侵染广西西番莲的双生病毒基因组克隆与序列分析

 2018—2020年,从南宁市武鸣区、宾阳县的西番莲果园中采集疑似感染双生病毒的西番莲叶片样品,利用PCR、RCA、基因克隆、序列比对和进化树分析等方法,明确了其感染的病毒及系统进化关系。结果显示:采集的23份西番莲样本中有19份扩增出一条570 bp的目的条带,证实受到双生病毒侵染;从部分阳性样品中共获得11条病毒全长基因组序列,其中10条序列与已报道的广东番木瓜曲叶病毒(papaya leaf curl Guangdong virus,PaLCuGdV)各分离物的核苷酸相似性达92%以上;1条序列与已报道的一品红曲叶病毒(euphorbia leaf curl virus,EuLCV)各分离物的相似性达92%以上;依据双生病毒分类标准,确定侵染广西西番莲的双生病毒为PaLCuGdV和EuLCV的分离物;进化树分析发现,PaLCuGdV广西西番莲分离物与PaLCuGdV韩国各西番莲分离物和中国台湾西番莲分离物处于同一大分支,说明PaLCuGdV广西西番莲各分离物与PaLCuGdV韩国各西番莲分离物和中国台湾西番莲分离物具有较近的亲缘关系;EuLCV广西西番莲分离物与EuLCV韩国分离物、中国山东一品红分离物和福建一品红分离物等处于一个大分支,但广西分离物却又独处一个小的分支,说明广西分离物虽然与上述几个分离物亲缘较近,但可能存在较为独立的进化。这是PaLCuGdV和EuLCV侵染广西西番莲的首次报道。

Detection and sequence analysis of begomoviruses from Passiflora caerulea L. in Guangxi,China

During 2018—2020, samples of Passiflora caerulea L. exhibiting leaf rolling and crinkling were collected from Wuming district and Binyang county, Guangxi province. Virus detection was done using PCR, RCA, gene cloning, sequence comparison and phylogenetic trees construction. PCR amplicons with expected size of 570 bp were obtained from 19 out of 23 samples, which confirmed that these samples were infected with begomoviruses. A total of 11 full-length viral genome sequences were obtained from several positive samples, and 10 of the 11 sequences had 92% nucleotide identities with other isolates of papaya leaf curl Guangdong virus (PaLCuGdV) available in GenBank. One sequence had 92% nucleotide identity with other isolates of euphorbia leaf curl virus (EuLCV) available in GenBank. Following guidelines for the classification of begomoviruses, the begomoviruses infecting Passiflora caerulea L. in Guangxi were identified as PaLCuGdV and EuLCV. Phylogenetic tree analysis showed that the PaLCuGdV Guangxi isolates were formed a big branch with the PaLCuGdV isolates from Korea and China (Taiwan), indicating their close evolutionary relationship. The EuLCV Guangxi isolate clustered with the EuLCV isolates from Korea and China (Shandong and Fujian) in a big branch, while the Guangxi isolate was in a small branch, indicating that although evolutionary linked with aforementioned isolates, EuLCV Guangxi isolate might have independently evolved. This is the first report of the PaLCuGdV and EuLCV infecting Passiflora caerulea L. in Guangxi.