Phytochrome C Is A Key Factor Controlling Long-Day Flowering in Barley

• Published in: Plant physiology (Bethesda) Vol. 163; no. 2; pp. 804 - 814
• Main Authors: Nishida, Hidetaka, Ishihara, Daisuke, Ishii, Makoto, Kaneko, Takuma, Kawahigashi, Hiroyuki, Akashi, Yukari, Saisho, Daisuke, Tanaka, Katsunori, Handa, Hirokazu, Takeda, Kazuyoshi, Kato, Kenji
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01.10.2013
• Subjects: Alleles; Amino Acid Sequence; Barley; Biological and medical sciences; Crosses, Genetic; Epistasis, Genetic; Flowering; Flowers - genetics; Flowers - physiology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Plant; Genes; GENES, DEVELOPMENT, AND EVOLUTION; Genes, Plant - genetics; Genetic Linkage; Genetic loci; Haplotypes - genetics; Hordeum - genetics; Hordeum - physiology; Inbreeding; Molecular Sequence Data; Oryza - genetics; Photoperiod; Phytochrome - chemistry; Phytochrome - genetics; Phytochrome - metabolism; Plant physiology and development; Plants; Plants, Genetically Modified; Proteins; Rice; Transformation, Genetic; Vernalization; Barley; Monocotyledones; Hordeum vulgare; Plant physiology; Gramineae; Angiospermae; Phytochrome; Flowering; Spermatophyta; Cereal crop
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.113.222570

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.