Gibberellins target shoot-root growth, morpho-physiological and molecular pathways to induce cadmium tolerance in mung bean

Abstract

Cadmium (Cd) inhibits plant growth, perturb nutrient uptake and affect chloroplast ultra structure. Cd soil pollution is mainly contributed by excessive use of phosphate fertilizers, nickel Cd batteries, plating and sewage sludge. Research investigations deciphering role of Cd in affecting overall performance of mung bean is least understood. Likewise ameliorative effects of gibberellins (GAs) in Cd induced toxicity in mung bean are lesser known. In this context, effects of Cd stress (CdCl2, IC50 −500 µM L−1) with or without GA3 application on mung bean (Vigna radiata L. Var. SML-668) plants were comprehensively investigated under controlled conditions. In brief, a total of 80 mung bean plants (15 days old of uniform height) were divided into four groups, with each group (n=20) subjected to four different treatments (Control, CdCl2, GA3, CdCl2+GA3), twice during the entire life cycle of mung bean plants (until harvest 85-90 days). Results revealed negative impacts of Cd stress on shoot morphometry (plant height, leaf surface area, stem diameter, shoot fresh weight, number of leaves, number of pods, length and diameter of pods), root morphometry (root length, root surface area, root dry weight, nodule number and nodule diameter), photosynthetic pigments and agronomic traits. GA3 ameliorated Cd stress by modulating shoot and root growth rates, improving overall plant metabolism, photosynthetic pigments, and shoot and root morphometry and transcript abundance of VgPCS1, VgPCS2, VgCdR and VgIRT1. Current study proposes GA3 application for the effective management of Cd induced phytotoxicity in mung bean plants.