Evolutionary systematics in dune species of Poa (Poaceae: Pooideae)
Liliana Monica Giussani1, Florencia Rocío Sabena2, Cintia Eleonora Celsi3 & Leopoldo Javier Iannone4
1Instituto de Botanica Darwinion-CONICET; 2Facultad de Ciencias Exactas y Naturales-UBA;
3Fundación Azara; 4Instituto de Micología y Botánica - INMIBO-CONICET.
liligiussani@yahoo.com.ar
Reproductive systems in American Poa evolved during the Late Miocene in the Northern and Southern hemispheres, independently. Dioecy appeared associated with geological episodes such as the Andean mountain uplift, and climatic oscillations associated to glacial cycles. The monophyletic section Dioicopoa originated during the Pliocene to Early Pleistocene in South America by a rapid evolutionary radiation. Coastal dunes are dynamic ecosystems due to aeolian formation and rapid modification where speciation and endemism occur. Dune environmental heterogeneity and vegetation patterns were studied using classification and ordination analyses. In this work, we studied the relationship between the presence of seed-transmitted Epichloë fungal endophytes and environmental characteristics on diversification of three close-related Poa species in coastal dunes. Through morphological multivariate analyses in a widely distributed species (Poa lanuginosa) and two narrowly endemic species (Poa bergii and Poa schizantha), quantitative and qualitative changes are detected among their populations. The morphological differentiation of the symbiont endophytic fungi and their association with P. bergii and P. lanuginosa species are evaluated through regression analyses; Poa schizantha was not associated with Epichloë.
Intermediate characteristics between P. lanuginosa and P. bergii suggest events of recent speciation and hybrid formation as an adaptative and evolutionary process in coastal dunes.
Key words: coastal dunes, dioecy, endophyte, grasses, speciation.
Systematics and evolution of the Neotropical woody bamboos (Poaceae: Bambusoideae:
Bambuseae)
Lynn G. Clark1, Ana Paula Santos-Gonçalves2, Cristielle de Jesus-Costa2, Ronaldo Vinicius da Silva2, Pedro Viana3, Edgar A. L. Afonso3, Eduardo Ruiz-Sanchez4, Christopher Tyrrell5, Ximena
Londoño6 & Reyjane Patrícia de Oliveira7
1Iowa State University; 2Universidade Federal de Vicosa; 3Museu Goeldi; 4Universidad de
Guadalajara; 5Milwaukee Public Museum; 6Colombian Bamboo Society; 7Universidade Estadual de Feira de Santana. lgclark@iastate.edu
Bambusoideae (bamboos), comprising 1,680+ species, are classified into three tribes: Arundinarieae (temperate woody bamboos, 581 species), Bambuseae (tropical woody bamboos, 976 species) and Olyreae (herbaceous bamboos, 123 species). Arundinarieae is primarily of eastern Asia and has no native species in the American tropics. Bambuseae consists of two major clades, the Paleotropical (PWB, 554 species) and the Neotropical woody bamboos (NWB, 422 species), and is distributed broadly in the tropics and subtropics with a few taxa in subtemperate regions, and extensive diversity in montane systems. Except for 1 genus endemic to New Guinea, and 1 species occurring in both the Neotropics and Africa, the rest of the Olyreae is restricted to the Neotropics. Recent molecular analyses using both plastid and nuclear DNA sequence data continue to support the topology of Chusqueinae (Arthrostylidiinae + Guaduinae) within the NWB, but suggest some generic realignments. In the usual absence of flowering material, complete vegetative collections are essential for discovery and identification; new species continue to be described. Brazil has the greatest diversity of NWB, but the Andes, Panama/Costa Rica, Mexico and the West Indies also harbor significant diversity and endemism. In the Neotropics, Chusquea, Guadua and Merostachys still require significant taxonomic attention.
Key words: Arthrostylidiinae, bamboo classification, Chusqueinae, Guaduinae, New World woody bamboos.
