Biodiversity And Agricultural Functional Assessment Of Trichoderma From Agricultural Ecosystem In Zhejiang, Anhui, Jiangsu, Shandong And Shanxi Province

Trichoderma is a genus of common filamentous fungi that display a remarkable economic value in industry and agriculture. And it is widely distributed in various environments, such as soils and plant residues. Trichoderma strains were first isolated from soils and plant tissues, which collected from agricultural system. Then the researches of species identification, biodiversity analyses and function assessment were carried out.The main results were as follows:1) Soil samples (920) and plant tissues (297) were collected from Zhejiang, Anhui, Jiangsu, Shandong and Shanxi province in three seasons. The number of Trichoderma strains which isolated from soils and plant tissues were 2438 and 16, respectively, by using soil dilution plating method.With the combination of morphological analysis and molecule method, we identified 17 species as followed:T. asperellum (427 isolates), T. atroviride (94 isolates), T. brevicompactum (80 isolates), T. capillare (2 isolates), T. erinaceum (16 isolates), T. fertile (26 isolates), T. hamatum (397 isolates), T. harzianum (729 isolates), T. saturnisporum (2 isolates), T. koningiopsis (260 isolates), T. longibrachiatum (22 isolates), T, oblongisporum (2 isolates), T. pleuroticola (16 isolates), T. polysporum (2 isolates), T. spirale (2 isolates), T. velutinum (8 isolates) and T. virens (361 isolates). And there still are 8 isolates failing to identify at species level. The dominance value was 0.023 (>0.02) indicating that the genus Trichoderma was dominant in the soil samples. T. hamatum, T. virens, T. harzianum and T. asperellum were the dominant species with dominance (Y) values of 0.101,0.036, 0.033 and 0.031, respectively.51 haplotypes from 17 species were subjected to parsimony and Bayesian analysis, and the phylogenetic structure was consistent with previously established sections and clades in most cases.2) Distribution and dominance conditions of Trichoderma were investigated in agricultural system. Jiangsu province comprised 12 species and T. asperellum, T. hamatum, T. harzianum and T. virens were dominant. T. virens, T. hamatum, T. harzianum and T. koningiopsis were the dominant species in 10 species that were found in Anhui. A total of 14 species were identified from Zhejiang, with T. asperellum, T. hamatum, T. koningiopsis and T. virens as the dominant species. In this study,13 and 9 species were found in Shandong and Shanxi, respectively. T. asperellum and T. harzianum were dominant species in both provinces. Groups of Trichoderma species from different crop soils showed significant differences. The biodiversity value of south area was higher than the north. Of interest is that T. asperellum and T. harzianum have few obvious changes between seasons. The rare species, such as T. capillare and T. saturnisporum, were only found in summer. These results suggest that Trichoderma biodiversity in agricultural fields varies depending on the season, region and crop.3) Antagonistic activity was carried out by dual culture assays against three phytopathogenic fungi(Fusarium oxysporum, Botrytis cinerea and Rhizoctonia solani). The results indicate that different species have varied antagonistic activity against phytopathogenic fungi and different isolates in the same species shown different antagonistic activity to three phytopathogenic fungi. Antagonistic strains were initially screened from 1425 isolates that collected in 2014 and 2015. The enzyme activity of 60 isolates that collected and screened in 2014, which including β-1,3-glucanase, chitinases and proteases, were measured. The phenomenon that screened antagonistic strains almost belong to the dominant species indicated that the potential value of Trichoderma dominant species in biocontrol.