Pink pigmented facultative methylotrophs (PPFMs) are diversified group of microorganisms that promote plant growth by producing indole acetic acid (IAA) and cytokinins. The objective of the present study is to isolate and characterize methylotrophic bacteria from the phyllosphere of mustard plant (Brassica niagra) and to study their plant growth promotion in tomato (Lycopersicon esculentum L.). Bacteria were isolated from the phyllosphere and the conserved mxaF gene sequence was amplified. Production of IAA was determined by High Performance Thin Layer Chromatography (HPTLC) and further quantified by spectrophotometric analysis. Effect of seed bacterization with the bacterial isolate MM2 was studied for percentage seed germination, root & shoot length. Based on NCBI BLAST search of the mxaF sequence obtained, the bacterial isolate was identified as Methylobacterium extorquens MM2. The amount of IAA produced by M. extorquens MM2 was 6.16 μg/ml. M. extorquens MM2 significantly increased seed vigour index (SVI) in tomato plants. The SVI of the treated plant was 1462.56 ± 83.96 as compared to the control, 1019.94 ± 113.61. Foliar application of M. extorquens MM2 also contributed a substantial impact on growth of tomato plant. The bacterial isolate M. extorquens MM2 thus can be employed in the crops for sustainable agriculture.
Key words: HPTLC, Indole acetic acid, Methylotrophs, mxaF, Seed vigour index
|
