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Plant growth promoting rhizobacteria (PGPR) found in the rhizosphere in association with roots are
beneficial bacteria which can enrich the growth of plant directly or indirectly. Rhizobacteria were
isolated using general microbiological media, from different locations of Karimganj District of
Barak Valley Region, Assam, India and were characterized on the basis of morphological,
biochemical and 16S rRNA gene sequencing analysis. All the isolates of were screened for their
plant growth promoting traits such as Indole acetic acid production (IAA), Siderophore (Fe-III
chelating agent), Hydrogen cyanide, Phosphate solubilization ability. IAA production was assayed
colorimetrically using ferric chloride (FeCl3) and perchloric acid. Siderophore and phosphate
solubilization ability were tested qualitatively on Chrome azurolSulfonate agar and Pikovskaya’s
agar respectively. Among all, KD7showed highest IAA production. Phosphate solubilization was
found to be positive for 61% isolates. Siderophore was produced by only 53% of the isolates and 1.6
cm was the highest zone diameter found. KD7 being the most promising isolate was identified at
their strain level by 16srDNA sequencing and found to be Bacillus cereus.
Keywords: Bacillus cereus, PGPR, Soil bacteria, Salinity.