Physiological And Molecular Mechanism Of Trichoderma To Control Tomato Late Blight

Tomato（Solarium lycopersicum）is a worldwide economic crop planted in a large area in Hebei,Henan,Shandong and other places in China.Tomato late blight is a disease that is devastating to tomato production worldwide.The pathogen is Phytophthora infestans,which can cause a 30%or even 80%reduction in tomato production,leading to serious Economic losses.Trichoderma spp.,As a broad-spectrum biocontrol fungus,has been widely used in the control of various plant diseases.This study first verified the role of Trichoderma in promoting growth and inducing plant disease resistance.Then,through transcriptome and metabolome analysis,the key genes related to lignin synthesis and related differential metabolism in Trichoderma improved tomato late blight resistance were screened.And its functional and regulatory mechanisms were verified and analyzed,finally revealing the molecular mechanism of Trichoderma improving the resistance of tomato late blight.Through measurement and analysis of the treatment growth of 4 groups inoculated with Phytophthora infestans,inoculated with Trichoderma T147,inoculated with Trichoderma T147 and then inoculated with Phytophthora infestans,and blank control,Trichoderma T147 significantly promoted the growth of tomato plants effect.Compared with the control,the plant height and root length of tomato increased significantly after inoculation with T147.The results of DAB and NBT in vivo staining of tomato leaves showed that the staining effect of the treatment group inoculated only with Phytophthora infestans was significantly deeper than that of the other treatments.The staining effect of the direct planting Trichoderma T147 treatment group was similar to that of the blank control group.The leaf color of the leaves treated with Phytophthora infestans was lighter,indicating that the tomato leaves inoculated with Phytophthora infestans were infected and seriously damaged,and the Trichoderma T147 strain not only caused no stress to the plants but also effectively reduced Infection and damage caused by Phytophthora infestans on tomato leaves.The content of active oxygen,active nitrogen and resistant enzymes showed that,compared with the treatment of inoculation with late blight only,inoculation with Trichoderma T147 followed by inoculation with tomato late blight pathogens,the content of H₂O₂,O₂–,MDA,NO,SNOs in tomato leaves Significantly decreased,indicating that Trichoderma can reduce the activity of nitrosoglutathione reductase by activation,thereby reducing the oxidative stress and reactive nitrogen stress caused by the infection of tomato leaves by Phytophthora infestans;and the content of PAL,CAT,POD increased significantly,Indicating that Trichoderma can regulate tomato plants to produce a large amount of phenolic substances to resist the invasion of pathogenic bacteria.Based on the analysis of transcriptome sequencing results of 4 processed tomato leaf samples,a total of 764 new genes were discovered,and 457 genes were functionally annotated.Compared with the CK treatment group,the Trichoderma T147treatment group,the tomato late blight military treatment group,and the Trichoderma T147 first inoculation tomato late blight pathogen treatment group obtained 390,1,591,and 1943 differentially expressed genes,respectively,with 144 These are common differentially expressed genes.The 144 genes were functionally annotated and metabolic pathways analyzed in the GO and KEGG databases.Five differential genes related to lignin synthesis were preliminarily screened,and qRT-PCR verification analysis results of these 5 genes were consistent with transcriptome data Consistent,which proves that the transcriptome test data is accurate and reliable,and lays the foundation for revealing the gene regulation pathway of Trichoderma to improve the resistance of tomato late blight.Analysis of the metabolome data of 12 samples by high performance liquid chromatography,with the help of KEGG metabolic pathway analysis,a total of 30coexpression differential metabolisms related to phenylalanine metabolism,phenylpropane biosynthesis,and ABC transporter were detected The contents of salicylic acid,protocatechuic acid,sodium ferulate,betaine,leucine and phenylalanine metabolites are significantly different.It is speculated that it may be related to Trichoderma induced plant regulation of lignin metabolism to resist pathogenic bacteria Infection related.