草莓根腐病拮抗细菌的分离筛选与鉴定

为筛选和鉴定草莓根际土壤中对草莓根腐病菌(Colletotrichum gloeosporioides)有拮抗作用的细菌,采用平板对峙培养法,对从北京市昌平区小汤山草莓种植基地土样中分离到的306株菌株进行初筛,复筛后获得了1株拮抗效果好且具有较好稳定性的菌株GF-98,其抑菌带宽度为9.3 mm。此外,菌株GF-98的抑菌谱较广,对草莓根腐尖孢镰刀病菌、草莓灰霉病菌、草莓根腐石楠拟盘多毛孢病菌等9种植物病原真菌均有较好的抑菌效果。在显微镜下观察发现,菌株GF-98的代谢产物对草莓根腐病菌有致畸作用,包括菌丝缩短、粗细不均、分枝增多扭曲、细胞原生质浓缩等现象。16S rDNA基因分析以及生理生化鉴定等方法表明,菌株GF-98为多粘类芽孢杆菌(Peanibacillus ploymyxa)。

Screening and identification of antagonistic bacteria against Colletotrichum gloeosporioides

The object of this research is to screen and identify antagonistic bacteria against strawberry root rot(Colletotrichum gloeosporioides) from strawberry rhizosphere soils.Totally,306 bacteria strains were isolated from strawberry rhizosphere soils.The contrarious cultivation method was adopted to screen antagonistic bacteria against Colletotrichum gloeosporioides.Among 306 bacteria strains,GF-98 had the highest antagonistic activity against Colletotrichum gloeosporioides with an antagonistis strip width of 9.3 mm using contrarious cultivation method.Furthermore,GF-98 also had high antagonistic effects against nine pathogens including Fusarium oxysporum,Botrytis cinerea Pers.,Pestalotiopsis photiniae of strawberry,and so on.Observed by light microscope and scanning electron microscope,the metabolic products of GF-98 had teratogenicity to the mycelium morphology and cellular structure of Colletotrichum gloeosporioides,including hyphae shorten,branch increased,branch distorted and bioplasm condensed,and so on.The results of 16S rDNA analysis and physiological and biochemical character analysis showed that GF-98 belonged to P.fluorescens.