CEA, DSV, IBEB, Laboratoire d'Ecophysiologie Moléculaire des Plantes, F-13108 Saint-Paul-lez-Durance, France.
J Exp Bot. 2013 Jan;64(3):799-805. doi: 10.1093/jxb/ers223. Epub 2012 Aug 21.
Carotenoids play a crucial protective role in photosynthetic organisms as quenchers of singlet oxygen ((1)O(2)). This function occurs either via a physical mechanism involving thermal energy dissipation or via a chemical mechanism involving direct oxidation of the carotenoid molecule. The latter mechanism can produce a variety of aldehydic or ketonic cleavage products containing a reactive carbonyl group. One such molecule, the volatile β-carotene derivative β-cyclocitral, triggers changes in the expression of (1)O(2)-responsive genes and leads to an enhancement of photooxidative stress tolerance. Thus, besides their well-known functions in light harvesting and photoprotection, carotenoids can also play a role through their nonenzymic oxidation in the sensing and signalling of reactive oxygen species and photooxidative stress in photosynthetic organisms. Enzymic carotenoid oxidation does not seem to play a significant role in this phenomenon. Elucidation of the carotenoid-mediated (1)O(2) signalling pathway could provide new targets for improving photooxidative stress tolerance of plants.
类胡萝卜素在光合作用生物体中起着至关重要的保护作用，可作为单线态氧 ((1)O(2)) 的猝灭剂。该功能可以通过涉及热能耗散的物理机制或通过涉及类胡萝卜素分子直接氧化的化学机制来实现。后一种机制可以产生各种含有反应性羰基的醛或酮裂解产物。其中一种分子，挥发性 β-胡萝卜素衍生物 β-环柠檬醛，触发对 (1)O(2) 反应基因的表达变化，并增强光氧化应激耐受性。因此，除了它们在光捕获和光保护中的已知功能外，类胡萝卜素还可以通过非酶促氧化在光合作用生物体中活性氧和光氧化应激的感应和信号转导中发挥作用。酶促类胡萝卜素氧化似乎在这种现象中不起重要作用。阐明类胡萝卜素介导的 (1)O(2) 信号通路可以为提高植物的光氧化应激耐受性提供新的目标。
