Endophytic Fungi for Biological Control, Plant Performance Enhancement, and Sources of New Compounds for Agricultural and Human Health Project Number 12148 Starting 01/15/2008 Ending 01/14/2013
	Description: OBJECTIVES: In this project we will explore endophtes and their secondary metabolite products in a broad range of plants that have not yet been explored for these symbionts; and we will evaluate the roles of reactive oxygen species and secondary metabolites in the hypha-plant cell interactions in the clavicipitacious endophyte-grass symbiosis. Endophytes frequently appear to function as defensive mutualists to their grass hosts. Much of the work of this proposal is targeted at identifying the defensive secondary metabolites and evaluating their utility as biorationals for agricultural applications in insect or microbial pathogen control and for medicinal applications. We will also seek to develop a more complete understanding of the ecology and physiological interactions of endosymbiotic fungi and their host plants. Specific objectives of this research are as follows: 1) Conduct studies to examine the effects of endophyte-produced reactive oxygen species (ROS) and secondary metabolites and test the hypothesis that these endophyte products play key roles in nutrient acquisition by endophytic mycelium from host cells and secondarily enhance performance of plants in enhancing disease resistance and stress tolerance in general; 2) Identify plants that naturally host epibionts and endophytes. Research on endophytes and epibionts in the fungal family Clavicipitaceae suggests that both epiphytes and endophytes are potentially valuable as producers of secondary metabolites. We intend to begin collection and screening of epibionts in the next period of this project; 3) Continue development of the strain collection library for natural product screening and agricultural applications; 4) Culture fungi on a range of media (including those containing known elicitors and screen extracts for bioactivity in program screens (Rutgers University and partner countries) and in collaboration with industrial partners; 5) Pursue scientific outputs using sampling and data-mining strategies employing the NAPIS database, including descriptions of new species, testing of the hypothesis that bioactive endophytes are encountered more frequently in plants in favorable habitats, and testing of the hypothesis that epiphytes of specific plant tissues rich in plant nutrients (e.g., meristems) are also rich as sources of bioactive metabolites. The nutritional abundance hypothesis predicts that endophytes or epibionts in or on plant tissues where they are exposed to abundant nutrients expend more energy in production of secondary metabolites. APPROACH: Surveys of plants for endophytes and epibionts in several natural vegetation regions will be conducted through use of the grow out technique to assess for the presence of the symbiotic fungi. Comparative studies will be conducted and should permit us to increase support for either the secondary metabolite fungal disease defense mechanism or the ROS fungal defense mechanism. Many of the secondary metabolites produced by endophytes are alkaloids. The ergot alkaloids have been shown using animal cell systems to affect electric potentials of cells by inhibiting the proton pumping system in cell membranes. We intend to evaluate whether alkaloids are affecting plant cell membrane electric potentials using the fluorescent dyes as a probes to detect membrane potential variations. These studies will permit us to test the hypothesis that endophyte-produced secondary metabolites function, at least in part, as modifiers of host cell physiology to permit acquisition of nutrients by endophytes from the closely associated host cells through a membrane depolarization mechanism resulting in increased leakage of nutrients from plant cells.
	Impact Statement: All plants maintain associations with fungal endophytes and epibionts. These associations between fungi and plants are generally a cryptic phenomenon in nature. Fungal endophytes may inhabit tissues of roots, stems, branches, twigs, bark, leaves, petioles, flowers, fruit, and seeds, including xylem of all available plant organs. These fungi have been found to impact on the ecology of plants, frequently enhancing capacity of host plants to survive and resist environmental and biological stresses through mechanisms that are only partially understood. In this project we will explore endophtes and their secondary metabolite products in a broad range of plants that have not yet been explored for these symbionts; and we will evaluate the roles of reactive oxygen species and secondary metabolites in the hypha-plant cell interactions in the clavicipitacious endophyte-grass symbiosis. Endophytes frequently appear to function as defensive mutualists to their grass hosts helping plants to survive drought, insect attack or pathogen infections. Much of the work of this proposal is targeted at identifying the defensive secondary metabolites and evaluating their utility as biorationals for agricultural applications in insect or microbial pathogen control and for medicinal applications. We will also seek to develop a more complete understanding of the ecology and physiological interactions of endosymbiotic fungi and their host plants. This research will directly impact New Jersey stakeholders in that our model system for examining the endophyte-plant interaction are the grass endophytes that are present in many turfgrasses. One of the key ecological outcomes of endophytes in turfgrasses is enhanced disease resistance. We will seek to understand the mechanism of disease resistance enhancement. Because the turfgrass industry is important in New Jersey and the United States this research has the potential to develop information that may be useful in producing more disease resistant turf cultivars and have a positive impact in the industry.