Student Research Projects

The role of Arabinogalactan proteins in plant reproduction

Student LeMar Callaway, '18
Faculty Mentor(s)
Department Biology
Course Biology 489: Research in the Natural Sciences


Arabinogalactan proteins are a diverse group of proteins located at the cell membrane protruding into the cell wall of plant cells. These glycosylated proteins may serve as key players in certain cell signaling pathways within the plants that employ them, especially in the reproductive tissues of flowering plants. Each AGP encoding gene can vary in the location and arrangement of the sugar backbone. We used the model moss Physcomitrella patens to probe the role of AGPs in sperm development in order to document their importance in the oldest lineage. Prior bioinformatic analysis identified a suite of AGP-encoding genes in the model moss. We are conducting an expression analysis to confirm the upregulation of the identified genes in moss with developing sperm cells, and have confirmed the strong upregulation of one gene, Pp1s45_69V, and we speculated that it may play a role in their development. While we are currently analyzing the expression of several other AGP-encoding genes, our goal was to confirm which cells are expressing the identified AGP using a promoter-reporter construct, and to elucidate its function using a knockout construct with Kanr used as the selection gene. We plan to incorporate this construct with the use of homologous recombination, because the model moss is amiable to this technique. After transforming the knockout construct into the model moss, we will then observe the moss to determine if sperm development is affected when the targeted AGP-encoding gene is missing. Unfortunately, the Kanr gene that was cut from another plasmid failed to correctly ligate, so we intend on using PCR to amplify the selection-gene in future tries.


American Society of Plant Biologist Summer Undergraduate Research Fellowship, 2015-16