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The sustainable development of people’s understanding to the agriculture and the side effect of agricultural chemicals have draw people’s attention on biological control of plant diseases.the bio-control strategy already became the safeguard of agriculture Many countries have reported it has the potential to prevent and control many kinds of plant diseases. fluorescence pseudomonad has certain prospects for development. It prevents disease through producing certain secondary metabolism material, like 2,4-DAPG This article, the subject of which was obtained by our country wheat take-all natural decline soil, studied phlG in 2,4-DAPG metabolism regulation.Few reports on genetic information of antibiotics 2,4-DAPG biosynthetic gene cluster upstream phlG phlACBD had been found and the phlG strain 2P24 and P. fluorescens CHA0 has been reported in the phlG amino acid homology was as low as 58.57%, and can not speculate relations of strains 2P24, the phlG gene and 2,4-DAPG biosynthesis, transport ormetabolism. In order to resolve phlG gene function, the test strain 2P24 the phlG by constructing the mutant gene, and using thin layer chromatography and liquidchromatography mutant 2,4-DAPG and MAPG changes, and GacS, RsmE Genes and gene regulatory relations phlG. Trial also measured traits and mutant strains of wheat root colonization in the circumstances and on the biological traits of wheat. The study also demonstrated 2,4-DAPG producing strains mixed with different types of colonization of biocontrol situation.phlG gene mutation fungus of the strain 2P24 for 2,4-DAPG produced was carried on the growth curve determination, the plate oppress the anti-determination andβ-galactosidase examination. We discovered it was not affect the growth speed of the strain 2P24, simultaneously not affect 2,4-DAPG the normal expression. In the thin layer chromatographic analysis experiment we found that the phlG gene was related with 2,4-DAPG degradation and was the important factor for the 2,4-DAPG degradation. Next, using liquid chromatography determination discovered it has produced its synthesis precursor MAPG after 2,4- DAPG degrades. Moreover, we also discovered that without the phlG gene only made 2,4- DAPG degeneration speeds slow, and according to the above extrapolated still have other regulation genes to degrade 2,4- DAPG in strain 2P24. For further examining other important factors to the phlG gene expression influenced, in the experiment we constructed strain 2P24 phlG gene LacZ to melt the zygote, and distinguished the flaw GacS gene and the RsmE gene. Throughβ-galactosidase examination discovered that the GacS gene was regulating the function to the phlG gene’s expression, the RsmE gene negative regulates the phlG gene the expression.In this experiment we also found after phlG gene mutation, it did not change lives the fungusproof to breed ability. We discovered that through the biocontrol bacteria mixed colonization the different type’s strain breeds quantity seeds and the root have the obvious difference surely, the pseudomonads compared to the subtilis bud spore fungus change by the seed surface adsorption, therefore the disease-carrying quantity is bigger; However along with adult plant’s growth, the subtilis bud spore bacillus is rapid in the root growth, and in the root breeds has process to display the strong competitive power surely.
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