title: High-resolution mapping and genetic characterization of the Lazy-2 gravitropic mutant of tomato.
abstract: Mutation of the Lazy-2 (Lz-2) gene in tomato (Lycopersicon esculentum mill.) produces a phytochrome-dependent reversal of shoot gravitropism, providing a unique genetic resource for investigating how signals from light modulate gravitropism. We mapped the Lz-2 gene using RFLPs and a PCR-based technique to assess the feasibility of positional cloning. Analysis of a 1338 plant backcross population between L. esculentum and L. pennellii placed Lz-2 within a 1.2 cM interval on chromosome 5, 0.4 cM from TG504-CT201A interval. The inabililty to resolve these markers indicates that Lz-2 resides in a centromeric region in which recombination is highly suppressed. Lazy-2 is tightly linked to but does not encode the gene for ACC4, an enzyme involved in ethylene biosynthesis. We also observed that Lz-2 is partially dominant under certain conditions and stages of development.
authors.affiliation: Department of Botany and Plant Pathology, Oregon State University, Corvallis, USA.
authors.forename: F J
authors.initials: FJ
authors.lastname: Behringer
authors.forename: T L
authors.initials: TL
authors.lastname: Lomax
mesh_terms: D000483:Alleles; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D017931:DNA Primers; D005799:Genes, Dominant; D017343:Genes, Plant; D008040:Genetic Linkage; D005819:Genetic Markers; D006112:Gravitation; D018551:Solanum lycopersicum / Q000235:genetics* / Q000502:physiology; D009154:Mutation; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D017931:DNA Primers; D005819:Genetic Markers