Origin and diversification of Neotropical orchids in the Andes
The Andes is a premier biodiversity hotspot, containing ca 15% of the world's plant species in just 1% of the earth surface. How different biotic and abiotic variables have affected the pace at which Andean lineages diversified, as well as their mode and tempo of evolution remain poorly understood. This is particularly true for iconic lineage such as orchids, where the lack of densely sampled, solid phylogenetic frameworks have precluded research on these issues. To answer these questions, I am currently compiling phylogenies of assorted orchid lineages distributed mainly in the Andes and Central America using Sanger and next generation sequencing methods. Using as a model group speciose Andean orchid lineages, we aim to trace in time and space their diversification, and to disentangle the contribution of main biotic (e.g. pollination syndromes, plant habits) and abiotic (e.g. Andean orogeny) diversification drivers. We are also interested on understanding how main geological events have affected migrations through time in the Neotropical region. Currently, we are building a phylogeny of the species-richest neotropical subtribe Pleurothallidinae using a target enrichment approach combined with genome skimming to resolve deep polytomies and provide support to nodes leading to rapid diversifications. An exciting paper derived from this project is available here, and was featured in the Kew Science blog (also available here). This project is supported by Prof. Alexandre Antonelli via a grant from the European Research council.
Gene evolution and diversification in the orchid genus Dendrobium
Changes in climatic niches and pollinators, and their corresponding morphological adaptations are recurrent across the evolutionary history of flowering plants. However, the genomic bases of those morpho-ecological transitions and their contribution to lineage diversifications are still poorly studied. To better understand the evolution of morphological novelty in plants and its link with lineage diversification, we are investigating changes in climatic envelopes and morphology through time in the orchid genus Dendrobium. This hyper-diverse clade of approximately 1500 species inhabits in a rich array of ecosystems in tropical Asia and Australasia, ranging from sea-level xerophytic forests to subalpine vegetation (>3000 m). The lineage is characterized by a remarkable diversity of vegetative and reproductive morphology, driven by repeated transitions contrasting morphological states. This system provides a unique opportunity to elucidate the role that duplication and loss of genes associated to plant development play in the evolution of morphological diversity and diversifications in plants. We are generating a well-resolved phylogenomic framework for Dendrobium, by combining newly sequenced skimmed-genomic data with GenBank sequences. Using a novel target enrichment approach optimized for complex gene families, we are sequencing genomic regions containing MADS-domain transcription factors for selected Dendrobium species spanning the entire morphological and climatic diversity of the lineage.
Building a family-wide orchid phylogeny using target enrichment and genome skimming
Using a combination of target enrichment and genome skimming approaches, this project aims to provide the first solid, genus-level phylogeny of one of the most speciose clades and spectacular diversifications among flowering plants: the orchid family. Perhaps equally important, it will also provide genomic data of several lineages for which DNA data is not available to date in public databases (i.e. ~40% of the genera). We aim to sample genome-wise ca. 30% of all current generic lineages, but will expand sampling in hyper-diverse clades (e.g. Bulbophyllum, Dendrobium, Epidendrum, Lepanthes). Orchid sampling makes part of the "Plant and Fungal Trees of Life" initiative developed at Kew gardens. This project is supported by the PAFTOL steering group, but additional funds top keep expanding the taxon sampling are always wellcome!