魔芋内生拮抗菌的筛选及鉴定

Screening and Identification of Endogenous Antagonistic Bacteria in Amorphophalms konjac

为了从魔芋组织中筛选得到有效抑制魔芋软腐病菌的内生拮抗菌，采用组织块法从魔芋块茎中分离到15株内生细菌，通过菌株发酵上清液抑菌试验筛选拮抗菌株，发现其中5株对魔芋软腐病具有拮抗作用，占所筛内生菌的33％，BS-4、5、8的抑菌圈较大，直径在14～16mm。魔芋块茎感病试验发现，抑菌活性较高的BS-8菌株发酵上清液能在-定程度上抑制魔芋块茎感病，经生理生化和16SrRNA基因序列分析鉴定，证实BS-8菌株为枯草芽孢杆菌（Bacillussubtilis）。BS-8菌株对魔芋软腐病菌具有很好的拮抗性，可作为-种新的植物生防制剂或工程菌进行更深一步的研究。

In this research, endogenous antagonistic bacteria which can effectively inhibit the growth of soft rot pathogen were screened from konjac tissues. Fifteen endogenous bacteria strains were screened by means of tissue method. Five strains were confirmed to have resistance to soft rot disease,three（BS-4,5,8） of which were observed with relatively bigger bacteriostasis circles,with diameter of 14--16 mm. The inoculation of pathogen on konjac corm indicated that the fermentation supernatant of BS-8, a strain with relatively higher inhibitory activity, could inhibit the infection of soft rot. The strain was identified as a kind of Bacillus subtilis by means of the analysis of physiology and biochemistry and 16S rRNA gene sequence. The BS-8 strain exhibits an obvious antagonism on soft rot pathogen and can be served as a novel plant biocontrol agent or engineering bacterium for further study.