Screening Of Plant Growth-promoting Rhizobacteria And Cloning Of The ACC Deaminase Gene

This study was put forward to get bacteria, which can effectively promote plants growth.Soil samples were gathered from the roots of different plants in the places of Innor Mongolia, Shandong, Yunnan, Henan, etc. Then the target bacteria, ZX-7 and ZX-9, were separated after promoting trails; and MX01 and LG, which have the genes of 1-aminocyclopropane-1-carboxylic(ACC)deaminase, by PCR introduction.Bacterial strains MX01 and LG, two biocontrol agents isolated from wheat soil of Shandong and canola soil of Xianggelila, were classified into Pseudomonas fluorescens biovarâ…¡and biovarâ…£, respectively,by analyzing the 16S rDNA sequences and detection of physiological and biochemical characteristics. Both MX01 and LG produced several antifungal compounds, such as, hydrogen cyanide (HCN), siderophore and extracellular proteinase, MX01 can produce antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG), but LG cannot howed inhibitory to Ralstonia solanacearum,Rhizoctonia solani and other pathogens in the dual-culture test on plates. In greenhouse, strain MX01 and LG showed high efficiency to control soil-borne disease such as tomato bacterial wilt and wheat take-all.For further understanding the growth-promoting mechanism, ACC deaminase gene were studied and clone in P. fluorescens MX01In addition, the effective gene library of MX01 was built to clone ACC deaminase by PCR introduction.