Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
Section of Molecular Plant Biology, Department of Biology, University of Oxford, Oxford, UK.
Nat Commun. 2023 Jun 3;14(1):3210. doi: 10.1038/s41467-023-38938-z.
Green organisms evolve oxygen (O) via photosynthesis and consume it by respiration. Generally, net O consumption only becomes dominant when photosynthesis is suppressed at night. Here, we show that green thylakoid membranes of Scots pine (Pinus sylvestris L) and Norway spruce (Picea abies) needles display strong O consumption even in the presence of light when extremely low temperatures coincide with high solar irradiation during early spring (ES). By employing different electron transport chain inhibitors, we show that this unusual light-induced O consumption occurs around photosystem (PS) I and correlates with higher abundance of flavodiiron (Flv) A protein in ES thylakoids. With P700 absorption changes, we demonstrate that electron scavenging from the acceptor-side of PSI via O photoreduction is a major alternative pathway in ES. This photoprotection mechanism in vascular plants indicates that conifers have developed an adaptative evolution trajectory for growing in harsh environments.
绿色生物通过光合作用产生氧气（O），并通过呼吸作用消耗氧气。一般来说，只有在光合作用受到抑制的夜间，净 O 消耗才会占据主导地位。在这里，我们发现，当早春（ES）期间，极低的温度与高太阳辐射同时出现时，即使在光照下，苏格兰松（Pinus sylvestris L）和挪威云杉（Picea abies）针叶的绿色类囊体膜也会显示出强烈的 O 消耗。通过使用不同的电子传递链抑制剂，我们发现这种不寻常的光诱导 O 消耗发生在光系统（PS）I 周围，并且与 ES 类囊体中黄素铁蛋白（Flv）A 蛋白的更高丰度相关。通过 P700 吸收变化，我们证明了通过 O 光还原从 PSI 的受体侧清除电子是 ES 中的主要替代途径。这种维管束植物的光保护机制表明，针叶树已经为在恶劣环境中生长发展出了适应性进化轨迹。
