Using genomic analysis to identify tomato Tm-2 resistance-breaking mutations and their underlying evolutionary path in a new and emerging tobamovirus.
Arch Virol
; 163(7): 1863-1875, 2018 Jul.
Article
em En
| MEDLINE
| ID: mdl-29582165
ABSTRACT
In September 2014, a new tobamovirus was discovered in Israel that was able to break Tm-2-mediated resistance in tomato that had lasted 55 years. The virus was isolated, and sequencing of its genome showed it to be tomato brown rugose fruit virus (ToBRFV), a new tobamovirus recently identified in Jordan. Previous studies on mutant viruses that cause resistance breaking, including Tm-2-mediated resistance, demonstrated that this phenotype had resulted from only a few mutations. Identification of important residues in resistance breakers is hindered by significant background variation, with 9-15% variability in the genomic sequences of known isolates. To understand the evolutionary path leading to the emergence of this resistance breaker, we performed a comprehensive phylogenetic analysis and genomic comparison of different tobamoviruses, followed by molecular modeling of the viral helicase. The phylogenetic location of the resistance-breaking genes was found to be among host-shifting clades, and this, together with the observation of a relatively low mutation rate, suggests that a host shift contributed to the emergence of this new virus. Our comparative genomic analysis identified twelve potential resistance-breaking mutations in the viral movement protein (MP), the primary target of the related Tm-2 resistance, and nine in its replicase. Finally, molecular modeling of the helicase enabled the identification of three additional potential resistance-breaking mutations.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Virais
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Tobamovirus
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Evolução Molecular
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Genômica
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Mutação
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article