title: Three novel alleles of FLOURY ENDOSPERM2 (FLO2) confer dull grains with low amylose content in rice.
abstract: Rice is a major food source for much of the world, and expanding our knowledge of genes conferring specific rice grain attributes will benefit both farmer and consumer. Here we present novel dull grain mutants with a low amylose content (AC) derived from mutagenesis of Oryza sativa, ssp. japonica cv. Taikeng 8 (TK8). Positional cloning of the gene conferring the dull grain phenotype revealed a point mutation located at the acceptor splice site of intron 11 of FLOURY ENDOSPERM2 (FLO2), encoding a tetratricopeptide repeat domain (TPR)-containing protein. Three novel flo2 alleles were identified herein, which surprisingly conferred dull rather than floury grains. The allelic diversity of flo2 perturbed the expression of starch synthesis-related genes including OsAGPL2, OsAGPS2b, OsGBSSI, OsBEI, OsBEIIb, OsISA1, and OsPUL. The effect of the flo2 mutations on the physicochemical properties of the grain included a low breakdown, setback, and consistency of rice, indicating a good elasticity and soft texture of cooked rice grains. The effects of FLO2, combined with the genetic background of the germplasm and environmental effects, resulted in a variety of different amylose content levels, grain appearance, and physicochemical properties of rice, providing a host of useful information to future grain-quality research and breeding.
authors.affiliation: Department of Agronomy, Chiayi Agricultural Experiment Station, Chiayi, Taiwan.
authors.forename: Yong-Pei
authors.initials: YP
authors.lastname: Wu
authors.affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan.
authors.forename: Chieh-Han
authors.initials: CH
authors.lastname: Pu
authors.affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan.
authors.forename: Hung-Ying
authors.initials: HY
authors.lastname: Lin
authors.affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan.
authors.forename: Hsin-Ya
authors.initials: HY
authors.lastname: Huang
authors.affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan.
authors.forename: Ya-Chen
authors.initials: YC
authors.lastname: Huang
authors.affiliation: Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Chwan-Yang
authors.initials: CY
authors.lastname: Hong
authors.affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan.
authors.forename: Men-Chi
authors.initials: MC
authors.lastname: Chang
authors.affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan. Electronic address: ylin@ntu.edu.tw.
authors.forename: Yann-Rong
authors.initials: YR
authors.lastname: Lin
mesh_terms: D000483:Alleles; D000688:Amylose / Q000378:metabolism*; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012639:Seeds / Q000235:genetics* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D000688:Amylose
keywords: Allelic variation; Dull grain; Floury grain; Rice (Oryza sativa); Tetratricopeptide repeat (TPR) domain-containing protein