The Research On Molecular Mechanisms Of Improving Biocontrol Efficacy Of Rhodotorula Mucilaginosa To Postharvest Diseases Of Strawberries By Inducing Incubation With Chitosan

Strawberries are easy to be infected by pathogens during transportation and storage which caused huge economic losses.Previous studies by our research team have shown that the biocontrol efficacy of Rhodotorula mucilaginosa on postharvest diseases of strawberries can be improved by chitosan-inducing incubation.The physiological mechanism involoved has been studied and reported,but the molecular mechanism is not clear.In this study,the mechanisms involved in the enhanced biocontrol efficacy of R.mucilaginosa induced by chitosan were explored based on transcriptomics and proteomics from the perspective of antagonistic efficacy of R.mucilaginosa and the disease resistance of strawberries.The main results of this study were as follows:(1)The differential expressed genes(DEGs)of R.mucilaginosa induced by chitosan for 24 h were analyzed by transcriptome and bioinformatics.The results showed that the function of 811 DEGs in R.mucilaginosa induced by chitosan were annotated.Of these DEGs,424 were up-regulated and 387 were down-regulated.The mechanisms involved in the enhanced antagonsitic efficacy of R.mucilaginosa induced by chitosan were revealed based on the functional analysis,GO and KEGG enrichment analysis of DEGs.The analysis results indicated that the genes of R.mucilaginosa involved in growth and reproduction,the adhesion and biofilm formation,energy synthesis,antioxidation and various stress resistance were up-regulated by chitosaninducing incubation to enchance the antagonistic efficacy of R.mucilaginosa.(2)The differential expressed proteins(DEPs)of R.mucilaginosa induced by chitosan were analyzed by proteome and bioinformatics.The results showed that a total of 312 DEGs in R.mucilaginosa induced by chitosan were annotated to database,of which 214 were up-regulated and 98 were down-regulated.The mechanisms involved in the enhanced antagonsitic efficacy of R.mucilaginosa induced by chitosan were revealed based on the functional analysis and GO,KEGG enrichment analysis of DEPs.The analysis results indicated that the proteins of R.mucilaginosa related to growth and reproduction,energy synthesis,antioxidation,various stress resistance and pathogen cell wall hydrolase were up-regulated by chitosan-inducing incubation to enchance the antagonistic efficacy of R.mucilaginosa.(3)The correlation analysis of the results of transcriptome and proteome of R.mucilaginosa showed that the effect of chitosan-inducing incubation on genes were significantly positively correlated with that on proteins of R.mucilaginosa.The results of GO and KEGG enrichment correlation analysis showed that the GO terms enriched more DEGs and DEPs were consistence with each other,as well as KEGG subclass,which suggested a good correlation between transcription level and protein abundance.The mechanisms involved in the enhanced antagonsitic efficacy of R.mucilaginosa induced by chitosan were comprehensively revealed by transcriptomic and proteomic analysis that the genes and proteins of R.mucilaginosa involved in growth and reproduction,energy synthesis,antioxidation and various stress resistance,and also genes involved in adhesion and biofilm formation,proteins involved in pathogen cell wall hydrolysis were up-regulated by chitosan-inducing incubation.(4)The DEGs of strawberries induced by R.mucilaginosa incubated with chitosan were analyzed by transcriptome and bioinformatics.The results showed that a total of 360 DEGs in strawberries were annotated to database,of which 202 were up-regulated and 158 were down-regulated.The mechanisms involved in the enhanced disease resistance of strawberries treated with R.mucilaginosa incubated with chitosan were revealed based on the functional analysis,GO and KEGG enrichment analysis of DEGs.The analysis results indicated that the genes involoved in plant hormone signal transduction pathway and downstream resistant genes,synthesis of disease-resistance substance,reactive oxygen species regulation and cell wall enhancement were upregulated to increase the disease resistance of strawberries.(5)The DEPs of strawberries induced by R.mucilaginosa incubated with chitosan were analyzed by proteome and bioinformatics.The results showed that a total of 26 DEPs in strawberries were annotated to database,of which 16 were up-regulated and 10 were down-regulated.The mechanisms involved in the enhanced disease resistance of strawberries treated with R.mucilaginosa incubated with chitosan were revealed based on the functional analysis and GO,KEGG enrichment analysis of DEPs.The analysis results indicated that the proteins including chitinase,flavonol synthase,long chain acyl-CoA synthetase and protein early-responsive to dehydration were upregulated.Combined with the transcriptomic data,the mechanisms involved in the enhanced disease resistance of strawberries by R.mucilaginosa incubated with chitosan were as follows: the genes and proteins involoved in plant hormone signal transduction pathway together with downstream resistant genes and proteins,the genes and proteins related to the synthesis of disease-resistance substance and reactive oxygen species regulation,and also genes involved in cell wall enhancement were up-regulated to increase the disease resistance of strawberries.