Reference "The gene FLORAL ORGAN NUMBER1 regulates floral meristem size in rice and encodes a leucine-rich repeat receptor kinase orthologous to Arabidopsis CLAVATA1"

Reference ID

11263

Title

The gene FLORAL ORGAN NUMBER1 regulates floral meristem size in rice and encodes a leucine-rich repeat receptor kinase orthologous to Arabidopsis CLAVATA1

Source

Development (Cambridge, England), 2004, vol. 131, pp. 5649-5657

Authors (6)

Suzaki-T	Sato-M
Ashikari-M	Miyoshi-M
Nagato-Y	Hirano-H-Y

Abstract

The regulation of floral organ number is closely associated with floral meristem
size. Mutations in the gene FLORAL ORGAN NUMBER1 (FON1) cause enlargement of the
floral meristem in Oryza sativa (rice), resulting in an increase in the number
of all floral organs. Ectopic floral organs develop in the whorl of each organ
and/or in the additional whorls that form. Inner floral organs are more severely
affected than outer floral organs. Many carpel primordia develop
indeterminately, and undifferentiated meristematic tissues remain in the center
in almost-mature flowers. Consistent with this result, OSH1, a molecular marker
of meristematic indeterminate cells in rice, continues to be expressed in this
region. Although floral meristems are strongly affected by the fon1-2 mutation,
vegetative and inflorescence meristems are largely normal, even in this strong
allele. We isolated the FON1 gene by positional cloning and found that it
encodes a leucine-rich repeat receptor-like kinase most similar to CLAVATA1
(CLV1) in Arabidopsis thaliana. This suggests that a pathway similar to the CLV
signaling system that regulates meristem maintenance in Arabidopsis is conserved
in the grass family. Unlike CLV1, which is predominantly expressed in the L3
layer of the shoot meristem, FON1 is expressed throughout the whole floral
meristem, suggesting that small modifications to the CLV signaling pathway may
be required to maintain the floral meristem in rice. In addition, FON1
transcripts are detected in all meristems responsible for development of the
aerial part of rice, suggesting that genes sharing functional redundancy with
FON1 act in the vegetative and inflorescence meristems to mask the effects of
the fon1 mutation.