RESUMEN
A rapid, high-resolution melting (HRM) analysis protocol was developed to detect sequence variations associated with resistance to the QoIs, benzimidazoles and dicarboximides in Botrytis cinerea airborne inoculum. HRM analysis was applied directly in fungal DNA collected from air samplers with selective medium. Three and five different genotypes were detected and classified according to their melting profiles in BenA and bos1 genes associated with resistance to benzimidazoles and dicarboximides, respectively. The sensitivity of the methodology was evident in the case of the QoIs, where genotypes varying either by a single nucleotide polymorphism or an additional 1205-bp intron were separated accurately with a single pair of primers. The developed two-step protocol was completed in 82 min and showed reduced variation in the melting curves' formation. HRM analysis rapidly detected the major mutations found in greenhouse strains providing accurate data for successfully controlling grey mould.
Asunto(s)
Antifúngicos/farmacología , Bencimidazoles/farmacología , Botrytis/efectos de los fármacos , Farmacorresistencia Fúngica , Técnicas de Genotipaje/métodos , Imidas/farmacología , Quinonas/antagonistas & inhibidores , Microbiología del Aire , Botrytis/clasificación , Botrytis/genética , Botrytis/aislamiento & purificación , ADN de Hongos/química , ADN de Hongos/genética , Genes Fúngicos , Genotipo , Datos de Secuencia Molecular , Mutación , Técnicas de Tipificación Micológica , Sensibilidad y Especificidad , Análisis de Secuencia de ADN , Factores de Tiempo , Temperatura de TransiciónRESUMEN
A severe leaf spot disease incited by the fungus Pyricularia oryzae was identified on Ctenanthe oppenheimiana and C. setosa "Greystar." Primary symptoms on young leaves consisted of individual circular to slightly irregular pinpoint spots with white necrotic centers zonated by narrow brown-yellow halos. On mature leaves, extended necrotic areas resembling those caused by phytotoxicity were formed. Artificially inoculated leaves with a spore suspension of the isolated fungus from the above case showed symptoms after 3 to 4 days' incubation at 25°C and high humidity. Fungal isolates obtained from Ctenanthe plants of Brazilian origin were found to be highly pathogenic on various plants within the family Marantaceae when they were tested by an excised leaf assay method. By contrast, P. oryzae isolates obtained from rice plants grown in Greece caused either hypersensitivity or immune response symptoms in various Marantaceae. Analysis of esterase and lactate dehydrogenase isozymes showed different banding patterns for rice and Ctenanthe isolates of P. oryzae. Conditions of prolonged leaf wetness combined with prevailing high temperature and humidity favored the epidemic appearance of the Pyricularia leaf spot disease on glasshouse-grown plants during the summer months of 1995 in Greece.
