Selection And Identification Of Antagonistic Bacteria Against Fusarium Solani And The Control And Promotion Effect

Pepper root rot caused by Fusarium solani (Mart.) App. et Wollenw is a kind of typical soil born disease. It could reduce output of pepper by 20%~30%, more than 50% severely and even have no harvests. The main method for contol of soil born diseases is to use fungicides with wide spectrum and good effect. Because pathogens are easy to be resistant to them, the increasing application rate make higher fungicide residuces, and damaged ecological balance and theaten human beings'heath and safety. Threrefore, it is of extreme importance to seek for new fungicides or more effective methods to control soil born diseases. Selection antagonistic bacteria, fungi or actinomycetes are effective biological control methods. An expanding workload will be brought, and the isolates have little enven no effect on the plant diseases because of inappropriate screening approach.This study is aim at a short-term and effective method to select antagonistic bacteria to control pepper root rot causede by Fusarium solani, promote pepper growth potentially, and clarify the raxonomic status.With Fusarium solani as indicator, 4 antagonistic bacteria were selected from the rhizosphere of pepper in Heilongjiang Province, and named D221, II621, 15-1-1 and 19-2-3 respectively.Strain D221, II621 and 15-1-1 was evaluted in greenhouse experiment, and pepper root rot caused by F. solani was controlled significantly by different treatments, including direct seeding with drench and seeds soaking, transplant with root drench. And the control efficacy of strain D221, II621 and 15-1-1 were 73.18%, 72.67% and 70.86% in transplant experiment. The control efficacy of strain D221 and II621 on pepper root rot caused by F. solani was siginificant more than that of 15% hymexazol AS, and the efficacy of strain 15-1-1 was equivalent with that of 15% hymexazol AS. In culture assay, several different pathogens including Phytophthora sojae, Sclerotinia sclerotinorum, F. oxysporum, Rhizoctonia solani, Bipolaris sorokiniana, Verticillium dahliae and F. moniliforme were inhibited significantly by strain D221, II621 and 15-1-1, respectively.Strain D221, II621 and 15-1-1 could promote pepper seeds germination and improve germination uniformity respectively. F. solani spores germinaton were inhibited to reduce the infection on pepper seeds. Pepper radicle growth was promoted by 34.33%, 37.61% and 33.83% respectively. The strain D221 and II621 were identified as Bacillus subtilis and srain 15-1-1 was identified as Bacillus amyloliquefaciens by morphological test, physiological and biochemical tests and 16S rDNA sequence analysis. And the sequences were registered in GenBank getting the accession No. JF495161, JF495162 and JF495163, respectively.