苹果树腐烂病拮抗细菌菌株BJ1的鉴定及其抑菌作用

为开发对苹果树腐烂病有效的生防措施,对从山东栖霞苹果果园根际土壤中分离的63株细菌进行了筛选,获得有显著拮抗作用的菌株BJ1。采用玻片法和对峙培养法测定BJ1对苹果树腐烂病菌孢子萌发和菌丝生长的抑制作用及其抑菌谱,根据菌株BJ1的形态特征、生理生化特性及16S rDNA序列对其进行鉴定,并用离体枝条烫伤接种法对腐烂病的防效进行测定。菌株BJ1对腐烂病菌的抑制率为78.38%,其发酵滤液的抑菌率达到70.54%;BJ1可显著降低腐烂病菌分生孢子的萌发率,致使菌丝畸形、分支增多及细胞质外渗;该菌株对常见的8株果树病原真菌具有显著的拮抗作用。经鉴定,菌株BJ1属于微嗜酸寡氧单胞菌Stenotrophomonas acidaminiphila。BJ1不同稀释倍数的发酵滤液均对苹果树腐烂病有明显的抑制作用,其稀释50倍发酵滤液的防效仍可达81.06%,表明该菌株具有良好的生防潜力。

Identification of the antagonistic bacteria BJ1 and its antifungal activity against Valsa ceratosperma

In order to develop an effective biocontrol measure against apple tree canker caused by Valsa ceratosperma, 63 bacterium strains were isolated and screened from the soil around the cultured apple root in Qixia, Shandong Province. The strain BJ1 which had significantly antagonistic effect on V.ceratosperma, was obtained using flat confrontation culture method. The inhibition rates of BJ1 and its fermentation supernatant were 78.38% and 70.54%, respectively. The antagonistic spectrum and the inhibitory efficiency of BJ1 on the conidial germination and hyphal growth of V.ceratosperma were investigated. The results showed that BJ1 could significantly reduce the conidial germination rate and induce alterations on mycelia morphology, such as deformity, branch increasing and cytoplasm exosmosis. In addition, BJ1 showed obvious antifungal activities on several fruit tree pathogenic fungi, such as Sclerotinia laxa, Phomopsis perniciosa and V.leucostoma. Based on the morphologic, physiological, biochemical characteristics and 16S rDNA sequence analysis, the strain BJ1 was defined as Stenotrophomonas acidaminiphila. The strain BJ1 fermentation supernatants with different dilution time exerted obvious inhibitory efficiency on V.ceratosperma growth in detached apple twigs. The control efficiency could reach 81.06% when the supernatant was diluted by fifty times. These results indicated that the strain BJ1 promised to provide a new biological control method in containing apple canker.