| Wheat stripe rust,caused by Puccinia striiformis f.sp.tritici pst),is a devastating fungal disease in wheat worldwide.To prevent and control the disease,it is important to investigate the molecular pathogenicity mechanism of Pst during wheat-Pst interaction.During infection,Pst forms a specialized infection structure,the haustorium,to take nutrients which contain sugars and amino acids from their host,and establish an intimate feeding relationship.Furthermore,haustoria are also involved in suppression of host defense responses.Therefore,we screen for the differential expression genes(DEGs)of haustoria and get candidate key factors which could promote pst pathogenicity.This study will provide gene resources and technical supports for sustainable control of wheat stripe rust.In this study,we isolated the haustoria from pst infected wheat leaves and sequenced the transcriptomes of urediniospore,germ tube and haustoria.We isolated genes which are specifically expressed in haustoria by bioinformatics assays.Then qRT-PCR were used to identified their transcription patterns.Finally we used BSMV-HIGS to analyze the functions of some candidate genes.1.Bioinformatics analysis showed that 3530 haustoria up-regulated DEGs were obtained compared to the transcriptomes of urediniospore and germ tube.146 DEGs were identified with the false discovery rate control(FDR)<0.01,annotation genes,and could find the corresponding genes on GO enrichment data.Then we selected 73 DEGs for qRT-PCR analysis.Among these genes,20 genes were highly expressed in urediniospore,7 were induced in in germ tube,and 46 were were up-regulated during infection stages.Among tne 46 genes,expression of 18 genes were peaked 24 hours post inoculation,15 genes were peaked at 48h,6 genes at 72 h and 7 genes at 216 h.These findings showed that the 73 DEGs were involved in different stages of pst-wheat interaction.2.According to the annotation and expression pattern of these DEGs,we selected eight genes(Pst1599,Pst4385,Pst5760,Pst 6346,Pst12394,Pst15148,Pst16188 and Pst 19493)which are involved in cell growth,differentiation and the biosynthesis of carbohydrates,amino acid and thiamine to further identified their pathogenicity functions.They were all induced in infection stages.We used BSMV-HIGS to access their virulence function in pst-wheat interaction.After inoculated virulent stripe rust race CYR32,we found that temporary silencing of Pst 5346,Pst 12394,Pst 15148,Pst 16188,Pst 19493 could decrease the number of pst pustules significantly and the length of fungal hyphae were significantly shortened.However,temporary silencing of Pst 1599,Pst 4385 and Pst 5760 showed no phenotype changes. |
