April 18, 2019 // What’s Stomata With You? Investigating the Role of a Protein Kinase Family in Stomatal Defense
Kristen Siegel, MSc Candidate, Dept Biology, Queen's University, Monaghan Lab
Stomata are microscopic pores found in leaf epidermal tissue that facilitate gas exchange between a plant and its environment during photosynthesis. Each pore is bordered with two specialized guard cells, which can modulate their turgidity to cause stomatal opening or closure. Photosynthetically favourable conditions, such as high levels of blue light, induce stomatal opening through guard cell water uptake. However, these openings are also commonly seized as a point of entry for plant microbial pathogens. Upon pathogen detection, plasma membrane-localized receptors will initiate intracellular signalling cascades, and ultimately cause stomatal closure though water efflux and guard cell deflation. This process, known as stomatal defense, contributes to a broad-spectrum immune response which is sufficient to defend against most pathogens. In a proteomics-based screen for regulators of immunity in Arabidopsis thaliana, we identified components of stomatal defense as well as several proteins with unknown function. Of particular interest was a novel protein belonging to a small family of mitogen-activated protein kinases involved in blue-light induced stomatal opening. This work investigates the putative role of this family in stomatal defense and immune signalling.