Hd18, Encoding Histone Acetylase Related to Arabidopsis FLOWERING LOCUS D, is Involved in the Control of Flowering Time in Rice.
Flowering time is one of the most important agronomic traits in rice (Oryza sativa L.), because it defines harvest seasons and cultivation areas, and affects yields. We used a map-based strategy to clone Heading date 18 (Hd18). The difference in flowering time between the Japanese rice cultivars Koshihikari and Hayamasari was due to a single nucleotide polymorphism within the Hd18 gene, which encodes an amine oxidase domain-containing protein and is homologous to Arabidopsis FLOWERING LOCUS D (FLD). The Hayamasari Hd18 allele and knockdown of Hd18 gene expression delayed the flowering time of rice plants regardless of the day-length condition. Structural modeling of the Hd18 protein suggested that the non-synonymous substitution changed protein stability and function due to differences in interdomain hydrogen bond formation. Compared with those in Koshihikari, the expression levels of the flowering-time genes Early heading date 1 (Ehd1), Heading date 3a (Hd3a) and Rice flowering locus T1 (RFT1) were lower in a near-isogenic line with the Hayamasari Hd18 allele in a Koshihikari genetic background. We revealed that Hd18 acts as an accelerator in the rice flowering pathway under both short- and long-day conditions by elevating transcription levels of Ehd1 Gene expression analysis also suggested the involvement of MADS-box genes such as OsMADS50, OsMADS51 and OsMADS56 in the Hd18-associated regulation of Ehd1 These results suggest that, like FLD, its rice homolog accelerates flowering time but is involved in rice flowering pathways that differ from the autonomous pathways in Arabidopsis.
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan These authors contributed equally to this work.
Taeko
T
Shibaya
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan These authors contributed equally to this work. horikiyo@affrc.go.jp.
Kiyosumi
K
Hori
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Eri
E
Ogiso-Tanaka
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Utako
U
Yamanouchi
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Koka
K
Shu
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Noriyuki
N
Kitazawa
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Ayahiko
A
Shomura
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Tsuyu
T
Ando
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Kaworu
K
Ebana
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Jianzhong
J
Wu
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Toshimasa
T
Yamazaki
National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan.
Masahiro
M
Yano
D029681:Arabidopsis Proteins / Q000235:genetics; D003001:Cloning, Molecular; D035264:Flowers / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D005816:Genetic Complementation Test; D051548:Histone Acetyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006655:Histone Deacetylases / Q000235:genetics; D026161:MADS Domain Proteins / Q000235:genetics; D012275:Oryza / Q000235:genetics / Q000502:physiology*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci; D034622:RNA Interference
D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; D010940:Plant Proteins; D051548:Histone Acetyltransferases; C479923:flowering locus D protein, Arabidopsis; D006655:Histone Deacetylases
Flowering time; Heading date 18 (Hd18); Map-based cloning; Natural variation; Oryza sativa L