Undergraduate Student Ohio University Maumee, Ohio
Body of Abstract: A plant’s survival is largely impacted by its ability to sense and respond to gravitational changes. Despite its importance, the pathway regulating gravitropism is not fully understood. To better understand this, the BRIC-20 experiment was performed in the microgravity environment of the International Space Station. This led to the discovery of differentially abundant proteins in Arabidopsis that are believed to be involved in the gravitropism pathway. One of these proteins was the proton pump AHA2, which was differentially phosphorylated, or less active, in microgravity compared to ground controls. AHA2 is hypothesized to be involved between auxin movement and differential growth during gravitropic signaling. Thus far, aha2 knockout mutants have been phenotyped and show a decreased gravitropic response, indicating that AHA2 is involved in gravity signaling. AHA2 has multiple phosphorylation sites. To determine which sites on AHA2 are needed for gravitropic signaling, several lines of transgenic Arabidopsis with modifications in these sites are being developed. Each AHA2 phosphorylation site is modified to keep the protein constitutively active or inactive. The transformants will then be phenotyped for altered gravitropic response, showing if the activation of the AHA2 protein is involved in gravitropism. These findings will further knowledge on the molecular mechanisms of gravitropism to develop space-tolerant plants for bioregenerative life support.
This research was partially funded by the Ohio Space Grant Consortium Undergraduate STEM Scholarship, the Ohio University Jeanette Grasselli Brown Award, the Ohio University Ivan K. Smith Fellowship Award, and the Ohio University Research Incentive Fund to S.E.W..