广西柑橘衰退病和黄脉病调查及其病原病毒的遗传多样性分析

为明确柑橘衰退病毒(citrus tristeza virus, CTV)和柑橘黄脉病毒(citrus yellow vein clearing virus, CYVCV)在广西柑橘上的发生?分布及其遗传变异情况, 于2020年至2021年对百色?北海?崇左?贵港?桂林?河池?贺州?来宾?柳州?南宁?梧州和玉林等12个柑橘产区进行了病毒病调查?采用RT-PCR对采集样品进行了病毒检测, 并基于病毒分离物外壳蛋白(coat protein, CP)基因的核苷酸序列进行比对分析, 构建系统发育树?结果表明:采集的737份柑橘样品中, CTV的检出率为20.62%, CYVCV检出率为18.32%, CTV的检出率略高于CYVCV?病毒复合侵染的现象在采集的柑橘样品中普遍存在, CTV和CYVCV复合侵染率高达34.50%?对RT-PCR产物测序共获得12个CTV分离物和6个CYVCV分离物的CP基因序列?遗传多样性分析发现, CTV和CYVCV的CP基因序列都较保守, CTV分离物的遗传进化与地理来源?寄主来源均没有明显相关性, 但CYVCV分离物的遗传进化与地理位置具有相关性, 而与寄主来源无明显相关性?上述研究结果可为深入了解CTV和CYVCV在广西的流行情况以及柑橘病毒病的检疫和防控提供参考?

Survey and genetic diversity analysis of citrus tristeza virus (CTV) and citrus yellow vein clearing virus (CYVCV) in Guangxi, China

In order to assess the occurrence, distribution and genetic variation of citrus tristeza virus (CTV) and citrus yellow vein clearing virus (CYVCV) on citrus in Guangxi, extensive virus disease surveys were conducted in 12 citrus growing areas including Baise, Beihai, Chongzuo, Guigang, Guilin, Hechi, Hezhou, Laibin, Liuzhou, Nanning, Wuzhou and Yulin from 2020 to 2021. The viruses were detected by RT-PCR, and phylogenetic trees were constructed based on nucleotide sequences of coat protein (CP) gene of virus isolates. The results showed that the detection rate of CTV and CYVCV in 737 citrus samples was 20.62% and 18.32%, respectively. The detection rate of CTV was slightly higher than that of CYVCV. Mixed-infection with CTV and CYVCV was common in the collected citrus samples and the mixed infection rate was as high as 34.50%. The CP gene sequences of 12 CTV isolates and six CYVCV isolates were obtained by sequencing RT-PCR products. Genetic diversity analysis showed that the CP gene sequences of CTV and CYVCV were relatively conserved, and the genetic evolution of CTV isolates had no significant correlation with geographical origin and host origin, while the genetic evolution of CYVCV isolates had correlation with geographical location but had no significant correlation with host origin. These results can provide reference for in-depth understanding of the prevalence of CTV and CYVCV in Guangxi as well as for the quarantine and prevention of citrus virus diseases.