灰盖鬼伞菌柄伸长生长停止过程中细胞壁成熟作用的分子机制研究

我们前期研究证明灰盖鬼伞几丁质酶起着细胞壁扩张蛋白功能，其水解作用介导菌柄细胞壁伸长生长。但几丁质酶只能重组热灭活菌柄顶端细胞壁伸长活性，而重组热灭活菌柄基部细胞壁伸长活性非常微弱或没有，提示菌柄细胞壁成熟过程中，细胞壁结构、组成和交联作用发生了改变，导致对几丁质酶敏感性丧失。预研发现多糖水解酶预处理能恢复成熟菌柄细胞壁可扩张性，被几丁质酶诱导伸长。本项目研究菌柄从伸长区到非伸长区转换的成熟过程中细胞壁化学组成、结构和交联作用的变化，通过多糖水解酶恢复成熟菌柄细胞壁可扩张性研究从上述的众多变化中确定起关键作用的化学成分或交联键，并采用RNAi干扰方法下调合成细胞壁成熟的关键多糖成分或交联键的关键酶基因表达，以功能验证是否可以阻遏细胞壁成熟作用发生，从而阐述灰盖鬼伞菌柄细胞壁成熟作用的分子机制。该研究结果对以菌柄为主要食材的食用菌品质改良和对食用菌多糖药物的开发都具有一定的指导意义。

We previously have explored that some chitinases from Coprinopsis cinerea function as a cell wall loosening reagent and the chitinase-hydrolysis mediates stipe cell wall extension. However，the chitinases only show a strong activity of reconstituted heat-inactivated apical stipe cell wall extension whereas show a little even no activity of reconstituted heat-inactivated basal and basal swollen stipe cell wall extension. These results suggest that some changes of the components, structures and linkages of cell wall should occur during the maturation of cell wall along with cessation of stipe elongation growth, which lead to loss of susceptibility of the cell wall to chitinases. In this project, our specific objectives are (1) Analyze and compare the differences of components, structures and linkages of cell wall between elongating apical stipe region and non-elongation basal and basal swollen stipe regions to elucidate the changes of cell walls during the maturation of cell wall along with cessation of stipe elongation growth; (2) Study on restoration of stipe mature cell wall susceptibility to chitinases by pretreatment with specific C. cinerea hydrolysases to find out which component or linkage among changed components, structures and linkages in cell walls is a key control factor for the maturation of cell wall; (3) Determine effects of RNAi-mediated downregulation of related polysaccharide synthase or linkage catalyzing enzyme on the maturation of stipe cell walls in vivo to functionally confirm the putative key control factor for the maturation of cell wall. We propose to elucidate the molecular mechanism of the maturation of stipe cell wall during the development of C. cinerea fruiting bodies.