Redox Interactome Status, Metabolic, and Transcriptional Reprograming Associated with Longevity Phenotypes as Seed Viability Markers in Natural and Accelerated Aged Seeds of Indigenous Aromatic Rice Cultivars

Regulation of internal redox cue at metabolic interface and expression of genes associated with longevity phenotypes plays a decisive role in seed aging and least studied in indigenous aromatic rice cultivars (IARCs) and hence was the theme of present study. Redox interactome status of naturally aged (6, 9, 12 months) and accelerated aged (RH 92% and 41 °C for 24 h) seeds of two experimental IARCs (Oryza sativa L., cultivars Tulaipanji and Jamainadu) has been done by fingerprinting redox metabolome [assessed in terms of pro-oxidant/antioxidant ratio, confocal microscopy-based in situ localization of ROS, redox tuning ability (enzymatic Rboh-Ascorbate–Glutathione pathway and non-enzymatic synthesis of bioactive polyphenolic compounds) and monitoring protein oxidation and lipid peroxidation]. Further, the impact of accelerated aging on transcriptional reprograming of important marker genes associated with seed longevity phenotypes, such as repair genes (OsPIMT1 and OsHSP18.2), phenylpropanoid pathway genes (OsPAL4 and OsCHS8), hormonal homeostatic genes (OsGA20ox2, OsGA2ox2, OsNCED1 and OsCYP707A5), redox hub genes (Osrboh, OsCatA, OsAPx2 and OsGRase) in germinating accelerated aged seeds of both the experimental IARCs has been studied and compared. Aged seed of cultivar Tulaipanji capable of fine tuning endogenous redox cue, exhibited significantly better transcriptional regulation of marker genes of seed longevity as compared to cultivar Jamainadu, corroborating strong correlation between aging induced redox interactome and seed longevity. Novelty of the study is that it consolidates a model that proposes how the redox interactome in aging seeds influence hormonal, defense, and repair processes for regulating aging and longevity of seed of IARCs.