GENOMIC CHARACTERIZATION OF RICE GERMPLASM
Location: Dale Bumpers National Rice Research Center
Title: A natural mutation in rc reverts white-rice-pericarp to red and results in a new, dominant, wild-type allele: Rc-g
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 10, 2008
Publication Date: June 1, 2008
Citation: Brooks, S.A., Yan, W., Jackson, A.K., Deren, C.W. 2008. A natural mutation in Rc reverts white-rice-pericarp to red and results in a new, dominant, wild-type allele: Rc-g. Theoretical and Applied Genetics. 117(4):575-580.
Interpretive Summary: During the domestication of crop plant species, certain core traits that are desirable in agricultural systems were selected and fixed within cultivated varieties of a species. ‘Domestication genes’ are often signatures for a crop, because selection made certain traits ubiquitous among cultivated varieties of a species. Pericarp color is one such trait in rice, where white pericarp has been extensively selected among cultivated varieties, and wild-type (red) is often associated with genetically linked weedy traits. Herein, natural mutation was shown to revert pericarp color from domesticated to wild-type. Identification of this rare mutant that also has agronomic value is a chance find that has great potential for agricultural exploitation.
The Rc locus regulates pigmentation of the rice bran layer, and selection for the rc allele (white pericarp) occurred during domestication of the crop. White bran is now ubiquitous among cultivated varieties throughout rice growing regions of the world. We identified a new allele that arose by natural mutation within the rc pseudogene of the cultivar ‘Wells’. The mutation restored the reading frame of the gene, and reverted the bran layer pigmentation to red (wild-type). By sequencing the Rc locus in plants derived from red seeds, and linkage analysis in a segregating population, we were able to demonstrate that mutation within rc resulted in the new, dominant, wild-type allele Rc-g.