Abstract
Increased grain yield will be critical to meet the growing demand for food, and could be achieved by delaying crop senescence. Here, via quantitative trait locus (QTL) mapping, we uncover the genetic basis underlying distinct life cycles and senescence patterns of two rice subspecies, indica and japonica. Promoter variations in the Stay-Green (OsSGR) gene encoding the chlorophyll-degrading Mg++-dechelatase were found to trigger higher and earlier induction of OsSGR in indica, which accelerated senescence of indica rice cultivars. The indica-type promoter is present in a progenitor subspecies O. nivara and thus was acquired early during the evolution of rapid cycling trait in rice subspecies. Japonica OsSGR alleles introgressed into indica-type cultivars in Korean rice fields lead to delayed senescence, with increased grain yield and enhanced photosynthetic competence. Taken together, these data establish that naturally occurring OsSGR promoter and related lifespan variations can be exploited in breeding programs to augment rice yield.
Highlights
Increased grain yield will be critical to meet the growing demand for food, and could be achieved by delaying crop senescence
Indica rice is thought to have evolved under r-selection in the tropical zone, emphasizing a rapid cycling life history strategy with a trade-off between rapid reproduction and parental survivorship
The plants were grown in a natural rice field in the National Institute of Crop Science, Korea (35.3° N; 128.5° E), and senescence was monitored by leaf color changes, for instance from green to yellow due to the loss of chlorophyll, and from yellow to brown due partly to oxidation of phenolic compounds in dying cells[10]
Summary
Increased grain yield will be critical to meet the growing demand for food, and could be achieved by delaying crop senescence. Japonica OsSGR alleles introgressed into indica-type cultivars in Korean rice fields lead to delayed senescence, with increased grain yield and enhanced photosynthetic competence. Taken together, these data establish that naturally occurring OsSGR promoter and related lifespan variations can be exploited in breeding programs to augment rice yield. Japonica OsSGR alleles introgressed into elite indica-type cultivars show delayed senescence, longer maintenance of photosynthetic competence, and improved grain yield. These results highlight that OsSGR promoter variations can be utilized to improve rice productivity
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