Main content area

The c-terminus of wheat streak mosaic virus coat protein is involved in differential infection of wheat and maize through host-specific long-distance transport

Tatineni, Satyanarayana, French, Roy
Molecular plant-microbe interactions 2014 v.27 pp. 150
RNA, Triticum aestivum, Wheat streak mosaic virus, Zea mays, aspartic acid, coat proteins, corn, host range, host specificity, host-pathogen relationships, mutants, mutation, signs and symptoms (plants), structure-activity relationships, wheat
Multifunctional viral coat proteins (CPs) play important roles in the virus life-cycle. The CP determinants and mechanisms involved in extension of host range of monocot-infecting viruses are poorly understood. The role of the C-terminal region of Wheat streak mosaic virus (WSMV) CP in virus transport was examined by mutating six negatively charged aspartic acid residues at positions 216, 289, 290, 326, 333 and 334. All of these amino acid residues are dispensable for virion assembly, and aspartic acid residues at positions 216, 333 and 334 are expendable for normal infection of wheat and corn. However, mutants D289N, D289A, D290A, DD289/90NA and D326A exhibited slow cell-to-cell movement in wheat, which resulted in delayed onset of systemic infection, followed by a rapid recovery of genomic RNA accumulation and symptom development. Mutants D289N, D289A and D326A inefficiently infected corn with mild symptoms, while D290A and DD289/90NA failed to infect systemically, suggesting that the C-terminus of CP is involved in extension of virus host range. Mutation of aspartic acid residues at amino acid positions 289, 290 and 326 severely debilitated virus ingress into the vascular system of corn but not wheat, suggesting that these amino acids are involved in extension of WSMV host range through host-specific long-distance transport.