RCO-3 and COL-26 form an external-to-internal module that regulates the dual-affinity glucose transport system in Neurospora crassa

To dissect the role of RCO-3 and COL-26 in glucose uptake and metabolism and to obtain a broad view of the mode of expression, we conducted high-throughput sequencing (RNA-Seq) of wild-type, Δcol-26, and Δrco-3 mycelia exposed to a gradient of glucose (0%, 0.05%, 0.5%, 2.0%) for 1 h. We found that the gene expression profiles of Δcol-26 and Δrco-3 mutants was dramatically different with that of WT strain. Transcriptional profiling analysis revealed that Δcol-26 and Δrco-3 mutants had similar transcriptional profiles, and both mutants had impaired response to a glucose gradient. The genes involved glycolytic pathway showed significantly decreased expression in both mutants. Our findings provide novel insight into the molecular basis of glucose uptake and signaling in filamentous fungi, which may aid in the rational design of fungal strains for industrial purposes. Conidia were inoculated into 100 mL liquid Vogel's minimal medium (VMM) supplemented with 2.0% sucrose and grown at 28˚C and 200 rpm in constant light for 16 h. Then the mycelia were transferred to 100 mL VMM with different glucose concentration (0%, 0.05%, 0.5%, 2%) for 1 h before RNA extraction. Duplicate cultures were sampled in each condition.