National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research (Wuhan), Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
Mol Plant. 2021 Jul 5;14(7):1168-1184. doi: 10.1016/j.molp.2021.04.013. Epub 2021 Apr 30.
Reproductive transition of grasses is characterized by switching the pattern of lateral branches, featuring the suppression of outgrowth of the subtending leaves (bracts) and rapid formation of higher-order branches in the inflorescence (panicle). However, the molecular mechanisms underlying such changes remain largely unknown. Here, we show that bract suppression is required for the reproductive branching in rice. We identified a pathway involving the intrinsic time ruler microRNA156/529, their targets SQUAMOSA PROMOTER BINDING PROTEIN LIKE (SPL) genes, NECK LEAF1 (NL1), and PLASTOCHRON1 (PLA1), which regulates the bract outgrowth and thus affects the pattern switch between vegetative and reproductive branching. Suppression of the bract results in global reprogramming of transcriptome and chromatin accessibility following the reproductive transition, while these processes are largely dysregulated in the mutants of these genes. These discoveries contribute to our understanding of the dynamic plant architecture and provide novel insights for improving crop yields.
禾本科植物的繁殖转变以侧枝模式的转变为特征，表现为抑制托叶（苞片）的生长和在花序（圆锥花序）中快速形成更高阶的分枝。然而，这种变化背后的分子机制在很大程度上仍然未知。在这里，我们表明，苞片的抑制是水稻生殖分枝所必需的。我们鉴定出了一条途径，该途径涉及内在的时间调节器 microRNA156/529、其靶基因 SQUAMOSA PROMOTER BINDING PROTEIN LIKE（SPL）基因、NECK LEAF1（NL1）和 PLASTOCHRON1（PLA1），它们调节苞片的生长，从而影响营养生长和生殖生长分枝之间的模式转换。抑制苞片会导致生殖转变后转录组和染色质可及性的全局重编程，而这些过程在这些基因的突变体中则受到很大程度的失调。这些发现有助于我们理解动态的植物结构，并为提高作物产量提供了新的见解。
