Al3+ toxicity resistance: Evaluation of residues mediating the phosphorylation of At-MATE1, a Multidrug and Toxicity Extrusion membrane transporter.

Acidic soils, representing more than 40% of the arable land in the world, contain high  levels of aluminum (Al) Al3+. This soluble form of aluminum common in acidic soils, is toxic to plants and affects many metabolic processes including cell wall extensibility, membrane transport, overall resulting in inhibition of root development. Previous research has determined that a membrane protein of the Multidrug and Toxin Exclusion family (MATE) is key for aluminum tolerance in Arabidopsis thaliana. Investigations into the regulation of this protein through phosphorylation have led to the wealth of knowledge which inspired this project.  Utilizing this information from previous experiments, we identified 5 potential residues of the AtMATE protein involved in phosphorylation. We replaced these sites in the MATE protein with residues which mimic phosphorylation events. These now mutated genes were transcribed into RNA, injected, and expressed  in Xenopus l. oocytes. The use of Xenopusoocytes allows for in vivo expression of proteins and a characterization of the functionality of transmembrane proteins using known methods of electrophysiology. Using the latter methodology, the functional characterization of oocytes expressing our variant proteins provided us with an array of results. These results allowed us to dismiss the involvement of the identified residues as potential sites underlying the phosphorylation mediated regulation of AtMATE. These and future experiments, provide a better understanding of plant aluminum tolerance and protein regulation through phosphorylation. This information may be useful in the future to improve plant performance grown in low pH soils.

My Experience

My experience at BTI in conjunction with the USDA has provided me with a unique experience in the laboratory. Working in the Kochian lab has peaked my interest in plant biology and the multitude of applications basic plant science provides. As an undergrad this summer experience has provided me with hands on experience using molecular techniques to alter and observe a biological process with a model organism, Xenopus L. (African clawed frog). The abundance of knowledge and resources here on the Cornell campus was truly inspiring.

This internship has provided not only an intellectual experience, but a social experience, living in the Ithaca area as an undergraduate.  Under similar conditions as a research student, I was able to explore science and interact with the region as a mock-grad student. This summer program has provided me with a working knowledge of how to communicate with mentors, PI’s, and my peers while also allowing me to have an inter and intrapersonal experience with graduate living.