Instituto de Tecnologia Química e Biológica António Xavier - Universidade Nova de Lisboa (ITQB-NOVA), Av. da República, 2780-157, Oeiras, Portugal.
Department of Biology and Biotechnology 'L. Spallanzani', via Ferrata 9, 27100, Pavia, Italy.
Sci Rep. 2019 Jul 18;9(1):10466. doi: 10.1038/s41598-019-46866-6.
In the present work, non-targeted metabolomics was used to investigate the seed response to kinetin, a phytohormone with potential roles in seed germination, still poorly explored. The aim of this study was to elucidate the metabolic signatures of germination triggered by kinetin and explore changes in metabolome to identify novel vigor/stress hallmarks in Medicago truncatula. Exposure to 0.5 mM kinetin accelerated seed germination but impaired seedling growth. Metabolite composition was investigated in seeds imbibed with water or with 0.5 mM kinetin collected at 2 h and 8 h of imbibition, and at the radicle protrusion stage. According to Principal Component Analysis, inositol pentakisphosphate, agmatine, digalactosylglycerol, inositol hexakisphosphate, and oleoylcholine were the metabolites that mostly contributed to the separation between 2 h, 8 h and radicle protrusion stage, irrespective of the treatment applied. Overall, only 27 metabolites showed significant changes in mean relative contents triggered by kinetin, exclusively at the radicle protrusion stage. The observed metabolite depletion might associate with faster germination or regarded as a stress signature. Results from alkaline comet assay, highlighting the occurrence of DNA damage at this stage of germination, are consistent with the hypothesis that prolonged exposure to kinetin induces stress conditions leading to genotoxic injury.
在本工作中，我们采用非靶向代谢组学方法研究了激素激动素（kinetin）对种子的作用，激素激动素在种子萌发中具有潜在作用，但研究仍不充分。本研究旨在阐明激动素触发种子萌发的代谢特征，并探索代谢组的变化，以鉴定蒺藜苜蓿种子活力/胁迫的新标志。暴露于 0.5 mM 激动素可加速种子萌发，但会损害幼苗生长。在吸水或用 0.5 mM 激动素吸水 2 小时和 8 小时以及胚根突出阶段收集种子，研究了代谢物组成。根据主成分分析，肌醇 pentakisphosphate、胍丁胺、双半乳糖甘油、肌醇 hexakisphosphate 和油酰胆碱是无论应用何种处理，将 2 小时、8 小时和胚根突出阶段分开的主要代谢物。总体而言，仅在胚根突出阶段，有 27 种代谢物的相对含量因激动素而发生显著变化。观察到的代谢物耗竭可能与更快的萌发有关，或被视为胁迫标志。在该萌发阶段进行的碱性彗星试验结果突出了 DNA 损伤的发生，这与延长激动素暴露会导致应激条件并导致遗传毒性损伤的假设一致。
