Journal of General Virology (2007) 88, 2611-2618

Hajime Yaegashi, Masamichi Isogai, Hiroko Tajima, Teruo Sano and Nobuyuki Yoshikawa (2007)
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
Journal of General Virology 88 (9), 2611-2618
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 (Ala⁴⁰-Val⁵⁹-Phe⁷⁵-Ser¹³⁰-Met¹⁸⁴ or Ser⁴⁰-Leu⁵⁹-Tyr⁷⁵-Thr¹³⁰-Leu¹⁸⁴) were highly conserved within each cluster. Site-directed mutagenesis using an infectious cDNA clone of ACLSV indicated that the combinations of two amino acids (Ala⁴⁰ and Phe⁷⁵ or Ser⁴⁰ and Tyr⁷⁵) are necessary for infectivity to Chenopodium quinoa plants by mechanical inoculation. Moreover, an agroinoculation assay indicated that the substitution of a single amino acid (Ala⁴⁰ to Ser⁴⁰ or Phe⁷⁵ to Tyr⁷⁵) 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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Database assignments for author(s): Nobuyuki Yoshikawa, Teruo Sano, Masamichi Isogai

Research topic(s) for pests/diseases/weeds:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Apple chlorotic leaf spot virus