Investigation On Anthracnose Of Landscape Plants And Prediction Of Effectors And Mechanisms Of Colletotrichum Fructicola,the Pathogenic Fungus

The fungal pathogen Colletotrichum spp.is a hemibiotrophic organism that can cause anthracnose disease in a variety of plant hosts,posing a significant challenge to urban landscaping.This study conducted a survey of anthracnose disease in 20 common ornamental plants in Fengxian district,Shanghai.Based on this survey,further research was conducted on the pathogenic fungus Colletotrichum fructicola,which causes anthracnose disease,with predictions made regarding its effectors and analysis of its mechanisms of action.The main results of this study are as follows:1.A survey was conducted on the incidence of anthracnose disease in 20 common garden plants in Fengxian district,Shanghai during the spring season.The results showed that all these plants were affected by anthracnose disease.The incidence of infected plants ranged from 10% to 40%,while the incidence of infected leaves ranged from 10% to 30%.Cinnamomum camphorar had the highest incidence of infected leaves and plants,with rates of 34.4% and 48%,respectively.The incidence of infected plants for hydrangeas was the lowest,at 12%,while that of Ophiopogon japonicus was the lowest,at 6.6%.The disease index analysis showed that Cinnamomum camphorar had the highest disease index of 13.2,while Ophiopogon japonicus had the lowest disease index of 2.2.2.Based on the investigation and analysis of anthracnose in 20 landscape plants,further analysis was conducted on the pathogenic fungus Colletotrichum fructicola,which causes anthracnose.Using bioinformatics methods and the general characteristics of effectors,355 candidate effectors of C.fructicola were predicted based on its whole genome sequence.The length of candidate effector protein sequences,cysteine content,and GO annotation were analyzed.3.Transcriptome sequencing data of Colletotrichum fructicola at 24,72 and 96 hours postinfection were subjected to quality control,sequence alignment,low-expressed gene removal,and standardization to obtain gene expression matrices.Using log Fold Change=2 and padj=0.05 as thresholds,2084,2162,and 2538 differentially expressed genes were obtained at 24 hpi,72hpi,and 96 hpi,respectively.GO enrichment analysis of differentially expressed genes showed that all three time points were related to transmembrane transport,transport activity,and cytoplasmic membrane,while genes related to vacuole lysis and oxidoreductase activity appeared at 96 hpi.4.Based on the predicted candidate effector proteins,4 genes with upregulated expression at96 hpi were selected.Primers were designed to amplify the full-length sequence of the effectors,and an expression vector was constructed.Through agroinfiltration-mediated transient expression system in tobacco,these four candidate effector genes were transiently expressed in tobacco,and the results showed that all of them could promote cell apoptosis induced by INF1.This study provides a theoretical basis and molecular targets for the subsequent investigation of the pathogenic mechanism of anthracnose fungus.By further identifying four candidate effector proteins that promote INF1-induced cell apoptosis through transient expression functional analysis,this study provides new genetic resources and theoretical evidence for the study of the action mechanism of anthracnose fungus effector proteins,and supports the breeding of disease-resistant garden plants to some extent.