Disentangling the intricate variation patterns in the diploid-polyploid complex veronica subsect. Pentasepalae benth. (veronica l., plantaginaceae sensu apg iv). Relationship with the quaternary climatic oscillations

Resumen

This PhD Thesis has been developed at the University of Salamanca (Spain) within the framework of the doctoral program “Biología y Conservación de la Biodiversidad”. This PhD Thesis has been funded by the Spanish Ministerio de Economía y Competitividad through the projects “Mecanismos evolutivos, filogenia, taxonomía y patrones filogeográficos en Veronica subsect. Pentasepalae Benth. (Veronica L., Plantaginaceae sensu APG II)” (reference CGL2009-07555), and “Desentrañando los intricados patrones de variación en el complejo diploide-poliploide de Veronica subsect. Pentasepalae Benth. (Veronica L., Plantaginaceae sensu APG III). Relación con el ultimo máximo glacial (UMG) y la recuperación climática del Holoceno Medio” (reference CGL2012-32574) and the Spanish Ministerio de Educación through a PhD scholarship within the program “Subprograma de Formación del Profesorado Universitario” (reference AP2010-2968). The research project has been conducted at the University of Salamanca in the Department of Botany and Plant Physiology and the Plant DNA Biobank. Further experiments and data analyses related with this PhD Thesis project have also been carried out during research stays performed at the Institute of Biology and Environmental Sciences (Carl von Ossietzky University of Oldenburg, Oldenburg, Germany), the Centre for Functional Ecology (University of Coimbra, Coimbra, Portugal), the Institute of Botany of the Czech Academy of Sciences (Průhonice, Czech Republic), and the Florida Museum of Natural History (University of Florida, Gainesville, USA). Additionally, field surveys related to the PhD Thesis project have been carried out all across Europe including the following countries: Albania, Austria, Bosnia and Herzegovina, Bulgaria, Croatia, Czech Republic, France, Germany, Greece, Hungary, Italy, Montenegro, Republic of Kosovo, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, and Switzerland. This manuscript is composed of VII chapters: In Chapter I, an overview of the main topics covered in this PhD Thesis is provided. The study group, Veronica subsect. Pentasepalae is here introduced with a specific focus on the diploid-polyploid ‘V. austriaca – V. orbiculata complex’ and the ‘V. austriaca complex’. Additionally, the main goals of the thesis are presented. In Chapter II, a thorough morphometric study of V. subsect. Pentasepalae —including for the first time all taxa currently recognized within the subsection for which sufficient material was available— is presented. A classical multivariate analysis (Discriminant Analysis) and two well-known data-mining techniques (Decision Trees and Artificial Neural Networks) were used in order to search for discriminant morphological characters to allow accurate taxon identification in a taxonomically intricate species group. This chapter has been published as a research article in the journal Plos One. In Chapter III, vouchered chromosome counts and ploidy level estimates for several species from Veronica subsect. Pentasepalae are provided. Some of them represent the first chromosome count available for particular species. This chapter has been published as a Chromosome Data Series in the journal Taxon. In Chapter IV, a new set of polymorphic microsatellite markers for Veronica subsect. Pentasepalae is reported. Twelve pairs of primers were identified and optimized using a microsatellite-enriched library method and 454 GS-FLX technique. Amplification success for these markers in the cross-transferability tests extends their potential usefulness to other subgenera. This chapter has been published as a Primer Note in the journal Applications in Plant Sciences. In Chapter V, a study that explores the genetic structure and relationships of the species belonging to the ‘V. austriaca – V. orbiculata diploid-polyploid complex’ is presented. This study is focused on the Western Balkans, where active hybridization and species diversification processes have been and are notably active. Nuclear microsatellites markers, plastid DNA regions and ploidy level estimations were employed to assess the genetic structure and evolutionary dynamics of this polyploidy complex. Approximate Bayesian computation analyses are combined with species paleodistribution models to evaluate hypothesis regarding evolutionary history. The manuscript related to this chapter has been submitted to the journal Molecular Phylogenetics & Evolution. In Chapter VI, a study about the perennial herbs included in the ‘V. austriaca complex’ is presented. A combined approach is applied using data from nuclear microsatellite markers, plastid DNA, and ploidy levels for investigating patterns of intraspecific biodiversity. Morphological and ecological variation is also evaluated though leaf and fruit measurements, and present potential distributions, respectively. The manuscript related to this chapter is currently in preparation for submission. In Chapter VII, the main conclusions of this PhD Thesis are displayed. Lastly, the Appendix comprises published papers —included in other PhD Dissertations— in which I have participated as co-author.