Fungal populations on sunflower (Helianthus annuus) anthosphere and their relation to susceptibility or tolerance to Sclerotinia sclerotiorurn attack

Analysis of the fungal flora from different floret parts of various sunflower (Helianthus annuus) varieties showed that there are differences in both fungal species and frequency, depending on whether the sunflower variety is susceptible (SV) or tolerant (TV) to attack of the flower heads by the ascomycete pathogen Sclerotinia sclerotiorum. The sunflower varieties analyzed were SV: HA 300 and Z 20028, and TV: HA 302, Z AV 8410 and Z 30629. The isolates showed different "in vitro" behavior as biocontrol agents. The most common types of interaction with Sclerotinia sclerotiorum were D2 and D2+ (hyphal contact) for isolates from SV and TV, while some of the isolates from TV displayed antibiosis. The microorganisms that colonize TV florets play a part in an indirect mechanism that protects flowers from ascospore germination and pathogen growth.

Fil: Rodríguez, M. A.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Fil: Venedikian, Nadia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Fil: Godeas, Alicia Margarita. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones en Biociencias Agrícolas y Ambientales; Argentina