Susceptibility to downy mildew in grape clusters: New microscopical and biochemical insights.
Plant Physiol Biochem
; 52: 140-6, 2012 Mar.
Article
em En
| MEDLINE
| ID: mdl-22305077
ABSTRACT
Grape clusters of different Vitis genotypes, including Vitis vinifera cvs Chasselas and Merlot, and two interspecific grape varieties, Solaris (cvs. Merzling* x (Saperavi severneyi x Muscat ottonel)) and 2091 (cvs. Gamaret x Bronner), are susceptible or resistant to downy mildew. These cultivars were inoculated with Plasmopara viticola at three developmental stages (BBCH stages 53, 69 and 75). Samples were examined by scanning electron microscopy and the synthesis of stilbenes was measured. Microscopical examinations of pedicels, rachis and calyptras showed important differences in stomatal structures within seasonal development. At BBCH 53, successful infections were observed on all tested cultivars and functional stomata were present, while no infections were observed after this stage. At BBCH 69 and 75, cracks were observed around the stomata and guard cells were unstructured or completely collapsed, leading to closed-like stomata. At BBCH 53, significant stilbene accumulation was quantified in 2091 and Solaris; pterostilbene and δ-viniferin were produced in large amounts. In the susceptible varieties, only piceid and resveratrol were induced. At the other two stages, the concentration of all measured stilbenes was undetectable. The critical roles of seasonal development and stilbenes in the resistance of grape clusters towards downy mildew are discussed.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Doenças das Plantas
/
Estilbenos
/
Vitis
Idioma:
En
Revista:
Plant Physiol Biochem
Assunto da revista:
BIOQUIMICA
/
BOTANICA
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Suíça