Reference "The rice SPINDLY gene functions as a negative regulator of gibberellin signaling by controlling the suppressive function of the DELLA protein, SLR1, and modulating brassinosteroid synthesis"

Reference ID

11382

Title

The rice SPINDLY gene functions as a negative regulator of gibberellin signaling by controlling the suppressive function of the DELLA protein, SLR1, and modulating brassinosteroid synthesis

Source

The Plant journal : for cell and molecular biology, 2006, vol. 48, pp. 390-402

Authors (9)

Shimada-A	Ueguchi-Tanaka-M
Sakamoto-T	Fujioka-S
Takatsuto-S	Yoshida-S
Sazuka-T	Ashikari-M
Matsuoka-M

Abstract

SPINDLY (SPY) encodes an O-linked N-acetylglucosamine transferase that is
considered to be a negative regulator of gibberellin (GA) signaling through an
unknown mechanism. To understand the function of SPY in GA signaling in rice, we
isolated a rice SPINDLY homolog (OsSPY) and produced knockdown transgenic plants
in which OsSPY expression was reduced by introducing its antisense or RNAi
construct. In knockdown plants, the enhanced elongation of lower internodes was
correlated with decreased levels of OsSPY expression, similar to the spindly
phenotype of Arabidopsis spy mutants, suggesting that OsSPY also functions as a
negative factor in GA signaling in rice. The suppressive function of OsSPY in GA
signaling was supported by the findings that the dwarfism was partially rescued
and OsGA20ox2 (GA20 oxidase) expression was reduced in GA-deficient and GA-
insensitive mutants by the knockdown of OsSPY function. The suppression of OsSPY
function in a GA-insensitive mutant, gid2, also caused an increase in the
phosphorylation of a rice DELLA protein, SLR1, but did not change the amount of
SLR1. This indicates that the function of OsSPY in GA signaling is not via
changes in the amount or stability of SLR1, but probably involves control of the
suppressive function of SLR1. In addition to the GA-related phenotypes, OsSPY
antisense and RNAi plants showed increased lamina joint bending, which is a brassinosteroid-
related phenotype, indicating that OsSPY may play roles both in GA signaling and
in the brassinosteroid pathway.