The non-canonical tomato yellow leaf curl virus recombinant that displaced its parental viruses in Southern Morocco exhibits a high selective advantage in experimental conditions

Belabess Zineb, Peterschmitt Michel, Granier Martine, Tahiri Abdessalem, Blenzar Abdelali, Urbino Cica. 2016. The non-canonical tomato yellow leaf curl virus recombinant that displaced its parental viruses in Southern Morocco exhibits a high selective advantage in experimental conditions. Journal of General Virology, 97 (12) : 3433-3445.

https://doi.org/10.1099/jgv.0.000633

Article de revue ; Article de recherche ; Article de revue à facteur d'impact

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Quartile : Q2, Sujet : BIOTECHNOLOGY & APPLIED MICROBIOLOGY / Quartile : Q2, Sujet : VIROLOGY

Résumé : Recombination events are frequently inferred from the increasing number of sequenced viral genomes, but their impact on natural viral populations has rarely been evidenced. TYLCV-IS76 is a recombinant (Begomovirus,Geminiviridae) between the Israel strain of tomato yellow leaf curl virus (TYLCV-IL) and the Spanish strain of tomato yellow leaf curl Sardinia virus (TYLCSV-ES) that was generated most probably in the late 1990s in southern Morocco (Souss). Its emergence in the 2000s coincided with the increasing use of resistant tomato cultivars bearing the Ty-1 gene, and led eventually to the entire displacement of both parental viruses in the Souss. Here, we provide compelling evidence that this viral population shift was associated with selection of TYLCV-IS76 viruses in tomato plants and particularly in Ty-1-bearing cultivars. Real-time quantitative PCR (qPCR) monitoring revealed that TYLCV-IS76 DNA accumulation in Ty-1-bearing plants was significantly higher than that of representatives of the parental virus species in single infection or competition assays. This advantage of the recombinant in Ty-1-bearing plants was not associated with a fitness cost in a susceptible, nearly isogenic, cultivar. In competition assays in the resistant cultivar, the DNA accumulation of the TYLCV-IL clone – the parent less affected by the Ty-1 gene in single infection – dropped below the qPCR detection level at 120 days post-infection (p.i.) and below the whitefly vector (Bemisia tabaci) transmissibility level at 60 days p.i. The molecular basis of the selective advantage of TYLCV-IS76 is discussed in relation to its non-canonical recombination pattern, and the RNA-dependent RNA polymerase encoded by the Ty-1 gene.

Mots-clés Agrovoc : géminivirus enroulement jaune tomat, résistance génétique, recombinaison, PCR, ADN recombiné, Solanum lycopersicum, virus des végétaux, begomovirus

Mots-clés géographiques Agrovoc : Maroc, France

Mots-clés complémentaires : Tomato yellow leaf curl virus, Émergence

Mots-clés libres : Begomovirus, Resistance gene, Fitness, Émergence, Real-time PCR, Competition

Classification Agris : H20 - Maladies des plantes

Champ stratégique Cirad : Axe 4 (2014-2018) - Santé des animaux et des plantes

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