Glycerol dehydrogenase has been identified and characterized functionally in many species. However, little is known about glycerol dehydrogenase genes and their functions in Aspergillus oryzae. Here, a total of 45 glycerol dehydrogenase genes in Aspergillus oryzae were identified and renamed from AoGld1 to AoGld45 according to their chromosome distribution. They were classified into three groups based on phylogenetic analysis. Synteny analysis revealed that thirteen AoGld genes are conserved among Aspergillus species. Promoter analysis displayed that AoGld3 and AoGld13 harbored multiple binding elements of GATA-type transcription factors and zinc-finger protein msnA that were involved in nitrogen and kojic acid metabolism, respectively. Moreover, the AoGld3 deletion strain Δgld3 was generated by the CRISPR/Cas9 system, which had no visible growth defects compared with the control wild-type strain under the control and osmotic stress treatments. However, disruption of AoGld3 led to the inhibition of kojic acid production, and the expression of kojA, kojR was down-regulated in the Δgld3 strain. Furthermore, when kojA or kojR was overexpressed in the Δgld3 strain, the yield of kojic acid was restored, suggesting that AoGld3 is involved in kojic acid production through affecting the expression of kojR and kojA. Taken together, these findings provide new insights into our understanding of glycerol dehydrogenase and establish foundation for further study of their roles in Aspergillus oryzae.

中文翻译：

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甘油脱氢酶的鉴定和功能表征揭示了米曲霉曲酸合成中的作用

甘油脱氢酶已在许多物种中得到鉴定和功能表征。然而，关于甘油脱氢酶基因及其在米曲霉中的功能知之甚少。在这里，共鉴定出米曲霉中的 45 个甘油脱氢酶基因，并根据其染色体分布将其从 AoGld1 重命名为 AoGld45。根据系统发育分析将它们分为三组。同线性分析表明，13 个 AoGld 基因在曲霉属物种中是保守的。启动子分析显示，AoGld3 和 AoGld13 分别含有 GATA 型转录因子和锌指蛋白 msnA 的多个结合元件，它们分别参与氮和曲酸代谢。此外，AoGld3 缺失菌株 Δgld3 是由 CRISPR/Cas9 系统产生的，与对照和渗透胁迫处理下的对照野生型菌株相比，其没有明显的生长缺陷。然而，AoGld3 的破坏导致曲酸产生的抑制，并且 kojA、kojR 的表达在 Δgld3 菌株中被下调。此外，当 kojA 或 kojR 在 Δgld3 菌株中过表达时，曲酸产量恢复，表明 AoGld3 通过影响 kojR 和 kojA 的表达参与曲酸生产。总之，这些发现为我们对甘油脱氢酶的理解提供了新的见解，并为进一步研究它们在米曲霉中的作用奠定了基础。Δgld3 菌株中 kojA、kojR 的表达下调。此外，当 kojA 或 kojR 在 Δgld3 菌株中过表达时，曲酸产量恢复，表明 AoGld3 通过影响 kojR 和 kojA 的表达参与曲酸生产。总之，这些发现为我们对甘油脱氢酶的理解提供了新的见解，并为进一步研究它们在米曲霉中的作用奠定了基础。Δgld3 菌株中 kojA、kojR 的表达下调。此外，当 kojA 或 kojR 在 Δgld3 菌株中过表达时，曲酸产量恢复，表明 AoGld3 通过影响 kojR 和 kojA 的表达参与曲酸生产。总之，这些发现为我们对甘油脱氢酶的理解提供了新的见解，并为进一步研究它们在米曲霉中的作用奠定了基础。