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Dissecting Functions of the Turnip yellows virus Suppressor of RNA Silencing P0 in Evasion and Elicitation of Plant Defenses
Author(s) -
Dughbaj Mansour,
Valdez Kevin,
Wang KenDer,
Nguyen Tan Tri,
Oza Shyamal Vishnu,
Sacco Melanie Ann
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1143.3
Subject(s) - nicotiana benthamiana , biology , hypersensitive response , rna silencing , gene silencing , mutant , rna interference , rna , amino acid , genetics , microbiology and biotechnology , virus , gene , plant disease resistance
The Turnip yellows virus (TuYV) protein P0 (P0 Tu ) is a viral suppressor of RNA silencing (VSR) that targets Argonaute (AGO) proteins for degradation. P0 Tu is also recognized in Nicotiana glutinosa accession TW59, in which it elicits hypersensitive response (HR) and resistance to TuYV. We are interested in understanding how P0 Tu interacts with the host plant cell as a VSR versus an elicitor of HR. To identify amino acids that are critical for these activities, P0 Tu has been subjected to serial deletion analysis and site‐directed mutagenesis at either several conserved sites or by systematic substitutions with the 6 amino acid sequence NAAIRS along the entire length of the coding sequence. We predicted that the modifications could potentially cause loss of VSR activity in Nicotiana benthamiana and/or loss of HR activation in N. glutinosa to dissect these two functions. Mutant clones were co‐infiltrated with GFP into the leaves of N. glutinosa accession TW59 and N. benthamiana to observe for suppression of RNA silencing and induction of cell death. Substitution of two conserved central arginine residues with lysine caused P0 Tu to activate more rapid and robust HRs on N. glutinosa . Deletion or mutation of the amino terminus inactivated P0 Tu , while modifications within or deletion of the last 22 carboxy‐terminal amino acid residues (227–249) resulted in mutants that maintained VSR activity, but had impaired ability to elicit HR on N. glutinosa , suggesting that P0 activities in suppression of silencing and elicitation of HR may be distinct. Support or Funding Information National Science Foundation (NSF) Grant #1122256 to M. A. Sacco.