侵染广东番茄的番茄褪绿病毒分子鉴定

摘要

A new disease on tomato recently occurs in Guangdong Province.The symptoms of the diseased tomato plants include leaf chlorotic,vein dark-greening and leaf thickening.The expected DNA fragments were amplified from all 6 diseased samples with two specific primer pairs for HSP70 gene of Tomato chlorosis virus (ToCV) by RT-PCR.And a full length of HSP70 (1 665 bp) was obtained by sequencing,which shared high nucleotides identity with those from other ToCV isolates.The result indicated that the collected tomato samples have been infected by ToCV in Guangdong.But there exists great difference in nucleotide sequence of HSP70 between the isolate from Guangdong (GD01) and other ToCV isolates from all over the world.The nucleotide sequence of HSP70 from isolate GD01 shared the highest identity (81.8％) with isolate tomato from Cyprus and JU_20 from Jordan.This paper was the first report on the occurrence of ToCV in Guangdong,and also the first report of significant difference in nucleotide sequence of HSP70 between ToCV GD01 and other isolates.%在广东番茄上发现一种新病害,病株表现为叶片褪绿,叶脉颜色变深及叶片增厚等症状.利用番茄褪绿病毒Tomato chlorosis virus (ToCV) HSP70基因的两对特异引物对番茄病样进行RT-PCR检测,结果表明,从所采集的6份病样中均扩增到预期大小的DNA特异片段.对其中1份样品的扩增片段进行克隆与序列分析,结果表明,扩增片段包括1个长度为1 665个核苷酸的完整病毒基因,其核苷酸序列与已报道的ToCV HSP70基因有较高的同源性,表明广东番茄受到了ToCV的侵染.但ToCV广东番茄分离物的HSP70序列与国内外已报道的各分离物的同源性均低于82％,存在较大差异,其中与塞浦路斯tomato、约旦JU_20分离物的同源性最高,为81.8％.这是ToCV在广东发生的首次报道,也是该病毒HSP70基因序列存在显著差异分离物的首次发现.