Citation: Tatineni, S., Kovacs, F., French, R.C. 2014. Wheat streak mosaic virus infects systemically despite extensive coat protein deletions: identification of virion assembly and cell-to-cell movement determinants. Journal of Virology. 88:1366-1380. Interpretive Summary: Wheat streak mosaic virus (WSMV) is the most economically important wheat virus in the Great Plains region. Previous investigations have developed resistance against WSMV based on host-plant expression of coat protein gene. Viral coat proteins have multiple roles in the life-cycles of viruses. Understanding the roles of coat protein in the virus life-cycle could provide important clues in identifying vulnerable sites in the disease cycle that can be used for the development of new management strategies. In this study, we found that WSMV is able to cause disease in wheat with shorter versions of coat protein. In addition, the coat protein regions that are required for virus to spread in wheat and form virus particles were identified. WSMV is able to infect wheat even when missing 30% of amino acids from its coat protein. The availability of WSMV mutants with shorter versions of coat protein will facilitate defining the roles of coat protein in wheat curl mite transmission and disease development. These results indicate that developing resistance based on viral coat protein antagonism should proceed with caution as such resistance will likely be overcome by WSMV after deployment to the field.