title: A novel factor FLOURY ENDOSPERM2 is involved in regulation of rice grain size and starch quality.
abstract: Rice (Oryza sativa) endosperm accumulates a massive amount of storage starch and storage proteins during seed development. However, little is known about the regulatory system involved in the production of storage substances. The rice flo2 mutation resulted in reduced grain size and starch quality. Map-based cloning identified FLOURY ENDOSPERM2 (FLO2), a member of a novel gene family conserved in plants, as the gene responsible for the rice flo2 mutation. FLO2 harbors a tetratricopeptide repeat motif, considered to mediate a protein-protein interactions. FLO2 was abundantly expressed in developing seeds coincident with production of storage starch and protein, as well as in leaves, while abundant expression of its homologs was observed only in leaves. The flo2 mutation decreased expression of genes involved in production of storage starch and storage proteins in the endosperm. Differences between cultivars in their responsiveness of FLO2 expression during high-temperature stress indicated that FLO2 may be involved in heat tolerance during seed development. Overexpression of FLO2 enlarged the size of grains significantly. These results suggest that FLO2 plays a pivotal regulatory role in rice grain size and starch quality by affecting storage substance accumulation in the endosperm.
authors.affiliation: Department of Biological Science and Technology, Tokyo University of Science, Noda, Japan.
authors.forename: Kao-Chih
authors.initials: KC
authors.lastname: She
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kusano
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Koizumi
authors.forename: Hiromoto
authors.initials: H
authors.lastname: Yamakawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Hakata
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Imamura
authors.forename: Masato
authors.initials: M
authors.lastname: Fukuda
authors.forename: Natsuka
authors.initials: N
authors.lastname: Naito
authors.forename: Yumi
authors.initials: Y
authors.lastname: Tsurumaki
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yaeshima
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Tsuge
authors.forename: Ken'ichiro
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Mari
authors.initials: M
authors.lastname: Kudoh
authors.forename: Eiko
authors.initials: E
authors.lastname: Itoh
authors.forename: Shoshi
authors.initials: S
authors.lastname: Kikuchi
authors.forename: Naoki
authors.initials: N
authors.lastname: Kishimoto
authors.forename: Junshi
authors.initials: J
authors.lastname: Yazaki
authors.forename: Tsuyu
authors.initials: T
authors.lastname: Ando
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yano
authors.forename: Takashi
authors.initials: T
authors.lastname: Aoyama
authors.forename: Tadamasa
authors.initials: T
authors.lastname: Sasaki
authors.forename: Hikaru
authors.initials: H
authors.lastname: Satoh
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shimada
mesh_terms: D000687:Amylopectin / Q000032:analysis; D000688:Amylose / Q000032:analysis; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D056625:Endosperm / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D005936:Glucans / Q000032:analysis; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D055314:Seed Storage Proteins / Q000235:genetics / Q000378:metabolism*; D013213:Starch / Q000032:analysis*
chemical_list: D018744:DNA, Plant; D005936:Glucans; D055314:Seed Storage Proteins; D013213:Starch; D000688:Amylose; D000687:Amylopectin; C040088:1,4-glucan