中国台湾番茄曲叶病毒侵染引起广东番茄黄化曲叶病

广东汕头番茄(Lycopersicon eseulentum)上发生的黄化曲叶病毒病,田间症状表现为病株明显矮化、病叶褪绿黄化、叶小且卷曲和叶质较脆硬。对该病毒代表分离物(BS)基因组DNA-A克隆和测定结果表明,其全长为2740nt(GenBank acces-sion No.DQ237918),具有菜豆金色花叶病毒属(Begomovirus)病毒基因组典型特征,为闭合环状单链DNA,有6个ORFs,分别位于病毒链上的AV1、AV2及位于互补链上的AC1、AC2、AC3和AC4;在基因AV2与AC1之间有269nt的非编码区。BLAST结果显示,BSDNA-A与Begomovirus中来自亚洲的病毒同源性较高,而与美洲、非洲等地的相对较低;其中与中国台湾番茄曲叶病毒(Tomato leaf curl Taiwan virus,ToLCTWV)DNA-A全序列同源性最高,为97.7%,而二者的AV1、AV2、AC1、AC2、AC3和AC4基因及IR的同源性分别为98.6%、98.0%、98.0%、97.5%、96.3%、98.6%和96.6%,推导编码的6个蛋白的氨基酸序列同源性分别为97.7%、99.1%、97.5%、95.6%、91.8%和99.0%%。全序列系统进化关系树显示,BS与ToLCTWV的亲缘关系最近,并形成一个独立分支,再与广东番茄曲叶病毒G2(Tomato leaf curl Guangdong virus G2,ToLCGDV-G2]和广东番茄曲叶病毒G3(Tomato leaf curl Guangdong virus G3,ToLCGDV-G3]形成一个大的分支,而与其它33种Begomovirus病毒的亲缘关系均相对较远。这些结果表明,BS应是ToLCTWV的一个分离物。

Tomato Yellow Leaf Curl Disease in Guangdong Caused by Tomato leaf curl Taiwan virus

The tomato plants infected by tomato yellow leaf curl disease in Shantou city of Guangdong Province showed stunting, which leaves were chlorotic, yellowish and leaflets reduced in size with upwards and inwards cupping (called curling), and stiffer than the normal. The virus isolation BS was isolated from the diseased plants. The complete nucleotide sequence of BS DNA-A was determined to be 2 740 nt encoding six potential ORFs located AV1 and AV2 in virus sense and AC1, AC2, AC3 and AC4 in complementary sense, respectively. BS DNA-A had a typical characteristic of Begomovirus genome organization. BLAST results showed that BS DNA-A had higher homology with the reported Begomovirus in Asia than those in America and Africa. Furtherly, pairwise comparisons indicated that BS DNA-A was most closely related to Tomato leaf curl Taiwan virus (ToLCTWV) (97.7% sequence identity), and their nucleotide sequence identities of AV1,AV2,AC1,AC2,AC3,AC4 and intergenic region (IR) between BS and ToLCTWV were 98.6%,98.0%,98.0%,97.5%,96.3%,98.6% and 96.6% ,respectively; while that of six ORFs encoded proteins were 97.7%,99.1%,97.5%,95.6%,91.8% and 99.0% ,respectively. Phylogenetic analysis based on the DNA-A sequences showed that BS was most related to ToLCTWV, and formed an independent branch, further formed a bigger branch with Tomato leaf curl Guangdong virus G2 (ToLCGDV-G2]) and Tomato leaf curl Guangdong virus G3 (ToLCGDV-G3]), and less related to the other 33 species of Begomovirus. All these results demonstrate that BS is an isolation of ToLCTWV.