Empowering rice resilience: elevating starch quality via seed priming amidst bio-molecular challenges during reproductive and maturation phases under drought stress.

Drought is a major global limiting factor for rice (Oryza sativa L.) production. Drought conditions reduce the quality and yield of rice. In the current research, we explored the effects of diverse seed priming agents and their combinations on multiple facets of grain quality, bio-molecular mechanisms, and enzyme activities. Combinations of the priming agents like MJ (methyl jasmonate) + Zinc sulphate heptahydrate (MJZ), MJ + Iron sulphate heptahydrate (MJI), and MJ + Zinc sulphate heptahydrate + Iron sulphate heptahydrate (MJIZ) were used for the seed priming. High performance liquid chromatography based abscisic acid content analysis showed 3.16 and 2.56-fold higher amounts in MJ-primed samples in N-22 and PS-5, respectively compared to unprimed controls. In unprimed controls, N-22 had lower amylose content (4.4%) than PS-5 (4.8%). The resistant starch content was increased in MJIZ primed samples by 253% in control samples in comparison to their unprimed samples. Enzyme activity assays revealed that pullulanase, activity increased significantly with priming and was found to be highest in MJIZ primed samples. Starch Synthase, and branching enzyme activity increased significantly in both genotypes with priming compared to unprimed controls. Gene expression analyses revealed upregulation of SS-I, SS-IIa, and Pull-2 genes in primed samples, indicating enhanced starch biosynthesis. Scanning electron microscopy-based starch granule morphology revealed differences in shape, size, and packing across the treatments and genotypes. The findings unravel the mechanisms triggered by seed priming to enhance the adaptability of plants for better survival under drought. To the best of our knowledge, this is the first comprehensive study to decipher the underlying mechanisms through physio-biochemical and molecular analysis on seed priming to alleviate the deleterious effect of drought stress. Being a cost-effective and user-friendly technique, seed priming can be utilized to improve the yield potential of rice under drought, which might help to achieve Sustainable Development Goal 2 (Zero hunger with improved nutrition) of the United Nations.

Supplementary information: The online version contains supplementary material available at 10.1007/s12298-025-01609-y.