Format: ORAL

Shawn K. Thomas1,2,Craig A. Schenck3, Jacob D. Washburn4, J. Chris Pires5

1 Division of Biological Sciences, University of Missouri, Columbia, USA 2 Bioinformatics and Analytics Core, University of Missouri, Columbia, USA 3 Department of Biochemistry, University of Missouri, Columbia, USA 4 Plant Genetics Research Unit, USDA-ARS, Columbia, USA 5 Department of Soil and Crop Sciences, Colorado State University, Fort Collins, USA

Gene duplications are one mechanism that provides raw material for the emergence of novel traits. The two major mechanisms for duplicating genes are polyploidy events resulting in whole genome duplications/triplications (WGD, WGT) and small-scale duplications (SSD). The combination of these is an important force in plant evolution. Mustard crops like bok choy, broccoli, cabbage, and canola among others (Brassica) share a relatively recent WGT. Duplicated genes from this WGT have been shown to influence patterns of domestication and phenotypic plasticity in mustard crops. However, it is unclear when and where on the mustard phylogeny this event has occurred. In this study we combine sequence and fossil data to both date and place this WGT event on the mustard phylogeny. Further we explore how gene/genome duplications influence the abiotic stress tolerance of a crop wild relative of mustard crops that shares this WGT. Using a combination of ionomics, metabolomics, and comparative genomics, we characterize aspects of salt stress response in Cakile maritima and identify retained duplicate genes that have likely enabled adaptation to salt and mild levels of cadmium. These findings help to phylogenetically localize and date this WGT. In addition, we demonstrate the power of using crop wild relatives as they can provide understanding of the evolution of environmental adaptation and genetic targets/tools for developing resilient crops in the face of global/climate change.