Screening of endophytic bacteria against Phytophthora infestans and prevention of potato late blight
JIANG Ji-zhi,ZHANG Lei,LIU Xuan,ZHENG Xu(College of Life Sciences,Hebei University,Baoding 071002,China)
The objective of this paper is to obtain some endophytic bacteria inhibiting mycelial growth of Phytophthora infestans and evaluate their prevention effectivities of potato detached tissues from potato late blight.The endophytic bacterial strains were isolated and purified with the traditional method from inside the potato,tomato,eggplant and pepper tissues.The suppression of bacterial livings,fermentation liquids,and bacterial fluids on mycelial growth of P.infestans were tested by dual-culture method and filter paper method.Disease control effects of bacterial fluid on potato tuber slices and leaves were investigated.The results showed that 81 endophytic strains were isolated and purified,63 of them could significantly restrain mycelial growth of P.infestans,in which the inhibition rates of 31 strains reached more than 50%.LT-6 isolated from pepper fruit and TD-12 from potato tuber among them displayed the strongest repressing effects on P.infestans,the inhibition rates were 93.12% and 92.24%,respectively.However,the fermentation liquids of all strains had no depressing effect on P.infestans. In addition, it was interested that inhibitory efficiencies of bacterial fluids from these strains on P.infestans were stronger than that of their livings.TD-12strain fluid could not only directly prevent potato tuber slices and leaves, protection effect was 91.89%and 76.23%, respectively, but enhance resistance of potato tuber slices to pathogen(protection effect was 91.35%). It is concluded that TD-12strain might have a great potential role in control potato late blight in future.