The evolution of the plastid chromosome in land plants: gene content, gene order, gene function.
Bottom Line: These include the organization of plastid genes in operons, the usually uniparental mode of plastid inheritance, the activity of highly effective repair mechanisms as well as the rarity of plastid fusion.Nevertheless, structurally rearranged plastomes can be found in several unrelated lineages (e.g. ferns, Pinaceae, multiple angiosperm families).Patterns of ndh-gene loss and functional analyses indicate that these losses are usually found in plant groups with a certain degree of heterotrophy, might rendering plastid encoded Ndh1 subunits dispensable.
Affiliation: Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, 1030 Vienna, Austria. email@example.comShow MeSH
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Mentions: Plastids are one of the main distinguishing characteristics of the plant cell. The central function of the plastid is to carry out photosynthesis, but other major cellular functions also take place in plastids, including synthesis of starch, fatty acids, pigments and amino acids (reviewed by Neuhaus and Emes 2010). As early as 1905, Konstantin S. Mereschkowski hypothesized that plant “chromatophores” are the result of the uptake of a cyanobacterium by a eukaryotic organism (English translation available by Martin and Kowallik 1999). It is now generally accepted that the plastid originated via incorporation of a free-living cyanobacterial-like prokaryote into a eukaryotic cell (primary endosymbiosis), thereby enabling the transition from heterotrophy to autotrophy by gaining the ability of utilizing photoenergy. Recent phylogenetic analyses of plastid genes from major plant lineages have converged on the hypothesis that plastids of the plant kingdom, i.e. the clade including Glaucophytes, Rhodophytes, Chlorophytes, and Streptophytes (Fig. 1; Keeling 2004), are derived from a single origin (Palmer 2000; McFadden and van Dooren 2004; Keeling 2010). This is also supported by several biochemical features, such as the composition of light harvesting complexes and their components, structural RNAs, membrane structure, and the protein import/targeting machinery (Weeden 1981; Bölter et al. 1998; Keeling 2004; Yang and Cheng 2004; Koziol et al. 2007; Vesteg et al. 2009).Fig. 1
Affiliation: Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, 1030 Vienna, Austria. firstname.lastname@example.org