Loperfido Domenico, Zumajo-Cardona Cecilia, Commisso Mauro, Guzzo Flavia, Ambrose Barbara, Colombo Lucia, Ezquer Ignacio
Department of BioScience, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy.
Department of Biology, Botanical Garden, University of Padova, Padua, Italy.
Planta. 2025 Jul 18;262(3):59. doi: 10.1007/s00425-025-04745-7.
Based on expression, functional, and metabolomic analyses in the seeds of the single-receptor mutants, each receptor has a specific function during seed development. Their redundant roles during this process are difficult to assess; moreover, the impact they have on plant development must also be taken into account. In this study, we investigated the role of cytokinin receptors in Arabidopsis thaliana seed development and their impact on the metabolomic profile. Our findings reveal distinct expression patterns among them in the seed: AHK2 expression is not detected in seed tissues, AHK3 is expressed in embryo, endosperm, and peripheral endosperm, while AHK4/CRE1 expression is restricted to a few embryo cells. These patterns are consistent with the observed phenotypes where ahk3 exhibits more severe seed phenotypes such as delayed embryo development and increased seed and endosperm size. Metabolomic analyses showed that the receptors impact the abundance of metabolites, with a remarkably high concentration of tannins in ahk2 with respect to wild type seeds, while ahk3 mutant seeds have a very low amount of tannins but elevated levels of other compounds such as sinapoylated glucosinolates (GSLs), important for plant defense. The metabolic profile performed further supports a link between cytokinin and the regulation of secondary metabolites such as flavonoids and glucosinolates. Our results suggest that each cytokinin receptor independently contributes to this regulation, reflected in the distinct metabolic profiles of each mutant.
基于对单受体突变体种子的表达、功能和代谢组学分析，每个受体在种子发育过程中都具有特定功能。在此过程中它们的冗余作用难以评估；此外，还必须考虑它们对植物发育的影响。在本研究中，我们调查了细胞分裂素受体在拟南芥种子发育中的作用及其对代谢组学特征的影响。我们的研究结果揭示了它们在种子中的不同表达模式：在种子组织中未检测到AHK2的表达，AHK3在胚、胚乳和外周胚乳中表达，而AHK4/CRE1的表达局限于少数胚细胞。这些模式与观察到的表型一致，其中ahk3表现出更严重的种子表型，如胚发育延迟以及种子和胚乳大小增加。代谢组学分析表明，这些受体影响代谢物的丰度，与野生型种子相比，ahk2中鞣质浓度极高，而ahk3突变体种子中鞣质含量极低，但其他化合物如对植物防御很重要的芥子酰化硫代葡萄糖苷（GSLs）水平升高。进一步的代谢特征分析支持了细胞分裂素与黄酮类化合物和硫代葡萄糖苷等次生代谢物调控之间的联系。我们的结果表明，每个细胞分裂素受体独立地参与这种调控，这反映在每个突变体独特的代谢特征中。
