Construction And Biocontrol Evaluation Of Trichoderma Atroviride With Overexpression Of Glucosyltransferase Taugt17b1

Trichoderma spp.is a biocontrol fungus with broad application prospects and great biocontrol potential,which is widely distributed in soil,ocean,plant and various substrates.Earlier studies showed that the Taugt17b1 protein secreted by Trichoderma atroviride which belongs to the glycosyltransferase family 17.In eukaryotes,most of the glycosyltransferase are found in Golgi apparatus,the taugt17b1 gene encodes an exocrine glycosyltransferase in T.atroviride,which is the only exocrine glycosyltransferase in T.atroviride and has the function of enhancing the colonization ability of Trichoderma spp.in the host root.In our laboratory,an excellent T.atroviride.strain H18-1-1 which was separated and identified.In order to obtain this strain with better biocontrol effect,we gained the taugt17b1 gene overexpression strain by using gene over-expressing technology in this study.And we compared the differences of phenotypes and biocontrol effect between over-expression strain and wild strains.The main results were summarized as follows:(1)Firstly,bioinformatics method was used to get the Taugt17b1 gene in genome of T.atroviride and then the over-expression vector was constructed.Using PEG mediated the protoplast transformation methods,the overexpression vector was successfully transferred into T.atroviride strain H18-1-1 and we gained the taugt17b1 gene overexpression strain.(2)The determination of genetic stability showed that taugt17b1 gene could still be over-expressed after 10 generations in taugt17b1 gene over-expression strain.(3)The relative colonization capacity of taugt17b1 gene over-expression strain and wild strain H18-1-1 in the root of wheat seedling in sand culture was determined by q RT-PCR method.The results showed that the over-expression of taugt17b1 gene could improve the colonization capacity of T.atroviride in the root of wheat.(4)Compared with the wild-type strain H18-1-1,colony diameter of over-expression strain was increased.There was no significant difference in spore production than that of the wild-type strain.(5)The over-expression of taugt17b1 gene can slightly increase the inhibition of T.atroviride H18-1-1 on Fusarium pseudograminearum,F.graminearum,Rhizoctonia cerealis and F.verticillatum.(6)The results of pot method in greenhouse showed that the control effect of over-expression strain on wheat sharp eyespot was higher than that of wild-type strain.In addition,the determination of defense enzymes in wheat leaves indicated that both the over-expression strain and the wild type strain could increase the activities of SOD,POD and CAT in wheat leaves,and the increased enzyme activity of wheat with over-expression strain was higher than that of wild type.(7)Determination of the growth promoting effect in greenhouse showed that the fresh weight of aerial and underground in wheat with over-expression strain,it had a significant effect on promoting the growth of wheat compared with that of wild type.And the root activity of wheat with over-expression strain was higher than that of wild type.Compared with the control treatment,there are significant differences in the above comparison indicators.These results indicate that the overexpression of taugt17b1 gene can significantly improve the colony growth rate,disease prevention and growth promotion effect,the activity of defense enzyme system and root colonization ability,and then enhance the biocontrol effect of T.atroviride H18-1-1.