Yang, S., Li, X., Ma, Y., Sun, X., Yang, Y. and Yang, Y. 2015. Proteome response of wild wheat relative Kengyilia thoroldiana to drought stress. Can. J. Plant Sci. 95: 237-249. Wild relatives of crops provide plant breeders with a broad pool of potentially useful genetic sources. The genus Kengyilia, being a member of the tribe Triticeae, is related to wheat, barley, and other cereals and forage grasses. We studied proteomic changes in K. thoroldiana seedlings in response to drought stress after withholding water for 0, 3, 6, 9 and 15 d. To determine the proteomic changes that occurred in leaves of K. thoroldiana under drought stress, two-dimensional gel electrophoresis (2-DE) and mass spectrometry were performed to identify protein expression changes. Seventy proteins showing reproducible and significant expression changes were identified. Among them, 28 proteins were up-regulated, whereas seven proteins were down-regulated. Based on database-annotated functions, these 70 proteins were categorized as energy metabolism, stress response, antioxidative enzyme, transcript and signal transduction, predicted proteins, and chloroplast-related proteins. Cluster analysis further showed that the up-regulated proteins were mainly stress response proteins and antioxidative enzymes. These results suggest that K. thoroldiana may resist drought stress by increasing the expression of stress response proteins and by producing antioxidative enzymes to remove reactive oxygen species. We conclude that the K. thoroldiana drought stress response mechanism could represent a useful genetic resource for related studies in wheat.