Lessons From 12,000 Years Of Wheat Evolution Under Domestication

The evolution of wheat is a tale of speciation through hybridization and polyploidization, followed by man-driven selection (domestication).  We consider domestication as an experiment in evolution that has been running for the past ~12,000 years, and we are asking how this process has affected the genetic makeup of wheat.  We have analyzed trancripts and metabolites in a collection of 48 lines representing four stages in tetraploid wheat evolution:  Wild lines (dicoccoides), primitive domestic lines (dicoccum), whose spike is non-fragile but are hard to thresh and have only 2 grains in each spikelet, durum landraces (traditional free threshing lines) and modern varieties developed after the green revolution (in the past ~40 years). The analysis presented in this lecture provides insight into aspects of productivity, such as upregulation of genes related to carbon metabolism in modern wheat, major changes in the past 12,000 years, in the composition of small molecules in the grains of wheat that are related to nutrition or resistance to biotic and abiotic stresses, as well as changes in the composition and digestibility of straw – a potential feedstock for biofuel.