Coordinated Regulation of the Genes Participating in Starch Biosynthesis by the Rice Floury-2 Locus.
The recessive floury-2 (flo-2) locus of rice (Oryza sativa L.), which is located on chromosome 4, causes a strong reduction in expression of the gene encoding an isoform of branching enzyme RBE1 in immature seeds 10 d after flowering. Mapping of the RBE1 gene demonstrated the localization on rice chromosome 6, suggesting that the wild-type Floury-2 (Flo-2) gene regulates RBE1 gene expression in trans. However, reduced expression of the genes encoding some other starch-synthesizing enzymes, including another isoform of branching enzyme RBE3 and granule-bound starch synthase, was also found in the flo-2 seeds. In spite of the low level of RBE1 gene expression in the immature seeds of the flo-2 mutants, the RBE1 gene was equally expressed in the leaves of the wild type and flo-2 mutants. Thus, these results imply that the Flo-2 gene may co-regulate expression of some of the genes participating in starch synthesis possibly in a developing seed-specific manner.
Kawasaki
T.
T
Mitsui Plant Biotechnology Research Institute (T.K., H. Shimada, S.O., N.I.), TCI D-21, Sengen 2-1-6, Institute of Applied Biochemistry (K.M., T.B.), University of Tsukuba Tennohdai 1-1-1, Tsukuba 305.
Mizuno
K.
K
Shimada
H.
H
Satoh
H.
H
Kishimoto
N.
N
Okumura
S.
S
Ichikawa
N.
N
Baba
T.
T