The bHLH transcription factor DevR significantly affects polysaccharide metabolism in Aspergillus oryzae .

basic-region helix-loop-helix (bHLH) proteins are a superfamily of transcription factors that are often involved in the control of growth and differentiation. Recently, it has been reported that the bHLH transcription factor DevR is involved in both asexual and sexual development in A. nidulans and regulates the conidial melanin production in A. fumigatus In this study, we identified and characterized an A. oryzae gene, which showed high similarity with devR of A. nidulans and A. fumigatus In the AodevR -disrupted strain, growth was delayed and the number of conidia was decreased on CD minimal agar plates, but the conidiation could be partially recovered by adding 0.6 M KCl. Simultaneously, the overexpression of AodevR was induced and resulted in extremely poor growth when the carbon source changed from glucose to polysaccharide (dextrin) in the CD agar plate. SEM indicated that the overexpression of AodevR resulted in extremely thin aberrant hyphal morphology. Conversely, the deletion of AodevR resulted in thicker hyphae and resulted in more resistance to Congo red relative to the control strain. Quantitative RT-PCR further indicated that AoDevR significantly affects chitin and starch metabolism, and especially, the overexpression of AodevR importantly inhibited the expression of the genes related to starch degradation. Yeast one-hybrid assay suggested that the DevR protein possibly interacted with promoter of amyR , which encodes a transcription factor involved in amylase production. In concert, AoDevR is importantly involved in polysaccharide metabolism and affects the growth of the A. oryzae strain. Importance Aspergillus oryzae is an industrially important filamentous fungus, and therefore, a clear understanding of its polysaccharide metabolism and utilization is very important for its industrial utilization. In this study, we revealed that the bHLH transcription factor AoDevR is importantly involved in chitin and starch metabolism in A. oryzae The overexpression of AodevR strongly suppressed the expression of amylase-related genes. Yeast one-hybrid assay suggested that the DevR protein can potentially interact with promoter of amyR , which encodes a transcription factor involved in amylase production and starch utilization. This study provides a new insight for further revealing the regulation mechanism of amylase production in A. oryzae .