Formation of a PSI-PSII megacomplex containing LHCSR and PsbS in the moss Physcomitrella patens
Formation of a PSI-PSII megacomplex containing LHCSR and PsbS in the moss Physcomitrella patens
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DOI：
10.1007/s10265-019-01138-2
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发表时间：
2019-11-01
影响因子：
2.8
通讯作者：
Takabayashi, Atsushi
中科院分区：
文献类型：
--
作者：
Furukawa, Ryo;Aso, Michiki;Takabayashi, Atsushi
苔藓是从淡水绿色藻类分化出来的最早的陆地植物之一。它们被认为已经获得了更高的热能耗散能力，以科普动态变化的太阳辐照度，利用“藻类型”捕光复合应力相关（LHCSR）依赖和“植物型”PsbS依赖机制。据推测，光系统（PS）I和II megacomplex的形成是另一种机制，以保护光合机构从强光。在此，我们描述了PSI-PSII megacomplex的分析模式藓，小立碗藓，这是解决使用大孔透明的天然聚丙烯酰胺凝胶电泳（lpCN-PAGE）。在IpCN-PAGE期间显示的立碗藓PSI-PSII megacomplex与拟南芥megacomplex的迁移距离的相似性表明立碗藓PSI-PSII和拟南芥megacomplex具有相似的结构。时间分辨的叶绿素荧光测量表明，激发能迅速，有效地从PSII转移到PSI，提供证据的有序关联的两个光系统。我们还发现LHCSR和PsbS与立碗藓PSI-PSII megacomplex共迁移。该复合物表现出pH依赖的叶绿素荧光猝灭，这可能是由LHCSR和/或PsbS蛋白与玉米黄质的协作诱导的。讨论了立碗藓两个光系统能量分配平衡的调节机制。
Mosses are one of the earliest land plants that diverged from fresh-water green algae. They are considered to have acquired a higher capacity for thermal energy dissipation to cope with dynamically changing solar irradiance by utilizing both the "algal-type" light-harvesting complex stress-related (LHCSR)-dependent and the "plant-type" PsbS-dependent mechanisms. It is hypothesized that the formation of photosystem (PS) I and II megacomplex is another mechanism to protect photosynthetic machinery from strong irradiance. Herein, we describe the analysis of the PSI-PSII megacomplex from the model moss, Physcomitrella patens, which was resolved using large-pore clear-native polyacrylamide gel electrophoresis (lpCN-PAGE). The similarity in the migration distance of the Physcomitrella PSI-PSII megacomplex to the Arabidopsis megacomplex shown during lpCN-PAGE suggested that the Physcomitrella PSI-PSII and Arabidopsis megacomplexes have similar structures. Time-resolved chlorophyll fluorescence measurements show that excitation energy was rapidly and efficiently transferred from PSII to PSI, providing evidence of an ordered association of the two photosystems. We also found that LHCSR and PsbS co-migrated with the Physcomitrella PSI-PSII megacomplex. The megacomplex showed pH-dependent chlorophyll fluorescence quenching, which may have been induced by LHCSR and/or PsbS proteins with the collaboration of zeaxanthin. We discuss the mechanism that regulates the energy distribution balance between two photosystems in Physcomitrella.