Department of Life Sciences & CFE, Faculty of Sciences and Technologies, University of Coimbra, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; Department of Chemistry & QOPNA, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Department of Chemistry & QOPNA, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
J Plant Physiol. 2018 Mar;222:39-50. doi: 10.1016/j.jplph.2018.01.004. Epub 2018 Feb 3.
Ultraviolet-B (UV-B) radiation plays an important role in plant photomorphogenesis. Whilst the morpho-functional disorders induced by excessive UV irradiation are well-known, it remains unclear how this irradiation modulates the metabolome, and which metabolic shifts improve plants' tolerance to UV-B. In this study, we use an important Mediterranean crop, Olea europaea, to decipher the impacts of enhanced UV-B radiation on the physiological performance and lipophilic metabolite profile. Young olive plants (cv. 'Galega Vulgar') were exposed for five days to UV-B biologically effective doses of 6.5 kJ m d and 12.4 kJ m d. Cell cycle/ploidy, photosynthesis and oxidative stress, as well as GC-MS metabolites were assessed. Both UV-B treatments impaired net CO assimilation rate, transpiration rate, photosynthetic pigments, and RuBisCO activity, but 12.4 kJ m d also decreased the photochemical quenching (qP) and the effective efficiency of PSII (Φ). UV-B treatments promoted mono/triperpene pathways, while only 12.4 kJ m d increased fatty acids and alkanes, and decreased geranylgeranyl-diphosphate. The interplay between physiology and metabolomics suggests some innate ability of these plants to tolerate moderate UV-B doses (6.5 kJ m d). Also their tolerance to higher doses (12.4 kJ m d) relies on plants' metabolic adjustments, where the accumulation of specific compounds such as long-chain alkanes, palmitic acid, oleic acid and particularly oleamide (which is described for the first time in olive leaves) play an important protective role. This is the first study demonstrating photosynthetic changes and lipophilic metabolite adjustments in olive leaves under moderate and high UV-B doses.
紫外线-B（UV-B）辐射在植物光形态发生中起着重要作用。虽然过量 UV 照射引起的形态功能障碍是众所周知的，但尚不清楚这种辐射如何调节代谢组，以及哪些代谢变化可以提高植物对 UV-B 的耐受性。在这项研究中，我们使用一种重要的地中海作物，油橄榄（Olea europaea），来破译增强的 UV-B 辐射对生理性能和脂溶性代谢物谱的影响。年轻的油橄榄植物（cv. 'Galega Vulgar'）暴露在 UV-B 生物有效剂量为 6.5kJ m d 和 12.4kJ m d 的环境中 5 天。评估了细胞周期/倍性、光合作用和氧化应激以及 GC-MS 代谢物。两种 UV-B 处理都损害了净 CO 同化率、蒸腾速率、光合作用色素和 RuBisCO 活性，但 12.4kJ m d 也降低了光化学猝灭（qP）和 PSII 的有效效率（Φ）。UV-B 处理促进了单萜/三萜途径，而只有 12.4kJ m d 增加了脂肪酸和烷烃，降低了香叶基香叶基二磷酸。生理学和代谢组学之间的相互作用表明，这些植物具有一定的能力来耐受中等剂量的 UV-B（6.5kJ m d）。它们对更高剂量（12.4kJ m d）的耐受性也依赖于植物的代谢调节，其中特定化合物的积累，如长链烷烃、棕榈酸、油酸和特别是油酰胺（这是在橄榄叶中首次描述）发挥了重要的保护作用。这是第一项研究表明，在中等和高剂量的 UV-B 下，油橄榄叶片的光合作用变化和脂溶性代谢物调节。
