YD4-6和NV11-4菌株抑菌活性及诱导水稻防御性相关酶活性变化

从麦田和蔬菜地土样中筛选到2株具有较高抗菌活性的生防菌株YD4-6和NV11-4,测定了其抑菌活性和诱导水稻防御性相关酶活性的变化。抑菌活性测定结果表明YD4-6和NV11-4对水稻纹枯病菌、水稻稻瘟病菌、油菜菌核病菌和白菜黑斑病菌均具有较强的抑菌活性。两菌株均不产生几丁质酶活性,但NV11-4能产生纤维素酶活性。针对其对水稻病原菌的抑菌活性和纤维素酶活性的差异及其特性,研究了2个菌株诱导水稻防御性酶活性的变化。结果表明,YD4-6和NV11-4菌株均可有效诱导水稻PPO、POD、PAL、SOD活性增强,MDA含量升高。接种水稻纹枯病菌和使用YD4-6和NV11-4菌株,在使用48 h后,水稻防御酶的活性增加并达到最高,其中NV11-4菌株诱导活性比较持久;YD4-6使用后,诱导水稻的MDA含量增幅较大。结果显示,2个菌株均可有效的诱导水稻防御性酶活性增强和MDA含量增加。经16S rRNA鉴定后,菌株Y4-6确定为蜡质芽孢杆菌,NV11-4确定为枯草芽孢杆菌。

The Inhibition Activities of Isolates YD4-6, NV11-4 and Their Induced Activities to Rice Defense Enzyme

YD4-6 and NV11-4 strains were isolated from wheat soil and vegetable soil, both of them exhibited a better antifungal activities to several plant pathogens. The results exhibited that YD4-6 and NV11-4 showed antifungal activities to Rhizoctonia solani, Magnaporthe grisease, Sclerotinia sclerotiorum and Alternaria brassicae, while NV11-4 also can inhibit the growth of Fusarium moniliforme. Both of these two isolates exhibited without chitinase activity, NV11-4 with cellulase activities. Based on these differences to antifungal and cellulase activities of the YD4-6 and NV11-4, their effects on rice defense enzyme were observed. The results indicated that YD4-6 and NV11-4 effectively increased rice PPO, POD, PAL and SOD activities, also promoted concentration of MDA. When the R. solani used with isolates YD4-6, NV11-4, respectively, the induced activities of PPO, POD, PAL, SOD and concentration of MDA were higher than that of only used R. solani, YD4-6 or NV11-4. Compared with two antagonistic bacteria induced activities to rice defense enzyme, NV11-4 exhibited more durable than that of YD4-6, also YD4-6 induced accumulation of MDA, these difference maybe related with character of these two isolates. These two isolates were identified in database by using 16S rRNA sequence of YD4-6 or NV11-4. YD4-6 identified as Bacillus cerecus, and NV11-4 as Bacillus subtilis.