Exogenous gibberellic acid reprograms soybean to higher growth and salt stress tolerance

The agricultural industry is severely affected by salinity due to its high magnitude of adverse impacts and worldwide distribution. We observed the role of exogenous gibberellic acid (GA₃) in salinity alleviation of soybean. We found that GA₃ application significantly promoted plant length and plant fresh/dry biomass while markedly hindered by NaCl induced salt stress. The adverse effect of salt stress was mitigated by GA₃, as growth attributes significantly recovered, when GA₃ was added to salt stressed soybean plants. Elevated GA₃ treatments increased daidzein and genistein contents (commonly known as phytoestrogens) of soybean leaves under control and salt stress conditions. Phytohormonal analysis of soybean showed that the level of bioactive gibberellins (GA₁ and GA ₄) and jasmonic acid increased in GA₃ treated plants, while the endogenous abscisic acid and salicylic acid contents declined under the same treatment. GA₃ mitigated the adverse effects of salt stress by regulating the level of phytohormones, thus aiding the plant in resuming its normal growth and development. The presence of GA₁ and GA₄ showed that both early-C13-hydroxylation and non-C13-hydroxylation pathways of GA biosynthesis are functional in soybean. It was concluded that GA₃ ameliorates the adverse effects of salt stress and restores normal growth and development of soybean.