Light intensity activation of alternative electron transport mechanisms in the moss Physcomitrium patens

作者：Shun-Ling Tan, Antoni M. Vera‐Vives, Alessandro Alboresi, Tomas Morosinotto · 发表于：Plant Physiology and Biochemistry · 年份：2025 · DOI：10.1016/j.plaphy.2025.109904 · 被引用次数：5 · 研究领域：Photosynthetic Processes and Mechanisms、Light effects on plants、Plant Stress Responses and Tolerance

Photosynthetic organisms exploit sunlight to drive an electron transport chain and obtain the chemical energy supporting their metabolism. In highly dynamic environmental conditions, excitation energy and electron transport need to be continuously modulated to prevent over-reduction and the consequent damage. An essential role in the regulation of electron transport is played by alternative electron transport mechanisms such as cyclic electron transport (CET) facilitated by PGRL1/PGR5 and NDH complex and pseudo-cyclic electron transport (PCET) mediated by the flavodiiron proteins (FLV) and the Mehler reaction. In this work mutant lines of the moss Physcomitrium patens depleted in PCET ( flva KO) or CET ( pgrl1/ndhm KO) were compared to wild-type plants for their ability to regulate photosynthetic electron transport in response to light fluctuations of different intensities. FLV activity enables a very fast increase in electron transport capacity but its impact is transient and becomes undetectable after 3 min from a light change. The FLV electron transport capacity is saturated at 100 μmol photons m −2 s −1 and does not increase even if exposed to stronger illumination. On the other hand, CET activation after an increase in illumination has a smaller contribution on electron transport capacity, but it provides a steady contribution for several minutes after a change in illumination intensity. Overall, these results demonstrate that light adapted plants CO 2 fixation capacity ...