Linking macro- and microevolution in Bromeliaceae Clarisse Palma da Silva1
1Unicamp. clarissepalma@yahoo.com.br
Bromeliads are good models for understanding how the interplay among evolutionary processes such as gene flow, drift and selection influence species-level patterns of diversification (speciation and extinction) in Neotropics. In Bromeliaceae limited gene flow due to geographic isolation may have influenced macroevolutionary patterns of diversity. Most species recognized in the family are endemic suggesting limited dispersal. Moreover, the few widespread species usually show morphological variation across their distributions, suggesting that intra-specific gene flow may not prevent divergence from drift or/and local adaptation. And finally, in several monophyletic bromeliad groups geographical proximity is a better indication of species relationships than morphological taxonomy. The same factors influencing population differentiation within a species are presumed to influence rates of species divergence over deep evolutionary time. However, geographic genetic structure does not always lead to speciation. Low effective population sizes may lead to high levels of local extinction, low efficacy of selection, and decreased speciation.
Furthermore, recent studies suggest that inter-specific gene flow may promote diversification by reducing extinction rates via introgression of adaptive alleles. In this context, other forces such as population persistence, evolution of reproductive isolation and ecological divergence may also influence diversification at the species-level.
Key words: diversification rates, extinction, phylogenetics, population genetics, speciation.
Funded by: FAPESP, CAPES, CNPq
Bromeliaceae life history evolution and conservation implications Dr. Rachel S. Jabaily1 & Dr. Erin N. Bodine2
1Colorado College; 2Rhodes College. rjabaily@coloradocollege.edu
Bromeliad taxa differ in life history attributes, including lifetime attempts at sexual reproduction (a single vs. multiple times), and relative ability to produced asexual clones, or pups. The diversity of life history across the Bromeliaceae provides a rich model for comparative study, and how life history evolves and impacts conservation of various bromeliad taxa is unknown. The bromeliad research and horticultural communities also lack consistent understanding of life history terminology and a consistent life history type has not been ascribed to most taxa. Semelparity, or a single and subsequently lethal attempt at sexual reproduction via flowers with no pupping, has evolved repeatedly within the Bromeliaceae. The majority of taxa are iteroparous, producing inflorescences repeatedly across the lifespan of the genetic individual, but the number, timing, and anatomical origin of pups differ between taxa. The talk will overview models of life history evolution as applied to bromeliads. Ongoing experimental data from multiple exemplar taxa, and field data from semelparous and iteroparous Tillandsia taxa in Florida and semelparous Puya raimondii in Bolivia, will be discussed. Mathematical modeling utilizes these data to provide a framework to theoretically and quantitatively explore and test the evolutionary drivers of different life history strategies.
Key words: Bromeliaceae, evolution, life history, monocarp, semelparous.
Towards understanding the genomic substrate of diversification in Tillandsia subgenus Tillandsia
Gil Yardeni1, Jaqueline Hess1, Michael H. J. Barfuss1, Margot Paris2, Thorsten Krömer3, Michael Kessler4, Walter Till1 & Christian Lexer1
1Department of Botany and Biodiversity Research, University of Vienna, Vienna, Austria;
2Department of Biology, University of Fribourg, Fribourg, Switzerland; 3Centro de Investigaciones Tropicales, Universidad Veracruzana, Xalapa, Veracruz, Mexico; 4Institute of Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland. gil.yardeni@univie.ac.at
The species-rich and ecologically diverse Bromeliaceae family provides an excellent system for studying adaptive radiation in Neotropical plants. The genus Tillandsia is the largest and most diverse within the family with over 600 species, extensive geographical range and a variety of ecological adaptations to different habitats such as epiphytism and various photosynthetic syndromes. Our research goal is to identify the genomic variability that provided the substrate for adaptive radiation within the enigmatic subgenus Tillandsia of genus Tillandsia using tree-, network, and coalescent-based approaches. To that end, we used whole-genome sequencing data
from selected species within a taxonomic clade (Core Group I, also known as ‘The Mexican clade’) to construct phylogenomic trees and networks and infer species delimitation. To shed light on the genomic processes that gave rise to diversity within the clade, we performed tests for reticulation, introgression and post-speciation gene flow. We will present our first results, describe the genomic tools used for inference and outline future prospects towards understanding of genomic processes at micro- and macro- scales. This research project provides a unique case study for emerging research on the evolutionary genomic underpinnings of plant species radiations in the neotropics.
