Aix Marseille Université, CEA, CNRS, Biosciences and Biotechnologies Institute of Aix-Marseille (BIAM), Equipe de Luminy de Génétique et Biophysique des Plantes, 13009, Marseille, France.
Cell Technology Laboratory-CFB, Vietnam National University of Forestry, Hanoi, Vietnam.
Plant Cell Rep. 2019 Jun;38(6):741-753. doi: 10.1007/s00299-019-02403-3. Epub 2019 Mar 26.
Arabidopsis single and double mutants for energy dissipation (npq4) and state transitions (pph1, blocked in State II) show enhanced growth and flowers + siliques production under controlled low-light conditions. Non-photochemical quenching (NPQ) is a short-term regulation important to maintain efficient photosynthesis and to avoid photooxidative damages by dissipation of excess energy. Full activation of NPQ in plants requires the protonation of the PsbS protein, which is the sensor of the low lumenal pH triggering the thermal dissipation. State transitions are a second important photosynthetic regulation to respond to changes in light quality and unbalanced excitation of photosystems. State transitions allow energy redistribution between PSI and PSII through the reversible exchange of LHCII antenna complexes between photosystems thanks to the opposite action of the STN7 kinase and PPH1 phosphatase: phosphorylation of LHCII promotes its mobilization from PSII to PSI, while dephosphorylation has the opposite effect. In this work, we produced the pph1/npq4 double mutant and characterized some photosynthetic, growth and reproduction properties in comparison with wild-type and single-mutant plants in high- and low-light conditions. Results indicate that in high light, the pph1 mutant maintains good photoprotection ability, while npq4 plants show more susceptibility to photodamages. The pph1/npq4 double mutant showed a resistance to high-light stress similar to that of the single npq4 mutant. In low-light condition, the single mutants showed a significant increase of growth and flowering compared to wild-type plants and this effect was further enhanced in the pph1/npq4 double mutant. Results suggest that photosynthetic optimisation to improve crop growth and productivity might be possible, at least under controlled low-light conditions, by modifying NPQ and regulation of state transitions.
拟南芥中能量耗散（npq4）和状态转变（pph1，在状态 II 中受阻）的单突变体和双突变体在受控低光照条件下显示出增强的生长和花+蒴果产量。非光化学猝灭（NPQ）是一种重要的短期调控机制，有助于维持高效光合作用，并通过耗散多余能量来避免光氧化损伤。NPQ 在植物中的完全激活需要 PsbS 蛋白的质子化，该蛋白是低腔室 pH 值触发热耗散的传感器。状态转变是对光质变化和光系统激发不平衡的另一种重要光合作用调控机制。状态转变允许通过 PSI 和 PSII 之间 LHCII 天线复合物的可逆交换来实现能量再分配，这得益于 STN7 激酶和 PPH1 磷酸酶的相反作用：LHCII 的磷酸化促进其从 PSII 向 PSI 的动员，而去磷酸化则产生相反的效果。在这项工作中，我们产生了 pph1/npq4 双突变体，并在高光和低光条件下与野生型和单突变体植物进行了一些光合作用、生长和繁殖特性的比较。结果表明，在高光下，pph1 突变体保持良好的光保护能力，而 npq4 植物对光损伤更敏感。pph1/npq4 双突变体表现出与 npq4 单突变体相似的对高光胁迫的抗性。在低光照条件下，与野生型植物相比，单突变体的生长和开花显著增加，而在 pph1/npq4 双突变体中，这种效应进一步增强。结果表明，通过修改 NPQ 和状态转变的调节，至少在受控低光照条件下，可能实现提高作物生长和生产力的光合作用优化。
