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Algal MIPs, high diversity and conserved motifs.

Anderberg HI, Danielson JÅ, Johanson U - BMC Evol. Biol. (2011)

Bottom Line: Our results suggest that at least two of the seven subfamilies found in land plants were present already in an algal ancestor.The total variation of MIPs and the number of different subfamilies in chlorophyte algae is likely to be even higher than that found in land plants.Our analyses indicate that genetic exchanges between several of the algal subfamilies have occurred.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry, Center for Molecular Protein Science, Center for Chemistry and Chemical Engineering, Lund University, PO Box 124, S-221 00 Lund, Sweden.

ABSTRACT

Background: Major intrinsic proteins (MIPs) also named aquaporins form channels facilitating the passive transport of water and other small polar molecules across membranes. MIPs are particularly abundant and diverse in terrestrial plants but little is known about their evolutionary history. In an attempt to investigate the origin of the plant MIP subfamilies, genomes of chlorophyte algae, the sister group of charophyte algae and land plants, were searched for MIP encoding genes.

Results: A total of 22 MIPs were identified in the nine analysed genomes and phylogenetic analyses classified them into seven subfamilies. Two of these, Plasma membrane Intrinsic Proteins (PIPs) and GlpF-like Intrinsic Proteins (GIPs), are also present in land plants and divergence dating support a common origin of these algal and land plant MIPs, predating the evolution of terrestrial plants. The subfamilies unique to algae were named MIPA to MIPE to facilitate the use of a common nomenclature for plant MIPs reflecting phylogenetically stable groups. All of the investigated genomes contained at least one MIP gene but only a few species encoded MIPs belonging to more than one subfamily.

Conclusions: Our results suggest that at least two of the seven subfamilies found in land plants were present already in an algal ancestor. The total variation of MIPs and the number of different subfamilies in chlorophyte algae is likely to be even higher than that found in land plants. Our analyses indicate that genetic exchanges between several of the algal subfamilies have occurred. The PIP1 and PIP2 groups and the Ca2+ gating appear to be specific to land plants whereas the pH gating is a more ancient characteristic shared by all PIPs. Further studies are needed to discern the function of the algal specific subfamilies MIPA-E and to fully understand the evolutionary relationship of algal and terrestrial plant MIPs.

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Schematic phylogeny of green plants. The chlorophytes (pink) and the streptophytes (light green) constitute the two phyla of green plants. The chlorophytes are further divided into a number of classes including chlorophyceae (yellow), trebouxiophyceae (orange) and mamiellophyceae (red) whereof mamiellophyceae is the basal clade. Terrestrial plants (embryophytes; green) are part of the streptophyte phylum. The position of red algae is indicated to root the schematic tree.
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Figure 1: Schematic phylogeny of green plants. The chlorophytes (pink) and the streptophytes (light green) constitute the two phyla of green plants. The chlorophytes are further divided into a number of classes including chlorophyceae (yellow), trebouxiophyceae (orange) and mamiellophyceae (red) whereof mamiellophyceae is the basal clade. Terrestrial plants (embryophytes; green) are part of the streptophyte phylum. The position of red algae is indicated to root the schematic tree.

Mentions: The clade of green plants (viridiplantae) together with the glaucophytes and the red algae (rhodophytes) form the larger monophyletic clade archaeplastida (the plant kingdom) which include all organisms with a chloroplast of primary endosymbiotic origin. The green plants are divided into the chlorophytes (consisting only of algal species) and streptophytes (containing both algae and land plants) and these clades are thought to have split 725-1200 Million Years Ago (MYA) [10-12] (Figure 1). The chlorophytes are further divided into several classes and even though the internal relationship between many of these classes is unresolved, there is a general consensus that mamiellophyceae is basal to chlorophyceae and trebouxiophyceae, which both belong to the well-defined UTC clade [13]. The other group of green plants, streptophytes, consists of a few classes of green algae (collectively known as the paraphyletic group charophyta) and the monophyletic group of land plants (embryophyta). The green algae studied in this work all belong to the chlorophyte clade with the Ostreococcus and Micromonas species belonging to the class mamiellophyceae [13], Volvox carteri and Chlamydomonas reinhardtii to the class chlorophyceae and Coccomyxa sp. C-169 and Chlorella sp. NC64A to the class trebouxiophyceae (Figure 1).


Algal MIPs, high diversity and conserved motifs.

