【摘要】 为揭示贝莱斯芽孢杆菌(Bacillus velezensis)3A3-15生防和促生作用相关机理,采用9对特异性引物对其抑菌基因和促生长基因进行PCR检测,并分别通过Sackowski法、Schwyn和Neiland法检测其分泌吲哚乙酸(IAA)和嗜铁素能力,通过高效液相色谱-电喷雾质谱(HPLC-ESI-MS)分析其发酵液抑菌成分,采用平板对峙实验和孢子萌发抑制实验分析该菌株的抑菌机理.结果表明,贝莱斯芽孢杆菌3A3-15中的抑菌基因包括yndJ、srfAB、ituC、bamC和fenD,促生长基因包括ysnE和dhbC.该菌株分泌嗜铁素能力较强,A_s/A_r值达到0.238,鉴定其抑菌物质为C14～C15 surfactinA,且贝莱斯芽孢杆菌3A3-15的次生代谢物能导致病原菌(尖孢镰刀菌)菌丝扭曲、膨大、畸形,对其孢子萌发抑制作用较强,抑制率达93.2%.以上结果说明贝莱斯芽孢杆菌3A3-15具有较好的生防和促生潜力,是防治尖孢镰刀菌引起的大豆根腐病的潜在菌株.更多还原

【Abstract】 In order to reveal the biocontrol and promotion mechanism of Bacillus velezensis 3 A3-15, PCR with 9 pairs of specific primers were used to detect genes related to inhibitory and growth promotion, and the ability to secrete indole-3-acetic acid(IAA) and siderophore was tested by the methods of Sackowski, Schwyn and Neiland, respectively. At the same time, the inhibitory substances of the fermentation broth were analyzed by high performance liquid chromatography-electrospray ionization mass spectrometry(HPLC-ESI-MS). Finally, the inhibitory mechanism of the strain was analyzed by plate dual-culture antagonistic test and spore germination inhibition test. Results showed that the inhibitory genes in B. velezensis 3 A3-15 include yndJ, srfAB, ituC, bamC and fenD, the growth-promoting genes include ysnE and dhbC. The strain had a strong ability to secrete siderophore with a A_s/A_r value of 0.238, and its inhibitory substance was C14～C15 SurfactinA. Moreover, the secondary metabolites production of B.velezensis 3 A3-15 could cause the hyphae of the pathogenic bacteria(Fusarium oxysporum)to distort,swellen,deform and had a strong inhibitory effect on the germination of spores,with the inhibition rate of 93.2%.These results indicated that B.velezensis 3 A3-15 had preferable biocontrol and growth promoting potential and was a potential strain to control soybean root rot caused by F.oxysporum.更多还原