Banca de DEFESA: JARLAN LUCAS DOS SANTOS SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : JARLAN LUCAS DOS SANTOS SILVA
DATA : 24/02/2025
HORA: 14:00
LOCAL: Google Meet (online)
TÍTULO:

CHARACTERIZATION AND AGGRESSIVITY OF Fusarium spp. ASSOCIATED TO ROOT ROT AND STEM ROT IN Carica papaya IN NORTHEAST BRAZIL

PALAVRAS-CHAVES:

Papaya; Fusariosis; Diagnose; Soil-borne Pathogens

PÁGINAS: 46
RESUMO:

Papaya (Carica papaya L.) is a crop of great socioeconomic importance in Northeastern Brazil. However, soil-borne pathogens cause significant losses for producers in the medium and long term. Control of diseases caused by soil-borne pathogens is difficult due to the lack of recommended commercial products and, in the case of papaya, due to the lack of information on the etiological agents related to these diseases. Rot caused by the Fusarium solani complex (FSSC 3 + 4) has been previously reported in Brazil, but the Fusarium species belonging to this complex have not been elucidated. The aim of this study is to molecularly and morphologically characterize Fusarium isolates associated with papaya rot in the states of Ceará (CE) and Rio Grande do Norte (RN). Papaya producers in Northeastern Brazil have reported significant losses in fruit production, almost 50% in some cases, due to problems with soil-borne pathogens. To diagnose the causal agents of this disease complex in the region (root and stem rot), we collected samples of roots and stems of papaya plants in commercial fields exhibiting yellowing, wilting, and collapse. Fifteen Fusarium isolates were obtained from six sampled production areas. Koch's postulates were performed to confirm the pathogenicity of these isolates on papaya seedlings (one-month-old), and all inoculated plants showed symptoms 2 months after inoculation. At the end of the experiments, stem and root rots were evaluated using a disease scoring scale: 1 = no symptoms, 2 = less than 10% symptoms, 3 = between 10 and 30%, 4 = between 31 and 50%, 5 = more than 50%, and 6 = dead plant. Treatments were compared by the Van der Warden test. The EF-1α (elongation factor 1-alpha) and RPB2 (second largest subunit of RNA polymerase) genes were partially amplified by PCR and sequenced from all isolates, then a maximum parsimony tree was constructed with the concatenated partial sequences. Five species were identified causing this disease in the region: F. falciforme (FSSC 3+4), F. petroliphilum (FSSC 1), F. pernambucanum (FIESC 17), F. sulawesiense (FIESC 16) and F. delphinoides (FDSC). Among these species, the most aggressive was F. delphinoides followed by F. pernambucanum, F. falciforme, F. petroliphilum, and the least aggressive was F. sulawesiense. The findings of this work will help producers to understand the causal agent of papaya root and stem rot, requiring the development of new management strategies for this crop.

MEMBROS DA BANCA:
Externo à Instituição - DAURI JOSÉ TESSMANN
Externo à Instituição - CÉSAR JÚNIOR BUENO
Interna - 2578315 - JAILMA SUERDA SILVA DE LIMA
Presidente - 1544411 - MARCIA MICHELLE DE QUEIROZ AMBROSIO
Interno - ***.076.546-** - WASHINGTON LUÍS DA SILVA - CAES