辣木果荚腐病病原菌分离及鉴定

摘要

【目的】明确辣木果荚腐病病原菌种类及其分类地位，为辣木果荚腐病防治提供理论依据。【方法】对云南省西双版纳州辣木种植基地感病、带黑色颗粒物病残体的辣木果荚进行症状观察、病原菌分离培养、致病性测定、显微形态特征观察、ITS和β-tubulin基因序列分析。【结果】辣木果荚腐病病原菌的分生孢子不分隔、透明，孢子顶端呈尖锥形弯曲，基部平截，具油滴，大小为15.7~22.1μm×2.5~4.3μm；厚垣孢子壁厚，呈黑褐色，簇生或成链状。该菌株ITS和β-tubulin基因的序列与Colletotrichum chlorophyti菌株IMI103806的同源性高达99%（ITS登录号：GU227894；TUB2登录号：GU228188）。多基因联合系统发育分析结果表明，供试菌株与兰生炭疽菌（C. chlorophyti）具有很近的遗传关系。【结论】兰生炭疽菌（C. chlorophyti）能侵染辣木引起果荚腐病，是为害辣木果荚的致病菌。%[Objective]In order to provide theory basis for controlling pod rot of Moringa oleifera, the pathogen was i-dentified, and its taxonomic status was studied. [Method]The infected M. oleifera pods with black particles were collected from M. oleifera planting base in Xishuangbanna, Yunnan province. Based on disease symptom observation, morphological characteristics of pathogen, pathogenicity, rDNA-ITS and β-tubulin gene sequence analysis, the pathogen causing pod rot of M. oleifera was identified. [Result]The conidia of pathogen were aseptate, hyaline, smooth, curved with tapered ends and a truncated base, and ranged from 15.7-22.1 μm×2.5-4.3 μm in size. Chlamydospores were dark brown, thick-walled, and fascicled or catenulate. The gene sequences of ITS and TUB2 gene showed 99% homology with Colletotrichum chlorophyti strain IMI103806 (ITS accession number: GU227894; TUB2 accession number: GU228188). Multi-gene phylogenetic analysis showed that the tested strain had the closest genetic relationship with C. chlorophyti. [Conclusion]C. chlorophyti can cause pod rot of M. oleifera, which is pathogen damaging pod of M. oleifera.