Newly resolved relationships in an early land plant lineage: Bryophyta class Sphagnopsida (peat mosses)

Abstract

Phylogenetic analyses of genome structure and nucleotide sequences from mitochondrial, plastid, and nuclear genes have corroborated the view held by botanists for over a century that the bryophyte groups (mosses, liverworts, hornworts) comprise early-diverging land plant lineages that originated before the appearance of vascular plants ( Haeckel, 1876 ;Campbell, 1895 ;Bower, 1935 ;Kenrick and Crane, 1997 ;Shaw and Renzaglia, 2004 ). Early cladistic analyses based on morphological characters ( Mishler and Churchill, 1984 ) showed that the three bryophyte groups, classifi ed by most botanists of the time as a single phylum because of their similar gametophyte-dominant life cycles, more likely represent a paraphyletic grade that diverged before the emergence of the vascular plants. In fact, Haeckel ' s (1876) tree similarly shows mosses and liverworts as a paraphyletic grade basal to the vascular plants. Recent data sets appear to favor the hypothesis that liverworts (phylum Marchantiophyta) comprise the earliest-diverging lineage, followed by the mosses (Bryophyta) and hornworts (Anthocerophyta) ( Qiu et al., 1998 ;Nickrent et al., 2000 ;Shaw and Renzaglia, 2004 ). However, the most data-rich studies to date, based on chloroplast or mitochondrial organellar proteins, like analyses based on sperm cell morphology ( Garbary et al., 1993 ), identify a clade uniting liverworts and mosses, and additional data are still needed before we can consider the branching order of early land plant lineages to be fi nally resolved ( Nishiyama et al., 2004 ;Rodr í guez-Ezpeleta et al., 2007 ;Terasawa et al., 2007 ; but see also Qiu, et al., 2006 ).Notwithstanding that much remains to do, great progress has been made toward resolving phylogenetic relationships within the mosses (phylum Bryophyta s.s.) (e.g., Cox and Hedderson, 1999 ;Cox et al., 2000 ;Newton et al., 2000 ; Goffi net et al., 2001 ;Stech and Frey, 2008 ; Goffi net et al., 2009 ;Wahrmund et al., 2010 ). Major clades resolved by molecular data to a large extent mirror previous classifi cations based on morphology (e.g., Fleischer, 1923 ; Brotherus, 1924 Brotherus, -1925Vitt, 1984 • Premise of the study : The Sphagnopsida, an early-diverging lineage of mosses (phylum Bryophyta), are morphologically and ecologically unique and have profound impacts on global climate. The Sphagnopsida are currently classifi ed in two genera, Sphagnum (peat mosses) with some 350 -500 species and Ambuchanania with one species. An analysis of phylogenetic relationships among species and genera in the Sphagnopsida were conducted to resolve major lineages and relationships among species within the Sphagnopsida.• Methods : Phylogenetic analyses of nucleotide sequences from the nuclear, plastid, and mitochondrial genomes (11 704 nucleotides total) were conducted and analyzed using maximum likelihood and Bayesian inference employing seven different substitution models of varying complexity.• Key results : Phylogenetic analyses resolved three lineages within the Sphagnopsida: (1) Sphagnum serice...

Internal Transcribed Spacer 1 Secondary Structure Analysis Reveals a Common Core throughout the Anaerobic Fungi (Neocallimastigomycota)

“…This is useful (1) for community diversity descriptions based on large amounts of data, and (2) for identifying novel candidate taxa that might warrant further effort for complete description. According to article 32 of the Vienna Code [44], the description of new taxa based on pure sequence information must include specific references to the molecular characters that distinguish the taxon (e.g., specific differences in nucleotide positions in a molecular alignment; [45], [46]). The implementation of using both primary sequence and secondary structure information for the taxonomic classification of anaerobic fungi could represent a first step towards developing broadly accepted standards for sequence-based taxonomy where isolated species are still lacking [12].…”

Bryophyte diversity and evolution: Windows into the early evolution of land plants

“…3 ) are unique among mosses, although early cell divisions Most phylogenetic analyses based on sequences from multiple loci suggest that Takakia plus the Sphagnopsida form a clade sister to other mosses. Takakia and the Sphagnopsida share little morphologically, and Goffi net et al (2001) , Cox et al (2004) , and Shaw et al (2010) suggest that the apparent sister-group relationship between them may refl ect phylogenetic artifact. Nevertheless, gene sequences from all three genomes repeatedly resolve them as a clade ( Newton et al, 2000 ;Nickrent et al, 2000 ;Beckert et al, 2001 ;Cox et al, 2004 ;Qiu et al, 2006 ;Qiu, 2008 ;Shaw et al, 2010 ).…”

Population structure in the tropical peatmoss, Sphagnum tumidulum Besch. (Sphagnaceae)

“…DNA was extracted from a small portion of one capitulum from each shoot using a modified CTAB protocol (Shaw et al 2010a). A total of 10 microsatellite markers were genotyped in the present study.…”