title: Ecological and evolutionary significance of genomic GC content diversity in monocots.
abstract: Genomic DNA base composition (GC content) is predicted to significantly affect genome functioning and species ecology. Although several hypotheses have been put forward to address the biological impact of GC content variation in microbial and vertebrate organisms, the biological significance of GC content diversity in plants remains unclear because of a lack of sufficiently robust genomic data. Using flow cytometry, we report genomic GC contents for 239 species representing 70 of 78 monocot families and compare them with genomic characters, a suite of life history traits and climatic niche data using phylogeny-based statistics. GC content of monocots varied between 33.6% and 48.9%, with several groups exceeding the GC content known for any other vascular plant group, highlighting their unusual genome architecture and organization. GC content showed a quadratic relationship with genome size, with the decreases in GC content in larger genomes possibly being a consequence of the higher biochemical costs of GC base synthesis. Dramatic decreases in GC content were observed in species with holocentric chromosomes, whereas increased GC content was documented in species able to grow in seasonally cold and/or dry climates, possibly indicating an advantage of GC-rich DNA during cell freezing and desiccation. We also show that genomic adaptations associated with changing GC content might have played a significant role in the evolution of the Earth's contemporary biota, such as the rise of grass-dominated biomes during the mid-Tertiary. One of the major selective advantages of GC-rich DNA is hypothesized to be facilitating more complex gene regulation.
authors.affiliation: Department of Botany and Zoology, Masaryk University, CZ-61137 Brno, Czech Republic; smardap@sci.muni.cz.
authors.forename: Petr
authors.initials: P
authors.lastname: Šmarda
authors.affiliation: Department of Botany and Zoology, Masaryk University, CZ-61137 Brno, Czech Republic;
authors.forename: Petr
authors.initials: P
authors.lastname: Bureš
authors.affiliation: Department of Botany and Zoology, Masaryk University, CZ-61137 Brno, Czech Republic;
authors.forename: Lucie
authors.initials: L
authors.lastname: Horová
authors.affiliation: Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey TW93DS, United Kingdom;
authors.forename: Ilia J
authors.initials: IJ
authors.lastname: Leitch
authors.affiliation: School of Plant Biology, University of Western Australia, Perth, WA 6009, Australia; Centre for Geographic Analysis, Department of Geography and Environmental Studies, Stellenbosch University, Stellenbosch 7600, South Africa; and.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Mucina
authors.affiliation: Department of Life Sciences, Siena University, 53100 Siena, Italy.
authors.forename: Ettore
authors.initials: E
authors.lastname: Pacini
authors.affiliation: Department of Botany and Zoology, Masaryk University, CZ-61137 Brno, Czech Republic;
authors.forename: Lubomír
authors.initials: L
authors.lastname: Tichý
authors.affiliation: Department of Botany and Zoology, Masaryk University, CZ-61137 Brno, Czech Republic;
authors.forename: Vít
authors.initials: V
authors.lastname: Grulich
authors.affiliation: Department of Botany and Zoology, Masaryk University, CZ-61137 Brno, Czech Republic;
authors.forename: Olga
authors.initials: O
authors.lastname: Rotreklová
mesh_terms: D000064:Acclimatization / Q000235:genetics; D001482:Base Composition; D032461:Chromosomes, Plant / Q000235:genetics; D018744:DNA, Plant / Q000737:chemistry* / Q000235:genetics*; D017753:Ecosystem; D019143:Evolution, Molecular; D014644:Genetic Variation; D018745:Genome, Plant; D019684:Magnoliopsida / Q000737:chemistry / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D006109:Poaceae / Q000737:chemistry / Q000145:classification / Q000235:genetics
chemical_list: D018744:DNA, Plant
keywords: Poaceae; genome size evolution; geographical stratification; phylogenetic regression; plant genome