Reference "Functional characterization of OsMADS18, a member of the AP1/SQUA subfamily of MADS box genes"

Reference ID

8348

Title

Functional characterization of OsMADS18, a member of the AP1/SQUA subfamily of MADS box genes

Source

Plant physiology, 2004, vol. 135, pp. 2207-2219

Authors (10)

Fornara-F	Parenicova-L
Falasca-G	Pelucchi-N
Masiero-S	Ciannamea-S
Lopez-Dee-Z	Altamura-M-M
Colombo-L	Kater-M-M

Abstract

MADS box transcription factors controlling flower development have been isolated
and studied in a wide variety of organisms. These studies have shown that
homologous MADS box genes from different species often have similar functions.
OsMADS18 from rice (Oryza sativa) belongs to the phylogenetically defined
AP1/SQUA group. The MADS box genes of this group have functions in plant
development, like controlling the transition from vegetative to reproductive
growth, determination of floral organ identity, and regulation of fruit
maturation. In this paper we report the functional analysis of OsMADS18. This
rice MADS box gene is widely expressed in rice with its transcripts accumulated
to higher levels in meristems. Overexpression of OsMADS18 in rice induced early
flowering, and detailed histological analysis revealed that the formation of
axillary shoot meristems was accelerated. Silencing of OsMADS18 using an RNA
interference approach did not result in any visible phenotypic alteration,
indicating that OsMADS18 is probably redundant with other MADS box transcription
factors. Surprisingly, overexpression of OsMADS18 in Arabidopsis caused a
phenotype closely resembling the ap1 mutant. We show that the ap1 phenotype is
not caused by down-regulation of AP1 expression. Yeast two-hybrid experiments
showed that some of the natural partners of AP1 interact with OsMADS18,
suggesting that the OsMADS18 overexpression phenotype in Arabidopsis is likely
to be due to the subtraction of AP1 partners from active transcription
complexes. Thus, when compared to AP1, OsMADS18 during evolution seems to have
conserved the mechanistic properties of protein-protein interactions, although
it cannot complement the AP1 function.