Analyzing plant growth promoting Bacillus sp. and related genera in Mizoram, Indo-Burma biodiversity Hotspot

Mizoram, a state of Northeast India is known as biodiversity hotspot having a large forest cover area of the total land. There are studies on fauna and flora of Mizoram, but no reports are available on plant growth promoting (PGP) bacillus species. Present study analysed the genotypic diversity and phylogenetic relationships among PGP Bacillus spp. and related genera isolated from the pristine forests from Mizoram. A total of 31 morphologically identified Bacillus and related isolates were screened for PGP traits. Nineteen Bacillus sp. was identified as potential strains which were further processed for quantitative estimation of phosphate solubilization and Indole acetic acid (IAA) production. Quantitative test using the potential PGP strains showed that the concentration of the soluble P were between 47.73-156.83 μg/ml whereas the concentration of the IAA was highest in PG36 (10.23 μg/ml) and lowest in PG16 (2.88 μg/ml). The highest soluble P production was present in the strain PG36 (156.83 μg/ml). Molecular phylogenetic study based on 16s rRNA assigned them under the genus Bacillus with maximum similarity with Bacillus thuringiensis, Paenibacillus sp., B. cereus, Lysinibacillus fusiformis, L. xylanilyticus and B. megaterium. PCR screenings were performed for PGP related genes involved in the biosynthesis of acid phosphatase (AcPho) and 1-aminocyclopropane-1-carboxylate deaminase (accd) and seven isolates were gave an amplified fragment for AcPho & accd gene. The Bacillus species with different multifunctional PGP capabilities, and genetic diversity found in this study could be further explored as inoculants for enhancing crops production in this region.