洞庭湖湿地木霉多样性及生防活性

【目的】了解湖南省洞庭湖湿地木霉种类及分布,丰富我国的木霉种质资源,为功能菌株筛选应用奠定基础。【方法】利用ITS序列比对分析结合形态学特征对分离到的木霉菌株进行种类鉴定,构建系统发育进化树分析其亲缘关系。通过菌丝生长速率法测定菌株的平板抑菌能力,根据水解带大小检测菌株的水解酶活性,利用灰色关联度分析筛选综合生防效果较好的木霉菌株。【结果】从52个土样和18个水样中分离得到114株木霉菌株,经鉴定分属16个木霉种类:哈茨木霉、绿木霉、刺孢木霉、土星孢木霉、钩状木霉、拟康宁木霉、短密木霉、深绿木霉、猥木霉、毛细木霉(中国新记录种)、长枝木霉、卵孢木霉、侧耳木霉、加纳木霉、厚木霉及一个疑似新种;哈茨木霉为洞庭湖湿地中的优势种,占总菌株数量的19.30%;16种木霉在系统发育树中归于7个进化支:Harzianum Clade、Virens Clade、Longibrachiatum Clade、Lutea Clade、Viride Clade、Hamatum Clade、Unknown Clade。灰色关联度分析表明,菌株TW21990、QT22040和QT22094的灰色关联度较高,分别为0.849 5、0.798 6和0.732 6,综合生防性状较好。【结论】洞庭湖湿地木霉具有种类多样性和分布多样性,发现了一个中国新记录种毛细木霉和一个疑似新种,哈茨木霉TW21990、长枝木霉QT22040和卵孢木霉QT22094是潜在的优良生防菌株。

Species diversity and biocontrol activity of Trichoderma in Dongting Lake wetland

[Objective] Investigated the distribution and species of Trichoderma in Dongting Lake wetland, Hunan province, supplemented Trichoderma resources of China, and farther more use of functional strains screening and applied. [Methods] Species were identified by analysis of internal transcribed spacer regions of the rRNA gene cluster (ITS) and morphological characteristics, and analyzed the genetic relationship based on ITS sequences phylogenetic tree. The antifungal activity were determined by mycelial growth rate method, and hydrolase activity were determined by hydrolyzation radius, screening the superior comprehensive biocontrol Trichoderma strains by gray correlative degree analysis. [Results] Total 114 Trichoderma strains were isolated from 52 soil samples and 18 water samples, 15 known species were identified as followed: T. harzianum, T. virens, T. asperellum, T. saturnisporum, T. hamatum, T. koningiopsis, T. brevicompactum, T. atroviride, T. erinaceum, T. capillare, T. longibrachiatum, T. ovalisporum, T. pleuroticola, T. ghanense, T. crassum, among them T. capillare was Chinese new record, besides Trichoderma sp. CK-2016 was an uncertain new species. T. harzianum was the dominant species with 19.30% quantity among them. All these Trichoderma species belonged to 7 Clade as followed: Harzianum Clade, Virens Clade, Longibrachiatum Clade, Lutea Clade, Viride Clade, Hamatum Clade, Unknown Clade. Gray correlative degree analysis showed that the grey relation degree of three strains TW21990, QT22040 and QT22094 were 0.849 5, 0.798 6 and 0.732 6, respectively, and were better comprehensive biocontrol Trichoderma strains among primary twenty-one strains. [Conclusion] The Trichoderma species in Dongting Lake wetland, Hunan province have diversity with a new China record of T. capillare and an uncertain new species among them, T. harzianum strain TW21990, T. longibrachiatum strain QT22040 and T. ovalisporum strain QT22094 are potential biocontrol agents.