Banca de DEFESA: MARIA CLEMENTE DE FREITAS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : MARIA CLEMENTE DE FREITAS
DATA : 29/06/2018
HORA: 09:30
LOCAL: Sala 14
TÍTULO:

Mycelial and conidial enzymatic activity of isolates of Metarhizium anisopliae s.l. and virulence for Rhipicephalus microplus

PALAVRAS-CHAVES:

biological control, arthropod pathogenic fungus, bovine tick, virulence factor, enzymes.

PÁGINAS: 33
GRANDE ÁREA: Ciências Agrárias
ÁREA: Medicina Veterinária
RESUMO:

Metarhizium anisopliae sesu latu (s.l.) is a pathogenic fungus for insects and arthropods, and its use is consolidated in the control of agricultural pests and seen as a promising agent in tick control, such as Rhipicephalus microplus. Studies involving fungal virulence factors, such as enzymatic activities, may help characterize isolates with potential for biological control. The present study evaluated the virulence of four Brazilian isolates of M. anisopliae s.l. under R. microplus females, as well as the morphology, conidial production and activity of proteases, Pr1 and Pr2, lipases and oxidative enzymes of these isolates. Macromorphological analyzes were performed through a single point of inoculum, from which spots were removed for conidial quantification. The virulence was evaluated from the biological parameters of engorged females of R. microplus after immersion in aqueous suspensions of M. anisopliae s.l. (1 × 10⁷ and 1 × 10⁸ conidia mL^-1). It was evaluated the enzymatic activity of two fungal structures, conidium (surface and intracytoplasmic fraction) and mycelium (mycelial secreted and intracytoplasmic fraction), the conidium was produced in rice and the mycelium in minimal medium plus 1% tick cuticle after 72 hours of fungal growth. Parametric data were analyzed by analysis of variance (ANOVA) followed by Tukey test and non-parametric by Kruskal Wallis test followed by Student-Newman-Keuls (SNK) with a significance level of 5%. The isolate IBCB 383 showed the highest conidial production in both BDA and rice medium and IBCB isolate 116 the least producer. The isolate IBCB 481 showed the highest percentage of control for R. microplus females (44, 67% in the concentration 1 × 10⁸ conidia mL^-1) and the IBCB 116 isolate, which obtained a lower percentage (14.19% in concentration 1 × 10⁸ conidia mL^-1). The activity of penetration enzymes: proteases and lipases was higher in the more virulent isolates. Isolate IBCB 481 showed a Pr1 activity almost three times higher than IBCB 116 isolate, both in the conidium and in the mycelium and lipolytic activity about 50 times higher in the intracytoplasmic conidial fraction. Oxidative enzymes had no correlation with the virulence of the isolates, being the isolate IBCB 383 with the highest activities of SOD, Catalase and peroxidase in most of the analyzed structures. Therefore, through the present work it can be taken into account that enzymatic analyzes of the fungi can aid in the selection of isolates for programs aiming at the biocontrol of ticks such as R. microplus.

MEMBROS DA BANCA:
Externo ao Programa - 1681790 - CRISTIANE MARTINS CARDOSO DE SALLES
Externo ao Programa - 2860277 - ISABELE DA COSTA ANGELO
Externo à Instituição - SIMONE QUINELATO BEZERRA - FIOCRUZ
Presidente - 387922 - VANIA RITA ELIAS PINHEIRO BITTENCOURT
Externo à Instituição - WENDELL MARCELO DE SOUZA PERINOTTO - UFRB