花生侵脉新赤壳菌果腐病生防芽孢杆菌的分离鉴定及防病效果

【目的】为了分离鉴定对花生侵脉新赤壳菌果腐病病原菌Neocosmospora vasinfecta具有抑制作用的根际芽孢杆菌。【方法】利用平板稀释法从花生的根际土壤分离芽孢杆菌,再采用平板对峙法筛选出对N.vasinfecta具有抑制作用的根际芽孢杆菌,通过形态观察、生理生化特性和分子生物学相结合的多相分类方法对生防根际芽孢杆菌进行分类鉴定,检测脂肽类抗生素合成基因类型,并进行花生侵脉新赤壳菌果腐病的田间防治试验。【结果】从花生根际土壤中分离到28株芽孢杆菌,其中对花生果腐病病原菌具有明显抑制作用有8株。多相分类法结果显示2株为枯草芽孢杆菌(Bacillus subtilis),6株为解淀粉芽孢杆菌(B.amyloliquefaciens)。脂肽类抗生素合成基因检测显示,8株生防芽孢杆菌含有至少1种脂肽类抗生素,其中所有生防菌均含有丰原素B合成基因,推测这些芽孢杆菌对N.vasinfecta的抑制机制可能与脂肽类抗生素的合成相关。田间防病实验结果显示,B.amyloliquefaciens GF-3和GF-22制备的生物有机肥均能有效降低NPRP的发病指数,其防治效率分别为32.35%和79.41%,增产率分别为19.12%和25.85%。【结论】分离鉴定了2株对花生侵脉新赤壳菌果腐病具有明显防治效果的根际芽孢杆菌,这不仅为花生侵脉新赤壳菌果腐病的生防制剂研制提供了菌株,还为研究防治机理奠定了基础。

Isolation and identification of Bacillus spp. controlling Neocosmospora pod rot of peanut

Objective] To isolate and identify Bacillus spp. to control Neocosmospora pod rot of peanut (NPRP).Methods] Bacillus spp. of peanut rhizosphere soil were isolated to inhibit Neocosmospora vasinfecta by plate confrontation method, and further classified by multiphase classification method. The lipopeptide synthesis gene type of biocontrol bacteria was detected by PCR. The control effect of Bacillus spp. on NPRP was tested in field trial.Results] Twenty-eight Bacillus spp. strains were isolated and eight obviously inhibited N. vasinfecta. Two were identified as B. subtilis and the others were B. amyloliquefaciens. The biocontrol bacteria harbored one type of lipopeptide synthesis genes at least and all harbored FenB gene. We speculated that the inhibitory mechanism of the Bacillus spp. may be related to the synthesis of lipopeptide antibiotics. B. amyloliquefaciens GF-3 and GF-22 both could effectively reduce the disease index of NPRP and increase the yield of peanut in field trial.Conclusion] Two strains B. amyloliquefaciens were isolated and identified to control NPRP. This study could provide strains to make biocontrol agents for prevention and control NPRP.