Seed ‘primeomics’: plants memorize their germination under stress

Abstract

Seed priming is a pre-germination treatment administered through various chemical, physical and biological agents, which induce mild stress during the early phases of germination. Priming facilitates synchronized seed germination, better seedling establishment, improved plant growth and enhanced yield, especially in stressful environments. In parallel, the phenomenon of 'stress memory' in which exposure to a sub-lethal stress leads to better responses to future or recurring lethal stresses has gained widespread attention in recent years. The versatility and realistic yield gains associated with seed priming and its connection with stress memory make a critical examination useful for the design of robust approaches for maximizing future yield gains. Herein, a literature review identified selenium, salicylic acid, poly-ethylene glycol, CaCl 2 and thiourea as the seed priming agents (SPRs) for which the most studies have been carried out. The average priming duration for SPRs generally ranged from 2 to 48 h, i.e. during phase I/II of germination. The major signalling events for regulating early seed germination, including the DOG1 (delay of germination 1)-abscisic acid (ABA)-heme regulatory module, ABA-gibberellic acid antagonism and nucleus-organelle communication are detailed. We propose that both seed priming and stress memory invoke a 'bet-hedging' strategy in plants, wherein their growth under optimal conditions is compromised in exchange for better growth under stressful conditions. The molecular basis of stress memory is explained at the level of chromatin reorganization, alternative transcript splicing, metabolite accumulation and autophagy. This provides a useful framework to study similar mechanisms operating during seed priming. In addition, we highlight the potential for merging findings on seed priming with those of stress memory, with the dual benefit of advancing fundamental research and boosting crop productivity. Finally, a roadmap for future work, entailing identification of SPR-responsive varieties and the development of dual/multiple-benefit SPRs, is proposed for enhancing SPRmediated agricultural productivity worldwide.

Osmopriming with Polyethylene Glycol (PEG) for Abiotic Stress Tolerance in Germinating Crop Seeds: A Review

“…As shown in Table 1, drought stress considerably decreased the germination performance of asparagus (Asparagus officinalis L.) [32], barley (Hordeum vulgare L.) [31], celery (Apium graveolens L.) [57], cumin (Cuminum syminum L.), rice (Oryza sativa L.) [58,59], sorghum (Sorghum bicolor L. Moench) [5], and wheat (Triticum aestivum L.) [2]. However, under the conditions of drought stress, the above-mentioned crops pretreated with PEG have shown improved seed germination and seedling establishment [31,57,[60][61][62][63][64].…”

Improving the Health-Benefits of Kales (Brassica oleracea L. var. acephala DC) through the Application of Controlled Abiotic Stresses: A Review

“…The application of abiotic stressors at larger scales remains labor intensive, especially in larger field areas and dense crop plantations. In addition, the dose-optimization requires variety-specific studies [189]. Further, under field conditions, various stresses occur in combinations that magnify stress severity.…”

Bacterial signaling molecules of acyl-homoserine lactone type: effect on plant growth and stress resistance

“…Öåé ïðîöåñ, ùî îòðèìàâ íàçâó «ñåíñèá³ë³çàö³ÿ çàõèñíèõ âëàñòèâîñòåé», âèêîðèñòîâóþòü ó ñ³ëüñüêîìó ãîñïîäàðñòâ³ ç ïî÷àòêó 1930-õ ðîê³â [36,37]. Îñòàíí³ì ÷àñîì ïðèâåðòຠîñîáëèâó óâàãó ôåíîìåí «ñòðåñîâî¿ ïàì'ÿò³», êîëè ñóáëåòàëüíèé ñòðåñ ïðèâîäèòü äî ïîë³ïøåííÿ ðåàêö³¿ íà íàñòóïí³ ñòðåñè [38]. Ïðàéìóâàííÿ íàëåaeèòü äî ïåðâèííèõ ñòðåñ³â, ÿê³ ïðèøâèäøóþòü ³ ïîñèëþþòü çàõèñí³ ðåàêö³¿ ðîñëèí [18].…”