GABA-dependent ethylene response mitigates salt-induced growth and yield inhibition through stabilizing carbon energy, nutrients accumulation and metabolomic fingerprinting in wheat

Wheat productivity has been influenced adversely by salt stress, and regarded as a major challenging issue to secure food status globally. Considering the salt-induced stress, the present study investigated the interplay between γ-aminobutyric acid (GABA) and ethylene could essentially aid in protecting plant growth, metabolic and yield responses in wheat (Triticum aestivum L.) under salt stress at vegetative and yield stages. The additive effects of GABA and ethylene has positively influenced GABA shunt pathway and tricarboxylic acid (TCA) cycle, with sustained carbon energy, nutrients retention, and optimized photosynthetic end-products in response to salt stress. In the present study, the modulation of GABA shunt pathway substantially influenced by GABA or ethylene in salt-stressed wheat. Strikingly, the regulatory enzymes of TCA cycle were significantly increased when a cumulative supplementation of GABA and ethylene was provided under salt stress. Additionally, metabolic profiling has shown the accumulation of nitrogenous compounds, secondary metabolites, lipids and its derivatives, along with compounds containing sulfur and silicon, which are primarily reported to be involved in plant defense. Substantiation of the findings through employing GABA (aminooxyacetic acid) and ethylene (aminoethoxyvinylglycine) biosynthesis inhibitors has indicated GABA-dependent ethylene responses in alleviating salt-induced abnormalities in wheat. In the future, understanding these responses could grant insights for translating wheat research towards breeding practices to navigate climatic challenges imposed on wheat security through GABA and ethylene interactions.