Fine mapping and candidate gene analysis of the floury endosperm gene, FLO(a), in rice.
In addition to its role as an energy source for plants, animals and humans, starch is also an environmentally friendly alternative to fossil fuels. In rice, the eating and cooking quality of the grain is determined by its starch properties. The floury endosperm of rice has been explored as an agronomical trait in breeding and genetics studies. In the present study, we characterized a floury endosperm mutant, flo(a), derived from treatment of Oryza sativa ssp. japonica cultivar Hwacheong with MNU. The innermost endosperm of the flo(a) mutant exhibited floury characteristics while the outer layer of the endosperm appeared normal. Starch granules in the flo(a) mutant formed a loosely-packed crystalline structure and X-ray diffraction revealed that the overall crystallinity of the starch was decreased compared to wild-type. The FLO(a) gene was isolated via a map-based cloning approach and predicted to encode the tetratricopeptide repeat domain-containing protein, OsTPR. Three mutant alleles contain a nucleotide substitution that generated one stop codon or one splice site, respectively, which presumably disrupts the interaction of the functionally conserved TPR motifs. Taken together, our map-based cloning approach pinpointed an OsTPR as a strong candidate of FLO(a), and the proteins that contain TPR motifs might play a significant role in rice starch biosynthetic pathways.
Qiao
Yongli
Y
Department of Plant Science, Research Institute for Agriculture and Life Sciences, and Plant Genomics and Breeding Institute, Seoul National University, Seoul, 151-921, Korea.
Lee
Song-I
SI
Piao
Rihua
R
Jiang
Wenzhu
W
Ham
Tae-Ho
TH
Chin
Joong-Hyoun
JH
Piao
Zhongze
Z
Han
Longzhi
L
Kang
Si-Yong
SY
Koh
Hee-Jong
HJ
D001483:Base Sequence; D020090:Chromosome Segregation; D003001:Cloning, Molecular; D056625:Endosperm / Q000235:genetics* / Q000648:ultrastructure; D005433:Flour; D017343:Genes, Plant / Q000235:genetics*; D005819:Genetic Markers; D008969:Molecular Sequence Data; D009154:Mutation; D012275:Oryza / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure; D010641:Phenotype; D020161:Physical Chromosome Mapping; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics; D017354:Point Mutation / Q000235:genetics; D011110:Polymorphism, Genetic; D017434:Protein Structure, Tertiary; D014961:X-Ray Diffraction
D005819:Genetic Markers; D010940:Plant Proteins