title: Quantitative trait loci controlling light and hormone response in two accessions of Arabidopsis thaliana.
abstract: We have mapped quantitative trait loci (QTL) responsible for natural variation in light and hormone response between the Cape Verde Islands (Cvi) and Landsberg erecta (Ler) accessions of Arabidopsis thaliana using recombinant inbred lines (RILs). Hypocotyl length was measured in four light environments: white, blue, red, and far-red light and in the dark. In addition, white light plus gibberellin (GA) and dark plus the brassinosteroid biosynthesis inhibitor brassinazole (BRZ) were used to detect hormone effects. Twelve QTL were identified that map to loci not previously known to affect light response, as well as loci where candidate genes have been identified from known mutations. Some QTL act in all environments while others show genotype-by-environment interaction. A global threshold was established to identify a significant epistatic interaction between two loci that have few main effects of their own. LIGHT1, a major QTL, has been confirmed in a near isogenic line (NIL) and maps to a new locus with effects in all light environments. The erecta mutation can explain the effect of the HYP2 QTL in the blue, BRZ, and dark environments, but not in far-red. LIGHT2, also confirmed in an NIL, has effects in white and red light and shows interaction with GA. The phenotype and map position of LIGHT2 suggest the photoreceptor PHYB as a candidate gene. Natural variation in light and hormone response thus defines both new genes and known genes that control light response in wild accessions.
authors.affiliation: Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
authors.forename: Justin O
authors.initials: JO
authors.lastname: Borevitz
authors.forename: Julin N
authors.initials: JN
authors.lastname: Maloof
authors.forename: Jason
authors.initials: J
authors.lastname: Lutes
authors.forename: Tsegaye
authors.initials: T
authors.lastname: Dabi
authors.forename: Joanna L
authors.initials: JL
authors.lastname: Redfern
authors.forename: Gabriel T
authors.initials: GT
authors.lastname: Trainer
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Werner
authors.forename: Tadao
authors.initials: T
authors.lastname: Asami
authors.forename: Charles C
authors.initials: CC
authors.lastname: Berry
authors.forename: Detlef
authors.initials: D
authors.lastname: Weigel
authors.forename: Joanne
authors.initials: J
authors.lastname: Chory
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins; D014644:Genetic Variation; D008027:Light; D010786:Photoreceptor Cells; D010834:Phytochrome / Q000235:genetics / Q000502:physiology; D051939:Phytochrome B; D010937:Plant Growth Regulators / Q000235:genetics* / Q000502:physiology; D019655:Quantitative Trait, Heritable; D014157:Transcription Factors
chemical_list: D029681:Arabidopsis Proteins; C497952:PHYB protein, Arabidopsis; D010937:Plant Growth Regulators; D014157:Transcription Factors; D010834:Phytochrome; D051939:Phytochrome B