The Role of N-Acylethanolamines in the Development of Physcomitrella Patens

Document Type

Presentation

Publication Date

4-5-2012

Description

Global demand for food, which is expected to double by 2050, presents plant biologists with a major challenge to generate higher yields on existing croplands. The long-term goal of the proposed research is to generate stress tolerant plants and improve crop productivity. Stress responses, in plants or animals, most often involve the activation stress-signaling pathways. One pathway is mediated by a group of bioactive lipid molecules, N-acylethanolamines (NAEs), and is highly conserved among eukaryotes. NAEs are composed mainly of amides of ethanolamine and fatty acids. In model Arabidopsis thaliana (At), NAEs inhibit germination and growth in seedlings via abscisic-dependent and independent mechanisms aimed at stress regulation. This work focuses on identifying the NAE pathway in the moss, Physcomitrella patens (P. patens), that shows higher resistant to stress than At and consequently the role played by NAE metabolites in the development of P. patens. Mosses are small seedless and fruitless early plants that have evolved successful mechanisms of surviving prolonged stresses during their transition from aquatic life to land. Previous studies have shown that P. patens is tolerant to high temperature, salinity and osmotic shock, to which most plants are fragile. I hypothesize that the NAE pathway is present in P. patens and that it plays a significant role in its development. NAE composition and metabolizing enzymes like FAAH and NAPE synthase will be measured to ascertain NAE pathway in P. patens. Further quantification of NAE content and composition during development will identify the key developmental time points that are associated with high metabolite levels. Total lipids will be extracted in triplicates from twelve tissue samples harvested at protonema stage; mature gametophyte stage which is subdivided into leafy tissue and rhizoids; antheridia and archegonia stage; zygotic stage and the mature and germinating developmental stages. The high lipid content of the mature spores was previously associated with extreme longevity in ephemeral habitats. It would be of interest to determine if such an association exists with NAE metabolite content. Key time points will then be used to determine the effect of exogenous NAE 12:0. Preliminary analysis shows that P. patens have higher levels of NAEs than other plants examined. Furthermore, fatty acid amide hydrolases (FAAH) that hydrolyses NAEs were identified in silico. Putative PpFAAH1 candidate showed 95 % homology with previously characterized AtFAAH in At. These results show the occurrence of NAEs in P. patens and a possible enzyme for its hydrolysis. Further confirmation of the NAE pathway in P. patens will be done by in silico identification of the precursor enzyme NAPE synthase. Understanding how P. patens tolerates stress using NAEs pathways by identifying key time points in its development will help other researchers know which specific NAEs affect the growth of P. patens and will facilitate the characterization of metabolic enzymes at specific times.

Location

Johnson City, TN

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