Reference "Conservation and divergence of FCA function between Arabidopsis and rice"

Reference ID

11175

Title

Conservation and divergence of FCA function between Arabidopsis and rice

Source

Plant molecular biology, 2005, vol. 58, pp. 823-838

Authors (9)

Lee-J-H	Cho-Y-S
Yoon-H-S	Suh-M-C
Moon-J	Lee-I
Weigel-D	Yun-C-H
Kim-J-K

Abstract

Although several genes have been identified in rice which are functionally
equivalent to the flowering time genes in Arabidopsis, primarily genes involved
in the photoperiod pathway, little data is available regarding the genes that
function in the autonomous pathway in rice. In order to acquire further insight
into the control of heading dates in rice, we isolated and conducted an
expression analysis on OsFCA, which exhibited 38% sequence homology with
Arabidopsis FCA. The N-terminal region of the OsFCA protein appears to be
unusually rich in glycine-residues, unlike the N-terminal region found in FCA.
However, the genetic structure of OsFCA is, in general, similar to that of FCA.
RT-PCR and in silico analyses also showed that alternative splicing and
polyadenylation at intron3 were conserved in the genetic expression of OsFCA. We
were able to detect alpha, beta, and gamma transcripts, but not the delta
transcript, of the OsFCA gene. The beta and gamma transcripts of the OsFCA gene
were detected via Northern analysis in the leaves, roots, and flowers of the
plant. Flowers in younger stages exhibited higher transcript levels. These data
suggest that intron3 may constitute a primary control point in the OsFCA pre-
mRNA processing of rice. The overexpression of OsFCA cDNA, driven by the 35S
promoter, was shown to partially rescue the late flowering phenotype of the fca
mutant, suggesting that the functions of the OsFCA and the FCA are partially
overlapped, despite the lack of an apparent FLC homologue in the rice genome.
The constitutive expression of OsFCA resulted in no downregulation of FLC, but
did result in the weak upregulation of SOC1 in the transgenic Arabidopsis. OsFCA
overexpression did not result in a reduction of the gamma transcript levels of
FCA in the transgenic Arabidopsis either, thereby suggesting that OsFCA had no
effects on the autoregulation of Arabidopsis FCA. All of these results imply
conservation and divergence in the functions of FCA between rice and
Arabidopsis.