核桃基腐病菌产生细胞壁降解酶的种类及其活性分析

The Kinds and Activities of Cell Wall-Degrading Enzymes Produced by Pythium oligandrum Drechsler

通过致病力的测定筛选出两株强致病力核桃基腐病菌菌株HA-1和KY-S,通过对酶活性的分析,研究证实核桃基腐病菌均能分泌4种细胞壁降解酶(CWDEs):β-葡萄糖苷酶、多聚半乳糖醛酸酶(PG)、果胶甲基半乳糖醛酸酶(PMG)、纤维素酶(Cx)。在不同碳源培养条件下,核桃基腐病产生细胞壁降解酶的活性存在一定差异,以蔗糖为碳源时,菌株分泌的各种细胞壁降解酶活性较高。在4种培养基中,达到各酶活性高峰的时间仅为3d。在蔗糖培养基中,核桃基腐病菌产生的Cx最大酶活性为1495.5mU/mL,明显高于其他3种酶,且显著高于其他培养基产生的Cx。但在树皮为碳源的培养基中Cx的活性最低。在CMC为碳源的培养基中PG、PMG的活性最高,分别为826.5mU/mL和661.3mU/mL,此外,以果胶为碳源时产生的PMG的活性最高为1068.0mU/mL。

Activities of the cell wall-degrading enzymes （CWDEs） Produced by Pythium oligandru Drechsler were detected .The results showed that Pythium oligandrum could produce a series of CWDEs including Polygalacturonase （PG） ,Polymethylgalacturonase（PMG） ,Cellulose（Cx） ,β-glucosidase .The different levels of enzymes activities were obtained with Pythium oligandrum grown on four media differing in carbon source used .Sucrose as carbon source ,the strain secreted by a variety of cell wall-degrading activity were higher .Time of each activity peak reached in four medium only three days .The sucrose medium walnut base rot Cx activity 1495 .5mU/mL ,signifi-cantly higher than the other three enzymes ,and significantly higher than other media generated CX .As a carbon source in the bark medium Cx lowest activity .As a carbon source in the CMC medium PG ,PMG highest activity ,were 826 .5mU/mL and 661 .3mU/mL In addition ,the high-est activity of pectin as a carbon source PMG were 1068 .0mU/mL .