一株生防菌LX-07的鉴定及其拮抗物的理化特性

Identification of a bio-control bacteria LX-07 and characterizations of its antifungal substance

LX-07菌株是从玉米根系土壤中分离筛选获得的一株具有抗真菌活性的细菌,通过菌落、菌体形态及16SrDNA序列分析,鉴定该菌株为枯草芽孢杆菌。抑菌谱测定结果表明,该菌产生的拮抗物对常见植物病原真菌具有不同程度的拮抗作用,表现广谱抗真菌活性。以链格孢霉作为指示菌,对拮抗物的理化特性进行了研究,结果表明:拮抗物在pH8.0下,在40～100℃范围内,抑菌活性不发生变化,121℃处理30min后抑菌活性略有下降,但仍为对照的90%以上;在室温下,pH2.0～12.0范围内拮抗物保持稳定,抑菌活性不受影响;拮抗物对胰蛋白酶不敏感,对胃蛋白酶、蛋白酶K敏感。

A bio control bacteria LX 07 producing antifungal substance was isolated from the soil of maize roots. It was identified as Bacillus subtilis on the basis of morphological characters as well as the sequence analysis of 16S rDNA.The inhibitory test showed that the antifungal substance produced by LX 07 exhibited extensive antagonistic effect on quite a number of plant pathogenic fungi. Characterizations of the antifungal substance were assayed with Alternaria alternate as indicative bacteria. The results suggested that the antagonists were very stable within the tested range from 40℃ to 100℃ under pH8. 0,but with 90% original activity after treated at 121℃ for 30min. In addition,the antifungal substance showed no change from pH2. 0 ~ 12. 0 under room temperature. With regard to the three proteinases,the results indicated that the antifungal substance was sensitive to pepsin and proteinase K,but it was very stable to trypsin.