Arabidopsis PsbP-Like Protein 1 Facilitates the Assembly of the Photosystem II Supercomplexes and Optimizes Plant Fitness under Fluctuating Light
Arabidopsis PsbP-Like Protein 1 Facilitates the Assembly of the Photosystem II Supercomplexes and Optimizes Plant Fitness under Fluctuating Light
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DOI：
10.1093/pcp/pcaa045
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发表时间：
2020-06-01
影响因子：
4.9
通讯作者：
Ifuku, Kentaro
中科院分区：
文献类型：
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作者：
Che, Yufen;Kusama, Shoko;Ifuku, Kentaro
在绿色植物中，光系统II(PSII)形成多亚单位超复合体(SCs)，其中包含一个二聚体核心和捕光复合体(LFIC)。在本研究中，我们证明了拟南芥PSBP样蛋白1(PPL1)参与了PSII SCs的组装，并且是适应不断变化的光强度所必需的。PPL1是PSBP蛋白的同系物，它优化了绿色植物中PSII的水氧化反应，是光损伤PSII有效修复所必需的；然而，它的确切功能尚不清楚。PPL1丰富于基质板层和基粒边缘，与PSII亚复合体(包括PSII单体和PSII二聚体)以及几个LHCII组合有关，而在PSII-LHCII SCs中未检测到PPL1。在Ppl1缺失突变体(ppl1-2)中，CP43、PSBR和PsbW的组装受到影响，导致即使在中等光强下PSII SCs的积累也减少。这导致了pPL1-2中LHCII的异常结合，表现为PSII的最大量子效率(F-v/F-m)较低，并加速了状态1到状态2的转变。这些差异会降低植物适应不断变化的光环境的能力，从而导致在自然波动的光环境下生长减少。系统发育和结构分析表明，PPL1与其蓝藻同源蓝藻蓝环密切相关，蓝藻蓝环在PSII生物发生的早期阶段起到组装因子的作用。我们的结果表明，PPL1具有类似的功能，但数据也表明，它可能有助于LHCII与PSII的联系。
In green plants, photosystem II (PSII) forms multisubunit supercomplexes (SCs) containing a dimeric core and light-harvesting complexes (LFICs). In this study, we show that Arabidopsis thaliana PsbP-like protein 1 (PPL1) is involved in the assembly of the PSII SCs and is required for adaptation to changing light intensity. PPL1 is a homolog of Psbp protein that optimizes the water-oxidizing reaction of PSII in green plants and is required for the efficient repair of photo-damaged PSII; however, its exact function has been unknown. PPL1 was enriched in stroma lamellae and grana margins and associated with PSII subcomplexes including PSII monomers and PSII dimers, and several LHCII assemblies, while PPL1 was not detected in PSII-LHCII SCs. In a PPL1 null mutant (ppl1-2), assembly of CP43, PsbR and PsbW was affected, resulting in a reduced accumulation of PSII SCs even under moderate light intensity. This caused the abnormal association of LHCII in ppl1-2, as indicated by lower maximal quantum efficiency of PSII (F-v/F-m) and accelerated State 1 to State 2 transitions. These differences would lower the capability of plants to adapt to changing light environments, thereby leading to reduced growth under natural fluctuating light environments. Phylogenetic and structural analyses suggest that PPL1 is closely related to its cyanobacterial homolog CyanoP, which functions as an assembly factor in the early stage of PSII biogenesis. Our results suggest that PPL1 has a similar function, but the data also indicate that it could aid the association of LHCII with PSII.