title: A Causal Gene for Seed Dormancy on Wheat Chromosome 4A Encodes a MAP Kinase Kinase.
abstract: Seed germination under the appropriate environmental conditions is important both for plant species survival and for successful agriculture. Seed dormancy, which controls germination time, is one of the adaptation mechanisms and domestication traits [1]. Seed dormancy is generally defined as the absence of germination of a viable seed under conditions that are favorable for germination [2]. The seed dormancy of cultivated plants has generally been reduced during domestication [3]. Bread wheat (Triticum aestivum L.) is one of the most widely grown crops in the world. Weak dormancy may be an advantage for the productivity due to uniform emergence and a disadvantage for the risks of pre-harvest sprouting (PHS), which decreases grain quality and yield [4]. A number of quantitative trait loci (QTLs) controlling natural variation of seed dormancy have been identified on various chromosomes [5]. A major QTL for seed dormancy has been consistently detected on chromosome 4A [6-13]. The QTL was designated as a major gene, Phs1, which could be precisely mapped within a 2.6 cM region [14]. Here, we identified a mitogen-activated protein kinase kinase 3 (MKK3) gene (designated TaMKK3-A) by a map-based approach as a candidate gene for the seed dormancy locus Phs1 on chromosome 4A in bread wheat. Complementation analysis showed that transformation of a dormant wheat cultivar with the TaMKK3-A allele from a nondormant cultivar clearly reduced seed dormancy. Cultivars differing in dormancy had a single nonsynonymous amino acid substitution in the kinase domain of the predicted MKK3 protein sequence, which may be associated with the length of seed dormancy.
authors.affiliation: HOKUREN Agricultural Research Institute, Naganuma, Hokkaido 069-1317, Japan. Electronic address: torada-atusi@hokuren.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Torada
authors.affiliation: HOKUREN Agricultural Research Institute, Naganuma, Hokkaido 069-1317, Japan.
authors.forename: Michiya
authors.initials: M
authors.lastname: Koike
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan.
authors.forename: Taiichi
authors.initials: T
authors.lastname: Ogawa
authors.affiliation: HOKUREN Agricultural Research Institute, Naganuma, Hokkaido 069-1317, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Takenouchi
authors.affiliation: HOKUREN Agricultural Research Institute, Naganuma, Hokkaido 069-1317, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Tadamura
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Wu
authors.affiliation: National Institute of Agrobiological Sciences, Tsukuba 305-8602, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: Kihara Institute for Biological Research, Yokohama City University, Yokohama 244-0813, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Kawaura
authors.affiliation: Kihara Institute for Biological Research, Yokohama City University, Yokohama 244-0813, Japan.
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Ogihara
mesh_terms: D019943:Amino Acid Substitution; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D018506:Gene Expression Regulation, Plant; D018525:Germination / Q000235:genetics; D048371:MAP Kinase Kinase 3 / Q000235:genetics* / Q000378:metabolism; D057445:Plant Dormancy / Q000235:genetics* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D040641:Quantitative Trait Loci; D012639:Seeds / Q000235:genetics; D014908:Triticum / Q000235:genetics / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D048371:MAP Kinase Kinase 3