7%,74.2%,respectively;The amino acid sequence similarities of CMV-YN 3a protein and CP with the corresponding proteins of the above three strains were 96.4% 97.7%,98.6% 98.2%,83.2% 83.1%,respectively.CMV-YN was found to be more closely related with CMV-Nt9,belonging to subgroup IB than strains of other subgroups based on the above analyses.The results of phylogenetic analyses on CP gene indicated that CMV-YN was divided into CMV subgroup IB.This is the first report of sequence analyses for CMV infecting Cruciferae in China.