Temperature-Dependent Stomatal Modulation in Arabidopsis Thaliana
Previous studies and preliminary investigation by my mentor have revealed a connection between temperature and the ability of some Arabidopsis thaliana autoimmune mutants (such as bon1-1, snc1-1 and cpk3-1) to modulate their stomatal apertures in response to abscisic acid (ABA). However, we do not know at which point in the signaling pathway temperature intervenes, or how. Since stomatal closure is the first line of defense against invasion by many bacterial pathogens, which cannot penetrate the epidermis and therefore must enter through stomata, it is important to know how rising environmental temperatures are likely to affect this process. Generating related data may eventually help plant breeders to breed varieties of crop species with enhanced disease resistance at higher temperatures and help to feed the Earth’s rapidly growing human population more efficiently. I therefore performed a series of experiments in which I observed the effects of ABA, Ca2+ (a second-messenger in ABA-induced stomatal closure) and Pseudomonas syringae tomato (Pst DC3000) on the stomata of ten different mutants of immune response regulators and related proteins. Almost all assays were performed at both 22°C and 28°C. I was able to characterize the extent of temperature-dependent stomatal modulation defects in several of the mutants, and found some evidence that the pathogen-associated molecular pattern (PAMP)-induced stomatal closure may utilize part of the same signaling pathway as ABA-induced stomatal closure. These results are helping to elucidate how temperature interacts with Resistance (R) genes and where and how temperature intervenes in the pathways that ultimately lead to stomatal closure.
During my summer in the Hua lab, under the supervision of my mentor, Jiapei Yan, I learned how to perform many basic procedures, such as DNA extraction, PCR and microscopy; I also developed a more thorough understanding of what is involved in the investigation of basic biology and genetics and feel far more capable of developing effective methods for exploring the scientific questions I would like to answer in my future research. Perhaps the most enlightening part of the experience was the opportunity to attend PGRP seminars and hear about the wide variety of plant research that is being performed and how it is revolutionizing plant breeding and how our food is and will be grown. When spending a lot of time on very specific experiments it can be easy to lose a sense of how the research can be practically applied, and the seminars provide excellent perspective in this area. I am grateful I had the opportunity to live and learn in Ithaca for a summer.