玉米茎腐病菌产生的细胞壁降解酶的致病作用

ON THE PATHOGENICITY OF CWDEs PRODUCED FROM STALK ROT PATHOGENS IN MAIZE

本文通过酶活分析和超微结构观察证明了玉米茎腐病菌能产生一系列细胞壁降解酶（ＣＷＤＥ），并能明显浸解胚根组织。浸解的组织发生质壁分离及原生质外流。随细胞壁降解酶浓度增加，酶浸解能力增强，两者呈显著的正相关。相比较而言，玉米赤霉病Ｆｕｓａｒｉｕｍｇｒａｍｉｎｅａｒｕｍ在病株内产生的细胞壁降解酶的浸解能力比玉米腐霉茎腐病Ｐｙｔｈｉｕｍａｐｈａｎｉｄｅｒｍａｔｕｍ强。２种病菌活体外产生的果胶酶与纤维素酶（Ｃｘ）存在明显的协同作用。毒素不能提高细胞壁降解酶的浸解能力，反而有一定的抑制作用。

Corn stalk rot pathogens produce a series of cell wall-degrading enzymes(CWDE) in vitro or in vivo, which macerated seedling radicle tissue of corn,causing the release of reduced sugar, plasmolysis and electrolyte leakage in the radicle tissue.The tissue maceration developed with the increasing concentration of CWDE and a significant positive relationship was found between the two factors. Results also suggested that CWDE from Fusarium graminearum showed a higher macerating ability than that from Pythium aphanidermatum . A synergistic action was found between pectinase and Cx produced in vitro. Toxins from pathogens inhibit to some extent, the maceration caused by CWDEs from pathogens.