EFFECTS OF BACTERIALAGENTS OF Bacillus subtilis ANDAcinetobacter SP ON MICROBIAL DIVERSITY INRHIZOSPHERE SOIL OF PEPPER SEEDLINGS

摘要

With the environmental and ecological securit y problems caused by the continuous use of chemic al fertilizers and pesticides, more and more biologic al agents have been developed and used in recent ye ars. Through in-depth analysis of the effects of two kinds of biological agents on microbial diversity in t he rhizosphere of pepper seedlings, this study explores probiotic strains that promote growth and disease resistance, and provides some theoretical basis an d data support for farmers to purchase and select biological agents. In the experiment of this study, two d ifferent kinds of biological agent were applied to the roots of pepper seedlings, whose rhizosphere soil w as collected after 10 days, 20 days, 30 days and 40 days respectively. The total DNA, of bacteria in rhizo sphere soil was extracted by soil genomic DNA extraction kit with magnetic bead method. Besides, theexperiment used polymerase chain reaction-denaturi ng gradient gel electrophoresis (PCR-DGGE) techni que to analyze the effects of two biological agents o n bacterial diversity in the rhizosphere soil of peppe r seedlings. The results showed that the total abunda nce and species of microflora in the rhizosphere soil of pepper seedlings irrigated with Bacillus subtilisand Acinetobacter sp. increased, while the plant growth in the Bacillus subtilis treatment group and Acinetobacter sp. treatment group was significantly bet ter than that of the blank control group, and the Bac illus subtilis treatment group was the best. It was fur ther found that Uncultured bacterium clone (JF236035), Bacillus firmus OrfA gene (U61539), Uncultur ed Gemmatimonadete (AY922177), and Uncultured methylibium sp. (KF469187) these four kinds of ba cteria exist alone in Acinetobacter sp. treatment gro up, while Uncultured pseudomonas sp. (JQ279040) existed separately in the Bacillus subtilis treatment group. At the same time, it was found that the abund ance of Bacillus firmus strain sctcc471(H0622343). Uncultured bacterium clone (FJ719098), andUncult ured alpha proteobacterium (KM978288) in rhizos phere soil of Bacillus subtilis treatment group wasmuch higher than that of Acinetobacter sp. treatment group and clear water control group on the y. To sum up, root irrigation withbiologii s ofBacillus subtilis and Acinetobacter sp.t the structure and abundance of microorgar crop rhizosphere and promote the colonizat icroflora and the growth of pepper seedling tain extent. The high abundance of five ba ains, Acinetobacter sp. (AM295822), Uncueudomonas sp. (JQ279040), Bacillus firmus tcc471(HQ622343), Uncultured bacterium 719098), and Uncultured alpha proteobact M978288), may play a positive role in prore growth of pepper seedlings, which lays aon for further research and development ofal agents, and provide new ideas and metho vironmental control and ecological security on.