辣木果荚腐病病原菌分离及鉴定

【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。

Isolation and identification of pathogens causing pod rot of Moringa oleifera

[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.