Efficacy of seed priming strategies for enhancing salinity tolerance in plants: An overview of the progress and achievements

Soil salinization adversely affects sustainability and productivity of cultivable land by altering seed germination, growth and physio-biochemical attributes consequently limiting agricultural output. To sustain crop productivity, therefore, the need to comprehend plant tolerance mechanism becomes imperative. Enhancement of stress resilience can be achieved through several methods but here, we delineate a novel cost-effective ecofriendly technique known as priming, which involves pre-germinative exposure of seeds to eliciting factors that induce mild stress and fortifies plants against subsequent stressful constraints. Priming and sensitizing the seeds in different chemicals prior to sowing enhances its imbibition capacity and pre-germinative metabolic processes to improve seedling emergence, growth, vigor and productivity. Enhanced activity of Na+/H+antiporters in invigorated seedlings favour Na+ exclusion and K+ uptake thereby stabilizing membrane potential. Priming mediated memory upregulates expression of genes associated with giberrellic acid (GA) biosynthesis and photosynthesis that accelerates seedling emergence. Priming induced reprogramming of antioxidant genes and polyamine metabolism genes improve adaptability under salt stress. Seed priming also enhances DNA repair, stabilizes RNA, increases de novo protein synthesis to maintain genome integrity. This review presents a comprehensive update on the efficacy of seed priming, its associated physio-biochemical and molecular modulations that would aid to eradicate salt-induced adversities conferring tolerance to the primed plants and enhance productivity.