ABSTRACT
Recently, priming with γ-aminobutyric acid (GABA) and β-aminobutyric acid (BABA) received wide acceptability due to their capacity to equip the plants for encountering abiotic stresses in a cost-effective manner, that is, without a heavy energy investment on defense-related processes. Non-protein amino acids like BABA and GABA exert their priming effects on plants by inducing the natural defense mechanisms against abiotic stresses. Even though, the precise mechanism of GABA/BABA priming in plants is still a mystery, their role as signaling molecules during abiotic stress is proven. In the case of GABA, it serves a dual role as a metabolite and/or as a signaling molecule in plants and is transported across the membrane through high-affinity transporter GAT1. Similarly, an aspartyl-tRNA synthetase (AspRS) protein encoded by the IBI1 gene is thought to function as the BABA receptor in plants. BABA-induced defense for biotic stress is mostly achieved by jasmonic acid (JA)-dependent regulated defense mechanisms, whereas abiotic stress resistance was found to be mainly mediated via ABA as well as SA-induced signaling cascades. Thus, as far as BABA is concerned, it acts at multiple levels to induce the plant for a faster and stronger activation of stress-specific defense mechanisms upon stress exposure.
