This is the first large-scale proteomic data for barnyardgrass among the weeds in the crop fields.

Ecological fitness costs are associated with multiple-herbicide resistance in barnyardgrass.

Photosynthesis-related proteins are found to be down-accumulated in the resistant biotypes of barnyardgrass.

Protein species involved in plant defense are found to be up-accumulated in the resistant biotypes of barnyardgrass.