| Fusarium crown rot(FCR)has been a new type of soil-borne disease in recent years,which has severely affected the yield of wheat.As an important biocontrol fungus,Trichoderma has an important contribution in the field of biological control.Preliminary studies in the laboratory found that Trichoderma atroviride HB20111,T.harzianum QT21990 and LTR-2 had strong effects on Fusarium pseudograminearum,which caused FCR.At the same time,the pot experiment also showed that it has a certain control effect on the FCR.Therefore,this thesis takes the three Trichoderma strains mentioned above as the research object,and investigates the emergence rate of wheat seedlings,the fresh weight of the seedlings,the growth quality status of tillers,plant height,and the control effect and yield impact of FCR after the three Trichoderma seed dressing treatments.In addition,this article also constructed a standard plasmid for the conserved sequences of fungi,Fusarium spp.,and F.pseudograminearum,and established a corresponding rapid detection method based on this as a standard.Real-time fluorescent quantitative PCR(q PCR)was used to achieve rapid quantitative detection of fungi,Fusarium spp.and F.pseudograminearum in wheat soil;through high-throughput sequencing,the influence of Trichoderma on the diversity of wheat rhizosphere fungal communities was analyzed.From an ecological point of view,the relevant mechanism of Trichoderma to control FCR was explored.After the plot experiment,T.atroviride HB20111 with good control effect was selected for field experiment.Trichoderma seed dressing experiments were carried out in six regions of Shandong Province to study the effect of Trichoderma HB20111 dressing treatment on FCR under different field environments.The effect of disease control,and the influence of Trichoderma in the above-mentioned environment on wheat rhizosphere soil microbial communities were investigated,which provided theoretical and technical support for the further demonstration and application of T.atroviride HB20111.The results of the experiment are as follows:(1)Using p MD-18 T as the vector,the standard plasmids p MD18-T-Fungal,p MD18-T-Fus,and p MD18-T-FP were successfully constructed.The successfully constructed plasmid was used as a fluorescent quantitative PCR standard,and a rapid detection method for the pathogens of FCR was established based on the fluorescent quantitative PCR technology.(2)The results of the plot experiments showed that T.atroviride HB20111 and T.harzianum LTR-2 had a good growth-promoting effect on wheat.Regardless of the type of Trichoderma,the disease index of FCR was significantly reduced(p<0.05).The control effect of HB20111 Trichoderma seed dressing was 74.13%,and the yield was increased by 7.67%;the control effect of T.harzianum LTR-2 was 66.77%,and the yield was increased by 7.43%;the control effect of QT21990 seed dressing was 66.92%,and the yield was increased by 6.94 %.The experimental results of q PCR and high-throughput sequencing technology showed that the three species of Trichoderma have an impact on the fungal microbial community structure in wheat rhizosphere,and can reduce the content of pathogenic fungi of wheat crown rot.Among them,HB20111 had the greatest impact,which reduced the content of F.pseudograminearum by 60%.(3)Trichoderma HB20111 seed dressing treatment reduced the amount of fungi,Fusarium spp.and F.pseudograminearum in the rhizosphere soil,and effectively reduced the incidence of FCR,which was consistent with the trend of the plot test results.The relationship between soil physical and chemical properties,disease index and fungal abundance indicated that the higher the soil fertility,the stronger the plant's resistance to disease.The soil fertility can be appropriately improved to help reduce the incidence of wheat crown rot.Among the six regions,Wu Cheng and Ling Xian counties had higher disease index and more serious disease.The Trichoderma HB20111 seed dressing treatment effectively prevented FCR,with an average control effect of 63.72%. |
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