Frequency-dependent assistance as a way out of competitive exclusion between two strains of an emerging virus

Péréfarres Frédéric, Thébaud Gaël, Lefeuvre Pierre, Chiroleu Frédéric, Rimbaud Loup, Hoareau Murielle, Reynaud Bernard, Lett Jean-Michel. 2014. Frequency-dependent assistance as a way out of competitive exclusion between two strains of an emerging virus. Proceedings - Royal Society. Biological Sciences, 281 (1781), 9 p.

https://doi.org/10.1098/rspb.2013.3374

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Quartile : Q1, Sujet : BIOLOGY / Quartile : Q1, Sujet : ECOLOGY / Quartile : Q1, Sujet : EVOLUTIONARY BIOLOGY

Liste HCERES des revues (en SHS) : oui

Thème(s) HCERES des revues (en SHS) : Psychologie-éthologie-ergonomie

Résumé : Biological invasions are the main causes of emerging viral diseases and they favour the co-occurrence of multiple species or strains in the same environment. Depending on the nature of the interaction, co-occurrence can lead to competitive exclusion or coexistence. The successive fortuitous introductions of two strains of Tomato yellow leaf curl virus (TYLCV-Mld and TYLCV-IL) in Réunion Island provided an ideal opportunity to study the invasion of, and competition between, these worldwide emerging pathogens. During a 7-year field survey, we observed a displacement of the resident TYLCV-Mld by the newcomer TYLCV-IL, with TYLCV-Mld remaining mostly in co-infected plants. To understand the factors associated with this partial displacement, biological traits related to fitness were measured. The better ecological aptitude of TYLCV-IL in single infections was demonstrated, which explains its rapid spread. However, we demonstrate that the relative fitness of virus strains can drastically change between single infections and co-infections. An epidemiological model parametrized with our experimental data predicts that the two strains will coexist in the long run through assistance by the fitter strain. This rare case of unilateral facilitation between two pathogens leads to frequency-dependent selection and maintenance of the less fit strain.

Mots-clés Agrovoc : virus des végétaux, interactions biologiques, compétition biologique, épidémiologie, modèle mathématique, Enquête pathologique, espèce envahissante

Mots-clés géographiques Agrovoc : La Réunion, France

Mots-clés complémentaires : Tomato yellow leaf curl virus

Classification Agris : H20 - Maladies des plantes
F30 - Génétique et amélioration des plantes

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

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