RNA sequencing analysis of Beauveria bassiana isolated from Ostrinia furnacalis identifies the pathogenic genes.

Beauveria bassiana (B. bassiana) is a broad-spectrum entomopathogenic species of fungi which is a natural enemy of Ostrinia furnacalis (O. furnacalis). Nevertheless, the precise mechanism of pathogenicity difference of B. bassiana strains on O. furnacalis has not been investigated before. In this study, two B. bassiana strains isolated from the infected O. furnacalis and exhibited different pathogenicity were chose to analyze the gene expression using RNA-sequencing analysis. To investigate the significantly differentially expressed genes (DEGs) of these two strains, total RNA was extracted and Cuffdiff software was applied to perform the significance analysis of the microarrays method. qRT-PCR was applied to verify the expression of DEGs. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway analyses were applied to evaluate the functions of DEGs. Data showed 72 up-regulated and 192 down-regulated genes in hyper-pathogenic strain ZK193 in comparison with hypo-pathogenic strain ZK203. Genes involved in fungal growth, sporulation and toxin production were up-regulated in hyper-pathogenic strain ZK193. GO enrichment analysis of DEGS showed that the most observably enriched biological processes of regulated genes were the single-organism process, the metabolic process, the cellular process and biological regulation. KEGG enrichment pathway demonstrated that the almost enriched groups were metabolic pathways, such as lipid metabolism, transport and catabolism, amino acid metabolism, and carbohydrate metabolism. In conclusion, these results will help us to further understand the reason why different B. bassiana strains exhibit different pathogenicity on the same host, even under the same conditions. In addition, transcriptome data will provide a theoretical basis for exploring latent virulence factors in the future.