一株拮抗稻瘟病菌细菌的筛选与鉴定

Isolation and Identification of an Antagonistic Bacterial Strain Against Rice Blast Fungus

生防微生物是一种具有开发创新和环境友好的防控稻瘟病策略,旨在发掘高效生防微生物资源。于2014年从湖南桃江山区一季稻感病品种湘早籼24号的感稻瘟病稻丛的健康稻株中分离出817株菌株,采用平板对峙法,筛选出1株对稻瘟病菌具有高效抑制作用的拮抗细菌JN005,通过菌丝生长速率法测定其活体菌代谢产物对稻瘟病菌的抑菌率高达84%;并对另外5种植物病原真菌、4种植物病原细菌和大肠杆菌及金黄色葡萄球菌等11种菌作了抑菌谱测定。结果表明,JN005菌株对禾谷镰刀菌、水稻稻曲病菌有较好的抑制作用,其抑制率分别为70.1%和73.6%。通过形态学观察、生理生化测定及16S r DNA序列系统发育分析,将JN005菌株鉴定为枯草芽孢杆菌(Bacillus subtilis)。

It is quite important to develop novel and environment-safe strategies to control rice blast caused by Magnaporthe oryzae, and screening effective microorganism resources is primary basis for the bio-control of blast. Total 817 strains were isolated from healthy ones among diseased rice plants of the susceptible cultivar Xiangzaoxian 24,a single-season cropping rice,in the mountainous area of Taojiang, Hunan,in 2014. One strain JN005 with efficient antagonism to M. oryzae among 817 strains was screened by the plate confrontation method. The inhibition rate of metabolite from active bacterium to the rice blast reached 84% by measuring the growth rate of mycelium of the blast fungus. Further,antimicrobial spectrum of JN005 against 5 plant pathogenic fungi,4 plant pathogenic bacteria,and also Escherichia coli and Staphylococcus aureussub. sp. aureus,was tested. The result revealed that JN005 also presented high inhibitory effect to Fusarium graminearum and Ustilaginoidea virens,and the inhibition rates to two fungi were 70.1% and 73.6%,respectively. Based on analysis of the morphological, physiological,and biochemical characteristics and the 16S rDNA phylogeny,strain JN005 was identified as Bacillus subtilis.