SG: Linking above and belowground interactions in highbush blueberry.

University Of Vermont & State Agricultural College, Burlington VT

Investigators

Abstract

Over 80% of all terrestrial plants form close relationships with soil-dwelling fungi called mycorrhizae (mycor, "fungus" and rhizae, "roots"). These fungi garner nutrients from the soil and exchange them for carbohydrates obtained by plants during photosynthesis. The vast majority of these plants also rely on animals for pollination. Plant interactions with these mutualists may be intertwined in important ways, but have most often been studied separately. This research will examine how mycorrhizal fungi affect plant traits important to pollination, and how the environmental context affects these interactions. These questions will be examined in an agricultural species of great economic importance in the United States - the highbush blueberry (Vaccinium corymbosum). Additionally, through existing farm-to-plate programs, relationships with K-12 teachers, and new collaborations with an agricultural outreach program, school children will be engaged in activities to learn about the importance of healthy below- and above-ground organisms, and high school and college students will be engaged in scientific research. The project will examine if mycorrhizae affect floral traits important to pollinators in host genotype-specific ways. Additionally, the identity and relative abundance of mycorrhizae will be examined for effects on floral trait expression in the host. Mycorrhizal-driven differences in floral traits will be explored for their effects on pollinator visitation and resulting pollen limitation. The links among mycorrhizae, floral traits, and pollination are hypothesized to depend on pollinator abundance, diversity, and identity. The work will capitalize on state-of-the-art molecular tools to understand if plant response to mycorrhizal fungi is dependent on the identity of fungal communities, and entail extensive field experiments to understand the importance of the native pollinator communities as well. To examine these hypotheses, highbush blueberry of two different cultivars (genotypes) will be inoculated with a commercially available inoculum or with soils containing native fungal spores and grown in pots in a common garden. Once they flower, plants will be placed at six farms in Vermont alongside existing blueberry bushes. Floral traits will be measured on each plant. In addition, a pollen limitation experiment will be conducted to examine if mycorrhizal inoculation affects pollen limitation. Experimental plants, as well as others growing at each site, will be observed and the number and identity of bee pollinators will be recorded to assess site-specific differences in pollinator communities. The data will be gathered over three years, analyzed and widely distributed to scientists and to farmers. 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.