拮抗细菌Tn5诱变菌株防治水稻纹枯病的研究

Transposon Tn5-Induced Mutants of Antagonistic Bacteria Used in Controlling Sheath Blight of Rice

以对水稻纹枯病菌有拮抗作用的荧光假单胞菌 P-91为受体菌;大肠杆菌 E.coliS17-1 SM10/pSUP2021∷Tn5为供体菌,通过接合转移技术,将转座子 Tn5从供体菌中引入到拮抗细菌 P-91的基因组 DNA 中,共获得2400个 Tn5插入突变体,接合频率为2.0×10^(-7)efu/ml。通过与自然菌株 P-91的一系列对比试验表明:2个 Tn5插入突变株完全丧失了拮抗作用和防病能力;4个突变株对纹枯病菌的离体拮抗作用是对照的128%～187%,对菌核萌发的抑制能力显著强于对照,其中3个突变株在苗期对纹枯病的防治效果比对照高11.7%～35.8%。

By conjugation mating,the transposon Tn5 from Escherichia coli S17-1 containing pSUP2021∷Tn5 was introduced into the DNA of Pseudomonas fluorescens strain P-91 suppressive to sheath blight of rice.The conjugation frequency was 2.0×10^(-7)per recipient CFU.2400 Tn5-in- duced mutants were randomly screened and tested for comparing with the natural strain P-91.The results showed that two mutants entirely lost their antagonistic ability against Rhizoctonia solani and were ineffective in controlling sheath blight.Four mutants got enhanced antagonistic ability 25%—87% higher than P-91,and were more effective in inhibition of sclerotial germination;the control effects of three of the four mutants against sheath blight at the seedling stage of rice were increased by 11.7%—35.0% over that of P-91.