黄瓜棒孢叶斑病（褐斑病）病菌细胞壁降解酶产生条件及活性分析

通过对活体外细胞壁降解酶产生条件、活体接种黄瓜棒孢叶斑病菌后细胞壁降解酶活性变化及活体内外产生的细胞壁降解酶活性比较的研究，结果表明：多聚半乳糖醛酸酶（PG）、果胶甲基半乳糖醛酸酶（PMG）、多聚半乳糖醛酸反式消除酶（PGTE）、果胶甲基反式消除酶（PMTE）、羧甲基纤维素酶（Cx）和β-葡萄糖苷酶6种酶均有特定的最适培养条件，持续振荡培养利于各种细胞壁降解酶的产生；Cx和β-葡萄糖苷酶在培养9 d时活性达到高峰，PG和PMG在培养12 d时活性达到高峰，PGTE、PMTE在培养15 d时活性最高；PG和PMG产生的最适温度为25 ℃，PGTE、PMTE、Cx、β-葡萄糖苷酶产生的最适温度为28 ℃；PG、PMG、Cx和β-葡萄糖苷酶的活性在pH为6时最高，PGTE和PMTE的活性在pH为8时达到最高峰。4种果胶酶的活性在接种后第3天活性最高；而两种纤维素酶在接种后第5天活性最高。病菌在活体内和活体外产生的细胞壁降解酶的活性明显不同。

Conditions and Activity Analysis of Cell Wall Degrading Enzymes Produced from Corynespora cassiicola of Brown Spot of Cucumber

A series of cell wall degrading enzymes（CWDEs）including polygalacturonase（PG）, polymethyl-galacturonase（PMG）, polygalacturonic acid trans-eliminase（PGTE）, pectin methyl- trans-eliminase（PMTE）carboxymethyl cellulase（Cx）and β-glucosidase were found both in vitro and  vivo from Corynespora cassiicola of brown spot of cucumber. Based on the cell wall degrading enzymes produced in vitro conditions, in vivo after inoculation of bacteria cell wall-degrading enzymes and in vivo produced outside the cell wall-degrading enzyme activity comparison study, the results show that every kind of cell wall degrading enzyme has a specific optimal culture conditions. Shake culture make more for the production of cell-wall degradation compared to the stationary culture. The activities of Cx and β- glucosidase reached a peak when cultured 9 d, PG and PMG reached a peak when cultured 12 d, while PGTE and PMTE reached a peak when cultured 15 d. PG and PMG showed maximum activities at 25 ℃ culture temperature. PGTE, PMTE, Cx and β-glucosidase showed maximum activities at 28 ℃ culture temperature. PG, PMG, Cx and β-glucosidase showed maximum activities at culture pH 6. PGTE and PMTE showed maximum activities at culture pH 8. Four kinds of pectinase showed maximum activities in the third day after inoculation. Two kinds of cellulase showed maximum activities in the fifthday after inoculation. The activity of cell wall degrading enzymes in vivo and in vitro was significantly different.