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.