Physiological properties and genomic insights into the plant growth‐promoting rhizobacterium Brevibacillus laterosporus K75 isolated from maize rhizosphere

Abstract BACKGROUND When looking for a safer alternative to pesticides that are potentially harmful to living organisms, one of the directions worth looking at are plant growth‐promoting rhizobacteria. The purpose of the research was a comprehensive characterization of Brevibacillus laterosporus K75, a strain isolated from maize rhizosphere. Many studies have proved B. laterosporus to be a biocontrol agent; however, little is known about B. laterosporus as a plant growth‐promoting rhizobacterium. RESULTS Ninety strains were screened for plant growth‐promoting activities. Four strains with the best plant growth‐promoting traits ( Rhodococcus qingshengii K8, Bacillus subtilis subsp . stercoris K73, Brevibacillus laterosporus K75, and Brevibacillus laterosporus K89) were used to research their effect on maize growth. Under sterile conditions, B. laterosporus K75 showed the best stimulatory effect, significantly improving the weight of roots, shoots and leaves, and considerably increasing content of chlorophyll. In unsterilized soil, B. laterosporus K75 significantly improved length of roots and weight of leaves compared to the K73, K89, and untreated control. Moreover, B. laterosporus K75 significantly increased specific leaf area compared to the untreated control and to other inoculant treatments. The genome of B. laterosporus K75 was compared to the recently published B. laterosporus MG64. Genome‐mining displayed differences in identified plant growth‐promoting genes and biosynthetic gene clusters of secondary metabolites. The B. laterosporus K75 genome possessed additional genes involved in indole‐3‐acetic acid production and phosphate solubilization that could be attributed to its ability to enhance maize growth. CONCLUSION Our study demonstrated that B. laterosporus K75 is a promising candidate for use in inoculant formulation, effectively facilitating maize growth. © 2022 Society of Chemical Industry.