论文部分内容阅读
大豆疫霉根腐病是世界范围内危害严重的毁灭性大豆病害,筛选内生菌进行生物防治是未来该病害防治的重要发展方向。以大豆根系为材料筛选得到67株内生细菌,采用平板对峙生长实验,发现其中18株对大豆疫霉菌的菌丝生长具有抑制作用,其中以A2、A4、A7和B8效果最佳,抑制率分别达到72.8%、55.5%、76.0%和87.1%。利用无菌发酵滤液与大豆疫霉孢子共培养发现,A2和A4对孢子萌发具有明显抑制效果,抑制率达75.4%和85.8%。盆栽实验表明,A2和A4无菌发酵滤液能使经大豆疫霉孢子侵染后的大豆种子萌发率由63.1%分别提高到80.0%和80.3%,健康幼苗率由31.4%提高到45.7%和50.9%。根据16S rDNA序列系统发育分析,初步确定A2为假单胞菌(Pseudomonas sp.),A4、A7和B8皆为芽孢杆菌(Bacillus sp.)。
Phytophthora sojae is a devastating soybean disease in the world. Screening endophyte for biological control is an important development direction for the prevention and control of this disease in the future. Sixty-seven strains of endophytic bacteria were screened from the roots of soybean. The growth of mycelium of Phytophthora sojae was inhibited by 18 strains. Among them, A2, A4, A7 and B8 had the best inhibition rate Reaching 72.8%, 55.5%, 76.0% and 87.1% respectively. The co-culture of sterile fermented filtrate with Phytophthora sojae showed that A2 and A4 had a significant inhibitory effect on spore germination with the inhibition rates of 75.4% and 85.8%. Pot experiments showed that the germination rate of soybean seed germinated by the sterile fermentation filtrate of A2 and A4 increased the seed germination rate of soybean seedlings from 63.1% to 80.0% and 80.3% respectively, while the percentage of healthy seedlings increased from 31.4% to 45.7% and 50.9% respectively %. According to the phylogenetic analysis of 16S rDNA sequences, A2 was identified as Pseudomonas sp., While A4, A7 and B8 were all Bacillus sp.