广东番茄巨芽病植原体的分子鉴定

2022年, 对在广东省湛江市廉江市田间发现的疑似番茄巨芽病病株, 利用分子生物学方法对其相关植原体进行了鉴定。以番茄病株叶片总DNA为模板, 利用植原体16S rRNA基因通用引物R16mF2/R16mR1进行PCR扩增, 获得了广东番茄巨芽病植原体(TBB-GD-2022)16S rRNA基因片段(1 430 bp, GenBank登录号为ON102780)。16S rRNA基因序列相似性分析显示, TBB-GD-2022与16SrⅡ组植原体菌株的相似性较高, 为96.82%~100%, 其中与隶属于16SrⅡ-V亚组的6个植原体株系相似性为100%。系统进化分析显示, TBB-GD-2022与16SrⅡ组各植原体株系聚类在一个大分支, 并与16SrⅡ-V亚组成员聚类在一个小分支, 亲缘关系较近。16S rRNA 基因相似系数分析表明, TBB-GD-2022与16SrⅡ-V亚组的参照株系‘Praxelis clematidea’ phyllody phytoplasma (GenBank登录号:KY568717) 的相似系数为1.00。上述研究结果表明, 广东番茄巨芽病植原体隶属16SrⅡ-V亚组成员。本文首次报道在广东发现番茄巨芽病, 通过其16S rRNA序列分析进一步确定了其相关植原体的分类地位, 为该病害的防控提供了科学依据。

Molecular identification of phytoplasma associated with tomato big bud disease in Guangdong province

In 2022, the suspected tomato big bud diseased plants were found in Lianjiang city, Zhanjiang city, Guangdong province. The related phytoplasma was detected and identified using molecular technology. The 16S rRNA gene fragment (1 430 bp, GenBank accession no. ON102780) of phytoplasma associated with tomato big bud disease in Guangdong province (TBB-GD-2022) was amplified from total DNA of diseased tomato plants using universal primers R16mF2/R16mR1. Sequence similarity based on 16S rRNA gene sequence showed that TBB-GD-2022 had higher similarity (96.82%-100%) with phytoplasmas from 16SrⅡ group, while had highest similarity (100%) with six phytoplasmas belonged to 16SrⅡ-V subgroup. Phylogenetic analysis showed that TBB-GD-2022 formed a large evolutionary branch with 16SrⅡ group phytoplasmas, and a small evolutionary branch with 16SrⅡ-V subgroup phytoplasmas. iPhyClassifier analysis for 16S rRNA gene showed that the similarity coefficient between TBB-GD-2022 and ‘Praxelis clematidea’ phyllody phytoplasma (GenBank accession no. KY568717) of the reference strain from 16SrⅡ-V subgroup was 1.00. These results showed that phytoplasma associated with tomato big bud disease in Guangdong province belonged to the 16SrⅡ-V subgroup. In this paper, tomato big bud disease was discovered firstly in Guangdong, and the taxonomic status of its related phytoplasma was further determined. The results provide the scientific basis for controlling tomato big bud disease in Guangdong province.