Phosphate starvation root architecture and anthocyanin accumulation responses are modulated by the gibberellin-DELLA signaling pathway in Arabidopsis1[OA]
Phosphate starvation root architecture and anthocyanin accumulation responses are modulated by the gibberellin-DELLA signaling pathway in Arabidopsis1[OA]
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DOI：
10.1104/pp.107.103788
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发表时间：
2007-12-01
期刊：
影响因子：
7.4
通讯作者：
Fu, Xiangdong
中科院分区：
文献类型：
--
作者：
Jiang, Caifu;Gao, Xiuhua;Fu, Xiangdong
磷酸盐(PI)是一种对植物生长发育至关重要的常量营养素。然而，PI的低流动性阻碍了吸收，从而降低了有效性。因此，植物已经制定了应对低磷有效性的生理策略。在这里，我们报道了拟南芥特有的饥饿反应在一定程度上依赖于核生长抑制蛋白(DELLA)的活性，DELLA蛋白是赤霉素(GA)信号通路的核心成分。我们首先证明了多个地上部和根部的PI饥饿反应可以被外源GA或导致Della功能大幅降低的突变所抑制。相反，具有增强的Della功能的突变体表现出增强的PI饥饿反应。我们还发现，PI缺乏促进了绿色荧光蛋白标记的della(GFP-RGA[GA1-3抑制因子])在根细胞核中的积累。在进一步的实验中，我们发现PI饥饿导致生物活性GA水平的下降以及编码GA代谢酶的基因转录水平的相关变化。最后，我们发现GA-DELLA系统调节了根毛长度的增加，这是PI饥饿的特征。综上所述，我们的结果表明，Della介导的信号有助于花青素的积累和PI饥饿反应特有的根构型变化，但不调控PI饥饿诱导的PI吸收效率的变化或选定的PI饥饿响应基因转录本的积累。PI饥饿导致生物活性GA水平的降低，进而导致Della的积累，从而调节几个适应性显著的植物PI饥饿反应。
Phosphate (Pi) is a macronutrient that is essential for plant growth and development. However, the low mobility of Pi impedes uptake, thus reducing availability. Accordingly, plants have developed physiological strategies to cope with low Pi availability. Here, we report that the characteristic Arabidopsis thaliana Pi starvation responses are in part dependent on the activity of the nuclear growth-repressing DELLA proteins (DELLAs), core components of the gibberellin (GA)-signaling pathway. We first show that multiple shoot and root Pi starvation responses can be repressed by exogenous GA or by mutations conferring a substantial reduction in DELLA function. In contrast, mutants having enhanced DELLA function exhibit enhanced Pi starvation responses. We also show that Pi deficiency promotes the accumulation of a green fluorescent protein-tagged DELLA (GFP-RGA [repressor of ga1-3]) in root cell nuclei. In further experiments, we show that Pi starvation causes a decrease in the level of bioactive GA and associated changes in the levels of gene transcripts encoding enzymes of GA metabolism. Finally, we show that the GA-DELLA system regulates the increased root hair length that is characteristic of Pi starvation. In conclusion, our results indicate that DELLA-mediated signaling contributes to the anthocyanin accumulation and root architecture changes characteristic of Pi starvation responses, but do not regulate Pi starvation-induced changes in Pi uptake efficiency or the accumulation of selected Pi starvation-responsive gene transcripts. Pi starvation causes a reduction in bioactive GA level, which, in turn, causes DELLA accumulation, thus modulating several adaptively significant plant Pi starvation responses.