基于rDNA-ITS和组蛋白3基因序列分析鉴定新疆棉花叶斑病病原

Identifying the Pathogen of Cotton Leaf Spot Based on the Analysis of rDNA-ITS and Histone 3 Gene Sequence in Xinjiang

【目的】明确新疆棉花叶斑病的病原种类。【方法】2016年和2017年在南疆、北疆7个地区30个植棉单位采集典型叶斑病样206份,采用常规组织分离法分离并纯化,依据采样时间、采样地点和菌落特征,在南疆、北疆分苗期和生长后期各选取10个代表性菌株,根据其形态特征,结合r DNA内转录间隔区(Internal transcribed spacer,ITS)和组蛋白3基因序列分析,对病原进行鉴定。【结果】北疆苗期(5―6月)棉花叶斑病病原以Alternaria alternata为主,A.tenuissima次之;生长后期(8―9月)棉花叶斑病病原以A.tenuissima为主,A.alternata次之,也分离到A.macrospora。南疆棉花苗期叶斑病病原为A.tenuissima;生长后期棉花叶斑病病原为A.tenuissima和A.macrospora。其中从陆地棉上分离的以A.tenuissima为主,从海岛棉上分离的以A.macrospora为主。【结论】新疆棉花叶斑病病原主要有3种,即A.alternata、A.tenuissima和A.macrospora。

[Objective] The objective of this experiment is to identify pathogens causing cotton leaf spot in Xinjiang. [Method] Two hundred and six leaf samples displaying typical leaf spot symptoms were collected from 30 loci in 7 different regions of Xinjiang in 2016 and 2017. The fungal isolates were purified using conventional methods. Ten representative fungal strains were selected for further tests based on different sampling times, locations, and colony characteristics. The strains were identified based on their morphological characteristics and the sequence analysis of both rDNA internal transcribed spacer and histone 3 gene. [Result] In north ofXinjiang, Altemaria altemata and A. tenuissima were the dominant pathogens at the seedling stage （from May to June）, whereas in August and September, A. tenuissima was the main pathogen and few were A. altemata and A. macrospora. In south ofXinjiang, A. tenuissima was the main pathogen at the seedling stage, whereas in August and September, A. tenuissiraa and A. raacrospora dominated. Further, Gossypimn hirsuttwa and G. barbadense was mainly infected with A. tenuissiraa and A. macrospora, respectively. [Conclusion] The main pathogens causing cotton leaf spot in Xinjiang are A. aRer- nat＆ A. tenuissima and A. macrospora.