A newly isolated Bacillus megaterium OQ560352 promotes maize growth in saline soils by altering rhizosphere microbial communities and organic phosphorus utilization

Abstract

Limited activity of the rhizosphere microbiome and reduced soil nutrient cycling, in particular phosphorus (P), in saline soils, leads to a loss in crop productivity. Using plant growth-promoting rhizobacteria (PGPR) as microbiological fertilizer to regulate rhizosphere ecology and increase nutrient uptake is a potential approach to improve plant growth in saline conditions. In present study, a novel Bacillus megaterium strain isolated from saline soil was found to promote crop growth. The results showed that a B. megaterium OQ560352 strain altered the composition of fungal and bacterial communities in the rhizosphere of maize and increased the relative abundance of genes involved in P cycling. Actinobacteria and Bacteroidetes were identified as phyla because they had a negative correlation with soil P concentration and a positive correlation with alkaline phosphatase (ALP) activity. Compared to chemical fertilizer applied alone on saline soil, NPK fertilizer mixed with B. megaterium improved shoot biomass, shoot P concentration, soil P concentration, and ALP activity by 4%, 6%, 10%, and 13%, respectively. Collectively, the present study suggests that the novel isolated B. megaterium is an efficient PGPR for regulating the rhizosphere microbiome in saline soils to promote plant resistance to salinity.