Study on the Response of <i>Lepista sordida</i> Sucrose Invertase 1 to Sugar Signals

Lepista sordida, a rare edible and medicinal mushroom, is currently in short supply in the market due to its declining wild availability and limited artificial cultivation. During cultivation, it has been observed that the mycelial growth rate is slow, making it imperative to explore methods for enhancing mycelial growth. As an essential energy source for edible fungi, the efficient conversion and utilization of carbon substrates significantly influence mycelial growth and fruiting body yield. Sucrose invertase (INV1), a hydrolase belonging to the glycosidase family, catalyzes the hydrolysis of sucrose into equimolar amounts of glucose and fructose. The resulting monosaccharides can be directly absorbed by cells and utilized for energy metabolism or biosynthetic processes. Studying this enzyme will provide a theoretical foundation for investigating the mycelial growth rate of Lepista sordida. In this study, a wild strain of L. sordida was obtained through tissue isolation, and the CDS and amino acid sequences of INV1 were acquired from the Institute of Biological and Medical Engineering, Guangdong Academy of Sciences, laying the groundwork for subsequent research. Using techniques such as reverse transcription quantitative PCR (RT-qPCR), the expression responses of L. sordida under sugar-free, glucose, lactose, and PDA culture conditions were examined. The results indicated that INV1 expression was lowest in the presence of glucose, moderate under PDA and sugar-free conditions, and highest when lactose was supplied as the carbon source. This suggests that sucrose invertase in L. sordida responds to lactose conversion when lactose is the sole carbon sourc. 花脸香蘑（Lepista sordida）作为一种珍稀的食药用菌，随着野生数量越来越少，目前只有少量的人工栽培，市场上供不应求；在对其栽培的过程中发现菌丝体生长缓慢，探究提高菌丝体生长速率势在必行。碳源作为食用菌必不可少的能量来源，对碳源的高效转化利用影响食用菌菌丝体生长与子实体产量。蔗糖转化酶（Sucrose Invertase, INV1）是一种水解酶，属于糖苷酶家族，能够催化蔗糖水解为等量的葡萄糖和果糖，生成的单糖可直接被细胞吸收并用于能量代谢或生物合成。对它的研究将为探究花脸香蘑菌丝体生长速率提供理论参考。本研究通过组织分离法获得了一株野生的花脸香蘑菌株菌丝体，并从广东省科学院生物与医学工程研究所获得花脸香蘑中INV1的CDS序列与氨基酸序列，为后面的研究奠定基础。通过实时荧光定量 PCR（Reverse Transcription Quantitative PCR, RT-qPCR）等技术手段，对花脸香蘑在无糖、葡萄糖与乳糖以及PDA培养条件下的响应情况做了检测。结果表明，在葡萄糖存在的情况下，其表达量最低，在PDA与无糖时表达量居中，而在乳糖的情况下，蔗糖转化酶表达量最高。这说明花脸香蘑中蔗糖转化酶在碳源只有乳糖存在的情况下，会响应乳糖的转化。