Hu Yifan, Zheng Yunfan, Liu Baixue, Gong Yunxia, Shao Yanchun
College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
Hubei International Scientific and Technological Cooperation Base of Traditionally Fermented Foods, Wuhan 430070, Hubei, China.
J Appl Microbiol. 2023 Mar 1;134(3). doi: 10.1093/jambio/lxad042.
In this study, Mrhst4, encoding a member of NAD+-dependent histone deacetylase (HDAC), was deleted to evaluate its regulation on the production of Monascus azaphilone pigments (MonAzPs) and mycotoxin, as well as the developmental process in Monascusruber.
Agrobacterium tumefaciens-mediated transformation was applied in this study to generate the Mrhst4 null strain. Mrhst4-deleted strain did not display obvious differences in the sexual and asexual reproduction, colonial morphology, and micro-morphology. UV-Vis scan and UPLC detection showed that disruption of Mrhst4 significantly increased the MonAzPs yields, and citrinin content was dramatically enhanced during the tested period. RT-qPCR results showed that the absence of Mrhst4 significantly increased the relative expression of citrinin biosynthetic pathway genes including pksCT, mrl1, mrl2, mrl4, mrl6, and mrl7. The Western blot assay suggested that deletion of Mrhst4 could significantly elevate the acetylation levels of H3K4, H3K9, H3K18, H3K56, and H4K12, but attenuated the lysine acetylation modification of H4Pan, H4K8, and H4K16.
MrHst4 is an important regulator involved in secondary metabolism in Monascus ruber. In particular, MrHst4 plays a pivotal role in regulation of citrinin production.
在本研究中，编码烟酰胺腺嘌呤二核苷酸（NAD⁺）依赖性组蛋白去乙酰化酶（HDAC）成员的Mrhst4被敲除，以评估其对红曲霉菌红素类色素（MonAzPs）和霉菌毒素产生的调控作用，以及对红曲霉发育过程的影响。
本研究采用根癌农杆菌介导的转化方法构建Mrhst4缺失菌株。Mrhst4缺失菌株在有性和无性繁殖、菌落形态及微观形态方面未表现出明显差异。紫外可见扫描和超高效液相色谱检测表明，Mrhst4的缺失显著提高了MonAzPs产量，并且在测试期间桔霉素含量显著增加。实时定量聚合酶链反应（RT-qPCR）结果显示，Mrhst4的缺失显著增加了桔霉素生物合成途径基因（包括pksCT、mrl1、mrl2、mrl4、mrl6和mrl7）的相对表达。蛋白质免疫印迹分析表明，Mrhst4的缺失可显著提高H3K4、H3K9、H3K18、H3K56和H4K12的乙酰化水平，但减弱了H4Pan、H4K8和H4K16的赖氨酸乙酰化修饰。
MrHst4是红曲霉次级代谢的重要调控因子。特别是，MrHst4在桔霉素产生的调控中起关键作用。
