Trichoderma Biodiversity In Agroecosystem And The Control Effect To The Gray Mold

Trichoderma spp. has an extremely important position in agricultural production, which can protect crops from diseases, promote plant growth and repair the soil. In this article, we firstly collected the soil samples from different areas of the four southern provinces of farmland ecosystems in China, which makes clear that the regional distribution, abundance and diversity characteristics of Trichoderma species, and can conduct the work of separating and separation. Then we used T-RFLP to clarify the relationship between abundance of Trichoderma and soil microbial community diversity, which makes a basis for isolating Trichoderma resources rapidly and effectively. We screened the Trichoderma strains with multifunction, which makes a contribution to the development of Trichoderma agent and prevention of the crops diseases. Real-time PCR was used to detect the pathogen spores content in field. It makes an effective judgment for the rapid diagnosis of grape gray mold and early warning. Finally we carried out the field control effect test, which makes clear that the Trichoderma agent can be used as the fine alternative agent of chemical pesticide, and is conducive to improve the quality and yield, plays an important role on the sustainable development of agriculture. The results of the study were as follows:As a result,277 Trichoderma strains were isolated from 156 soil samples, utilizing comprehensive approaches of phylogenetic analysis by detecting molecular markers (ITS-rRNA and Tef1-a) and morphological microscopic observation,16 taxa were eventually classified into species as follows:T. asperellum, T. atroviride, T. aureoviride, T. brevicompactum, T. crassum, T. erinaceum, T. hamatum, T. harzianum, T. koningiopsis, T. longibrachiatum, T. oblongisporum, T. reesei, T. spirale, T. stromaticum, T. virens, T. viridescens. Among those species, T. oblongisporum and T. spirale were identified as the new record species in China. In terms of geographic distribution of Trichoderma species, T. harzianum and T. asperellum were the dominant species of farmland ecosystem in south China, and accounted for 43.32%,22.38% of the total number of strains respectively.Furthermore, we used T-RFLP to analyze the diversity of microbial community of the soil. The results showed that different areas in the soil microbial community structure had great differences. The microbial community abundance of Anhui areas are higher than the other areas, and the soil microbial abundance of Guangxi is the worsT. The diversity of microbial community has the overall downward trend from north to south in this study. Finally we find that the number of separable Trichoderma species in the region had a closed relationship with the richness of microorganism, which showed a weak positive correlation.In this study, by confronting incubation, growth promotion test, chitinase activity detection, we were trying to get some multifunctional Trichoderma strains. Research found that the control effect to the Botrytis cinerea, Fusarium graminearum, Fusarium oxysporum greater than 80% included 26,3,3 Trichoderma strains. The strain ASD50062 (T. asperellum) of the control effect to grey mould with the highest inhibition rate was 89.93%, and the strain AYC50376 (T. asperellum) of the control effect to wheat gibberellic disease had the highest inhibition rate at 84.07%, the strain AXM50042 (T asperellum) of the control effect to cucumber fusarium with the highest inhibition rate was 89.05%. Chitinase activity detection found that most Trichoderma chitinase enzyme activity was positively related with anfungal capability, namely the Trichoderma strains of antagonism ability stronger, the higher the activity of chitinase.By Real-time PCR detection, we could detect the lowest detection limit of the DNA of Botrytis cinerea is 12.67 fg. Using this method to figure out the DNA of Botrytis cinerea from the o.5g leaf of grape, we can effectively make an accurate judgment of the disease severity of grape gray mould in the field. For the excellent biocontrol Trichoderma strains screened, the field experimental study of control effect which was carried out in Shanghai under different mulch cultivation studies the effect of treatment and prevention of biological pesticide (T. harzianum T4 and chitosan) and chemical pesticide (Pyrimethanil) to the grape grey mould. The experiment results showed that the dual mulch cultivation accelerate the maturity of grape, it led to the onset of the grape grey mould in advance, sicker. And it made the onset period earlier than single mulch cultivation and rain shelter cultivation 7 d-10 d. The field disease control efficacy results showed that Trichoderma water dispersible granules and chitosan agent can effectively prevent the occurrence of the grape grey mold under different grape cultivation patterns on Shanghai area, provides effective techniques and reasonable methods for the safety production of organic grapes.