莲子草假隔链格孢SF．193的细胞壁降解酶研究

采用3，5一二硝基水杨酸法分析了莲子草假隔链格孢NimbyaalternantheraeSF一193菌株在活体内外产生的羧甲基纤维素酶（Cx）、口．葡萄糖苷酶、木聚糖酶、聚甲基半乳糖醛酸酶（PMG）和多聚半乳糖醛酸酶（PG）的活性。结果表明，SF一193可产生cx、伊葡萄糖苷酶、木聚糖酶和PG，且4种细胞壁降解酶在活体外和活体内的活性显著不同。其发酵滤液中以PG活性最高，其次为木聚糖酶、,β-葡萄糖苷酶和Cx；在空心莲子草叶片内以Cx活性最高，其次为β一葡萄糖苷酶、木聚糖酶和PG。在活体内，4种酶活性随接种天数和温度的变化而不同。Cx和卢．葡萄糖苷酶的活性在接种第3d达到最大，木聚糖酶和PG活性则分别在第2d和第5d达到最大；Cx、卢一葡萄糖苷酶和PG活性在30℃时最高，而木聚糖酶活性在35℃时最高。

Cell Wall Degrading Enzymes Produced by Nimbya alternantherae Strain SF-193

Five pathogenesis-related cell wall degrading enzymes including carboxymethyl cellulose （Cx）, fl-glucosidase, xylanase, polymethylgalacturonate （PMG） and polygalacturonase （PG）, produced by Nimbya alternantherae strain SF-193 were analyzed in vitro and in vivo by using the 3,5-dinitrosalicylic acid technique. Results showed that SF-193 could produce Cx, β-glucosidase, xylanase and PG and their activities were significant different between in vitro and in vivo tests. In its fermentation filtrate, PG showed the highest activity, while xylanase,β-glucosidase, and Cx showed relatively lower activities. In infected leaves of Alternanthera philoxeroides by the pathogen, the activity of Cx was the highest, and fl-glucosidase, xylanase and PG were less active than Cx. In vivo test, activities of four enzymes changed with time and temperature progression. The activity of Cx and fl-glucosidase reached the highest 3 d after inoculation, while xylanase and PG were the most active on the 2nd and 5th d, respectively. The optimal temperature for activity ofCx, fl-glucosidase and xylanase was 30 °C and that of PG was 35°C.