Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 9/8/2007
Publication Date: 1/12/2008
Citation: Foley, M.E., Gu, X., Anderson, J.V., Horvath, D.P. 2008. Positional cloning of a seed dormancy QTL from weedy rice (Oryza sativa). Plant and Animal Genome VX Conference Abstracts. W508: Weedy and Invasive Plant Genomics. p.115.
Technical Abstract: We developed weedy rice (SS-18-2) as a genetic system to investigate mechanisms regulating natural variation in seed dormancy. This included introduction of a set of quantitative trait loci (QTL) enhancing seed dormancy into the non-dormant genetic background of cultivated rice (EM93-1) to clone and characterize the underlying genes. We focused on qSD7-1, the QTL associated with the red pericarp/testa color trait. A high-resolution map and a progeny test for seed dormancy of the selected recombinants demonstrated that qSD7-1 is the Os07g11020 locus, a predicted basic helix-loop-helix (OsbHLH017) transcription factor. We obtained one rare intragenic recombinant for the Os07g11020 locus and developed isogenic lines (IL) for the dormancy and non-dormancy alleles. The genomic region for the predicted gene was cloned from wild and mutant parents and the dormant IL. A 14-bp deletion in the segment accounted for the natural variation in seed dormancy, which was also confirmed with cDNA sequences cloned from seed and leaf tissues of the dormant and non-dormant IL. We conclude that qSD7-1 has pleiotropic effects on seed dormancy, red pericarp color, and grain weight. The pleiotropic effects enhance the adaptability of weedy rice.