Key words: adaptive radiation, introgression, phylogenomics, reticulation, Tillandsia.
Circumscription, diversity, and evolution of Tillandsia subg. Tillandsia based on a multi-locus DNA phylogenetic approach.
Juan Pablo Pinzon Esquivel1, Walter Till2, Ivon Mercedes Ramirez Morillo3, German Carnevali Fernandez-Concha3 & Michael Harald Johannes Barfuss2
1Departamento de Botánica, Campus de Ciencias Biológicas y Agropecuarias, Universidad
Autónoma de Yucatán, carretera Mérida-Xmatkuil km. 15.5, Apdo, Postal 4-115 Itzimná, CP 97100 Merida, Yucatan, Mexico; 2Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030, Vienna, Austria; 3Unidad de Recursos Naturales, Centro de Investigación Científica de Yucatán, A. C., A.C., Calle 43 No. 130 Colonia Chuburná de Hidalgo, CP 97205, Merida, Yucatan, Mexico. juan.pinzone@correo.uady.mx
Tillandsia subg. Tillandsia is the largest subgenus within the genus, comprising great morphological variability and ecological distribution. It is diagnosed by having exserted stamens and style, with naked petals. However, previous studies have shown that these characters are homoplastic. The aim of this study is to assess the phylogenetic relationships of T. subg. Tillandsia, representing its full geographical range and morphological variation. We used four DNA markers, two nuclear (PhyC, PRK) and two from the plastid genome (ycf1 and matK-trnK), and indels.
Bayesian inference, Maximum Parsimony and Bootstrap analyses were performed. The genus Tillandsia was supported as monophyletic (including Viridantha and Pseudovriesea) in a sister relationship with Pseudalcantarea. The Tillandsia multicaulis group is confirmed as not related to T. subg. Tillandsia. The remainder of the subgenus is paraphyletic. Three large groups can be recognized: the T. secunda and T. paniculata groups (mainly from South America and the Antilles), and a Mexican (mostly) clade, inside which several groups are recovered: T. utriculata s.
l. clade; T. circinnatoides clade (xerophytic Mexican species); Southern Mexico Highlands clade; Allardtia clade, and finally a large unresolved clade, in which many representative species complexes are found, including T. capitata, T. fasciculata, T. juncea (pro parte) and T. ionantha.
Key words: biogeography, Neotropics, phylogeny, Tillandsia, Tillandsioideae.
Insights about the evolutionary history of species of Aechmea subgenus Ortgiesia from southern Brazil
Márcia Goetze1, Camila Martini Zanella2, Laís Mara Santana Costa1, Miriam Valli Büttow3, Clarisse Palma da Silva4 & Fernanda Bered1
1Universidade Federal do Rio Grande do Sul, Brazil; 2The John Bingham Laboratory, National Institute of Agricultural Botany, United Kingdom; 3Fundação Estadual de Pesquisa Agropecuária, Fepagro Serra do Nordeste, Brazil; 4Universidade Estadual de Campinas, Brazil.
marciagoetze@yahoo.com.br
The study of microevolutionary processes clarifies how speciation and extinction took place at the population level. A great opportunity to understand these processes is provided by studying closely related but geographically restricted taxa. We investigated the evolutionary history of seven species of Aechmea subgenus Ortgiesia endemic to southern Brazil. We combined data from chloroplast and nuclear markers and applied phylogeographical and population genetic approaches to develop the study. The origin of the seven species was dated to the late Pliocene, with most of the lineages diversifying in the early Pleistocene. The genetic structure found suggests the taxa had their geographical distribution fragmented during the Pleistocene, surviving in multiple refugia. This fragmentation may have contributed to the genetic differentiation observed for A. blumenavii, A.
calyculata, and A. kleinii. For A. calyculata, the advance of grassland over Atlantic forest during the Pleistocene was an important barrier to gene flow among populations. The remaining four species showed less genetic structure, which was attributed to incomplete lineage sorting and hybridization.
