甘薯褪绿斑病毒山东分离物全基因组扩增及遗传进化分析

Complete genome sequence and phylogenetic analysis of sweet potato chlorotic fleck virus isolated from Shandong Province

为了解甘薯褪绿斑病毒(sweet potato chlorotic fleck virus,SPCFV)在山东省的发生及遗传进化情况,分别于2019年和2020年采集了131份甘薯样品,针对SPCFV进行病毒检测、全基因序列扩增、序列分析及遗传进化树构建。结果显示:SPCFV两年的检出率分别为7.1%和5.6%,所有SPCFV感染样品中皆为SPCFV与其他病毒的复合侵染。通过RACE和RT-PCR获得CFV-SD1和CFV-SD2两个全基因组序列,全长均为9105 bp;与已报道分离物核苷酸序列一致性为72.9%~89.5%。全基因组遗传进化分析显示所有SPCFV分离物聚为两簇。且从不同样品中获得6个SPCFV山东分离物的外壳蛋白(coat protein,CP)序列,基于CP氨基酸序列开展遗传进化分析表明,山东分离物均归于亚洲类群的第一簇(Asian isolates 1)。氨基酸偏好性分析显示,CP氨基酸序列N端前35位同样存在多变区。本研究表明了山东省已成为SPCFV的常发区域,且病毒群体存在多样性,研究结果为指导SPCFV的有效防控提供了理论依据。

To understand the occurrence and genetic evolution of sweet potato chorotic fleck virus(SPCFV)in Shandong province,China,131 sweet potato samples were collected for the detection of SPCFV in 2019 and 2020,and two complete sets of genome sequences were amplified and analyzed.The SPCFV detection rate in 2019 and 2020 was 7.1%and 5.6%,respectively.All positive samples were co-infected with SPCFV and other sweet potato viruses.The two complete sets of genome sequences(CFV-SD1,CFV-SD2)were obtained by RACE and RT-PCR,with a total length of 9105 bp and a nucleotide similarity with the reported isolates was 72.9%to 89.5%.Phylogenetic analysis of genome sequences revealed that all SPCFV isolates clustered into two groups based on the CP genes of six Shandong isolates and that all Shandong isolates belong to the Asian group(Asian isolates 1).Amino acid preference analysis showed that the first 35 amino acids in the N-terminal region of the SPCFV CP protein exhibited variation.This study indicated that Shandong province has become a frequent occurrence area of SPCFV and the virus population was diverse.The results provide a theoretical basis for the effective prevention and control of SPCFV.