A 250 plastome phylogeny of the grass family (Poaceae)
Melvin R. Duvall1, Jeffery M. Saarela2, Sean V. Burke1, William P. Wysocki3, Matthew D. Barrett4, Lynn G. Clark5, Joseph M. Craine6, Paul M. Peterson7, Robert J. Soreng8 & Maria S. Vorontsova9
1Plant Molecular and Bioinformatics Center, Biological Sciences, Northern Illinois University, DeKalb, IL, USA; 2Beaty Centre for Species Discovery and Botany Section, Canadian Museum of Nature, Ottawa, ON, Canada; 3Center for Data Intensive Sciences, University of Chicago, Chicago, IL, USA; 4Botanic Gardens and Parks Authority, Kings Park and Botanic Garden, West Perth, WA, Australia; 5Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, USA; 6Jonah Ventures, Manhattan, KS, USA; 7Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington DC, USA; 8Department of Botany,
National Museum of Natural History, Smithsonian Institution, Washington DC, USA; 9Comparative Plant & Fungal Biology, Royal Botanic Gardens, Kew, Richmond, Surrey, UK.
mel-duvall@niu.edu
Plastome phylogenomic studies have contributed to advances in systematics, but in grasses these studies have been taxonomically restricted. Here we present a family-wide study of 250 grass plastomes (179 genera, 44 tribes). Plastome assemblies represented over 28.7 Mbases. Phylogenetic signal was characterized in 14 partitions: (1) complete plastomes; (2) protein coding and (3) noncoding regions; and (4) three loci widely used in grass phylogenetics. Each partition was further refined to alternatively include or exclude positively selected codons and gaps introduced by the alignment. All 76 protein coding loci were found to be predominantly under purifying selection, but specific codons in 65 loci showed evidence of positive selection. Widely used loci of prior studies had high numbers of positively selected codons. Our analyses fully supported the backbone topology for BOP taxa. Among the 14 analyses, 82 of 309 resolved clades were maximally
supported. Analyses of new plastomes agreed with current classifications. Five (of seven) partitions from which alignment gaps were removed retrieved Panicoideae as sister to other PACMAD subfamilies incongruent with topologies recovered from partitions with alignment gaps. This suggests that alignment ambiguities in these uncertain regions introduced false signal. Our study indicates how different data partitions affect phylogenomic inferences.
Key words: partition, phylogenomics, plastome, Poaceae, selection.
Funded by: National Science Foundation, USA. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
A phylogeny of Poeae chloroplast group 1 including genera in the Agrostidinae,
Anthoxanthinae, Aveninae, Brizinae, Calothecinae, Echinopogoninae, Phalaridinae, and Torreyochloinae (Poaceae: Pooideae)
Paul M. Peterson1, Robert J. Soreng1, Konstantin Romaschenko1, Patricia Barberá2, Carlos Aedo Pérez2, Alejandro Quintanar2 & Jeffery M. Saarela3
1Smithsonian Institution; 2Real Jardín Botánico; 3Canadian Museum of Nature. peterson@si.edu
A phylogeny based on analysis of four molecular DNA sequence markers (ITS, rpl32-trnL, rps16 intron, and rps16-trnK; 4477 total aligned sequences) was made on members of Poeae chloroplast group 1 including genera in the Agrostidinae, Anthoxanthinae, Aveninae, Brizinae, Calothecinae, Echinopogoninae, Phalaridinae, and Torreyochloinae. Our sample included 1341 accessions (190 additional accessions were unsuccessful due to poor material) representing 523 species selected from herbarium specimens (@80%) and silica field-collected matieral (@20%). Trisetum s.l. is polyphyletic and splinters into seven clades: Acrospelion (Trisetum sect. Acrospelion), Calothecinae (Trisetum bulbosum, T. juergensii, and T. brasiliense), Graphephorum, Koeleria, Peyritschia, Siberotrisetum gen. nov. (Trisetum sect. Sibirica), and Tristeum s.s. Species of Deyeuxia are subsumed within Calamagrostis, Cinnagrostis (South American Calamagrostis), and Deschampsia (Deyeuxia sect. Stylagrostis). Calothecinae includes Chascolytrum s.l., Paramochloa gen. nov.
