Exploring Ancient Plant Metabolism: Resurrection and Characterization of a Sabath Methyltransferase from the 475-Million-Year-Old Land Plant Ancestor
Date of Award
Master of Science
Dr. Todd Barkman
Dr. Yan Lu
Dr. Jian Yao
Molecular evolution, SABATH methyltransferase, ancestral reconstruction, plant metabolism, phylogenetic analysis
Masters Thesis-Abstract Only
Restricted to Campus until
One of the fundamental goals of evolutionary biology is understanding how protein function and structure have evolved over time to produce the diversity of life observed in the present day. Widely regarded as one of the drivers of this diversity is the occurrence of gene duplication events. The SABATH family of methyltransferases are critical to many components of plant specialized metabolism and have developed diverse substrate preferences and activities through several gene duplication events. Prior phylogenies demonstrating the evolutionary history of this family have been generated using small datasets; however, this risks the exclusion of sequences from underrepresented groups of land plant lineages. By generating the largest, most comprehensive phylogeny of the SABATH methyltransferases to date, this study explored the evolutionary history of this family. In doing so, it was determined that the first land plants that emerged ca. 475mya likely only possessed one SABATH gene. Using a powerful tool known as ancestral sequence reconstruction (ASR), this ancestral gene was resurrected and functionally characterized. The putative SABATH ancestor was revealed to have promiscuous catalytic activity, providing evidence that although the first land plants were likely more genetically limited than their descendants, they were capable of achieving metabolic complexity.
Dubs, Nicole M., "Exploring Ancient Plant Metabolism: Resurrection and Characterization of a Sabath Methyltransferase from the 475-Million-Year-Old Land Plant Ancestor" (2020). Master's Theses. 5177.