Banca de QUALIFICAÇÃO: KEVISON ROMULO DA SILVA FRANÇA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : KEVISON ROMULO DA SILVA FRANÇA
DATE: 29/08/2023
TIME: 09:00
LOCAL: Sala de aula do prédio da pós-graduação
TITLE:

Identification of Lasiodiplodia spp. Associated with crown rot of banana in the north and northeast regions of Brasil

KEY WORDS:

Botryosphaeriaceae, Molecular characterization, Musa spp.

PAGES: 60
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitossanidade
SPECIALTY: Fitopatologia
SUMMARY:

Crown rot is a post-harvest disease with a major negative impact on the quality of banana fruit. Infections occur during harvest, but symptoms appear post-harvest, during the physiological ripening of the fruit. Different fungi are associated with this disease, which may vary according to geographical region, especially species of the genus Lasiodiplodia. In this context, this study aims to identify Lasiodiplodia spp. associated with crown rot in states in the North and Northeast regions of Brazil. Isolation was carried out directly, by observing the presence of pycnidia, or indirectly from symptomatic tissue. Morphocultural characterization was carried out using colonies that had been growing for 15 days on Potato Dextrose Agar (BDA). Conidia were measured from pycnidia produced on autoclaved pine acicles, obtaining the length, width and L/W ratio of mature (n=50) and immature (n=50) conidia. The genomic DNA of all the isolates was extracted, the gene sequences of the translation elongation factor (EF1- α) amplified by PCR and the products sent for sequencing. The internal transcribed spacer (ITS) regions and a portion of the β-tubulin (TUB) gene will be used to further support the identity of the species. Pathogenicity and virulence were determined for all isolates on 'prata' banana fruit. A total of 114 isolates were obtained from symptomatic fruit collected in 33 municipalities located in different states in the North and Northeast regions. The isolates varied in their morphological and cultural characteristics, presenting dense aerial mycelia of a white to grayish-black color. Mycelial growth ranged from 17.9 to 42.5 mm.day-1. Immature conidia were ovoid to cylindrical in shape (10.1–23.1 x 5.4–11.2 µm), turning brown with median septa and longitudinal striations when mature (10.2–19.7 x 6.0–9.9 µm). All the isolates were pathogenic, showing visible lesions four days after inoculation. The more aggressive isolates produced lesions ranging from 49.8 to 53.3 mm (Ø), while the less aggressive isolates produced lesions ranging from 12.7 to 13.0 mm (Ø).

BANKING MEMBERS:
Interno(a) - 1790557 - GILDEMBERG AMORIM LEAL JUNIOR
Presidente - 1546023 - IRAILDES PEREIRA ASSUNCAO
Externo(a) ao Programa - 3339094 - MAYRA MACHADO DE MEDEIROS FERRO