ARS | Publication request: Characterization of calcium oxalate defective (cod) 6 mutant from Medicago truncatula

Submitted to: International Conference on Legume Genomics and Genetics
Publication Type: Proceedings
Publication Acceptance Date: September 1, 2008
Publication Date: N/A
Repository URL: http://www.ccg.unam.mx

Technical Abstract: Many plants invest a considerable amount of resources and energy into the formation of calcium oxalate crystals. A number of roles for crystal formation in plant growth and development have been assigned based on their prevalence, spatial distribution, and variety of crystal shapes. These assigned roles include functions in plant defense, calcium regulation, and aluminum tolerance. Although calcium oxalate is common and plays important roles in plant development, our understanding of how these crystals form is still incomplete. To gain insight into the mechanisms regulating crystal formation we initiated a mutant screen to identify the genetic determinants. In this study we report the characterization of one of these mutants, cod6, which was isolated from an EMS-mutagenized Medicago truncatula population by visually screening for alterations in crystal formation. Microscopic examination of the cod6 revealed that this mutant had a reduction in both crystal size and number compared to wild type. This decrease in calcium oxalate formation was confirmed by measuring calcium and oxalate levels. The mutant had about 88% of the wild type calcium levels and only 9% of the wild type oxalate levels. Genetic mapping studies were conducted as an initial step toward positional cloning of the affected gene. These studies place the cod6 locus in the bottom half of linkage group 5. It is our hope that the information gained through the characterization and analysis of such calcium oxalate mutants will be applicable toward future efforts to improve the production and nutritional content of plant foods.