VIB1, a link between glucose signaling and carbon catabolite repression, is essential for plant cell wall degradation by Neurospora crassa

Purpose: To explore the function of VIB1 in regulating cellulase production in Neurospora crassa. Method: mRNA from vib-1 mutants were collected after a culture shift from sucrose to Avicel (crystaline cellulose) or carbon-free media. Expression profiles of vib-1 mutants were compared with published profiles of wild type created under the same conditions. Results: We found that many genes that specifically upregulated in wild type upon exposure to Avicel were expressed at low levels in ∆vib-1 and many other genes involved in metabolism and energy were expressed at high levels compared to wild type. Conclusions: Our study shows that VIB1 is required for suppression of glucose response and carbon catabolite repression to allow proper expression of clr-2 and subsequent cellulase production in response to cellulosic induction. Biological triplicates of liquid culture N. crassa were harvested at 4 hours after a switch from sucrose media to media of interest. Global mRNA abundances were measured by sequencing on the Illumina Genome Analyzer Iix and HiSeq2000 platforms.