Wang Jinjing, Li Mengqi, Hou Dan, Xu Weina, Zheng Feiyun, Liu Chunfeng, Niu Chengtuo, Li Qi
Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China.
Laboratory of Brewing Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, China.
Sheng Wu Gong Cheng Xue Bao. 2019 Jun 25;35(6):1059-1070. doi: 10.13345/j.cjb.180530.
The autolysis of brewer's yeast seriously affects the quality of beer and the quality of yeast is considered as one of the key factors in beer brewing. Previous studies on brewer's yeast autolysis showed that RLM1 gene, an important transcription factor in cell integrity pathway, is closely related to the autolysis of yeast. In this study, RLM1 was knocked out and overexpressed in a haploid brewer's yeast. RLM1 disruption resulted in poor anti-autolysis performance of yeast, whereas overexpression of RLM1 contributed to the anti-autolytic ability of yeast. In addition, RLM1 gene knockout affected the osmotic stress resistance, cell wall damage resistance, nitrogen starvation resistance and temperature tolerance of yeast strain. The transcriptional level of GAS1 involved in cell wall assembly and DNA damage response was regulated along with the expression of RLM1, whereas other genes in CWI pathway did not show apparent regularity. RLM1 might mainly affect the expression of GAS1 so as to improve the stress resistance of lager yeast in harsh environment. The result from this study help further understand the mechanism of yeast autolysis and lay a foundation for breeding brewer's yeast strain with better anti-autolytic ability.
啤酒酵母的自溶严重影响啤酒品质，酵母质量被认为是啤酒酿造的关键因素之一。以往关于啤酒酵母自溶的研究表明，RLM1基因作为细胞完整性途径中的一个重要转录因子，与酵母自溶密切相关。在本研究中，RLM1在单倍体啤酒酵母中被敲除和过表达。RLM1的破坏导致酵母抗自溶性能较差，而RLM1的过表达有助于酵母的抗自溶能力。此外，RLM1基因敲除影响了酵母菌株的抗渗透胁迫、抗细胞壁损伤、抗氮饥饿和耐热性。参与细胞壁组装和DNA损伤反应的GAS1的转录水平随着RLM1的表达而受到调控，而CWI途径中的其他基因没有表现出明显的规律性。RLM1可能主要通过影响GAS1的表达，从而提高贮藏酵母在恶劣环境下的抗逆性。本研究结果有助于进一步了解酵母自溶的机制，为培育具有更好抗自溶能力的啤酒酵母菌株奠定基础。
