Screening, Identification And Biocontrol Effect Of Antagonistic Bacteria On Phytophthora Capsici

Pepper phytophthora blight, caused by Phytophthora capsici, is a widely distributed and important soil borne disease in pepper. It is a very value controlling measure to study and develop bio-control bacteria for pepper phytophthora blight.In this study, PSB06was screened from30strains photosynthetic bacteria with obvious inhibitory effect on Phytophthora capsici. Selected Phytophthora capsici LN2as the tested pathogen, according to the occurrence regularity of pepper phytophthora blight, preliminary discussed thed disease-resistant mechanism of PSB6of pepper phytophthpra blight in laboratory. Main results are as follows:The PSB06can restrain to pepper phytophthora blight, according to morphologic observation, physiological and biochemical and16SrDNA sequence result,we can identify PSB06with Rhodopseudomonas sp.LN2was isolated from a pepper plant which was infected with pepper phytophthora blight, according to morphologic observation and ITS sequence result, identify LN2with Phytophthora capsici.Fermentation supernatant of PSB06had obvious antagonism to LN2, the experiment showed that:the inhibition rate of pepper Phytophthora LN2was30.36%on the plate which made of fermentation and PDA in an equal volume; fermentation supernatant liquid can significantly inhibit the formation sporangia, the inhibition rate was58%; fermentation supernatant of pepper blight fungus spore germination inhibition rate was58.41%.PSB06broken bacteria liquid had obvious control effect on hypha growth, the inhibition rate was33.91%, and the sporangium formation inhibition rate was16%.Photosynthetic bacteria PSB06Prevention pepper phytophthora blight in greenhouse and field tests showed that:in greenhouse experiment the control effect reached57.34%; in the field the relative efficacy was45.80±6.18aA under the amount of7500mL/hm2.