Transcriptomic of Beauveria bassiana during in vitro blastospore production

Culturing the entomopathogenic fungus Beauveria bassiana under high glucose concentrations coupled with high aeration results in a fungal developmental shift from hyphae growth to mostly blastospores (yeast-like cells). The underlying molecular mechanisms involved in this shift remains elusive. Therefore, this has motivated us to realize a systematic analysis of the differential gene expression to uncover the fungal transcriptomic response to osmotic and oxidative stresses associated with the resulting high blastospores yield. Differential gene expression was compared under moderate glucose concentration (10% w/v) and high glucose concentration (20% w/v) daily for the three-day culturing. The RNAseq-based transcriptomic results underpinned a higher proportion of down- than up-regulated genes when the fungus was grown under 20% glucose than at 10%. A follow-up study explored a broader glucose range (4, 8, 12, 16, 20% w/v) with phenotype assessment and qRT-PCR of selected genes. Antioxidant, calcium transport, conidiation, and osmosensor related genes were highly up-regulated in higher glucose titers (18-20%) than at lower titers. These findings improved the knowledge of the molecular mechanisms during blastospore development and may help the large scale blastospores industrial production. Overall design: 2 treatments with 3 replicates and sampled at 3 times =18