Indeed, hybridization was confirmed as occurring among A. caudata, A. comata, and A. kertesziae where they are sympatric. This group of seven species presents a complex evolutionary history with a speciation process with gene flow.
Key words: Atlantic rainforest, diversification, molecular markers, phylogeography, speciation.
Whole-genome and transcriptome signatures of diversification in bromeliads: crossing the micro / macro divide
Marylaure de la Harpe1, Margot Paris2, Jaqueline Hess1, Martha Serrano3, Michael Barfuss1, Walter Till1, Nicolas Salamin3, Rob van Buren4, Ray Ming5, Christian Lexer1
1University of Vienna; 2University of Fribourg; 3University of Lausanne; 4Michigan State University; 5University of Illinois. christian.lexer@univie.ac.at
Bromeliads (Bromeliaceae) represent an ecologically important and intensively studied adaptive radiation among Neotropical plants. Understanding patterns, drivers, and limits of plant
diversification and radiation is greatly facilitated by analytical approaches from ecological and evolutionary genomics and related “-omics” - sciences, embedded within a systems biology
framework. Bromeliads are well suited for this type of research, because they offer a great diversity of species (>3000), numerous interesting shifts in functionally important adaptive traits, and
abundant genome and transcriptome resources, compared to most other Neotropical groups. We have addressed the genetic underpinnings of diversification in two different groups of Bromeliaceae within highly collaborative research efforts, based on combinations of whole genome and
transcriptome sequencing and molecular phenotyping of selected taxa. This includes research to understand the genomic substrate of adaptive radiation in tillandsioid bromeliads (genus Tillandsia and related genera), and research to understand genomic patterns and drivers of diversification in the genus Ananas, which includes the cultivated pineapple. Selected results from this work will be presented. We will place special emphasis on aspects of relevance for evolutionary biologists and systematists wishing to tackle patterns and processes across micro- and macro-evolutionary time scales.
Key words: adaptation, phylogenomics, population genomics, radiation, speciation.
Funded by: Swiss National Science Foundation (SNF) and University of Vienna
Biogeographic history and macroevolutionary patterns in the core-Tillandsioideae with a focus on Vriesea
Oriane Loiseau1, Talita Mota Machado2, Margot Paris3, Leonardo M. Versieux4, Christian Lexer5
& Nicolas Salamin1
1University of Lausanne; 2UFOPA- Federal University of West Pará; 3University of Fribourg;
4Univesidade Federal do Rio Grande do Norte; 5University of Vienna. oriane.loiseau@unil.ch
Bromeliads are an iconic group of Neotropical plants that represents a well-studied case of adaptive radiation triggered by the appearance of specific traits such as the tank-habit or CAM photosynthesis. The large diversity of Bromeliads combined with the low rate of molecular evolution has complicated phylogenetic studies and no species-level phylogeny is available for the largest genera. Because of this limitation, the macroevolutionary dynamic shaping bromeliad diversity at shallower levels such as subfamilies or genera remains unknown. Here, we use a large dataset of 122,664 SNPs obtained from genome skimming to reconstruct the first time-calibrated phylogeny of Vriesea with more than half of Vriesea species included. We analysed the dynamics of diversification in Vriesea to better understand the factors that contributed to the emergence of its species richness. We combined these diversification analyses with biogeographic reconstruction to place the macroevolutionary processes within the geographic context where these species occur.
Our results highlight the opportunity offered by genome-wide sequencing approaches to provide informative data for robust phylogenetic inferences. These data are essential to enable the investigation of the macroevolutionary processes driving the evolution of large and complex plant groups such as the genus Vriesea.
Key words: Atlantic forest, biogeography, Bromeliads, diversification, genome skimming.