MtPT4: A vital protein for arbuscular mycorrhizal symbiosis within Medicago truncatula
Although the importance of phosphorous in overall plant health is well known, the acquisition of phosphorous from arbuscular mycorrhizal (AM) fungi to plant root cortical cell in AM symbiosis is still not well understood. However, using the model legume, Medicago Truncatula, certain components involved in the mechanism have been illuminated. MtPT4 is a proton coupled phosphate transporter located on the periarbuscular membrane of cortical cells undergoing symbiosis. It has been shown through research that this protein is necessary for not only phosphate transport into the plant, but for the morphological changes that is required to form the symbiotic infrastructure between fungus and plant. From the identification of the MtPT4 gene, transcription factors leading to the expression of this gene have been found. A designated MtTF1 is one of these transcription factors. Its expression has been shown to only occur in cortical cells containing arbuscules of the fungi. It is speculated that TF1 is not alone in the process of expression and using cDNA libraries from gene data banks, 60 proteins have been selected as potential candidates. Using the yeast two hybrid method, several of these proteins have been confirmed as interacting partners of TF1. Now further testing is needed to conclude that the proteins do interact. Another area of study is the expression pattern of MtTF1. Expression of MtTF1 has been shown to be significantly high in roots undergoing colonization and almost no expression exists elsewhere. Thus, the expression pattern of this transcription factor is also of interest and is currently being studied using promoter-Gus staining analysis of the roots of plants undergoing symbiosis with AM fungi.
The Harrison lab partakes in unraveling the mystery behind the mechanisms that occur between arbuscular mycorrhizal fungi and plant symbiosis. I was fortunate to be part of that team. The experiences that I had in this lab have been ineffable pleasures. The lab members were tremendously amiable and enamored by their projects. At first, the information seemed insurmountable as everything was new, but the lab members made me feel at home. Soon I began understanding the new lab experiments and techniques used in genomic plant research. Having mentor guidance gave me an ambivalence of excitation and intimidation. I felt excited because I never knew what new technique I was going to learn from my mentor and I felt intimidated because my knowledge of this new universe was inadequate in comparison to his. However, as time progressed, I became much more confident in my abilities as I learned lab techniques and was eventually allowed to conduct work independently (After making a few mistakes of course). The time spent here has definitely solidified my plans of going into the research field. It is an experience I would have all over again.