Anderberg HI, Danielson JÅ, Johanson U - BMC Evol. Biol. (2011)

Schematic phylogeny of green plants. The chlorophytes (pink) and the streptophytes (light green) constitute the two phyla of green plants. The chlorophytes are further divided into a number of classes including chlorophyceae (yellow), trebouxiophyceae (orange) and mamiellophyceae (red) whereof mamiellophyceae is the basal clade. Terrestrial plants (embryophytes; green) are part of the streptophyte phylum. The position of red algae is indicated to root the schematic tree.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3111385&req=5

Figure 1: Schematic phylogeny of green plants. The chlorophytes (pink) and the streptophytes (light green) constitute the two phyla of green plants. The chlorophytes are further divided into a number of classes including chlorophyceae (yellow), trebouxiophyceae (orange) and mamiellophyceae (red) whereof mamiellophyceae is the basal clade. Terrestrial plants (embryophytes; green) are part of the streptophyte phylum. The position of red algae is indicated to root the schematic tree.
Mentions: The clade of green plants (viridiplantae) together with the glaucophytes and the red algae (rhodophytes) form the larger monophyletic clade archaeplastida (the plant kingdom) which include all organisms with a chloroplast of primary endosymbiotic origin. The green plants are divided into the chlorophytes (consisting only of algal species) and streptophytes (containing both algae and land plants) and these clades are thought to have split 725-1200 Million Years Ago (MYA) [10-12] (Figure 1). The chlorophytes are further divided into several classes and even though the internal relationship between many of these classes is unresolved, there is a general consensus that mamiellophyceae is basal to chlorophyceae and trebouxiophyceae, which both belong to the well-defined UTC clade [13]. The other group of green plants, streptophytes, consists of a few classes of green algae (collectively known as the paraphyletic group charophyta) and the monophyletic group of land plants (embryophyta). The green algae studied in this work all belong to the chlorophyte clade with the Ostreococcus and Micromonas species belonging to the class mamiellophyceae [13], Volvox carteri and Chlamydomonas reinhardtii to the class chlorophyceae and Coccomyxa sp. C-169 and Chlorella sp. NC64A to the class trebouxiophyceae (Figure 1).

Bottom Line: Our results suggest that at least two of the seven subfamilies found in land plants were present already in an algal ancestor.The total variation of MIPs and the number of different subfamilies in chlorophyte algae is likely to be even higher than that found in land plants.Our analyses indicate that genetic exchanges between several of the algal subfamilies have occurred.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Biochemistry, Center for Molecular Protein Science, Center for Chemistry and Chemical Engineering, Lund University, PO Box 124, S-221 00 Lund, Sweden.

ABSTRACT

Background: Major intrinsic proteins (MIPs) also named aquaporins form channels facilitating the passive transport of water and other small polar molecules across membranes. MIPs are particularly abundant and diverse in terrestrial plants but little is known about their evolutionary history. In an attempt to investigate the origin of the plant MIP subfamilies, genomes of chlorophyte algae, the sister group of charophyte algae and land plants, were searched for MIP encoding genes.

Results: A total of 22 MIPs were identified in the nine analysed genomes and phylogenetic analyses classified them into seven subfamilies. Two of these, Plasma membrane Intrinsic Proteins (PIPs) and GlpF-like Intrinsic Proteins (GIPs), are also present in land plants and divergence dating support a common origin of these algal and land plant MIPs, predating the evolution of terrestrial plants. The subfamilies unique to algae were named MIPA to MIPE to facilitate the use of a common nomenclature for plant MIPs reflecting phylogenetically stable groups. All of the investigated genomes contained at least one MIP gene but only a few species encoded MIPs belonging to more than one subfamily.

Conclusions: Our results suggest that at least two of the seven subfamilies found in land plants were present already in an algal ancestor. The total variation of MIPs and the number of different subfamilies in chlorophyte algae is likely to be even higher than that found in land plants. Our analyses indicate that genetic exchanges between several of the algal subfamilies have occurred. The PIP1 and PIP2 groups and the Ca2+ gating appear to be specific to land plants whereas the pH gating is a more ancient characteristic shared by all PIPs. Further studies are needed to discern the function of the algal specific subfamilies MIPA-E and to fully understand the evolutionary relationship of algal and terrestrial plant MIPs.

Show MeSH
Related in: MedlinePlus