广东不同地区柑橘黄龙病菌的遗传多样性分析

Genetic diversity of Candidatus Liberibacter isolates from different geographical regions of Guangdong Province

不同基因型的黄龙病菌可能具有不同的致病模式,为了探明广东省不同基因型黄龙病菌的分布特点,为该病害的流行学研究提供重要依据,本研究利用PCR-RFLP的方法研究了广东省柑橘产区7个市县黄龙病菌外膜蛋白(outer membrane protein,OMP)基因的遗传多样性,并对各地黄龙病菌的omp基因进行克隆测序,构建了系统发育树。采用4种限制性内切酶消化各地区的柑橘黄龙病菌omp基因分别产生了不同的RFLP指纹图谱,每种限制性内切酶均产生了2种类型的酶切谱带;系统进化分析结果显示:广东地区的柑橘黄龙病菌属于韧皮部杆菌亚洲种,且亲缘关系非常近。广东地区黄龙病菌在omp基因水平上未见显著差异,未发现其他优势种类。

Huanglongbing （HLB） is a destructive disease on citrus, and pathogens with different genotypes may possess different pathogenicity. Ascertain the distribution of Candidatus Liberibacter asiaticus with different gen- otypes in Guangdong Province could provide an important basis for the studies of disease epidemics. In this study, PCR-RFLP analysis based on the outer membrane protein gene （omp） was conducted with disease samples from different regions. These omp sequences were further sequenced and phylogenetic tree was constructed. The ampli- fied omp genes of Ca. Liberibacter asiaticus were digested with four different restrictive endonucleases and several different gene polymorphisms were produced. Each restrictive endonuclease generated two types of DNA bands, and the pathogen isolates from Guangdong Province all belonged to Ca. Liberibacter asiaticus. There existed no obvious distribution feature among HLB pathogens with different genotypes, suggesting that there were no domi- nant species of HLB pathogen in Guangdong Province.