Neoxanthin (Neo), which is only bound to the peripheral antenna proteins of photosystem (PS) II, is a conserved carotenoid in all green plants. It has been demonstrated that Neo plays an important role in photoprotection and its deficiency fails to impact LHCII stability in vitro and indoor plant growth in vivo. Whether Neo is involved in maintaining the PSII complex structure or adaptive mechanisms for the everchanging environment has not yet been elucidated. In this study, the role of Neo in maintaining the structure and function of the PSII‐LHCII supercomplexes was studied using Neo deficient Arabidopsis mutants. Our results show that Neo deficiency had little effect on the electron transport capacity and the plant fitness, but the PSII‐LHCII supercomplexes were significantly impacted by the lack of Neo. In the absence of Neo, the M‐type LHCII trimer cannot effectively associate with the C₂S₂‐type PSII‐LHCII supercomplexes even in moderate light conditions. Interestingly, Neo deficiency also leads to decreased PSII protein phosphorylation but rapid transition from state 1 to state 2. We suggest that Neo might enforce the interactions between LHCII and the minor antennas and that the absence of Neo makes M‐type LHCII disassociate from the PSII complex, leading to the disassembly of the PSII‐LHCII C₂S₂M₂ supercomplexes, which results in alterations in the phosphorylation patterns of the thylakoid photosynthetic proteins and the kinetics of state transition.

中文翻译：

---

新黄质影响拟南芥中C2S2M2型光系统II超复合物的稳定性和状态转变的动力学

新黄质（Neo）仅与光系统（PS）II的外围触角蛋白结合，是所有绿色植物中一种保守的类胡萝卜素。已经证明，Neo在光保护中起着重要作用，其缺乏不能影响LHCII的体外稳定性和体内室内植物的生长。尚未阐明Neo是否参与维护PSII复杂结构或适应不断变化的环境的自适应机制。在这项研究中，使用Neo缺陷型拟南芥突变体研究了Neo在维持PSII-LHCII超复合物的结构和功能中的作用。我们的结果表明，新缺乏对电子传输能力和植物适应性影响不大，但缺少新对PSII-LHCII超复合物有显着影响。在没有Neo的情况下，M型LHCII三聚体不能有效地与C ₂ S ₂缔合。即使在中等光照条件下，PSII型LHCII型也可以形成超级复合物。有趣的是，Neo缺乏还导致PSII蛋白磷酸化降低，但从状态1迅速转变为状态2。我们建议Neo可能会增强LHCII和小触角之间的相互作用，而Neo的缺失会使M型LHCII与PSII分离。复合物，导致PSII-LHCII C ₂ S ₂ M ₂超复合物解体，从而导致类囊体光合蛋白的磷酸化模式改变和状态转变动力学。