(Calamagrostis effusa), and Echinopogoninae includes Dichelachne, Echinopogon, Greeneochloa gen nov. (Calamagrostis coarctata and C. tweedii), and Relchela. Lachnagrostis and Polypogon are reticulate genera where species of each genus align as clades within Calamagrostis (ITS signal) and within Agrostis (plastid signal). Species of Ammophila are reticulate aligning within Calamagrostis (plastid signal) and Agrostis (ITS signal). Species of Podagrostis are reticulate aligning within Calamagrostis (ITS signal) and as sister to Agrostis (plastid signal).
Key words: classification, ITS and plastid DNA sequences, phylogeny, Poaceae, systematics.
Taxonomy, phylogeny and biogeography of the temperate woody bamboos (Bambusoideae:
Arundinarieae)
Peng-Fei Ma1, Cen Guo1, Xia-Ying Ye1, Ying Guo1, Yu-Xiao Zhang2, Zhen-Hua Guo1 & De-Zhu Li1
1Kunming Institute of Botany, Chinese Academy of Sciences; 2Southwest Forestry University.
mapengfei@mail.kib.ac.cn
The Bambusoideae (Poaceae) consists of three monophyletic tribes: Arundinarieae, Bambuseae, and Olyreae. With more than 500 described species from 31 genera mostly endemic to East Asia,
Arundinarieae, i.e., the temperate woody bamboos, exhibits a wide range of morphological diversity. The taxonomy of Arundinarieae has long been controversial. After nearly two decades of molecular phylogenetic studies, twelve clades based on plastid DNA sequences have been recognized which deviated markedly from the morphology-based classification, and many genera were resolved as polyphyletic. Recently, we sampled more than 400 species from all of the recognized clades and genera of the tribe around the world for the plastid genome and ddRAD sequencing. In the ddRAD phylogeny, the majority of the tribe falls into two clades, a pachymorph one and a leptomorph one, along with three basal ones, and the monophyly of several genera was corroborated. However, highly conflicting topologies were obtained between nuclear and plastid phylogenies. We discuss the origin, divergence times, species diversification, and reticulate evolution of the temperate woody bamboos in the context of the newly reconstructed phylogenetic framework. In addition, we propose to establish two new genera, Hsuehochloa and Ravenochloa.
Key words: Arundinarieae, diversification, East Asia, evolution, phylogeny.
Funded by: This work was supported by NSFC (31430011).
Systematics and evolution of herbaceous bamboos (Bambusoideae: Olyreae)
Reyjane Patrícia de Oliveira1, Iasmin Laiane de Castro Oliveira1, Fabricio Moreira Ferreira2, Maria Luiza Silveira de Carvalho3, Marcos da Costa Dórea1, Christian da Silva1, Cassiano Aimberê Dorneles Welker2 & Lynn G. Clark4
1Universidade Estadual de Feira de Santana; 2Universidade Federal de Uberlândia; 3Universidade Federal da Bahia; 4Iowa State University. rpatricia@uefs.br
The tribe Olyreae is the grass lineage that includes the herbaceous bamboos, often with culms weakly lignified and unisexual dimorphic spikelets. Members of Olyreae typically inhabit the understory of tropical forests, with several rare and/or poorly known species, mostly endangered.
Olyreae is strongly supported as monophyletic and sister to the tropical woody bamboos (tribe Bambuseae). It includes 22 genera, of which 17 are found in Brazil. Based on field work and multidisciplinary studies, we have improved knowledge about its diversity, systematics and evolution. Three subtribes are accepted, with Buergersiochloinae as sister to the Olyrinae + Parianinae clade. In Parianinae, Parianella is sister to Pariana + Eremitis. Olyrinae includes 18 genera, several of them of complex delimitation, grouped in four main lineages which are being analyzed using plastid and nuclear sequences, as well as macro- and micromorphological features.
We have recovered the monophyly of some genera (i.e. Raddia, Cryptochloa and Diandrolyra), whereas Sucrea, Parodiolyra and Olyra are not monophyletic and their generic status is being reassessed. Our forthcoming efforts involve understanding past and present biogeographic patterns and evolutionary processes in this group.
Key words: molecular phylogenetics, Neotropical grasses, Olyreae, Olyrinae, Parianinae.
Funded by: CNPq, CAPES, FAPESB