Etiologia da mancha de curvularia em gladíolo e aspectos da interação planta-patógeno

• Autor(a) principal: Torres, Denise Pereira
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4433
• topic: Curvularia gladioli; Fungos fitopatogênicos; Gladiolo - Doenças e pragas; Plantas ornamentais; Curvularia gladioli; Pathogenic fungi; Gladiolo - Diseases and pests; Ornamental plants; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA

The flowers and ornamental market is a promising sector which is expanding in Brazil. The gladiolus is worldwide recognized due to the variety of colors, size and shape of its flowers. Among the diseases reported to gladiolus, the curvularia spot is one of the most destructive. The aims of this study were to identify the pathogen associated with this leaf spot in Brazil; evaluating the susceptibility of the main gladiolus genetic material, grown in this country, to curvularia spot and relating it with the development of pathogen infective structures (rate of germination and appressoria formation); and elucidate the fungus infection process in susceptible and resistant varieties of gladiolus leaves. Plants of Gladiolus grandiflorus varieties T-704 and Amsterdam showing curvularia spot were found in Crop science Department / Division of Floriculture of the Universidade Federal de Viçosa. The pathogen was identified as Curvularia gladioli based on conidia and conidiophores morphometric characteristics and phylogenetic analysis of ITS and 28S rDNA regions. The susceptibility to pathogen was evaluated on genotypes Gladiolus callianthus and G. grandiflorus varieties Amsterdam, Red Beauty, Rose Friendship, T-704, Verônica and Yester Gold. The genetic materials presented different level of susceptibility to C. gladioli. G. grandiflorus varieties T-704 and Red Beauty were the most susceptible followed by Tradehorn variety and Gladiolus callianthus. The remaining genetic materials did not differentiate between them. There was no difference in the germination rate between susceptible and resistant varieties. As for the appressorium, differences were observed between the percentages of formation of this structure between G. callianthus and G. grandiflorus variety Amsterdam and G. grandiflorus variety T-704. The infection process of C. gladioli was studied on G. grandiflorus varieties T-704 and Amsterdam using light and scanning electron microscopy techniques. There was no difference in the germination and appressorium formation rate between these varieties. Regarding the colonization, it was observed a lower hyphae development in the leaf tissues of resistant variety. Conidiophores were observed emerging through trichomes and stomatal openings in both the varieties from seven to eight days after inoculation. C. gladioli showed a similar development during pre-penetration in both varieties. The colonization and sporulation were more abundant in the susceptible variety. These information have a great importance to understand the C. gladioli - gladiolus interaction and contribute to development of strategies for the disease management.