ARS | Publication request: Identification of distinct functions of Wheat streak mosaic virus coat protein in virion assembly and virus movement

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: May 30, 2012
Publication Date: June 1, 2012
Citation: Tatineni, S., French, R.C. 2012. Identification of distinct functions of Wheat streak mosaic virus coat protein in virion assembly and virus movement. Phytopathology. 112: S4.118.

Technical Abstract: Wheat streak mosaic virus (WSMV) is the type member of Tritimovirus genus of the family Potyviridae. The WSMV coat protein (CP) was subjected to point and deletion mutation analyses. WSMV mutants changing aspartic acid residues at amino acid (aa) positions 289, 290, 326, 333, and 334 to alanine elicited mild to moderate symptoms on wheat, but failed to infect SDp2 corn. Mutants with W165A, D216A, R237A, D282A, and D331A in CP did not infect wheat systemically, suggesting that these aa are required for virion assembly and/or virus transport. WSMV with a C-terminal 14 aa deletion infected wheat systemically with a slight delay in symptom onset. In contrast, deletion of 6-27 aa at the N-terminal region resulted in a fewer chlorotic streaks, suggesting that the N-terminal region of CP is required for efficient long-distance transport. Surprisingly, deletions consisting of three individual SGSGS amino acid repeats, all three SGSGS repeats (aa position 36-57), and 27 aa residues comprising 58-84 aa positions infected wheat similar to wild-type virus. WSMV with a deletion of 49 aa residues (aa positions 36-84) infected wheat systemically with slightly reduced symptoms. Taken together, our data suggest that the C-terminal 14 aa residues and 49 aa residues (position 36-84) are dispensable for virion assembly and virus transport in wheat. However, the N-terminal amino acids are required for efficient long-distance transport, but not for cell-to-cell movement of the virus.