南疆温室番茄黄化曲叶病病毒种类的分子鉴定

Molecular identification of begomovirus species of tomato yellow leaf curl disease from greenhouse in southern Xinjiang

为明确南疆温室番茄黄化曲叶病的病毒种类,利用双生病毒的兼并引物通过PCR扩增,对采集的20个番茄病株进行了分子检测。从20个病株中均扩增到约500 bp的目标片段,对其中4株进行克隆和测序,其相互间序列同源性为97.1%～99.3%,与番茄黄化曲叶病毒(Tomato yellowleaf curl virus,TYLCV)的同源性较高,为98.6%～99.5%。随机选取莎车分离物KS2-5进行全基因组的克隆和测序,KS2-5 DNA全长为2781 nt(序列号:JQ807735),具有典型的双生病毒基因组特征,与TYLCV其它分离物同源性达到98.9%～99.5%,而与其它粉虱传双生病毒的序列同源性较低,为68.3%～75.5%,表明危害南疆温室番茄的病毒种类为番茄黄化曲叶病毒TYLCV。

In order to ascertain the virus species of tomato yellow leaf curl disease occurring in greenhouse in southern Xinjiang, 20 greenhouse-grown tomato plants with yellow leaf curl symptoms were subjected to PCR-based diagnosis of begomovirus infection. Using universal primers of begomoviruses, fragments of about 500 bp were amplified from all samples and 4 fragments were chosen to clone and sequence. The sequences of the 4 fragments shared 97.1%-99.3% nucleotide sequence identities each other and had high nucleotide sequence identities （98.6%-99.5%） with DNA of Tomato yellow leaf curl virus （TYLCV）. Isolate KS2-5 from Shache was chosen to determine complete sequence of DNA. The results showed that it was comprised of 2 781 nucleotides and had typical genomic organization of begomoviruses（JQ807735）. DNA of KS2-5 had 98.9%-99.5% sequence identities with those of TYLCV isolates, while less than 75.5% identities with other whitefly-transmitted begomoviruses. It was concluded that tomato plants with viral symptoms were caused by TYLCV in southern Xinjiang.