Taxonomy and pathogenicity of fungi associated with stem, pod and seed diseases of soybean

• Autor(a) principal: Silva, Athus Diego Azevedo
• Data de Publicação: 2021
• Tipo de documento: Tese
• Idioma: eng
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: https://locus.ufv.br//handle/123456789/30122
• topic: Soja - Doenças e pragas; Etiologia; Colletotrichum; Diaporthe; Leptosphaerulina; Moniliophthora; Fitopatologia

Soybean (Glycine max) was introduced in Brazil in the late 19th century, in the state of São Paulo, and from 1950 its cultivated area expanded rapidly. It is currently grown in almost all national territory, with Brazil being the largest producer in the world. Diseases play a crucial factor in the management of this culture, being limited to production. In 2017, and in subsequent years, soybean plants with early death, stem and pod drying and showing necrotic lesions along the stem, were detected in production fields in the state of Mato Grosso. The plants had sudden death, however with a root system without visible symptoms of necrosis, suggesting a possible resurgence of stem canker or another disease not yet known. This work aimed to survey fungi species associated with soybean plants with symptoms described previously and pathogenicity tests in different soybean cultivars. Analyzes of reproductive structures under microscope and culture morphology indicated the presence of 6 associated fungal genera, namely Fusarium, Macrophomina, Diaporthe, Colletotrichum, Leptosphaerulina and Moniliophthora. Through phylogenetic analyzes it was possible to identify the species Colletotrichum truncatum, Colletotrichum plurivorum, Diaporthe ueckerae, Diaporthe longicolla and a probable new species of Moniliophthora. In pathogenicity tests, the incidence (% of dead plants) varied from 0% to 63%, where the pathogenic isolates caused internal necrosis in the stems, which could even lead to plant drought and death. The results indicate the association of different fungal species with the symptoms described on soybean in Mato Grosso. The new pathogenic species of Monilophthora will be described and published according to the International Nomenclature Code for fungi, algae and plants. Keywords: Colletotrichum. Diaporthe. Etiology. Leptosphaerulin. Moniliophthora.