Laboratory of Molecular Genetics of Plant Development, Escola Superior de Agricultura 'Luiz de Queiroz' (ESALQ), University of Sao Paulo, 13418-900, Piracicaba, Sao Paulo, Brazil.
Laboratory of Hormonal Control of Plant Development, Escola Superior de Agricultura 'Luiz de Queiroz' (ESALQ), University of Sao Paulo (USP), 13418-900, Piracicaba, Sao Paulo, Brazil.
New Phytol. 2019 Feb;221(3):1328-1344. doi: 10.1111/nph.15492. Epub 2018 Oct 19.
Age-regulated microRNA156 (miR156) and targets similarly control the competence to flower in diverse species. By contrast, the diterpene hormone gibberellin (GA) and the microRNA319-regulated TEOSINTE BRANCHED/CYCLOIDEA/PCF (TCP) transcription factors promote flowering in the facultative long-day Arabidopsis thaliana, but suppress it in the day-neutral tomato (Solanum lycopersicum). We combined genetic and molecular studies and described a new interplay between GA and two unrelated miRNA-associated pathways that modulates tomato transition to flowering. Tomato PROCERA/DELLA activity is required to promote flowering along with the miR156-targeted SQUAMOSA PROMOTER BINDING-LIKE (SPL/SBP) transcription factors by activating SINGLE FLOWER TRUSS (SFT) in the leaves and the MADS-Box gene APETALA1(AP1)/MC at the shoot apex. Conversely, miR319-targeted LANCEOLATE represses floral transition by increasing GA concentrations and inactivating SFT in the leaves and AP1/MC at the shoot apex. Importantly, the combination of high GA concentrations/responses with the loss of SPL/SPB function impaired canonical meristem maturation and flower initiation in tomato. Our results reveal a cooperative regulation of tomato floral induction and flower development, integrating age cues (miR156 module) with GA responses and miR319-controlled pathways. Importantly, this study contributes to elucidate the mechanisms underlying the effects of GA in controlling flowering time in a day-neutral species.
年龄调节 microRNA156（miR156）及其靶标同样控制着不同物种开花的能力。相比之下，二萜激素赤霉素（GA）和 microRNA319 调控的 TEOSINTE BRANCHED/CYCLOIDEA/PCF（TCP）转录因子促进了兼性长日照拟南芥的开花，但抑制了非长日照番茄（Solanum lycopersicum）的开花。我们结合了遗传和分子研究，描述了 GA 和两个不相关的 miRNA 相关途径之间的新相互作用，这种相互作用调节了番茄向开花的转变。番茄 PROCERA/DELLA 活性通过在叶片中激活 SINGLE FLOWER TRUSS（SFT）和在茎尖中激活 MADS-Box 基因 APETALA1（AP1）/MC，与 miR156 靶向的 SQUAMOSA PROMOTER BINDING-LIKE（SPL/SBP）转录因子一起促进开花。相反，miR319 靶向的 LANCEOLATE 通过增加 GA 浓度和在叶片中失活 SFT 以及在茎尖中失活 AP1/MC 来抑制花的转变。重要的是，高 GA 浓度/反应与 SPL/SPB 功能丧失的组合损害了番茄中典型分生组织的成熟和花的起始。我们的研究结果揭示了番茄花诱导和花发育的协同调控，将年龄线索（miR156 模块）与 GA 反应和 miR319 控制的途径整合在一起。重要的是，这项研究有助于阐明 GA 控制非长日照物种开花时间的机制。
