基于2个保守基因分析湘赣南部区域野生柑橘上衰退病毒分离株的种群特征  

Population characteristics analysis of citrus tristeza virus isolates from wild citrus in southern Hunan and Jiangxi based on two conserved genes

作　　者：王长宁 易龙[1] 周俊[1] 钟可 陈毅群 WANG Changning;YI Long;ZHOU Jun;ZHONG Ke;CHEN Yiqun(School of Life Science,Gannan Normal University,Ganzhou 341000,Jiangxi,China)

机构地区：[1]赣南师范大学生命科学学院,江西赣州341000

出　　处：《果树学报》2021年第6期957-966,共10页Journal of Fruit Science

基　　金：国家自然科学基金(31860488);赣州市科技创新人才计划([2018]50)。

摘　　要：【目的】比较分析湘赣南部地区野生柑橘上的CTV种群特征,为解析CTV种群的遗传进化提供重要依据。【方法】应用RT-PCR对江西崇义、湖南道县、湖南莽山和湖南江永4个不同地理区域的野生柑橘CTV分离株的CP基因和p23基因进行扩增、测序,所获得序列与从GenBank下载的国内外具有代表性的分离株相应基因序列进行碱基组成、分子变异(AMOVA)分析、系统发育和中介网状关系结构分析。【结果】碱基组成分析显示,4个地区的CTV分离株上2个基因的A+T碱基含量均高于G+C含量;CP基因和p23基因AMOVA分析结果显示,种群内分子变异分别占85.8%和82.38%,种群间分别占14.20%和17.62%,基因流Nm分别为6.749和1.475;碱基错配分析显示,2个基因均呈多峰分布曲线,表明4个地区CTV种群变化保持稳定;重组分析显示,2个基因均未检测出重组事件的发生,基于2个基因构建的系统发育树显示,相同地理来源的CTV种群大部分聚集在同一簇中,少部分分散在不同簇,表明研究分析的CTV种群间亲缘关系与其地理来源存在相关性,中介网状关系结构图得出类似分析结果。【结论】4个地区的野生柑橘上CTV种群间遗传变异主要来自种群内,各地区间基因交流频繁,遗传差异小,CTV种群保持稳定,CP基因和p23基因构建的系统发育分析和中介网状关系结构图表明,湘赣南部地区的野生柑橘上CTV种群间亲缘关系与其地理来源存在相关性。【Objective】The experiment aimed to clarify the population characteristics of Citrus tristeza virus(CTV)in wild citrus,and to provide an important basis for analyzing the genetic evolution of CTV population.【Methods】With 10 positive CTV samples from four different geographic regions of Chongyi(Jiangxi),Daoxian(Hunan),Mangshan(Hunan)and Jiangyong(Hunan),the CP gene and p23 gene amplification were carried out.The samples were named Chongyi 1-10(C-1 to C-10),Daoxian 1-10(D-1 to D-10),Mangshan 1-10(M-1 to M-10),and Jiangyong 1-10(Y-1 to Y-10).The samples were preserved at-40℃for later assay.After purification and recovery,the PCR products were sent to Shanghai Bioengineering Company for paired and sequencing.MEGA-X was used to calculate the conservative site,abbreviated information site,mutation site,descent locus and the ratio of the base transition rate Ts to the transversion rate Tv.The software Arlequin 3.1 was used for the analysis of molecular variance(AMOVA),and GenAIEx 6.5 was used for gene flow Nm calculation.DnaSP was used to perform three neutrality tests and mismatch analysis to infer population expansion and genetic evolution.RDP 5 was used to perform recombination event analysis.In order to clarify the genetic relationship among the CTV isolates of wild citrus from different regions of the same gene,this study combined the40 CP gene sequences and p23 gene sequences obtained by sequencing and the CP gene sequences and p23 genes of eight CTV isolates downloaded from GenBank and built phylogenetic trees.In the process,it used maximum likelihood(ML)and the Kimura 2-parameter model respectively,and each branch node confidence in the phylogenetic tree underwent repetitive verification for 1000 times based on bootstrap.The isolates data downloaded from GenBank included those of US isolates T36(U16034)and T30(AF260651),Spanish isolates T318 A(DQ151548)and T385(Y18420),Israeli isolates VT(U56902),Egyptian isolates Qaha(AY340974),the Mexican isolate Mexico-ctv(DQ272579)and the Japanese isolate NuagA(AB04

关 键 词：野生柑橘 柑橘衰退病毒 种群特征 分子系统地理学 

分 类 号：S666[农业科学—果树学] S436.661[农业科学—园艺学]