Exploring the Bacillus from vegetable rhizosphere for plant growth.

Bacillus is a ubiquitous soil bacterium for its plant growth-promoting properties, and it is widely used as a biofertilizer. This research aimed to isolate and determine the morphology and biochemical properties associated with plant-growth promotion ability characterizing Bacillus strains. The bacteria were isolated from the rhizosphere of various highland vegetables grown in Andisols soil in Indonesia. Bacillus isolation was conducted using the serial dilution plate method by means of tryptic soy agar. Characterization of the isolated bacteria included Gram staining, biochemical characteristics, pathogenicity testing, and the production of metabolites, including organic acids, phytohormones, and exopolysaccharides. Four bacterial isolates were identified as Bacillus based on colony and cell morphology, the presence of endospore, as well as biochemical properties and metabolite production. The species determination by PCR amplification and 16S rRNA gene sequence analysis revealed that the four Bacillus were identified as Bacillus safensis strain MDL5, Bacillus altitudinis strain RPW2, and Bacillus sp. strain SZ057. The study presents the occurrence of Bacillus within the rhizosphere of vegetables and the understanding of their properties being considered for biofertilizer development. [ABSTRACT FROM AUTHOR]