Salicylic acid (SA) plays an important role in plants responding to invasion by microbial pathogens. The recently identified SA-binding protein 2 (SABP2) plays a critical role in SA-mediated disease resistance signaling. SABP2 catalyzes the conversion of inactive methyl salicylate into salicylic acid, which is essential for activation of disease resistance response. Effects of high levels of SA may range from mild growth defects to cell death. Tight control over cellular levels of SA may be achieved through modulating SABP2 activity. Identification and characterization of proteins which may regulate SABP2's activity may provide insights in this area. In this project, yeast two-hybrid screen and biochemical protein-protein pull down techniques will be employed to identify SABP2-interacting partners from healthy plants and plants resisting pathogen attack. The role of putative SABP2-interacting proteins in disease resistance signaling will be determined though the use of genetics and biochemical techniques. SABP2 activity may also be regulated through changes in its subcellular localization in response to stress. Cellular location of SABP2 in plant cell will be determined using a combination of cellular fractionation, immunological and biochemical techniques. The role of SABP2 beyond R gene mediated disease resistance will be explored. The overall aim of this project is to better understand the salicylic acid mediated disease resistance pathway in plants. Results from this project may help develop disease resistant crop, plants reducing our dependence on use of harmful pesticides in agriculture.
Broader Impacts
This project will benefit undergraduate and MS students who will receive training in plant biochemistry and molecular biology. The majority of students attending East Tennessee State University are from economically disadvantaged families. A number of these students are either underrepresented or first time college attendees. The majority of these students are female students. This project will provide students with a unique opportunity to learn and conduct research. Students will be encouraged to think and design their own experiments. To enhance their understanding of research, weekly meetings will be held. Some of the research methods developed during this project will be incorporated into an undergraduate laboratory course. The PI is committed and will continue to recruit students through the McNair program. Students will be encouraged to participate in regional and national meetings and weekly departmental seminars. In addition, the PI participates in "Talent in Quantitative Biology", an NSF-STEP program at ETSU through which freshman undergraduate students get the opportunity to conduct research.
Plants are important source of food, medicine, fibers, biofuels etc. for humans. Plants also are important source of nutrients for various microorganisms including bacteria, virus, fungi etc. While using plants as source of nutrients, some of these microorganisms cause damages leading to diseases resulting in significant losses to their hosts. Crop plants sustain substantial losses due to these diseases worldwide each year. Uses of pesticides have greatly helped to control some of these harmful pathogens and pests and have ensured steady supply of food for growing world population. Due to widespread usage, trace amounts of some of these pesticides have reached our food supply chain. Harmful effects of these pesticides are increasingly being noticed and are cause of a number of diseases. People are getting concerned and have started to buy and use organically grown food. One way to limit usage of pesticides is to use plants own defense mechanisms to fight harmful microbial pathogens. Recent advances in molecular and biochemical techniques have resulted in enhancing our knowledge on plants own natural defense mechanisms. One such defense mechanism is mediated by plants own endogenous hormone, salicylic acid. Plants resisting pathogen infections synthesize and accumulate high levels of salicylic acid. To understand the role of salicylic acid in plant signaling pathways leading to resistance, several salicylic acid binding proteins including SABP2 have been identified. SABP2 is an enzyme which catalyzes the conversion of methyl salicylate into salicylic acid. Presence of SABP2 is critical for plants ability in utilizing salicylic acid to defend itself against microbial pathogens. Understanding the role of SABP2 and its partners inside the cell may hold key information related to the regulation of this all important plant immune signaling pathway. This research project has helped us to better understand some of these key interacting partners of SABP2. Further characterization these interacting partners is likely to enhance our knowledge and help to develop crop plants with better disease fighting capabilities. Better and adequate food availability will ensure a healthy society. A numbers of MS, undergraduate and high school students participated in successful completion of this project. These students learned to make hypothesis, design experiments to test hypothesis, learn and perform experiment’s, analyze the results, participate in scientific discussions, write manuscripts, present their research to their peers and other’s in community. Many of these MS students have successfully completed their dissertations and moved on to pursue Ph.D. at other institutions. Some have these students have joined research laboratories at other institutions and are conducting research in life sciences while some chose to pursue Medical, Dental, and Pharmacy Schools. Undergraduate students gained valuable research experience and are continuing to pursue higher education. This project has resulted in several research publications, MS dissertations, presentations by MS and undergraduate students at regional, national and international conferences.
