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为探明甘蔗花叶病的病原病毒之一高粱花叶病毒(sorghum mosaic virus,SrMV)在我国华南地区的发生情况,从广东广州、翁源、博罗及广西南宁等地甘蔗产区采集表现花叶症状的甘蔗叶片样品,采用1对病毒CP基因引物(P1:5′-ACAGCAGAWGCAACRGCACAAGC-3′、P2:5′-CTCWCCGACATTCCCATCCAAGCC-3′,Y=C/T,W=T/A,K=G/T,R=A/G),进行一步法RT-PCR检测,结果表明48%的样品受到SrMV侵染。根据寄主类型和地理来源,选取10份代表性样品,对经P1、P2扩增获得的病毒CP基因片段进行直接测序,所得序列经Blast比对确认均为SrMVCP序列。为揭示SrMV种内的遗传多样性,采用Clustal W方法对本文鉴定的10个SrMV分离物与GenBank中已报道的全部18个SrMV株系或分离物的CP基因序列进行多序列联配,并计算核苷酸同一性,结果显示各个SrMV分离物之间的CP基因核苷酸同一性为76%~100%。基于病毒CP基因核苷酸同一性的遗传多样性分析,SrMV种内分化成2个遗传变异类群,即杂种甘蔗组(HS group)和高贵甘蔗组(NS group),它们的分离物大多分别来自杂种甘蔗(hybrid sugarcane)寄主和高贵甘蔗(noble sugarcane)寄主。分离物之间的平均CP基因核苷酸同一性,在两组组内分别为87%和90%,两组间为80%。说明两组SrMV之间存在较大的遗传差异,寄主隔离是导致该病毒种内分化的主要因素。因此,在甘蔗花叶病的防治和抗病毒育种工作中,除需注意病原的种类和寄主类型外,还应充分考虑病原种内的遗传多样性。
To identify the occurrence of sorghum mosaic virus (SrMV), one of the pathogenic viruses of sugarcane mosaic disease, in southern China, we collected data from sugarcane producing areas in Guangzhou, Wengyuan, Boluo and Guangxi Nanning Mosaic leaf symptom sugarcane leaf samples were analyzed using a pair of viral CP gene primers (P1: 5’-ACAGCAGAWGCAACRGCACAAGC-3 ’, P2: 5’-CTCWCCGACATTCCCATCCAAGCC-3’, Y = C / T, W = T / A, G / T, R = A / G), one-step RT-PCR assay showed that 48% of the samples were infected with SrMV. According to the host type and geographical origin, 10 representative samples were selected to directly sequence the CP gene fragments amplified by P1 and P2. All the sequences were identified as SrMVCP sequences by Blast comparison. To reveal the genetic diversity within the SrMV species, the Clustal W method was used to sequence the CP genes of the 10 SrMV isolates identified in this study and all 18 SrMV strains or isolates previously reported in GenBank and to calculate Nucleotide identities showed that nucleotide identity of CP gene was 76% -100% among the individual SrMV isolates. Based on the analysis of the genetic diversity of the nucleotide identities of the CP genes of the virus, SrMV differentiated into two genetic variation groups, namely, the HS group and the NS group. Most of their isolates were derived from Host of hybrid sugarcane and noble sugarcane. The average nucleotide CP identity between isolates was 87% and 90% in both groups, with 80% between the two groups. This indicated that there was a large genetic difference between the two groups of SrMVs. Host isolation was the main factor that led to the intraspecific differentiation of the virus. Therefore, in the prevention and control of sugarcane mosaic disease and antiviral breeding work, in addition to pay attention to the species and host type of pathogen, but also give full consideration to the genetic diversity within the pathogen species.