ASCORBIC ACID PRODUCTION IN ROOT, ROOT NODULE AND IN CULTURE BY RHIZOBIUM UNDICOLA ISOLATED FROM THE AQUATIC LEGUME NEPTUNIA OLERACEA LOUR.

Abstract

The root nodules of Neptunia oleracea Lour. aquatic legume contained higher amount of ascorbic acid than root. A symbiont was isolated from root nodule of the plant and was identified as Rhizobium undicola based on biochemical and 16S rDNA sequence based molecular phylogenetic approach. The symbiont produced large amount of ascorbic acid (224μg/ml) from glucose supplemented basal medium. The production of ascorbic acid by the symbiont was increased to 187 % over control under optimized nutrient condition. The higher amount of ascorbic acid in nodule might be produced by Rhizobium sp. to meet its metabolic requirements, particularly in facilitating root infection for nodulation and delay nodule senescence. Results of the study supported the hypothesis of synthesis of ascorbic acid in root nodules of legume plant.