Cryptic species and population genetic structure of Plasmopara viticola in Sao Paulo State, Brazil

Autor(es)

Camargo, M. P. ^[1] ; Hong, C. F. ^[2] ; Amorim, L. ^[1] ; Scherm, H. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Escola Super Luiz de Queiroz, Dept Plant Pathol, BR-13418900 Piracicaba, SP - Brazil

^[2] Univ Georgia, Dept Plant Pathol, Athens, GA 30602 - USA

• Tipo de documento: Artigo Científico
• Fonte: PLANT PATHOLOGY; v. 68, n. 4, p. 719-726, MAY 2019.
• Citações Web of Science: 1

Resumo

Downy mildew (Plasmopara viticola) is one of the most important diseases in grape-growing areas worldwide, including Brazil. To examine pathogen population biology and structure, P. viticola was sampled during the 2015/16 growing season from 516 lesions on nine grape cultivars in 11 locations in subtropical areas of Sao Paulo State, Brazil. For identification of cryptic species, a subsample of 130 isolates was subjected to cleaved amplified polymorphic sequence (CAPS) analysis, and for 91 of these isolates the ITS1 region was sequenced. These analyses suggest that the population of P. viticola in Sao Paulo State consists of a single cryptic species, P. viticola clade aestivalis. Seven microsatellite markers were used to determine the genetic structure of all 516 P. viticola isolates, identifying 23 alleles and 55 multilocus genotypes (MLGs). Among these MLGs, 34.5% were clonal and represented 93% of the isolates sampled. Four dominant genotypes were present in at least five different locations, corresponding to 65.7% of the isolates sampled. Genotypic diversity (11c; = 0.21-0.89) and clonal fraction (0.58-0.96) varied among locations (populations). Most populations showed significant deviation from Hardy-Weinberg expectations; in addition, excess of heterozygosity was verified for many loci. However, principal coordinate analysis revealed no clusters among locations and no significant isolation by distance was found, suggesting high levels of migration. The results indicate that downy mildew epidemics result from multiple clonal infections caused by a few genotypes of P. viticola, and reproduction of P. viticola in Sao Paulo State is predominantly asexual. (AU)

• Processo FAPESP: 14/05522-8 - Progresso espaço-temporal da ferrugem e do míldio da videira em plantas com arquiteturas distintas
• Beneficiário: Meyriele Pires de Camargo
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 15/26106-5 - Míldio da videira: progresso espacial e temporal da doença, diversidade populacional e papel da reprodução sexuada na dinâmica de epidemias em regiões subtropicais
• Beneficiário: Meyriele Pires de Camargo
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado