Screening, evaluation and identification of antagonistic bacteria against Fusarium oxysporum f. sp. lycopersici and Ralstonia solanacearum.

Tomato Fusarium wilt and bacterial wilt caused by Fusarium oxysporum and Ralstonia solanacearum are two common diseases throughout tomato-growing areas.Use of antagonistic bacteria to control the diseases can potentially reduce the negative effects of chemical fungicides on vegetable and the environment.Here,we screened and evaluated the control efficiencies of antagonistic bacteria against F.oxysporum f.sp.lycopersici and R.solanacearum in vitro.367 strains were isolated and purified from rhizosphere soil of tomato,pepper and watermelon plant’s in Ningxia,Jiangsu and Fujian provinces.Test on antagonistic ability revealed that 22 strains showed strong and steady antagonism against F.oxysporum and R.solanacearum.All the above 22 strains could produce protease,whereas they could not produce chitinase.Three strains could produce cellulase and siderophore,separately.In pot experiment,strains PTS-394 could control Fusarium wilt and bacterial wilt effectively,with control efficiency of 77.4% and 80%,respectively,and control efficiencies of strains H-70,L-1 and SJ-280 were all above 60%.16S rRNA sequence analysis showed that the four strains were Bacillus subtilis.