title: Phytochrome C is a key factor controlling long-day flowering in barley.
abstract: The spring-type near isogenic line (NIL) of the winter-type barley (Hordeum vulgare ssp. vulgare) var. Hayakiso 2 (HK2) was developed by introducing VERNALIZATION-H1 (Vrn-H1) for spring growth habit from the spring-type var. Indo Omugi. Contrary to expectations, the spring-type NIL flowered later than winter-type HK2. This phenotypic difference was controlled by a single gene, which cosegregated only with phytochrome C (HvPhyC) among three candidates around the Vrn-H1 region (Vrn-H1, HvPhyC, and CASEIN KINASE IIα), indicating that HvPhyC was the most likely candidate gene. Compared with the late-flowering allele HvPhyC-l from the NIL, the early-flowering allele HvPhyC-e from HK2 had a single nucleotide polymorphism T1139C in exon 1, which caused a nonsynonymous amino acid substitution of phenylalanine at position 380 by serine in the functionally essential GAF (3', 5'-cyclic-GMP phosphodiesterase, adenylate cyclase, formate hydrogen lyase activator protein) domain. Functional assay using a rice (Oryza sativa) phyA phyC double mutant line showed that both of the HvPhyC alleles are functional, but HvPhyC-e may have a hyperfunction. Expression analysis using NILs carrying HvPhyC-e and HvPhyC-l (NIL [HvPhyC-e] and NIL [HvPhyC-l], respectively) showed that HvPhyC-e up-regulated only the flowering promoter FLOWERING LOCUS T1 by bypassing the circadian clock genes and flowering integrator CONSTANS1 under a long photoperiod. Consistent with the up-regulation, NIL (HvPhyC-e) flowered earlier than NIL (HvPhyC-l) under long photoperiods. These results implied that HvPhyC is a key factor to control long-day flowering directly.
authors.affiliation: Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Nishida
authors.forename: Daisuke
authors.initials: D
authors.lastname: Ishihara
authors.forename: Makoto
authors.initials: M
authors.lastname: Ishii
authors.forename: Takuma
authors.initials: T
authors.lastname: Kaneko
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kawahigashi
authors.forename: Yukari
authors.initials: Y
authors.lastname: Akashi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Saisho
authors.forename: Katsunori
authors.initials: K
authors.lastname: Tanaka
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Handa
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Takeda
authors.forename: Kenji
authors.initials: K
authors.lastname: Kato
mesh_terms: D000595:Amino Acid Sequence; D003433:Crosses, Genetic; D004843:Epistasis, Genetic; D035264:Flowers / Q000235:genetics / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D008040:Genetic Linkage; D006239:Haplotypes / Q000235:genetics; D001467:Hordeum / Q000235:genetics / Q000502:physiology*; D007178:Inbreeding; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics; D017440:Photoperiod; D010834:Phytochrome / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D014170:Transformation, Genetic
chemical_list: D010834:Phytochrome