稻瘟菌侵染后水稻幼苗活性氧的产生与抗病性的关系

Active Oxygen Production in Rice Seedlings Infected by Magnaporthe grisea Is Involved in the Blast Resistance

以对稻瘟菌ZB1小种表现抗病 (H8R)和感病反应 (H8S)的两种水稻为材料接种稻瘟菌后 ,表现不亲和反应的水稻幼苗叶片中O- ·2 产生速率提高 ,于 2 4h和 6 0h出现两个高峰 ;H2 O2 量在 3h和 48h分别出现高峰 ;·OH量在 36h后略高于对照 ;过氧化物酶 (POD)活性从 6h起显著升高。而在表现亲和反应的水稻中O- ·2 、H2 O2 和·OH的产生及POD活性的增加均迟于表现不亲和反应的 ,且强度也小。SOD和过氧化氢酶活性在两类反应中基本保持不变。同时发现 ,不亲和反应中丙二醛量增加 (2 4h)及其两个高峰 (30h和 6 0h)分别出现在活性氧的产生及其两个峰值之后或同时。这些结果表明水稻幼苗中产生的活性氧可能启动了膜脂过氧化 。

The generation and accumulation of superoxide anion (O [DD(;-2]-· 2), hydrogen peroxide (H 2O 2)and hydroxyl radical (·OH), and activities of scavenger enzymes in rice seedling leaves were analyzed after inoculation with Magnaporthe grisea. In rice seedling leaves with incompatible reaction, the rate of O [DD(;-2]-· 2 production increased rapidly after 6 h, and reached its maximum at 24 h and 60 h (Fig.1). A rapid and transient increase in H 2O 2 level was also detected in these leaves 3 h after inoculation, and the H 2O 2 level reached its maximum at 48 h (Fig.2). In addition, the ·OH level increased in incompatible reaction at 36 h (Fig.3). Peroxidase activity was found to increase in the incompatible reaction at 6 h (Fig.5). In rice seedling leaves with compatible reaction, however, generation of O [DD(;-2]-· 2, H 2O 2 and ·OH occurred later than those in incompatible reaction, and their levels were low (Figs.1～3). The malondialdehyde level in rice seedling leaves with incompatible reaction went up rapidly 24 h after inoculation and reached its maxima at 30 h and 60 h (Fig.4). These results indicated that generation of active oxygen may initiate lipid peroxidation during incompatible reaction, which causes the cell death in hypersensitive response and plays a role in the resistance of rice seedlings to blast.