College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing, 210014, China.
Antonie Van Leeuwenhoek. 2022 Mar;115(3):365-374. doi: 10.1007/s10482-021-01705-5. Epub 2022 Jan 31.
Annulohypoxylon stygium, a companion fungus of Tremella fuciformis, provides nutrition for growth and development of T. fuciformis. Alternative oxidase (AOX), which is the terminal oxidase of the alternative respiration pathway, functions to transfer electrons from ubiquinol to O with the production of HO. In this study, an AOX encoded gene, Asaox, was cloned from A. stygium. The coding sequence of Asaox gene contains 1056 nucleotides and encodes 351 amino acids. RNA interference was used to study the function of Asaox in A. stygium. The Asaox-silenced strains were confirmed by PCR, quantitative real-time PCR, and Southern blot. The Asaox-silenced strains exhibited increased relative growth inhibition rates when inoculated on PDA plates with 50 mM HO, compared with wild-type strain. The growth rate in sawdust medium, melanin content, and laccase activity of Asaox-silenced strains were decreased. The expression levels of tyr and pks genes were decreased in Asaox-silenced strains, indicating that there might be two melanin synthesis pathways, DHN and DOPA, in A. stygium. In summary, the results have demonstrated that Asaox gene was involved in oxidative stress resistance and melanin synthesis in A. stygium.
纹被孔菌是银耳的伴生菌，为银耳的生长发育提供营养。交替氧化酶（AOX）是交替呼吸途径的末端氧化酶，其功能是将电子从泛醌传递给 O，同时产生 HO。在这项研究中，从纹被孔菌中克隆了一个 AOX 编码基因 Asaox。Asaox 基因的编码序列包含 1056 个核苷酸，编码 351 个氨基酸。利用 RNA 干扰技术研究了 Asaox 在纹被孔菌中的功能。通过 PCR、定量实时 PCR 和 Southern blot 证实了 Asaox 沉默菌株的存在。与野生型菌株相比，当在含有 50mM HO 的 PDA 平板上接种时，Asaox 沉默菌株的相对生长抑制率增加。在木屑培养基中的生长速率、黑色素含量和漆酶活性降低。Asaox 沉默菌株 tyr 和 pks 基因的表达水平降低，表明纹被孔菌中可能存在两种黑色素合成途径，DHN 和 DOPA。综上所述，结果表明 Asaox 基因参与了纹被孔菌的氧化应激抗性和黑色素合成。
