Isolation And Identification Of Pathogens And Antagonistic Bacteria Of Rotted Root On Pinellia Ternata In Guizhou Province

Objective: Isolate and identify microbes from rotted root of Pinellia ternata, and their antagonistic bacterium were screened from the rhizosphere soil of Pinellia ternate, so as to provide information for develop an efficient biological control method for this plant disease. Methods: Pathogens were isolated by tissue isolation and their pathogenicity was confirmed by Koch’s Rule. Pinellia rhizosphere microorganisms were isolated and purificated by dilution coated tablet and the antagonistic bacterias were screened by plate confrontation and agar punching method. In addition, idenficaton of fungal pathogens according to the characteristic of colony and spores, and phylogenetic of ITS, TEF. These bacteria pathogens and antagonistic bacteria were further studied through etiological, morphological,bacteriological techniques and 16 S r RNA. Results: 1. 111 strains of microorganisms were isolated from 86 rotted tuber of Pinellia ternata samples collected from 3 different cultivating places in Guizhou province. 12 strains of bacterial pathogens and 10 strains of fungalpathogens were found in rotted tuber of Pinellia ternata. 12 strains of bacterial pathogens belonged to Pectobacterium carotovorum subsp. carotovorum. Among the fungal pathogens, 6 strains belonged to F. Oxysporum and 4 strains belonged to F. solani. 2. 357 strains of microorganisms were isolated from the rhizosphere soil of pinellia ternata of Da Fan, He Zhang, Zun Yi and Qian Lin mountain in Gui Zhou. 9 strains were screened from the rhizosphere soil of pinellia ternata to resist to pathogens. Among the antagonistic bacterias, 6(HM9-1、HM9-2、HD3、HK2、GZDF1、DFJ) strains could resist to bacterial pathogens, 3(GZDF2、GZDF3、GZDF4) strains could resist to both bacterial pathogens and fungal pathogens. 4 strains(HM9-1、HM9-2、HD3、HK2)belonged to Bacillus megaterium, 3(GZDF2、GZDF3 、 GZDF4) belonged to Brevibacillus brevis, GZDF1 strain belonged to bacillus thuringiensis, DFJ strain belonged to Bacillus subtilis. Conclusion: 1. Root-rot of Pinellia ternate caused by bacterial pathogens and fungal pathogens in Guizhou. The pathogenicity of bacterial pathogens was stronger than fungal pathogens. The bacterial pathogens and fungal pathogens can cause tuber rot of Pinellia ternata alone, composite infection also occurred in Pinellia ternata tuber. 2.The rhizosphere soil of Pinellia ternata contained rich resources of biocontrol strains. 3(GZDF2、GZDF3、GZDF4)strains were screened from the rhizosphere soil of pinellia ternata had strong antibacterial activity on bacterial pathogens and fungal pathogens and potential to develope for biocontrol agents.