Identification and antibacterial activity of antagonistic bacteria R2-2 from the rhizosphere of vegetables

Abstract

Strain R2-2 antagonistic against the fungi and bacterial pathogen was isolated on NA and potato dextrose agar from the rhizosphere of vegetables from Kunming suburbs in Yunnan.On basis of phenotypic properties and Biolog automatic microbiology analysis system and on basis of 16S rDNA determination and analysis,strain R2-2 was identified to be B.methylotrophicus.In vitro antagonistic assay showed strain R2-2 could suppress the growth of five plant bacterial pathogens(Xanthomonas campestris pv.campestris,Erwinia carotovora subsp.carotovra,Xanthomonas campestris pv.begoniae,Xanthomonas oryzae pv.oryzae,Xanhomonas oryzae pv.oryzicola) an d four plant fungal pathogens(Phytophthora capsici,Fusarium oxysporum,Fusarium solani,Rhizoctonia solani),and showed strong antibiosis activity to Xanthomonas oryzae pv.oryzae and Xanhomonas oryzae pv.oryzicola with inhibition zone diameter of 6.83 and 7.03 cm,respectively.16S rDNA sequence of the strain was registered in GenBank and the accession No.is JN648098.