A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice
A Gibberellin-Mediated DELLA-NAC Signaling Cascade Regulates Cellulose Synthesis in Rice
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DOI：
10.1105/tpc.15.00015
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发表时间：
2015-06-01
期刊：
影响因子：
11.6
通讯作者：
Zhou, Yihua
中科院分区：
文献类型：
--
作者：
Huang, Debao;Wang, Shaogan;Zhou, Yihua
纤维素可以转化为多种工业产品，对全球经济具有重要影响。人们早就知道植物中的纤维素合成受到各种植物激素的严格调控。然而，纤维素合成调节的潜在机制仍然难以捉摸。在这里，我们发现，在水稻（Oryza sativa）中，赤霉素（GA）信号通过减轻 SLENDER RICE1（SLR1）（GA 信号的 DELLA 抑制子）与 NAC（次生壁形成的顶层转录因子）之间的相互作用来促进纤维素合成。 GA 相关基因的突变和生理处理改变了纤维素合酶基因 (CESA) 的转录和纤维素水平。多项实验证明转录因子NAC29/31和MYB61是水稻中的CESA调节因子； NAC29/31 直接调节 MYB61，进而激活 CESA 表达。这种分层调节途径被 SLR1-NAC29/31 相互作用阻断。根据解剖分析和水稻节间发育中 GA 含量检测的结果，发现该信号级联受到不同内源 GA 水平的调节，并且是节间发育所必需的。在拟南芥 GA 相关突变体中进一步进行了遗传和基因表达分析。总而言之，我们的研究结果揭示了 GA 调节陆地植物次生壁纤维素合成的保守机制，并为操纵纤维素生产和植物生长提供了策略。
Cellulose, which can be converted into numerous industrial products, has important impacts on the global economy. It has long been known that cellulose synthesis in plants is tightly regulated by various phytohormones. However, the underlying mechanism of cellulose synthesis regulation remains elusive. Here, we show that in rice (Oryza sativa), gibberellin (GA) signals promote cellulose synthesis by relieving the interaction between SLENDER RICE1 (SLR1), a DELLA repressor of GA signaling, and NACs, the top-layer transcription factors for secondary wall formation. Mutations in GA-related genes and physiological treatments altered the transcription of CELLULOSE SYNTHASE genes (CESAs) and the cellulose level. Multiple experiments demonstrated that transcription factors NAC29/31 and MYB61 are CESA regulators in rice; NAC29/31 directly regulates MYB61, which in turn activates CESA expression. This hierarchical regulation pathway is blocked by SLR1-NAC29/31 interactions. Based on the results of anatomical analysis and GA content examination in developing rice internodes, this signaling cascade was found to be modulated by varied endogenous GA levels and to be required for internode development. Genetic and gene expression analyses were further performed in Arabidopsis thaliana GA-related mutants. Altogether, our findings reveal a conserved mechanism by which GA regulates secondary wall cellulose synthesis in land plants and provide a strategy for manipulating cellulose production and plant growth.