苯并噻二唑诱发水稻对纹枯病的抗性

Systemic acquired resistance of rice against sheath blight disease induced by benzothiadiazole

研究了苯并噻二唑(BTH)诱发水稻产生对纹枯病的抗性。离体条件下,1.0mmol/L BTH对纹枯病菌菌丝生长无明显抑制作用。BTH叶面或灌根处理四叶一心期水稻幼苗,并将植株第2、3和4叶离体接种纹枯病菌,水稻叶片纹枯病病斑长度明显下降,BTH诱发苗期水稻产生抗性的最佳诱导期在处理后的3～5天,最佳浓度为0.1mmol/L,BTH灌根处理诱发抗性的效果较好。用BTH溶液叶面喷雾处理成株期水稻倒二叶后离体接种纹枯病菌,倒二叶、倒一叶和剑叶上病斑长度显著低于对照,最佳诱导期在处理后3～5天。用BTH处理苗期水稻第2叶或成株期倒二叶,可使未经处理的苗期水稻第3和4叶以及成株期水稻倒一叶和剑叶上纹枯病病斑长度显著下降。

Systemic acquired resistance (SAR) of rice against sheath blight disease (Rhizoctonia solani) induced by benzothiadiazole (BTH) was investigated. No inhibitory effect of BTH at 1.0 mmol/L on the mycelium growth of R. solani in vitro was detected. Four-leaf rice seedlings were treated by foliar spraying or root drenching with BTH, and the 2nd, the 3rd and the 4th leaves were detached and inoculated with the pathogen. The lesion lengths of the sheath blight disease in the detached leaves treated with BTH were significantly reduced as compared with those in the controls. Resistance of rice seedlings induced by BTH required an interval of 3 - 5 days between BTH treatment and inoculation, and the optimum concentration of BTH for inducing resistance at seedling stage was at 0.1 mmol/L. Treatment by root drenching gave a relatively higher level of resistance than that by foliar spraying. Lesion lengths of the sheath blight disease on the 2nd leaves from the top, the 1st leaves from the top and the flag leaves were reduced markedly after the 2nd leaves from the top of the rice adult plants were treated by foliar spraying with BTH. Resistance of rice adult plants induced by BTH also required an interval of 3 - 5 days between BTH treatment and inoculation . When the 2nd leaves of 4-leaf seedlings or the 2nd leaves from the top of the adult plants were treated by foliar spraying with BTH, lesion lengths of the sheath blight disease on the detached untreated 3rd and 4th leaves of the seedlings or the detached 1st leaves from the top and the detached flag leaves of the adult plants were significantly reduced, indicating that resistance of rice induced by BTH shows systemic feature.