Molecular epidemiology of cassava mosaic disease in Madagascar

Harimalala Mireille Aurélie, Chiroleu Frédéric, Giraud-Carrier Charlotte, Hoareau Marie Murielle, Zinga Innocent, Randriamampianina Jean Augustin, Velombola S., Ranomenjanahary Sahondramalala, Andrianjaka Alice, Reynaud Bernard, Lefeuvre Pierre, Lett Jean-Michel. 2015. Molecular epidemiology of cassava mosaic disease in Madagascar. Plant Pathology, 64 (3) : 501-507.

https://doi.org/10.1111/ppa.12277

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Quartile : Q1, Sujet : AGRONOMY / Quartile : Q2, Sujet : PLANT SCIENCES

Résumé : Cassava is the staple food for hundreds of millions of people in Africa but its cultivation is seriously constrained by cassava mosaic disease (CMD) in Madagascar, and in Africa in general. This study identified the cassava mosaic geminiviruses (CMGs) involved in CMD in Madagascar and their associated epidemiological characteristics from countrywide surveys. Molecular characterization of CMGs in Madagascar revealed an unprecedented diversity and co-occurrence of six viruses: African cassava mosaic virus (ACMV), East African cassava mosaic Cameroon virus (EACMCV), East African cassava mosaic Kenya virus (EACMKV), East African cassava mosaic virus (EACMV), South African cassava mosaic virus (SACMV) and the recently described Cassava mosaic Madagascar virus (CMMGV). Distinct geographical distributions were observed for the six viruses. While ACMV was more prevalent in the central highlands, EACMV and EACMKV were prevalent in lowlands and coastal regions. Both EACMCV and SACMV occurred in almost all the localities visited. PCR diagnosis revealed that mixed infection (up to four co-infected viruses) occurred in 21% of the samples and were associated with higher symptom severity scores. Pairwise comparisons of virus associations showed that EACMCV was found in mixed infections more often than expected while ACMV and SACMV were mostly found in single infections. A greater abundance of whiteflies was observed in lowland and coastal areas. Nevertheless, infected cuttings remain the primary source of CMD propagation (95%) in Madagascar.

Mots-clés Agrovoc : virus des végétaux, Manihot esculenta, Geminiviridae, épidémiologie, diagnostic, biologie moléculaire, PCR, distribution géographique, virus mosaïque manioc

Mots-clés géographiques Agrovoc : Madagascar

Mots-clés complémentaires : Virus de la mosaïque africaine du manioc

Classification Agris : H20 - Maladies des plantes
U30 - Méthodes de recherche

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

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