Author
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GU, XINGYOU - NDSU |
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KIANIAN, SHAHRYAR - NDSU |
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Foley, Michael |
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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 12/18/2005 Publication Date: 1/14/2006 Citation: Gu, X., Kianian, S., Foley, M.E. 2006. Towards positional cloning of genes for dormancy and its related adaptive traits from weedy rice. [Abstract] Plant & Animal Genome XIV Conference. P. 96. Interpretive Summary: An array of physiological and morphological traits, such as seed dormancy, shattering and appendages, and pigmentations on seed covering tissues contribute to the adaptation of weeds in agro-ecosystems. We have developed weedy rice (Oryza sativa) as an experimental system primarily to investigate genetic, evolutionary, and molecular mechanisms underlying seed dormancy in grass species. Weedy rice contains the most dormant genotypes compared with traditional and modern cultivars. Dormancy is mainly coat-imposed and is associated with shattering, awn, and black hull and red pericarp colors. Seven dormancy quantitative trait loci (QTL) have been identified from a wild-like weedy accession. All these dormancy loci are networked by epistases and interact with seed developmental environments and time of after-ripening. Five of the seven QTL tightly link with one to three genes/QTL for other adaptive traits. We introduced five dormancy QTL alleles into a non-dormant genetic background by seven generations of phenotypic or marker assisted selections alone for dormancy. Four of the five dormancy alleles could not be separated from their linked alleles for other weedy traits during the introduction, suggesting that genes responsible for major weedy traits inherit as units across generations or organize as haplotypes during evolution. Two dormancy QTL, including the putative haplotype harboring qSD7-1 and the red pericarp color gene Rc, have been narrowed down to genomic regions of a few to several hundred kilobases. The finished genome sequence of the rice cultivar Nipponbare, a mutant genotype for all the above traits, is used as a reference to delimit the target regions and predict candidate genes. Technical Abstract: An array of physiological and morphological traits, such as seed dormancy, shattering and appendages, and pigmentations on seed covering tissues contribute to the adaptation of weeds in agro-ecosystems. We have developed weedy rice (Oryza sativa) as an experimental system primarily to investigate genetic, evolutionary, and molecular mechanisms underlying seed dormancy in grass species. Weedy rice contains the most dormant genotypes compared with traditional and modern cultivars. Dormancy is mainly coat-imposed and is associated with shattering, awn, and black hull and red pericarp colors. Seven dormancy quantitative trait loci (QTL) have been identified from a wild-like weedy accession. All these dormancy loci are networked by epistases and interact with seed developmental environments and time of after-ripening. Five of the seven QTL tightly link with one to three genes/QTL for other adaptive traits. We introduced five dormancy QTL alleles into a non-dormant genetic background by seven generations of phenotypic or marker assisted selections alone for dormancy. Four of the five dormancy alleles could not be separated from their linked alleles for other weedy traits during the introduction, suggesting that genes responsible for major weedy traits inherit as units across generations or organize as haplotypes during evolution. Two dormancy QTL, including the putative haplotype harboring qSD7-1 and the red pericarp color gene Rc, have been narrowed down to genomic regions of a few to several hundred kilobases. The finished genome sequence of the rice cultivar Nipponbare, a mutant genotype for all the above traits, is used as a reference to delimit the target regions and predict candidate genes. |
