Regulation of the early steps of wound-activated jasmonate biosynthesis

University Of Missouri-Columbia, Columbia MO

Investigators

Abstract

To meet the growing needs of global food production, crop losses due to pests must be minimized. Many of pest resistance responses in plants are mediated by the hormonal signal, jasmonate (JA). The broader aim of this project is to understand plant’s built-in defense mechanisms mediated by JA as an important step toward developing sustainable pest mitigation measures. More specifically this project will elucidate the very first step(s) of JA biosynthesis and how it is linked to the perception of pest attacks by the plant cells. Available evidence points toward involvement of enzymes called lipases that hydrolyze membrane lipids as primary regulatory point. Uncovering biochemical regulation of lipases has potential applications in the food, cosmetics, detergent, and pharmaceutical industries. Additionally, membrane ion channels analogous to those involved in animal neurotransmission are involved in pest activated defense responses in plants. Learning how these elements are organized and engaged to carry out analogous functions across kingdoms is fascinating and will lead to more fundamental understanding about cell signaling. This project will contribute to STEM education and public science literacy in several ways. First, undergraduate participation in research will be promoted directly and indirectly through the PI’s core and institutional programs. Second, public science literacy will be enhanced through Sci-LiFT (Science Literacy for Future Teachers) program aimed at including future secondary school science teachers in authentic research. Training of future teachers and undergraduates will have far reaching impacts on society. Tissue injury such as that caused by insect herbivory triggers numerous defense responses in plants. The synthesis of the plant hormone jasmonate (JA) that begins within few minutes of tissue damage is key to these defense responses, but how such rapid synthesis of JA is achieved is still a mystery. The major goal of this project is to investigate the initial steps of JA biosynthesis to understand how these steps are regulated. The PI hypothesizes that the relevant lipases such as DEFECTIVE IN ANTHER DEHISCENCE1 (DAD1) and GLYCEROL LIPASE A1 (GLA1) are subject to distinct transcriptional and post-transcriptional modes of regulation: the latter being responsible for the initial bust of JA, while the former primes the plant for defense against future attacks. They further hypothesize that the post-transcriptional mode of activation occurs after signaling from GLUTAMATE RECEPTOR LIKE (GLR) ion channels that propagate wound response plant-wide. A diverse range of molecular, genetic, and analytical tools developed in the PI’s lab will be used in the well-established model systems of Arabidopsis and Nicotiana to address following specific aims: i) determine biochemical regulation of DAD1 and GLA1 lipases for wound-elicited JA biosynthesis, ii) identify and characterize novel proteins regulating lipase activity, and iii) determine the spatial and structural features that facilitate systemic GLR signaling to the JA pathway. Both lipases and membrane ion channels are fundamental to cell function across kingdoms and thus, understanding how these pathways have evolved in plants will contribute to understanding their general roles in life. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.