| Summary: | Rice (Oryza sativa L.) varieties exhibiting phenotypic features of high/low seed vigor-viability were used to explore genetic controls associated with a varietal difference in seed vigor and viability traits. Since germination rate i.e. vigor is a reflection of the onset of metabolic activity of a hitherto quiescent embryo and seed viability reflects cell molecular events controlling macromolecular damage/protection in post-harvest (dry) quiescent embryo, expression of a house-keeping gene viz. Acetyl CoA Carboxylase (ACCase), that through its dual role controls lipid biosynthesis for germination and flavonoid biosynthesis for macromolecular protection during post-harvest aging, was studied. Our data revealed variation in ACCase gene expression among high and low vigor-viability varieties although Southern blot analysis demonstrated single copy of this gene in all the varieties regardless of their vigor-viability status. Methylation Sensitive Restriction Enzyme assay revealed methylation in CpG island of ACCase promoter in the phenotypically designated low vigor-viability varieties confirming that low seed vigor in rice varieties is due to low expression of ACCase gene brought about by its promoter methylation. Since promoter methylation is transferable through breeding lines this study opens up an opportunity for introgressing high seed vigor-viability trait into otherwise desirable varieties.
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