Reference "Loss of function of a rice brassinosteroid insensitive1 homolog prevents internode elongation and bending of the lamina joint"

Reference ID

5076

Title

Loss of function of a rice brassinosteroid insensitive1 homolog prevents internode elongation and bending of the lamina joint

Source

The Plant cell, 2000, vol. 12, pp. 1591-1606

Authors (9)

Yamamuro-C	Ihara-Y
Wu-X	Noguchi-T
Fujioka-S	Takatsuto-S
Ashikari-M	Kitano-H
Matsuoka-M

Abstract

Brassinosteroids (BRs) are plant growth-promoting natural products required for
plant growth and development. Physiological studies have demonstrated that
exogenous BR, alone or in combination with auxin, enhance bending of the lamina
joint of rice. However, little is known about the function of endogenous BR in
rice or other grass species. We report here the phenotypical and molecular
characterization of a rice dwarf mutant, d61, that is less sensitive to BR
compared to the wild type. We cloned a rice gene, OsBRI1, with extensive
sequence similarity to that of the Arabidopsis BRI gene, which encodes a
putative BR receptor kinase. Linkage analysis showed that the OsBRI1 gene is
closely linked to the d61 locus. Single nucleotide substitutions found at
different sites of the d61 alleles would give rise to amino acid changes in the
corresponding polypeptides. Furthermore, introduction of the entire OsBRI1
coding region, including the 5' and 3' flanking sequences, into d61 plants
complemented the mutation to display the wild-type phenotype. Transgenic plants
carrying the antisense strand of the OsBRI1 transcript showed similar or even
more severe phenotypes than those of the d61 mutants. Our results show that
OsBRI1 functions in various growth and developmental processes in rice,
including (1) internode elongation, by inducing the formation of the intercalary
meristem and the longitudinal elongation of internode cells; (2) bending of the
lamina joint; and (3) skotomorphogenesis.