过表达gpx和cat基因研究草菇菌种退化机理

菌种退化是众多食用菌共同存在的共性问题。草菇不耐低温的特性，使其菌种退化现象尤为严重，严重制约了产业的发展。我们前期利用菌丝体连续继代法获得草菇退化菌种，并通过转录组学和生化分析发现，草菇退化菌种内的活性氧含量显著增加，谷胱甘肽过氧化物酶（gpx）、过氧化氢酶（cat）基因表达量持续下调。本项目拟在前期工作的基础上，克隆草菇gpx和cat基因，构建过表达载体，利用PEG介导原生质体转化法转入2株草菇退化菌株VD1（能出菇，产量降低了50%）和VD2（无法出菇）。综合农艺学性状、生理生化检测、分子生物学等方法，分析转化子的生产恢复能力、抗氧化应激能力、线粒体功能等指标变化；探讨gpx和cat基因在草菇菌种退化过程中的分子功能及草菇菌种退化与活性氧积累、抗氧化酶之间的关系，为草菇菌种退化的分子机理研究提供理论基础，也为利用生物技术手段控制草菇及其他食用菌菌种退化提供新思路。

Strain degeneration is a common problem of many edible fungi. Volvariella volvacea, with intolerance to low temperature, is particularly severely degraded, which seriously restricts the development of industry. Our previous results indicated that degeneration strains were obtained by continuous mycelium subculture, the content of reactive oxygen species (ROS) significantly increased, and the expression levels of gpx and cat genes were continuously down-regulated in the degeneration strains using transcriptome and biochemical analysis. On the basis of the previous work, the gpx and cat genes of V. volvacea were cloned and constructed into expression vectors, which were transferred into two degeneration strains of VD1 (able to produce fruiting body with 50% reduction in yield) and VD2 (unable to produce fruiting body) by PEG mediated protoplast transformation in this proposal. The changes of production recovery ability, antioxidant ability and mitochondrial function of transgenic strain were analyzed by means of agronomy, physiology, biochemistry and molecular biology. In addition, the molecular functions of gpx and cat genes in the process of strain degeneration and the relationship between strain degeneration, ROS accumulation and antioxidant enzymes were investigated, which provided a theoretical basis for the molecular mechanism of V. volvacea strain degeneration and a new idea for the control of strain degeneration of V. volvacea or other edible fungi by means of biotechnology.