姜瘟病菌拮抗放线菌的筛选与鉴定

Screening and identification of antagonistic Actinomyces strains against Ralstonia solanacearum

从山东各地区姜田随机采集土样30份,利用稀释分离法分离到放线菌菌株621株。采用琼脂移块法测定这些菌株对姜瘟病菌(Ralstonia solanacearum)的拮抗作用,共筛选出具有拮抗作用的放线菌菌株53株。选择抑菌活性最强的菌株Y7进行进一步研究。菌株Y7孢子丝顶端呈小螺旋形或钩状,孢子椭圆形至圆柱形。在5种供试培养基中,菌株Y7只在燕麦培养基上产生黄色色素。该菌株能利用麦芽糖、葡萄糖、果糖、L(+)树胶醛糖、半乳糖和山梨糖,不能利用蔗糖、木糖、肌醇、纤维二糖和山梨醇。形态特征、生理生化特征和16S rDNA序列分析结果表明,Y7为淡紫灰链霉菌(Streptomycetes lavendulae)。正交实验结果表明其最佳发酵条件是小米培养基pH7.0,28℃,培养14 d。

Six hundred and twenty-one actinomycetes strains were obtained from thirty soil samples collected from ginger fields by routine methods in different parts of Shandong province. Fifty-three strains had been proved to possess antagonistic effect against Ralstonia solanacearum, among which strain Y7 had the best inhibitory effects. The mycelium of strain Y7 was spiral, and its spores oval or cylindrical. It could produce yellow pigment only in the oat medium among the five media tested. The strain could use maltose, glucose, fructose, L（＋） arabinose, galactose and sorbose, but not sucrose, xylose, inositol, cellobiose, or sorbitol. The results on morphological, physio-biochemical characteristics and 16S rDNA sequence alignment revealed that strain Y7 belonged to Streptomycetes lavendulae. The optimal fermentation conditions, concluded from orthogonal experiments, consisted of millet medium, pH 7.0, 28℃ and 14 d.