Phylogeny of Calvin cycle enzymes supports Plantae monophyly
Phylogeny of Calvin cycle enzymes supports Plantae monophyly
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DOI：
10.1016/j.ympev.2007.02.026
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发表时间：
2007-10-01
影响因子：
4.1
通讯作者：
Bhattacharya, Debashish
中科院分区：
文献类型：
--
作者：
Reyes-Prieto, Adrian;Bhattacharya, Debashish
光合作用是地球上一个关键的生化过程，为大多数生命提供食物。植物及其藻类姐妹的共同祖先通过吞噬和保留蓝藻初级内共生菌获得光合作用，该内共生菌进化成光合器官--质体(Bhattacharya等人，2004年)。在光合作用真核生物中，捕捉光合作用光反应(ATP和NADPH2)的产物以固定二氧化碳(图1)的基本系列反应，被称为Calvin循环(CC；Calvin和Benson，1948)，发生在叶绿体基质中。真核CC包括11种不同的酶(表1)，它们是核编码的，以表达其功能为目标的质体，除了核酮糖-1，5-二磷酸羧基(Rubisco)亚单位(大的和小的)，在红色和白藻中仍然是叶绿体编码的。在绿藻(和陆地植物)中，Rubisco大亚基是在叶绿体基因组中编码的，但小亚基是核编码的。光合作用真核生物还含有参与糖酵解和糖异生的胞浆酶，这些酶催化的反应类似于CC中的反应，并且在叶绿体起源之前就存在于真核生物中(Martin和Schnarrenberger，1997)。分子系统发育分析表明，陆地植物(Martin和Schnarrenberger，1997)和红藻在绿藻和红藻分化之前，通过细胞内(内共生)基因转移(EGT)从捕获的蓝藻中获得了至少一个CC酶亚组(Matsuzaki等人，2004年)。然而，众所周知，陆地植物和红藻中的一些CC酶具有非蓝藻来源(Martin和Schnarrenberger，1997；Matsuzaki等人，2004)。一种可能的解释是，这些先前存在的宿主酶取代了原始蓝藻蛋白的作用，这些蛋白随着进化时间的推移而丢失。目前尚不清楚这些假定的基因替换是否是真核生物CC进化的一个古老特征，或者基因招募替换是否发生在不同的光合作用谱系中。为了更清楚地了解早期CC酶的进化，分析三个主要类群的基因组数据至关重要，这三个类群可能是从第一个光合作用真核生物分化而来的：红藻、绿藻(包括陆地植物)和白藻。这些分类群被称为植物门(Cavalier-Smith，1981)或古生物门(Adl et al.，2005)，它们被认为共享一个起源。利用多基因核和叶绿体数据进行的系统发育分析有力地支持植物科的单系性(例如，Rodriguez-Ezpeleta等人，2005年)，然而，一些单基因和多基因分析不能恢复这一分支(例如，Nozaki等人，2003年；Stiller和Harrell，2005年)。对参与保守的、古老的代谢过程的酶进行系统发育分析，对于阐明主要真核生物群体的进化史是一个潜在的有价值的信息来源。在这里，我们使用这种比较的方法来解释CC酶的系统发育，使用来自所有三个共享蓝藻内共生体的主要光合作用谱系的分子数据，即包括我们实验室从蓝藻蓝藻产生的表达序列标签(EST)数据(Reyes-Prieto等人，2006年)。
Photosynthesis is a critical biochemical process on our planet providing food for most life. The common ancestor of plants and their algal sisters gained photosynthesis through the engulfment and retention of a cyanobacterial primary endosymbiont that evolved into a photosynthetic organelle, the plastid (Bhattacharya et al., 2004). In photosynthetic eukaryotes, the essential series of reactions that capture the products of photosynthetic light reactions (ATP and NADPH2) to fix CO2 (Fig. 1), known as the Calvin cycle (CC; Calvin and Benson, 1948), takes place in the plastid stroma. The eukaryotic CC involves 11 different enzymes (Table 1) that are nuclear encoded and plastid targeted to express their function, with the exception of ribulose-1, 5-bisphosphate carboxylase (RuBisCO) subunits (large and small) that remain plastid encoded in red and glaucophyte algae. In green algae (and land plants) the RuBisCO large subunit is encoded in the plastid genome but the small subunit is nuclear encoded. Photosynthetic eukaryotes also contain cytosolic enzymes involved in glycolysis and gluceoneogenesis that catalyze reactions similar to those in the CC and were present in eukaryotes before plastid origin (Martin and Schnarrenberger, 1997). Molecular phylogenetic analyses suggest that land plants (Martin and Schnarrenberger, 1997) and red algae acquired at least a subset of the CC enzymes via intracellular (endosymbiotic) gene transfer (EGT) from the captured cyanobacterium prior to the divergence of green and red algae (Matsuzaki et al., 2004). However, it is well known that some CC enzymes in land plants and red algae have a non-cyanobacterial origin (Martin and Schnarrenberger, 1997; Matsuzaki et al., 2004). A likely explanation is that these pre-existing host enzymes took over the role of the original cyanobacterial proteins that have been lost over evolutionary time. It is unknown whether these putative gene replacements were an ancient feature of eukaryotic CC evolution or whether gene recruitments-replacements occurred more recently in different photosynthetic lineages. To gain a clearer picture of early CC enzyme evolution it is critical to analyze genome data from the three major groups that presumably diversified from the first photosynthetic eukaryote: the red algae, the green algae (including land plants), and the glaucophyte algae. These taxa, referred to as the Plantae (Cavalier-Smith, 1981) or Archaeplastida (Adl et al., 2005), are postulated to share a single origin. Phylogenetic analyses using multi-gene nuclear and plastid data strongly support Plantae monophyly (eg, Rodriguez-Ezpeleta et al., 2005), however some single-and multi-gene analyses do not recover this clade (eg, Nozaki et al., 2003; Stiller and Harrell, 2005). Phylogenetic analysis of enzymes involved in conserved, ancient metabolic processes is a potentially valuable source of information for elucidating the evolutionary history of major eukaryotic groups. Here, we use this comparative approach to elucidate the phylogeny of CC enzymes with molecular data from all three primary photosynthetic lineages that share the cyanobacterial endosymbiont; ie, including expressed sequence tag (EST) data generated in our lab from the glaucophyte alga Cyanophora paradoxa (Reyes-Prieto et al., 2006).