State Key Laboratory of Plant Genomics and National Center for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100039, China.
Plant Cell. 2018 Jul;30(7):1461-1475. doi: 10.1105/tpc.18.00063. Epub 2018 Jun 18.
Tiller angle in cereals is a key shoot architecture trait that strongly influences grain yield. Studies in rice () have implicated shoot gravitropism in the regulation of tiller angle. However, the functional link between shoot gravitropism and tiller angle is unknown. Here, we conducted a large-scale transcriptome analysis of rice shoots in response to gravistimulation and identified two new nodes of a shoot gravitropism regulatory gene network that also controls rice tiller angle. We demonstrate that HEAT STRESS TRANSCRIPTION FACTOR 2D (HSFA2D) is an upstream positive regulator of the LAZY1-mediated asymmetric auxin distribution pathway. We also show that two functionally redundant transcription factor genes, () and , are expressed asymmetrically in response to auxin to connect gravitropism responses with the control of rice tiller angle. These findings define upstream and downstream genetic components that link shoot gravitropism, asymmetric auxin distribution, and rice tiller angle. The results highlight the power of the high-temporal-resolution RNA-seq data set and its use to explore further genetic components controlling tiller angle. Collectively, these approaches will identify genes to improve grain yields by facilitating the optimization of plant architecture.
在谷类作物中，分蘖角度是一个关键的茎秆结构特征，强烈影响着籽粒产量。对水稻的研究表明，茎的向地性在分蘖角度的调节中起作用。然而，茎的向地性和分蘖角度之间的功能联系尚不清楚。在这里，我们对水稻茎在重力刺激下的转录组进行了大规模分析，鉴定出一个新的调控茎向地性的网络节点，该网络节点也控制着水稻的分蘖角度。我们证明，热应激转录因子 2D（HSFA2D）是 LAZY1 介导的不对称生长素分布途径的上游正调控因子。我们还表明，两个功能冗余的转录因子基因和在响应生长素时表现出不对称表达，将向地性反应与对水稻分蘖角度的控制联系起来。这些发现定义了上游和下游的遗传成分，它们将茎的向地性、不对称的生长素分布和水稻的分蘖角度联系起来。这些结果突出了高时间分辨率 RNA-seq 数据集的强大功能，并利用它来进一步探索控制分蘖角度的遗传成分。总的来说，这些方法将通过促进植物结构的优化来鉴定出提高籽粒产量的基因。
