title: Level of VERNALIZATION 1 expression is correlated with earliness in extra early-flowering mutant wheat lines.
abstract: Four extra early-flowering mutants, named extra early-flowering1 (exe1), exe2, exe3, and exe4, were identified in Triticum monococcum strain KU104-1 following heavy-ion beam mutagenesis. The four exe mutants fell into two groups, namely Type I (moderately extra early-flowering type; exe1 and exe3) and Type II (extremely extra early-flowering type; exe2 and exe4). Analysis of plant development in a growth chamber showed that the speed of leaf emergence was accelerated in exe mutants at the reproductive stage compared to wild-type (WT) plants. The speed of leaf emergence was faster in Type II than Type I plants. Analysis of VERNALIZATION 1 (VRN1), a flowering promoter gene, showed that it was more highly expressed in seedlings at early developmental stages in Type II mutants than Type I mutants. These findings indicate that the difference in earliness between Type I and Type II mutants is associated with the level of VRN1 expression. The original KU104-1 is an einkorn wheat strain that carries a null allele of the VRN2 gene, a repressor of flowering. Thus, our results indicate that the level of VRN1 expression controls earliness in exe mutants independently of VRN2.
authors.affiliation: Department of Bioscience, Fukui Prefectural University , 4-1-1 Matsuoka-Kenjojima, Eiheiji, Yoshida, Fukui 910-1195 , Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Nishiura
authors.affiliation: RIKEN, Nishina Center , 2-1 Hirosawa, Wako, Saitama 351-0198 , Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kazama
authors.affiliation: RIKEN, Nishina Center , 2-1 Hirosawa, Wako, Saitama 351-0198 , Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Abe
authors.affiliation: Graduate School of Agriculture, Kyoto University , Kitashirakawaoiwake, Sakyo, Kyoto 606-8502 , Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Mizuno
authors.affiliation: Graduate School of Agriculture, Kyoto University , Kitashirakawaoiwake, Sakyo, Kyoto 606-8502 , Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Nasuda
authors.affiliation: Department of Bioscience, Fukui Prefectural University , 4-1-1 Matsuoka-Kenjojima, Eiheiji, Yoshida, Fukui 910-1195 , Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Murai
keywords: Triticum monococcum; VERNALIZATION 1; early-flowering; ion beam mutagenesis; wheat