The filamentous fungus Metarhizium robertsii(M.robertsii)is an entomopathogenic fungus and widely used for biological control via conidia application.Metarhizium conidia are also the asexual propagation units and play important roles in fungal propagation and host infection.However,there are few reports about the quantitative proteomic analysis of conidia in M.robertsii.Hence,quantitative proteomic analysis of conidia and mycelia in M.robertsii was performed to explore some of the vital and key pathways and proteins in conidia of M.robertsii.Isobaric tags for relative and absolute quantification(iTRAQ)MS/MS was used to detect statistically significant changes between conidia and mycelium.The results show that a total of 2,129 proteins were detected,and 239 showed differential expression between conidia and mycelium.These differentially expressed proteins(DEPs)mainly included enzymes involved primary metabolic pathways and general(oxidative)stress responsive proteins.Further KEGG enrichment analysis showed that styrene degradation,ethylbenzene degradation,geraniol degradation,valine,leucine and isoleucine degradation and ubiquitin mediated proteolysis were the key pathways in the physiology of conidia.Moreover,quantitative real-time PCR analysis validated the protein expression results for 10 proteins.These results deepened our understanding of conidia proteome in M.robertsii and also provide a basis for further exploration of improving efficiency of the fungi as biocontrol agents.