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Pathogenicity of Alternanthera mosaic virus is affected by determinants in RNA-dependent RNA polymerase and by reduced efficacy of silencing suppression in a movement-competent TGB1.
- Source :
-
The Journal of general virology [J Gen Virol] 2010 Jan; Vol. 91 (Pt 1), pp. 277-87. - Publication Year :
- 2010
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Abstract
- Four biologically active cDNA clones were derived from the Alternanthera mosaic virus (AltMV; genus Potexvirus) isolate, AltMV-SP, which differ in symptoms in infected Nicotiana benthamiana plants. Two clones induced necrosis and plant death; a mixture of all four clones induced milder symptoms than AltMV-SP. Replication of all clones was enhanced by a minimum of fourfold at 15 degrees C. A mixture of clones 4-7 (severe) and 3-1 (mild) was indistinguishable from AltMV-SP, but the ratio of 4-7 to 3-1 differed at 25 and 15 degrees C. RNA copy numbers of mixed infections were always below those of 4-7 alone. Determinants of symptom severity were identified in both Pol and TGB1; the mildest (4-1) and most severe (3-7) clones differed at three residues in the 'core' Pol domain [R(1110)P, K(1121)R, R(1255)K] and one [S(1535)P] in the C-terminal Pol domain of RNA-dependent RNA polymerase, and one in TGB1 [P(88)L]. Pol [P(1110),R(1121),K(1255)]+TGB1(L(88))] always induced systemic necrosis at 15 degrees C. Gene exchanges of Pol and TGB1 each affected replication and symptom expression, with TGB1(P(88)) significantly reducing silencing suppression. The difference in silencing suppression between TGB1(P(88)) and TGB1(L(88)) was confirmed by an agroinfiltration assay. Further, co-expression of TGB1(P(88)) and TGB1(L(88)) resulted in interference in the suppression of silencing by TGB1(L(88)). Yeast two-hybrid analysis confirmed that TGB1(P(88)) and TGB1(L(88)) interact. These results identify a TGB1 residue that significantly affects replication and silencing suppression, but maintains full movement functions.
- Subjects :
- Amino Acid Sequence
Amino Acid Substitution genetics
DNA Mutational Analysis
Gene Silencing
Molecular Sequence Data
Mutation, Missense
Potexvirus growth & development
Protein Interaction Mapping
RNA-Dependent RNA Polymerase genetics
Recombination, Genetic
Sequence Alignment
Sequence Analysis, DNA
Suppression, Genetic
Temperature
Two-Hybrid System Techniques
Viral Proteins genetics
Virulence Factors genetics
Virus Replication
Plant Diseases virology
Potexvirus pathogenicity
RNA-Dependent RNA Polymerase metabolism
Nicotiana virology
Viral Proteins metabolism
Virulence Factors metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1465-2099
- Volume :
- 91
- Issue :
- Pt 1
- Database :
- MEDLINE
- Journal :
- The Journal of general virology
- Publication Type :
- Academic Journal
- Accession number :
- 20019006
- Full Text :
- https://doi.org/10.1099/vir.0.014977-0