Joint International Research Laboratory of Metabolic & Developmental Sciences, State Key Laboratory of Hybrid Rice, Shanghai Jiao Tong University and University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Valencia 46022, Spain.
J Integr Plant Biol. 2017 Sep;59(9):693-707. doi: 10.1111/jipb.12594.
Grasses display highly diversified inflorescence architectures that differ in the arrangement of spikelets and flowers and determine cereal yields. However, the molecular basis underlying grass inflorescence morphogenesis remains largely unknown. Here we investigate the role of a functionally diversified SEPALLATA MADS-box transcription factor, OsMADS34, in regulating rice (Oryza sativa L.) inflorescence and spikelet development. Microarray analysis showed that, at the very early stages of inflorescence formation, dysfunction of OsMADS34 caused altered expression of 379 genes that are associated with protein modification and degradation, transcriptional regulation, signaling and metabolism activity. Genetic analysis revealed that OsMADS34 controls different aspects of inflorescence structure, branching and meristem activity synergistically with LAX PANICLE1 (LAX1) and FLORAL ORGAN NUMBER4 (FON4), as evidenced by the enhanced phenotypes of osmads34 lax1 and osmads34 fon4 compared with the single mutants. Additionally, double mutant between osmads34 and the sterile lemma defective mutant elongated empty glume (ele) displayed an enhanced phenotype, that is, longer and wider sterile lemmas that were converted into lemma/palea-like organs, suggesting that ELE and OsMADS34 synergistically control the sterile lemma development. OsMADS34 may act together with OsMADS15 in controlling sterile lemma development. Collectively, these findings provide insights into the regulatory function of OsMADS34 in rice inflorescence and spikelet development.
草具有高度多样化的花序结构，在小穗和花的排列上存在差异，决定了谷类作物的产量。然而，禾本科植物花序形态发生的分子基础在很大程度上仍然未知。在这里，我们研究了一个功能多样化的 SEPALLATA MADS 框转录因子 OsMADS34 在调控水稻（Oryza sativa L.）花序和小穗发育中的作用。微阵列分析表明，在花序形成的早期阶段，OsMADS34 的功能障碍导致 379 个与蛋白质修饰和降解、转录调控、信号转导和代谢活性相关的基因表达发生改变。遗传分析表明，OsMADS34 与 LAX PANICLE1（LAX1）和 FLORAL ORGAN NUMBER4（FON4）协同控制花序结构、分枝和分生组织活性的不同方面，这一点从 osmads34 lax1 和 osmads34 fon4 与单突变体相比增强的表型中得到证实。此外，在 osmads34 和 sterile lemma defective mutant elongated empty glume (ele) 的双突变体中显示出增强的表型，即更长更宽的不育外稃转化为外稃/内稃样器官，表明 ELE 和 OsMADS34 协同控制不育外稃的发育。OsMADS34 可能与 OsMADS15 一起控制不育外稃的发育。总之，这些发现为 OsMADS34 在水稻花序和小穗发育中的调控功能提供了新的见解。
