Characterization of Ammonium Transporters from the Model Plant Marchantia
Name of Award
3M Student-Faculty Collaborative Grants - Small Scale
Tami McDonald, PhD, Assistant Professor of Biology was awarded a 3M Student-Faculty Collaborative Small Scale grant for $2000 for her study Characterization of Ammonium Transporters from the Model Plant Marchantia. Organisms need nitrogen to live. Because ammonium and ammonia are the easiest forms of nitrogen for living things to use, almost all organisms have proteins dedicated to importing either the ammonium ion (NH 4 + ) or ammonia gas (NH 3 ) from the environment. Collectively, these proteins are known as the AMT/MEP/Rh family and are encoded by AMT, MEP or Rh genes. Over evolutionary time, the function of the proteins encoded by these genes has changed in some lineages. Although most of these transporters transport ammonia gas, a subset of these transporters from flowering plants transports ammonium ions. However, it is unknown when the new function of ammonium ion transport evolved—was it along with flowering plants, or was it even earlier? Previous work from the McDonald lab has demonstrated that some transporters from the model plant Marchantia polymorpha (a liverwort) transport ammonium ions, pushing back the appearance of this novel trait by more than 100 million years to the colonization of land by nonflowering plants. To demonstrate whether the transporters transport ammonia gas or the ammonium ion, the liverwort proteins are introduced into frog eggs, because frog eggs are easy to pierce with an electrode in order to detect the electrical current generated when an ion such as ammonium passes through an ion channel into a cell. However, not all liverwort proteins are adapted to the environment of the frog cells, so some of the proteins don’t work in frog eggs. Therefore, to test whether these proteins transport ammonia or ammonium, a different organism must be used. This proposal is to support work by an undergraduate student to test the function of liverwort ammonium transporter proteins that have been introduced into the model yeast Saccharomyces cerevisiae.
McDonald, Tami, "Characterization of Ammonium Transporters from the Model Plant Marchantia" (2016). External Grant Awards. 92.