Ras subfamily proteins are molecular switches in signal transduction pathways of many eukaryotes that regulate a variety of cellular processes. Here, the Ras subfamily, encoded by six genes, was identified in Aspergillus flavus: rasA, rasB, rasC, rab-33, rheb and rsr1. The rsr1 deletion mutant (Δrsr1), rheb deletion mutant (Δrheb) and double deletion mutant (Δrheb/ rsr1) displayed significantly decreased growth and sporulation. Sclerotia formation was significantly decreased for Δrheb or Δrheb/rsr1 but increased for Δrsr1. Aflatoxin production was significantly increased in Δrheb but decreased in Δrsr1 and Δrheb/rsr1. We found that rsr1 and rheb are crucial for the pathogenicity of A. flavus. Quantitative proteomics identified 520 differentially expressed proteins (DEPs) for the Δrsr1 mutant and 133 DEPs for the Δrheb mutant. These DEPs were annotated in multiple biological processes and KEGG pathways in A. flavus. Importantly, we identified the cytokinesis protein SepA in the protein-protein interaction network of rsr1, and deletion mutants showed that SepA has pleiotropic effects on growth and AF biosynthesis, which may depend on Rsr1 for regulation in A. flavus. Our results indicated that these Ras subfamily proteins exhibited functional redundancy with each other but there were also differences in A. flavus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.