Banca de DEFESA: LUCAS CARVALHO SOARES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUCAS CARVALHO SOARES
DATE: 15/06/2026
TIME: 09:00
LOCAL: On-line
TITLE:

Biological control of fusarium wilt in tomato using non-pathogenic isolates of Fusarium sp.

KEY WORDS:

Fusarium oxysporum; biological control; Fusarium wilt; tomato; endophytism; biocontrol.

PAGES: 207
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Manejo e Tratos Culturais
SUMMARY:

The present study aimed to evaluate the potential of non-pathogenic isolates of Fusarium oxysporum for the biological control of Fusarium wilt in tomato plants caused by Fusarium oxysporum f. sp. lycopersici (Fol). Isolates belonging to the collection of the Seed Epidemiology and Pathology Laboratory of the Federal Rural University of Rio de Janeiro (LabEPS/UFRRJ), obtained from tomato plants cultivated in the state of Rio de Janeiro, Brazil, were used. Initially, in Chapter I, twenty-eight isolates were subjected to morphological characterization, pathogenicity tests on tomato seedlings, and statistical analysis using a generalized linear model (GLM) to estimate the probability of vascular necrosis and identify non-pathogenic isolates with biocontrol potential. The isolates FENA LX104, FENA LX105, FENA LX201, FENA LX102, and FENA LX301 were identified as non-pathogenic and endophytic, standing out due to the absence of symptoms and their ability to asymptomatically colonize vascular tissues. In Chapter II, the effect of inoculating tomato seeds with isolates FENA LX102, FENA LX104, FENA LX201, and FENA LX301 was evaluated through blotter tests, seedling emergence in sand, and greenhouse assays, using water, a dicarboximide fungicide, and a biological product based on Trichoderma harzianum as controls. Seeds and seedlings were challenged with the pathogenic isolates Fol 113, Fol 3201, and Fol 3302. The results demonstrated that the non-pathogenic isolates did not impair seed germination and promoted a higher percentage of normal seedlings, lower incidence of non-germinated seeds, and greater initial plant vigor, even in the presence of the pathogen. Isolate FENA LX104, especially at the concentration of 10⁴ microconidia mL⁻¹ (c2), showed superior and more consistent performance under different experimental conditions, being considered the most promising isolate for the subsequent stages of the study. In Chapter III, seedlings of different tomato varieties, including Perinha Água Branca (PAB), Santa Cruz Kada, Serato, and the commercial rootstocks Shincheonggang, Green Power, Contrattack, and Gumgang, were previously inoculated with the non-pathogenic isolates and subsequently challenged with pathogenic Fol isolates. Disease incidence, severity, vascular necrosis, and fungal reisolation capacity were evaluated. The isolates FENA LX104, FENA LX201, and FENA LX301 showed high efficiency in controlling Fusarium wilt, drastically reducing disease symptoms and maintaining plants asymptomatic even in the presence of the pathogenic isolates Fol 113 and Fol 3201, in addition to presenting stable endophytic behavior. In some assays, control efficiency reached up to 100%, confirmed by the absence of symptoms throughout the experimental period. In Chapter IV, the reaction of agronomically important species, such as lettuce, arugula, common bean, soybean, cucumber, and eggplant, to inoculation with the non-pathogenic isolates FENA LX104, FENA LX201, and FENA LX301 was evaluated. The experiments were conducted through seed and seedling inoculation using spore suspensions standardized at 1 × 10⁶ microconidia mL⁻¹. The results demonstrated that the isolates showed broad compatibility with most evaluated species, without inducing pathogenic symptoms, in addition to evidencing endophytic colonization and plant growth-promotion potential. However, isolate FENA LX201 showed differential behavior in some crops, such as arugula, soybean, and common bean, indicating the need for monitoring the phenotypic stability of these isolates for safe use in biological control programs. In Chapter V, the biocontrol potential of isolates FENA LX104, FENA LX201, and FENA LX301 was investigated in a hydroponic system using tomato cv. Santa Cruz Kada. Seedlings were inoculated by root immersion in suspensions containing 1 × 10⁶ microconidia mL⁻¹ and later transplanted into nutrient solutions inoculated or not with Fol 3302. The results demonstrated a significant reduction in Fusarium wilt symptoms and maintenance of plant growth even in the presence of the pathogen in seedlings inoculated with the non-pathogenic isolates. Based on the results, it was possible to verify that non-pathogenic isolates of Fusarium oxysporum, especially FENA LX104, FENA LX201, and FENA LX301, have a high protective capacity against tomato Fusarium wilt, acting as beneficial endophytes and promising biological control agents.

COMMITTEE MEMBERS:
Externa à Instituição - ALICE MARIA GONÇALVES SANTOS - UFPI
Externo à Instituição - CARLOS ANTÔNIO DOS SANTOS
Interna - ***.210.947-** - MARCIA SOARES VIDAL - EMBRAPA
Interna - 1213072 - MARGARIDA GORETE FERREIRA DO CARMO
Externo à Instituição - MARUZANETE PEREIRA DE MELO - UFPI