摘要： 通过对酶活性的分析,研究证实苹果树腐烂病菌在活体外和寄主体内均能分泌一系列的细胞壁降解酶: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)、β-葡萄糖苷酶和木聚糖酶。不同碳源培养条件下,腐烂病菌产生细胞壁降解酶的活性及达到酶活性高峰的时间存在显著差异;诱导酶液对苹果愈伤组织具有明显的浸解作用,其中木聚糖为碳源产生的细胞壁降解酶,破坏能力最强。此外,研究发现,腐烂病菌在寄主体内产生细胞壁降解酶的活性变化规律不同,PMG和木聚糖酶在接种后最先被检测到活性显著升高,PMG酶活性于接种后第13天达到高峰,随后活性降低,而木聚糖酶和其他3种酶活性则随接种天数的增加活性不断增强;5种细胞壁降解酶中,Cx最大酶活性最低,而木聚糖酶活性最高,是其他酶最大活性的1.74～7.44倍。

关键词: 苹果树腐烂病菌, 细胞壁降解酶, 致病作用, 木聚糖酶

Abstract: Activities of the cell wall-degrading enzymes (CWDEs) produced by V． ceratosperma in vitro and in?vivo were detected． The results showed that V． ceratosperma could produce a series of CWDEs including polygalacturonase (PG)，polymethylgalacturonase (PMG)，cellulose (Cx)，β-glucosidase and xylanase． The different levels of?enzyme activities were obtained with V． ceratosperma grown on five media differing in carbon sources． These corresponding days when maximum enzyme activity were detected varied also with the type of carbon source used． The?CWDEs produced by V． ceratosperma grown on three different carbon source all could macerate apple callus，however，the CWDEs produed in xylan medium showed the most powerful macerating ability． In addition，time-course experiments showed that the changes of CWDEs activities in detached apple branches inoculated by V． ceratosperma?were different． The activities of PMG and xylanase were first detected at enhanced levels in diseased branches． The?PMG activity reached the peak at 13 days post-inocualtion and then it decreased，while activities of the other four?enzymes increased as the disease development． In all the CWDEs，the maximum activity of Cx was the lowest，and?xylanase maximum activity was the highest which was 1． 74 －7． 44 times of the other four enzymes．

Key words: Valsa ceratosperma, Cell wall-degrading enzymes, Pathogenicity, Xylanase

中图分类号: 

• S436.611