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The tobacco the PGPR preliminary research. The study includes Isolation, Screening and Identification of bacteria; marked with antibiotics dual notation in sterilized soil and non-sterile soil the chemoattractant medium and no chemoattractant medium under strain colonization sites and colonization determined the amount of relations marked strain population dynamics in the soil, four rhizosphere bacterial chemotaxis; conducted a preliminary study of the mechanism of disease prevention and growth promotion. 1. The smoke the Conveyancing like 13 were collected from Yunnan Province, Dali, Chuxiong, Kunming, Qujing and Yuxi, isolated on different media in the press outside the rhizosphere, root surface and within the rhizosphere, isolated from the rhizosphere bacterial 753. The tablet antagonistic Screening of Pythium sp., Rhizoctonia solani and of Phytophthora parasitica var. nicotianae Tucker antagonism antagonistic bacteria 97, further determination of the impact of these strains on the the tobacco germination rate and seedling growth screened 20 growth-promoting bacteria, and then screened through greenhouse pot experiment 7, two greenhouse relative control The disease effects reached 42.22% and 37.78%, respectively. 2. Seven bacterial morphology, cultural characteristics and physiological and biochemical characteristics, and semi-automatic identification system to adopt ID32GNATB bacterial, the RB-42 and RB-78 and RB-89 was identified as fluorescent Pseudomonas -1 (Pseudomonas fluorescens-1), verdigris Pseudomonas (Pseudomonas aeruginosa), Pseudomonas fluorescens bacilli -2 (Pseudomonasfluorescens-2), RB-1 and RB-59 were identified as the day hook dimensional Enterobacter cloacae (Enterobacter gergoviae) and Enterobacter cloacae ( Enterobacterclocae), R2 was identified as radioactive Agrobacterium (Agrobacterium radiobacter), R4 identified as Bacillus (Bacillus sp.) 3. Selection of fluorescent Pseudomonas strains were RB-42 and RB-89 double labeling of rifampicin and streptomycin sulfate genetic marker strains are able to successfully colonize in the tobacco plant, the root table in sterilized soil processing chemoattractant under the conditions of the medium, the strain in the amount of colonization of the apical are greater than the non-sterilized soil and without chemotactic medium. The dynamics that strains in the root table: marked strain, followed by a gradual decline in the the tobacco seedlings root surface colonization amount has a pre rise process was applied to four weeks after the tobacco seedlings roots there is still some colonization amount. 4. For the RB-89, RB-42, R2, and the RB-1 and other 4 bacterial chemotaxis measurement showed that 4 of bacteria on the root exudate chemotactic value greater than 1. Selection of RB-42 and RB-89 strain Determination of chemotactic substances, amino acids chemotaxis strongest organic acids, followed by the weakest of carbohydrate. Chemotaxis to organic acids tyrosine, proline, glycine, phenylalanine showed strong chemotaxis of the group table acid, threonine no chemotaxis; strains no significant difference, RB called lactate chemotaxis performance than its dead organic acids and strong. 5. This article determination on behalf of the recruits and the mechanism of action. Determination of the strain capacity of production of HCN, RB-4 2, the RB-9 and M-7 8 having a higher spoon production muscle N capability, combined with the result of promoting the screening process comparison found that the strain of the high ability of producing HCN its growth promoting good results. RB-2, RB-89 strains inhibit the growth of pathogenic Phytophthora wire by microscopic examination, the strains treated hyphae, hyphae were fingers forked rough dwarf shorter, stubby branches, protoplast concentrated hold ascus also deformed, sterilization of fermentation broth processing the pathogenic Phytophthora wire growth also has a similar result, the degree of inhibition of strong or weak. Prove screened strains can promote the absorption of the tobacco plant, P, K nutrition elements. Rhizosphere bacteria can cause the rhizosphere pH value decline, enabling the rhizosphere microenvironment Mn, Zn, P, L, Ca, Mg ion content increased. Through this study, it is found that screening of rhizosphere bacterial disease prevention and promoting and improving the ability of K content in tobacco plants.
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