Endophytic bacterial metagenomics and phosphate solubilization activities in an endemic legume Humboldtia brunonis Wall.

Abstract

Phosphate's abiotic stress and bioavailability limit its availability to plants. Plants collaborate with phosphorus solubilizing microorganisms to resolve this issue, resulting in a distinct microbial ecology. Bacterial diversity and other functional attributes of plant-associated microbial ecology in the endemic legume Humboldtia brunonis Wall. have been studied using 16s metagenomic amplicon analysis and culture-dependent selective media-based culture techniques. This study aimed to gain insight into bacterial diversity and isolate phosphate solubilizing bacteria. Bacterial isolates were grown in Pikovskaya's medium and incubated at a required temperature for 48 h before getting characterized by examining colony morphology with physiological and biochemical properties. The pure culture of bacterium is identified and assigned to its taxonomy using 16S rRNA gene sequence analysis as a tool. Brevibacillus brevis is the phosphate solubilizing endophyte associated with this endemic plant. A clear zone encircling the bacterial colony on Pikovskaya's medium indicates that this bacterium can solubilize phosphate. To better apprehend the endophytic root bacterial diversity, Illumina MiSeq metagenomics using the GAIA workflow, discovered forty-three endophytic bacterial species. The use of METAGENassist and KEGG database examined taxonomic and functional attributes of the endophytes. Exploration of biofertilizing, biocontrolling, and phytostimulating abilities is evident by the presence of the bacteria contributing to dinitrogen and nitrogen fixers, carbon fixers, ammonia oxidizers, and nitrite reducers. The figure also emphasizes their energy sources, oxygen requirement, sporulation, and their nature of interaction with the plant. The endophyte community also delivers information on this endemic plant's survival strategy.