UC Berkeley

With the technological advent of bioinformatics, next-generation sequencing, and population genomics, recent studies can rely on high-throughput molecular data to investigate the evolution and diversification of Neotropical plant lineages. Here, we review one of the most widespread and dominant plant groups in the Neotropics based on a multidisciplinary approach. We integrate molecular data based on next-generation sequencing, morphological and functional data to unveil the evolutionary history of Protium heptaphyllum (Aubl.) Marchand, a plant taxon recently classified as one of the top hyperdominant trees in Amazonia. The results have direct implications for biodiversity conservation, taxonomy, and systematics of tropical plants. The dissertation chapters are described below.

The first chapter aimed to perform the most comprehensive review ever done in a hyperdominant taxa, long considered to be a taxonomically difficult group. By using morphological, genomic, and functional data, we showed that P. heptaphyllum sensu lato represents eight separately evolving lineages warranting species status. In addition, most of these newly discovered lineages are rare and threatened; few if any of them could be considered hyperdominant on their own. There is an urgent need to improve the classification of hyperdominant taxa in order to avoid oversimplified assumptions regarding diversity and functional aspects of tropical regions.

The second chapter comprises a taxonomic review and a detailed description of P. cordatum. Molecular phylogeny indicates that populations of P. cordatum should not be classified as an intraspecific taxon within Protium heptaphyllum (Burseraceae), while morphology and near-infrared spectroscopy data provide additional support for the recognition of a separate entity. Species delimitation remains a challenge worldwide and this study demonstrates the importance of using multiple tools to characterize and distinguish plant species in highly diverse tropical regions.

In the third chapter, I aimed to generate a novel genomic resource for Burseraceae, a family globally recognized for producing resins and essential oils with medical properties and economic values. In this section, I provide the transcriptome assembly of Protium copal, a widespread aromatic tree in Central America, and describe the functional annotation of terpene biosynthetic genes. Most of the aromatic and non-aromatic properties of Burseraceae resins are composed by terpene and terpenoid chemicals. The identification of terpene genes will be relevant for understanding the synthesis of economically important chemicals in Burseraceae.