Combinations of two amino acids (Ala40 and Phe75 or Ser40 and Tyr75) in the coat protein of apple chlorotic leaf spot virus are crucial for infectivity.
J Gen Virol
; 88(Pt 9): 2611-2618, 2007 Sep.
Article
em En
| MEDLINE
| ID: mdl-17698674
ABSTRACT
Amino acid sequences of apple chlorotic leaf spot virus (ACLSV) coat protein (CP) were compared between 12 isolates from apple, plum and cherry, and 109 cDNA clones that were amplified directly from infected apple tissues. Phylogenetic analysis based on the amino acid sequences of CP showed that the isolates and cDNA clones were separated into two major clusters in which the combinations of the five amino acids at positions 40, 59, 75, 130 and 184 (Ala(40)-Val(59)-Phe(75)-Ser(130)-Met(184) or Ser(40)-Leu(59)-Tyr(75)-Thr(130)-Leu(184)) were highly conserved within each cluster. Site-directed mutagenesis using an infectious cDNA clone of ACLSV indicated that the combinations of two amino acids (Ala(40) and Phe(75) or Ser(40) and Tyr(75)) are necessary for infectivity to Chenopodium quinoa plants by mechanical inoculation. Moreover, an agroinoculation assay indicated that the substitution of a single amino acid (Ala(40) to Ser(40) or Phe(75) to Tyr(75)) resulted in extreme reduction in the accumulation of viral genomic RNA, double-stranded RNAs and viral proteins (movement protein and CP) in infiltrated tissues, suggesting that the combinations of the two amino acids at positions 40 and 75 are important for effective replication in host plant cells.
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Base de dados:
MEDLINE
Assunto principal:
Fenilalanina
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Doenças das Plantas
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Serina
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Tirosina
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Folhas de Planta
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Alanina
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Flexiviridae
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article