Species diversity and biocontrol activity of Trichoderma in Dongting Lake wetland

Abstract:

[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.

Key words:Trichoderma, Dongting Lake wetland, Species identification, Phylogeny, Biocontrol activity