Reference "A brassinolide-suppressed rice MADS-box transcription factor, OsMDP1, has a negative regulatory role in BR signaling"

Reference ID

11197

Title

A brassinolide-suppressed rice MADS-box transcription factor, OsMDP1, has a negative regulatory role in BR signaling

Source

The Plant journal : for cell and molecular biology, 2006, vol. , pp. -

Authors (6)

Duan-K	Li-L
Hu-P	Xu-S-P
Xu-Z-H	Xue-H-W

Abstract

The MADS-box transcription factor-encoding genes are expressed mainly during
plant reproductive development, where they play important roles in controlling
floral organ initiation and identity. Few previous reports have investigated the
functions of MADS-box transcription factors expressed in vegetative tissues.
Here we describe the functional characterization of a rice AG-like MADS-box
protein, OsMDP1 (Oryza sativa MADS-domain-containing protein 1). A partial cDNA
encoding a MADS-box domain was identified via high-throughput screening of rice
brassinolide-regulated genes, and the full-length cDNA was subsequently isolated
via screening of a cDNA library constructed from rice materials at tillering
stage. Expression pattern analyses indicated that OsMDP1 is transcribed mainly
in vegetative tissues, including the mature leaf, coleoptile, root-elongation
zone, culm internode, and especially the joint region between the leaf blade and
sheath. Further studies revealed that transcription of OsMDP1 is stimulated by
darkness and suppressed by brassinolide treatment. OsMDP1 deficiency resulted in
shortened primary roots, elongated coleoptiles and enhanced lamina joint
inclinations. Moreover, transgenic plants showed hypersensitivities to exogenous
brassinolide in terms of lamina joint inclination and coleoptile elongation.
OsMDP1 deficiency resulted in enhanced expression of OsXTR1, which encodes
xyloglucan endotransglycosylase, the cell-wall loosening enzyme necessary for
cell elongation, and modulated expressions of multiple genes involved in cell
signalling and gene transcription, indicating the key negative regulatory role
of OsMDP1 in BR signalling.