Analysis of antimicrobial substances and inhibition of bacteria S34-1to Phytophthora infestans

The purpose of this experiment is to test the effect of bacteria S34-1strain on different development stages of Phytophthora infestans and control efficiency of potato late blight,and to analyze the anti-oomycetes substances of this strain.The dual culture method was used for evaluating the inhibition effect of S34-1strain living and bacterial fluid on mycelia growth of P.infestans,and sporangia suspension mixed with bacterial fluid method for assessing effect of the bacterial fluid on mycelia shape,and potato tuber slices method for estimating the control efficience of late blight,and exclusive method for analysis antimicrobial substances.The results showed that living and bacterial fluid of S34-1strain strongly suppressed the mycelial growth P.infestans,the inhibition rates were 89.32% and 97.12%,respectively.The bacterial fluid not only led in mycelia deformation with irregular enlargement and inclusion leak,but significantly depressed zoospores release from sporangia and germination of zoospores.In addition,the evident control efficiency of bacterial fluid for late blight was obtainedon potato tuber slices.The antagonistic substance produced by S34-1 might be volatile matter.It is suggested that S34-1strain has a great potential in restraining P.infestans and control late blight in future.