The Translation Initiation Factor eIF2Bα Regulates Development, Stress Response, Amylase Production, and Kojic Acid Synthesis in the Fungus Aspergillus oryzae.

Translation initiation, which involves numerous protein factors and coordinated control steps, represents the most complicated process during eukaryotic translation. However, the roles of eukaryotic translation initiation factor (eIF) in filamentous fungi are not well clarified. In this study, we investigated the function of eIF2Bα in Aspergillus oryzae, an industrially important filamentous fungus. The ΔeIF2Bα mutants showed slow colony growth and decreased conidia production, suggesting the critical roles of eIF2Bα in the growth and development of A. oryzae. In addition, the loss of eIF2Bα significantly impaired the ability to produce amylase and kojic acid, indicating the involvement of eIF2Bα in the amylase synthesis and secondary metabolite production. Interestingly, the elimination of eIF2Bα improved the tolerance of A. oryzae to diverse adverse stresses, including endoplasmic reticulum stress, oxidative stress, cell wall-perturbing stress, and cell membrane-damaging stress. Overall, our results indicate that eIF2Bα is a crucial regulator of growth, development, stress response, amylase production, and kojic acid synthesis in A. oryzae.