title: Isolation of Medicago truncatula mutants defective in calcium oxalate crystal formation.
abstract: Plants accumulate crystals of calcium oxalate in a variety of shapes, sizes, amounts, and spatial locations. How and why many plants form crystals of calcium oxalate remain largely unknown. To gain insight into the regulatory mechanisms of crystal formation and function, we have initiated a mutant screen to identify the genetic determinants. Leaves from a chemically mutagenized Medicago truncatula population were visually screened for alterations in calcium oxalate crystal formation. Seven different classes of calcium oxalate defective mutants were identified that exhibited alterations in crystal nucleation, morphology, distribution and/or amount. Genetic analysis suggested that crystal formation is a complex process involving more than seven loci. Phenotypic analysis of a mutant that lacks crystals, cod 5, did not reveal any difference in plant growth and development compared with controls. This finding brings into question the hypothesized roles of calcium oxalate formation in supporting tissue structure and in regulating excess tissue calcium.
authors.affiliation: United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street, Houston, Texas 77030-2600, USA. pnakata@bcm.tmc.edu
authors.forename: P A
authors.initials: PA
authors.lastname: Nakata
authors.forename: M M
authors.initials: MM
authors.lastname: McConn
mesh_terms: D002118:Calcium / Q000378:metabolism; D002129:Calcium Oxalate / Q000737:chemistry / Q000378:metabolism*; D003460:Crystallization; D000455:Medicago sativa / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism
chemical_list: D002129:Calcium Oxalate; D002118:Calcium