Tracing the evolution of the light-harvesting antennae in chlorophyll a/b- containing organisms
Tracing the evolution of the light-harvesting antennae in chlorophyll a/b- containing organisms
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DOI：
10.1104/pp.092536
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发表时间：
2007-04-01
期刊：
影响因子：
7.4
通讯作者：
Durnford, Dion G.
中科院分区：
文献类型：
--
作者：
Koziol, Adam G.;Borza, Tudor;Durnford, Dion G.
陆生植物和绿色藻类的捕光复合体（LHC）在光捕获和光保护方面具有重要作用。虽然在许多陆生植物中LHC蛋白的功能多样性已被很好地描述，但该家族在大多数绿色藻类群体中的程度尚不清楚。为了研究叶绿素a/B天线系统的进化并推断其祖先状态，我们从分类学上广泛的含叶绿素a/b的原生生物中启动了几个表达序列标签项目。这包括来自石莼纲（髋臼藻）、中气门藻纲（绿色中气门藻）和Prasinophyceae（微单胞菌属）的代表，以及来自裸藻门（Euglena gracilis）和绿藻门（Bigelowiella natans）的各一个代表，其质体从绿色藻次级进化而来。很明显，核心天线系统在绿色藻类多样化之前发育良好，并且可能由与光系统II相关的CP 29（Lhcb 4）和CP 26（Lhcb 5）蛋白加上光系统I天线组成，光系统I天线由至少Lhca 3编码的蛋白和Lhca 2和9基因编码的两种绿色藻类特异性蛋白组成.在含有次生质体的生物体中，我们没有发现与植物/藻类触角同源的证据，除了CP 29。我们还确定了PsbS同系物在石莼科和Prasinophyceae，表明这种独特的蛋白质出现之前，绿色藻类多样化。这种分析提供了一个快照的天线系统在不同的绿色藻类，并允许我们推断天线系统的复杂性变化过程中的绿色藻类的演变。
The light-harvesting complexes (LHCs) of land plants and green algae have essential roles in light capture and photo-protection. Though the functional diversity of the individual LHC proteins are well described in many land plants, the extent of this family in the majority of green algal groups is unknown. To examine the evolution of the chlorophyll a/b antennae system and to infer its ancestral state, we initiated several expressed sequence tag projects from a taxonomically broad range of chlorophyll a/b-containing protists. This included representatives from the Ulvophyceae (Acetabularia acetabulum), the Mesostigmatophyceae (Mesostigma viride), and the Prasinophyceae (Micromonas sp.), as well as one representative from each of the Euglenozoa (Euglena gracilis) and Chlorarachniophyta (Bigelowiella natans), whose plastids evolved secondarily from a green alga. It is clear that the core antenna system was well developed prior to green algal diversification and likely consisted of the CP29 (Lhcb4) and CP26 (Lhcb5) proteins associated with photosystem II plus a photosystem I antenna composed of proteins encoded by at least Lhca3 and two green algal- specific proteins encoded by the Lhca2 and 9 genes. In organisms containing secondary plastids, we found no evidence for orthologs to the plant/algal antennae with the exception of CP29. We also identified PsbS homologs in the Ulvophyceae and the Prasinophyceae, indicating that this distinctive protein appeared prior to green algal diversification. This analysis provides a snapshot of the antenna systems in diverse green algae, and allows us to infer the changing complexity of the antenna system during green algal evolution.