水稻稻瘟病拮抗菌L1鉴定及抑菌特性的初步研究

本研究对水稻稻瘟病菌的拮抗菌L1形态、生理生化特性等进行测定, 结果发现其为杆状细胞、革兰氏阳性、菌落不规则有褶皱、好氧生长、颜色较深等, 初步鉴定为枯草芽孢杆菌; 拮抗菌L1培养5 d的发酵液抑菌活性最高, 抑菌率为74.57%; 拮抗菌L1对水稻稻瘟病菌的拮抗活性物质对温度不敏感; 拮抗菌L1的发酵液用硫酸铵梯度沉淀法提取粗蛋白, 在50%~60%硫酸铵饱和度下沉淀的粗蛋白质对水稻稻瘟病菌抑菌效果最好, 平均抑菌半径达0.51 cm。

Identification and Characterization of an Antagonistic Strain L1 Against Phyricularia grisea

On the basis of morphological, physiological and biochemical characterization, the antagonistic bacterium strain L1 against Phyricularia grisea was identified. The strain L1 was bacilliform, Gram-positive, fuscous and draped colonies, aerobiosis. The result showed that the strain L1 belongs to Bacillus subtilis. The antimicrobial activity of fermentation liquid reached the highest after 5 days-old cultures. And inhibitory rate accounted for 74.57%, but it had not changed along with the time increase. The activity effect of antimicrobial substances was insensitive to heat. The filtrated Bacillus subtilis strain L1 was precipitated in grades with the ammonium sulfate to draw the antimicrobial proteins and crude proteins were obtained. One crude protein drawn with ammonium sulfate at 50%~60% saturation showed strong antimicrobial activities to Phyricularia grisea. Average radius was accounted for 0.51 cm.