DROOPY LEAF1 controls leaf architecture by orchestrating early brassinosteroid signaling
DROOPY LEAF1 controls leaf architecture by orchestrating early brassinosteroid signaling
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DROOPY LEAF1 通过协调早期油菜素类固醇信号传导来控制叶子结构
DOI：
10.1073/pnas.2002278117
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发表时间：
2020-09-01
影响因子：
11.1
通讯作者：
Diao, Xianmin
中科院分区：
文献类型：
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作者：
Zhao, Meicheng;Tang, Sha;Diao, Xianmin
叶构型直接决定冠层结构，从而决定作物的产量。叶片下垂是一个主要影响禾谷类作物叶结构的农艺性状，但其遗传基础和分子机制尚不清楚。在这里，我们报告说，下垂叶1（DPY 1），LRR受体样激酶，起着至关重要的作用，在确定叶下垂通过控制油菜素类固醇（BR）信号输出狗尾草，一个新兴的模式Panicoideae草。DPY 1功能缺失突变导致了叶片中厚壁组织的畸形和木质素含量的降低，从而导致了一种非常下垂的叶片表型，这与其在叶片维管组织中的优先表达相一致。DPY 1与SiBAK 1相互作用并竞争SiBAK 1，结果导致SiBRI 1-SiBAK 1相互作用、SiBRI 1磷酸化和下游BR信号传导的连续减少。相反，在BR处理下，DPY 1积累和DPY 1-SiBAK 1相互作用的亲和力增强，从而防止SiBRI 1过度活化。因此，这些发现揭示了一种负反馈机制，通过防止早期BR信号对过量BR的过度反应来抑制叶片下垂。值得注意的是，过表达DPY 1的植物具有更多的直立叶、更厚的茎和更大的圆锥花序，这表明其具有提高产量的潜力。DPY 1的玉米直向同源物拯救了DPY 1中的下垂叶片，表明其在黍亚科中的保守功能。总之，我们的研究提供了关于BR信号如何被DPY 1仔细检查以确保向上的叶结构的见解。
Leaf architecture directly determines canopy structure, and thus, grain yield in crops. Leaf droopiness is an agronomic trait primarily affecting the cereal leaf architecture but the genetic basis and underlying molecular mechanism of this trait remain unclear. Here, we report that DROOPY LEAF1 (DPY1), an LRR receptor-like kinase, plays a crucial role in determining leaf droopiness by controlling the brassinosteroid (BR) signaling output in Setaria, an emerging model for Panicoideae grasses. Loss-of-function mutation in DPY1 led to malformation of vascular sclerenchyma and low lignin content in leaves, and thus, an extremely droopy leaf phenotype, consistent with its preferential expression in leaf vascular tissues. DPY1 interacts with and competes for SiBAK1 and as a result, causes a sequential reduction in SiBRI1-SiBAK1 interaction, SiBRI1 phosphorylation, and downstream BR signaling. Conversely, DPY1 accumulation and affinity of the DPY1-SiBAK1 interaction are enhanced under BR treatment, thus preventing SiBRI1 from overactivation. As such, those findings reveal a negative feedback mechanism that represses leaf droopiness by preventing an overresponse of early BR signaling to excess BRs. Notably, plants overexpressing DPY1 have more upright leaves, thicker stems, and bigger panicles, suggesting potential utilization for yield improvement. The maize ortholog of DPY1 rescues the droopy leaves in dpy1, suggesting its conserved function in Panicoideae. Together, our study provides insights into how BR signaling is scrutinized by DPY1 to ensure the upward leaf architecture.