Isolation, Identification and Biological Characteristics of An Endophytic Bacterium from Juncao "Oasis No.1" in Hainan

【Objective】The study aimed to explore the growth-promoting properties and antagonism of pathogenic fungi of an endophytic bacterium HLY3-2 isolated and identified from the leaves of Hainan Juncao"Oasis No.1", with a view to providing basic theory for the biological control of plant pathogenic fungi and the study of plant probiotic mechanism.【Method】The endophytic bacterium HLY3-2 was isolated from the leaves of Hainan Juncao "Oasis No.1" by using the dilution plating method. Through morphological identification, 16SrDNA sequencing and homology analysis, a phylogenetic tree was constructed to identify the genus and species of this strain. The biological characteristics were explored by using the plate antagonism method and various physiology and biochemistry culture medium and growth-promoting property culture medium.【Result】HLY3-2 was identified as a strain of Bacillus thuringiensis through the endophytic bacterium morphology, physiology and biochemistry characteristics and 16SrDNA sequencing. The results of antagonism of pathogenic fungi showed that the strain HLY3-2 had some inhibition effect on Magnaporthe oryzae and Foctropical race4 with the bacteriostasis rates of 18.45% and 30.65% respectively. Then, according to results of the analysis on physiology and biochemistry characteristics, the strain did not have the ability of utilizing citrate, cellulose and starch. And it could not produce ester substances and hydrolyze gelatin during growth, but it had the ability of producing proteases and catalase during its growth and metabolism process. The results of growth-promoting property analysis showed that the strain had the ability to dissolve inorganic phosphorus and organophosphorus and degrade silicates, and could not produce iron carriers, but had strong IAA-producing ability.【Conclusion】The experiment results show that the endophytic bacterium HLY3-2 has a role in promoting plant growth and controlling disease.