“Subcellular localization and role in pollen development of the jasmonic acid receptor (COI) protein family in Zea mays“
The jasmonic acid (JA) signaling pathway regulates plant development and environmental responses. In the pathway, the Coronatine Insensitive (COI) protein binds JA-Ile and initiates degradation of the Jasmonate-Zim Domain (JAZ) repressors, which inhibit activity of JA gene transcription factors. Six COI orthologs (four COI1s and two COI2s) are present in maize as a result of gene duplication events. Preliminary experimental results inspired two independent experiments: (1) subcellular localization of the COI1 proteins, and (2) COI2 pollen viability assays. For Experiment 1, previous COI1 and COI2 subcellular localization experiments in N. benthamiana showed that COI2s were localized primarily in the nucleus, while COI1s were localized in cytosolic organelles. Additionally, bimolecular fluorescence complementation in N. benthamiana leaves showed that, while COI1s only weakly interacted with JAZ proteins in the nucleus, COI2s showed strong interactions. We hypothesized that, if COI1 has a lower affinity for JAZ than COI2, expression of COI1 in maize protoplasts should restore nuclear localization due to the presence of the host JAZ. When maize protoplasts were transformed with COI-GFP plasmids, COI1 appeared to localize in the nucleus. However, the results were difficult to interpret since the cells ruptured and the expressing nuclei were free-floating. For Experiment 2, previous work suggested that the homozygous coi2 double mutations are lethal. To determine when the coi2a coi2b double mutant pollen dies, pollen viability and germination assays were performed. COI2a/coi2a coi2b/coi2b and coi2a/coi2a COI2b/coi2b plants had significantly higher amounts of non-viable pollen and exhibited lower pollen germination rates than their single-mutant siblings.
Surrounded by a diverse group of plant scientists, I have learned far more than lab techniques and greenhouse protocols during my time at BTI. The most valuable lesson I learned from this experience is the importance of thoughtful discourse and collaboration in science and research. I realized that one of the most essential skills to have as a scientist is the ability to clearly communicate complex topics in a way that is not intimidating or confusing for scientists or non-scientists. Additionally, my lab has demonstrated that open dialogue amongst fellow scientists is also crucial in the pursuit of refining and uncovering scientific conclusions. My project would not have been successful without the guidance and support of my peers, lab mates, and mentor. BTI’s emphasis on collaboration has amplified my appreciation for working with a team and constantly considering new ideas, questions, and perspectives that help me develop as a scientist.