大豆疫霉菌诱导的β-1,3-葡聚糖酶与寄主抗病性的关系

Relationship Between Induced β-1,3-Glucanase and Resistance of Soybean to Phytophthora Root Rot

为明确-1,3-葡聚糖酶与大豆抗大豆疫霉根腐病的关系,分别测定了具有不同抗性的3个大豆品种的真叶和第1片复叶被大豆疫霉菌侵染后β-1,3-葡聚糖酶的活性,并分析其与抗病性的关系。侵染大豆真叶和第1片复叶后各品种的β-1,3-葡聚糖酶活性均明显升高。接种大豆真叶后抗病品种48 h出现酶活性高峰,酶活性增加105.9%;中感品种和感病品种72 h出现酶活性高峰,酶活性增加量分别为66.3%和65.7%。接种大豆复叶后酶活性的变化与真叶反应一致。说明β-1,3-葡聚糖酶的活性与大豆品种的抗病性呈正相关,抗病品种较感病品种酶活性峰值出现早,酶活性增加量高。对酶的部分性质的研究结果表明：酶的最适反应温度为55℃,最适反应pH为5.0,在55℃以下,pH 4.5-7.5范围内酶活性较稳定。Ca^2＋、Mn^2＋、K^＋、A l^3＋对酶均有激活作用,Mg^2＋、Cu^2＋、Zn^2＋、Fe^3＋、Fe^2＋、Hg^2＋、Ba^2＋对酶有抑制作用。抑菌试验表明,β-1,3-葡聚糖酶粗酶液对大豆疫霉菌的菌丝生长和游动孢子萌发有明显的抑制作用。

To know the relationship between induced β-1,3- glucanase and resistance of soybean to phytophthora root rot,the activities of β-1,3- glucanase in true leaves and first compound leaves of three soybean cuhivars with different resistance after infection by Phythophthora sojae were detected. After infecting true leaves and first compound leaves, the activities of β- 1,3- glucanase were enhanced in all euhivars. The enzyme-activity in true leaves of resistance cuhivar reached the peak at 48 hours after inoculation, increasing 105.9% , and middle susceptible and susceptible cuhivars reached the peck at 72 hours after inoculation,increasing 66.3% and 65.7% ,respectively. The results showed the relationship between the activities of β-1,3- glucanase and the resistance of soybean euhivars were positive. The increase peaks of enzyme-activity changes appeared earlier in the resistant cuhivars than the susceptible ones, and showed a higher level of enzyme-activity changes in the resistant cultivars. Still, the results of the partial enzyme properties indicated that the optimal temperature and pH of the β-1,3- glucanase was 55℃ and 5.0,respectively. The enzyme was stable at pH 4.5-7.5 and temperature below 55℃. The activities of β-1,3- glueanase were stimulated by Ca^2＋ , Mn^2 ＋ , K ^＋ , Al^3＋ and inhibited by Mg^2 ＋ , Cu^2 ＋ , Zn^2 ＋ , Fe^3＋ , Fe^2 ＋ , Hg^2 ＋ , Ba^2 ＋. Antifungal activities showed that the mycelia growth and zoospore germination of P. sojae were significantly inhibited by crude enzyme.