Plant growth promoting potential of Brevibacterium sediminis A6 isolated from the tea rhizosphere of Assam, India

Abstract

Abstract The Tea rhizosphere microbial community harbor diverse plant growth promoting (PGP) rhizobacteria and are relatively less explored. In our study, we isolated 23 distinct bacterial morphotypes from the tea garden of Assam, India. The isolates were screened for their plant growth promotion (PGP) and antifungal traits against three pathogenic fungi, namely Rhizoctonia solani, Corticium rolfsii, and Fomes lamaensis. Out of 23 isolates, 7 isolates showed potential in antifungal activities, amongst which, isolate A6 was found to have promising PGP and antifungal traits. Isolate A6 also exhibited biosurfactant production abilities in the presence of 2% dextrose as a carbon source. Biochemical and molecular characterization revealed its identity as Brevibacterium sediminis. Further quantification assay showed the amount of indole acetic acid (IAA) production (72.51 ± 2.18 μg/mL) and phosphate solubilization (60.644 ± 3.098 μg/mL) by the isolate A6. The PGP activity of the isolate was validated by in vitro trials on rice seedlings. A6 treated seedlings showed a significantly higher root length (p = 0.0350), shoot length (p