The gibberellin signaling negative regulator RGA-LIKE3 promotes seed storage protein accumulation
The gibberellin signaling negative regulator RGA-LIKE3 promotes seed storage protein accumulation
复制标题
赤霉素信号负调节因子RGA-LIKE3促进种子贮藏蛋白积累
DOI：
10.1093/plphys/kiaa114
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发表时间：
2021-01-13
期刊：
影响因子：
7.4
通讯作者：
Hou, Xingliang
中科院分区：
文献类型：
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作者：
Hu, Yilong;Zhou, Limeng;Hou, Xingliang
种子贮藏蛋白(SSP)是种子贮藏储备的主要组成部分，其积累受到一个复杂的调控网络的密切调控。然而，赤霉素(GA)信号是否以及如何参与这一重要的生物学事件尚不完全清楚。在此，我们发现GA显著降低了拟南芥中SSP的含量，而GA生物合成三重突变体ga3ox1/3/4中的SSP含量显著增加。进一步的研究表明，作为GA信号负调控因子的Della蛋白RGA-LIKE3(RGL3)对SSP的积累是重要的。与野生型相比，rgl3和35S：RGL3-HA中SSP基因的表达分别下调和上调。RGL3在体内和体外都与脱落酸INSENSITIVE3(ABI3)相互作用，ABI3是种子发育过程中控制SSP积累的关键转录因子，从而极大地促进ABI3对SSP基因的转录激活能力。此外，遗传证据表明，RGL3和ABI3以相互依赖的方式调节SSP的积累。因此，我们揭示了Della成员RGL3在种子成熟过程中作为ABI3的共激活子促进SSP生物合成的功能。这一发现促进了对GA介导的种子储藏储备积累机制的理解。
Seed storage protein (SSP) acts as one of the main components of seed storage reserves, of which accumulation is tightly mediated by a sophisticated regulatory network. However, whether and how gibberellin (GA) signaling is involved in this important biological event is not fully understood. Here, we show that SSP content in Arabidopsis (Arabidopsis thaliana) is significantly reduced by GA and increased in the GA biosynthesis triple mutant ga3ox1/3/4. Further investigation shows that the DELLA protein RGA-LIKE3 (RGL3), a negative regulator of GA signaling, is important for SSP accumulation. In rgl3 and 35S:RGL3-HA, the expression of SSP genes is down- and upregulated, respectively, compared with that in the wild-type. RGL3 interacts with ABSCISIC ACID INSENSITIVE3 (ABI3), a critical transcription factor for seed developmental processes governing SSP accumulation, both in vivo and in vitro, thus greatly promoting the transcriptional activating ability of ABI3 on SSP genes. In addition, genetic evidence shows that RGL3 and ABI3 regulate SSP accumulation in an interdependent manner. Therefore, we reveal a function of RGL3, a little studied DELLA member, as a coactivator of ABI3 to promote SSP biosynthesis during seed maturation stage. This finding advances the understanding of mechanisms in GA-mediated seed storage reserve accumulation.