Misión Biológica de Galicia (MBG-CSIC), Pontevedra, Galicia, Spain.
Department of Plant Biology, Faculty of Biology, Institute of Biotechnology and Biomedicine, University of Valence, Valence, Spain.
Plant Biol (Stuttg). 2023 Aug;25(5):785-792. doi: 10.1111/plb.13530. Epub 2023 May 16.
Recent discoveries pointed out the importance of the mutual correlation between timing of environmental stress and plant fitness. However, the internal reshaping of plant growth under daily stress sensing, and their metabolic coordination remain to be investigated. Thus, we studied the connection between time of day, growth and defence to understand how plant fitness is affected by diurnal stress inputs. We examined if simulated herbivory (leaf wounding) in the morning, at midday or the evening differentially influence plant defence state vs growth in three crop species of Brassica: broccoli (Brassica oleraceae), turnip greens (B. rapa) and rapeseed (B. napus). The data revealed that plant's tolerance of wounding stress is diurnally regulated in Brassica crops. Trade-offs between biomass and investment in glucosinolates (GSL) and phenolics were affected by timing of leaf stress. Negative correlations between biomass and induction of defence compounds were found for plants treeated in the morning and evening. However, the correlations were positive for midday treatment. Interestingly, we revealed a new connection between plant growth and changes in aliphatic GSLs and flavonoids in response to wounding. These data suggest that metabolic stress-dependent circadian oscillations in leaf defences could be one mechanism conferring a competitive advantage to plants to anticipate daily environmental variations by synchronizing them with growth. Moreover, this work provides first insights into how secondary metabolites are linked to growth response in a timing-related manner.
最近的发现指出了环境胁迫时间与植物适应性之间相互关联的重要性。然而，植物在日常胁迫感知下的生长内部重塑及其代谢协调仍有待研究。因此，我们研究了时间、生长和防御之间的联系，以了解日节律应激输入如何影响植物适应性。我们研究了在一天中的早晨、中午或晚上模拟的草食性（叶片损伤）是否会对三种芸薹属作物（西兰花、萝卜和油菜）的植物防御状态和生长产生不同的影响。研究结果表明，植物对损伤胁迫的耐受性在芸薹属作物中具有昼夜节律调节。生物量与芥子油苷（GSL）和酚类物质投资之间的权衡受到叶片应激时间的影响。对于在早晨和晚上处理的植物，生物量与防御化合物诱导之间存在负相关。然而，对于中午处理的植物，相关性是正的。有趣的是，我们发现了植物生长与应激诱导的脂族 GSL 和类黄酮变化之间的新联系。这些数据表明，依赖代谢应激的叶片防御昼夜节律振荡可能是一种机制，通过与生长同步来赋予植物一种竞争优势，以预测日常环境变化。此外，这项工作首次揭示了次生代谢物如何以时间相关的方式与生长反应相关联。
