The Preliminary Study On The Induced Plant Resistance Mechanism Of Trichoderma Hamatum Against Root-knot Nematode

Root-knot nematode?Meloidogyne spp.?is a worldwide pest that can cause tens of billions of losses annually.Trichoderma as a beneficial biocontrol fungus is often used to control various pests and diseases.The Trichoderma hamatum T21 strains were isolated from soil in our previous study and we preliminarily found that T21 strains could induce tomato to resist root-knot nematode.In this paper,bioinformatics methods were used to analyze the mechanism of resistance induced by Trichoderma harzianum in genomics.The relevant results are as follows:1.It was verified that Trichoderma hamatum can colonize tomato roots by using green fluorescent protein-labeled GFP-T21 strain.In the tomato split-root experiments,the number of root knots of tomato treated with Trichoderma harzianum T21 was reduced by 67.23% compared to the control,and confirmed that the T21 strain can induce the resistance of tomato to against root knot nematodes.2.We performed genome sequencing and assembly of Trichoderma hamatum T21 strain,and predicted the secondary metabolite gene clusters.The assembly results are: The genomic size of the T21 strain was 40.61 Mb,containing 251 scafford,the length of scafford N50 was 1996.67 bp,and the GC content was 46.8% in the genome.Gene prediction was carried out by using Augustus?v 2.7?,Genemark-ES?v 4.33?,and Braker?v 1.10?,combined with transcriptome data validation,finialy,a total of 11,274 genes were accurately predicted.During the prediction of secondary metabolite genes and secreted protein genes,a total of 52 secondary metabolite synthetic genes were obtained,including 15 PKS synthetase genes,1 PKS-like synthetic gene,13 NRPS synthetase genes,11 NRPS-like synthetase genes,1 HYBRID synthetase gene,4 Terpene synthetase genes,and 7 other key enzyme synthesis genes.The number of secreted protein genes was 1180,which was 9.83% of the total number of genes.In order to study the evolution of PKS synthase and NRPS synthetase of T21 strain,we constructed the phylogenetic tree of the KS domain and the A domain,and preliminary analyzed the phylogenetic relationship and product structure of T21 strain PKS synthase and NRPS synthase.We screened secondary genes or secreted protein genes related to resistance inducement by combining the transcriptome data of interaction between T21 and Arabidopsis thaliana.Based on gene expression and predicted gene domains,we preliminarily identified that the secondary metabolite T21₀2693 gene was the key gene for inducing plant resistance.In summary,our study demonstrated that Trichoderma hamatum T21 strain has an effect on inducing the resistance to root-knot nematode.In addition,we preliminary speculated that the genes associated with induced resistance was T21₀2693 through the analysis of the genome of Trichoderma hamatum,and these works also provided genetic support for the analysis of the mechanism of resistance to root-knot nematode induced by Trichoderma hamatum T21.