OCE-PRF: Sink or swim: how have transitions between land and sea affected the evolution and ecology of plant-fungal associations?

University Of California-Riverside, Riverside CA

Investigators

Abstract

Seagrasses are marine plants and powerhouses in coastal ecosystems globally. Sometimes referred to as the “whales of the plant world”, seagrasses evolved from a land plant ancestor that invaded and then adapted to the sea. On land, fungi are known to be plant friends and foes. In fact, fungal friendships were critical to the successful movement of plants onto land. However, little is known about the roles of fungi in the ocean or when associated with marine plants. The proposed work will increase knowledge of marine fungal biology and marine plant-fungal interactions. With goals including the perspectives of both plant and fungal partners, this work may also inform seagrass restoration efforts. Undergraduate interns from groups underrepresented in STEM will be mentored throughout this work and encouraged to undertake their own related research projects. Experimental results and core topics related to this work will be adapted for Frontiers for Young Minds, an open-access journal read and reviewed by kids. The goals of this project are to use publicly available data, culture-dependent and culture-independent methods (1) to assess the evolutionary history and genetic potential of seagrasses to form associations with arbuscular mycorrhizal fungi (AMF), a group of fungi important for the movement of plants onto land, (2) to characterize the phenotypic and functional diversity of previously cultured seagrass-associated fungi, and (3) to compare the genomes of seagrass-associated fungi to those of terrestrial relatives to identify adaptations related to land to sea transitions and predict their ecological roles when associated with seagrasses. The genome and transcriptomes of seagrasses and close relatives will be searched for genes required to form AMF associations and then placed in a phylogenetic context. Experiments will measure the tolerance of seagrass fungal isolates (from an in-hand isolate collection) to a range of conditions that mimic marine stresses. Transcriptomic analyses will be used to identify genes correlated with stress tolerance that may relate to living in the ocean and which may also play a role in alleviation of phytotoxins during symbiosis. Finally, genomes and metagenome-assembled genomes will be placed into the fungal tree of life and then compared with each other and with the genomes of close land relatives obtained from public databases to reveal insights into their ecology. Fungi were critical for the movement of plants onto land and understanding how a shift back into the marine ecosystem may have affected plant-fungal relationships could be transformative for our understanding of the evolution, ecology, and maintenance of fungal symbioses. 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.