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
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
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DOI：
10.1111/j.1365-313x.2006.02875.x
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发表时间：
2006-11-01
期刊：
影响因子：
7.2
通讯作者：
Matsuoka, Makoto
中科院分区：
文献类型：
--
作者：
Shimada, Asako;Ueguchi-Tanaka, Miyako;Matsuoka, Makoto
SPINDLY （SPY）编码一种o连接的n -乙酰氨基葡萄糖转移酶，该酶被认为是赤霉素（GA）信号传导的负调控因子，其机制尚不清楚。为了了解SPY在水稻遗传信号中的作用，我们分离了一个水稻SPINDLY同源基因（OsSPY），并通过引入OsSPY的反义或RNAi构建体来降低OsSPY的表达。在敲除植株中，下节间伸长的增强与OsSPY表达水平的降低相关，这与拟南芥间谍突变体的细长表型相似，表明OsSPY也在水稻GA信号传导中起负性作用。OsSPY在GA信号传导中的抑制作用得到了支持，研究发现，通过敲低OsSPY功能，在GA缺乏和GA不敏感突变体中，部分侏儒症得以恢复，OsGA20ox2 （GA20氧化酶）的表达降低。在ga不敏感突变体gid2中，OsSPY功能的抑制也导致水稻DELLA蛋白SLR1的磷酸化增加，但没有改变SLR1的量。这表明OsSPY在GA信号中的作用不是通过改变SLR1的数量或稳定性，而可能与控制SLR1的抑制功能有关。除了GA相关表型外，OsSPY反义和RNAi植物还表现出增加的板关节弯曲，这是一种与油菜素内酯相关的表型，表明OsSPY可能在GA信号通路和油菜素内酯途径中都起作用。
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.