Format: ORAL

Michael R. McKain1, Fae D. Bramblepelt1, Roger Cain2, and Michael Fedoroff3

1 Department of Biological Sciences, The University of Alabama, Tuscaloosa, Alabama, USA 2 Office of Environmental Services and Historic Preservation, United Keetoowah Band of Cherokee Indians, Tahlequah, Oklahoma, USA 3 Alabama Water Institute, The University of Alabama, Tuscaloosa, Alabama, USA

Giant rivercane (Arundinaria gigantea (Walter) Muhl., Poaceae) is a woody bamboo species native to the eastern United States. Prior to European colonization, large stands of giant river canecalled canebrakesformed unique ecosystems across the Southeast. However, these ecosystems have undergone significant reduction, diminishing to a mere fraction of their original size. This decline has resulted in the dwindling or extinction of multiple species that depended on canebrakes for survival. Moreover, giant river cane holds considerable significance in the cultural practices of numerous Indigenous Peoples, making it both a cultural and ecological keystone species. As a member of the tribe Arundinarieae, Arundinaria shares a polyploidy event with other temperate woody bamboo species and is part of a complex subgenomic history associated with multiple polyploid events and reticulate evolution across the bamboos. In this study, we present the first chromosome-scaffolded genome of Arundinaria gigantea. Using this genome and other available bamboo genomes, we characterize variation in how shared and different polyploid events have diploidized in the bamboos. We consider patterns of transposon diversity, retention of paralogs, differences in post-polyploid tandem gene duplications, structural changes, and homoeologous exchange, and examine how they influence overall subgenome contribution to genes associated with potentially adaptive phenotypes. Given the uniquely high discrepancy across bamboos for flowering cycle times, we focus on genes identified through transcriptomes generated from floral and fruit tissue taken at various developmental stages to investigate how these genes have evolved across different bamboo lineages. Finally, we discuss the future of how the Arundinaria genome will be used to assess genotypic and phenotypic diversity across populations of giant river cane in efforts to restore these lost ecosystems and promote the protection of threatened species and Indigenous cultural practices.