Banca de DEFESA: ELIZABETH TEIXEIRA DE ALMEIDA RAMOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : ELIZABETH TEIXEIRA DE ALMEIDA RAMOS
DATA : 27/09/2018
HORA: 13:00
LOCAL: Sala 1 - Fitotecnia
TÍTULO:

Biotechnological potential of bacteriocin gluconacin produced by endophytic diazotrophic bacteria Gluconacetobacter diazotrophicus, PAL5, on microorganisms of agricultural importance for sugar cane and tomato crops

PALAVRAS-CHAVES:

bacteriocin

biological control

diazotrophic bacteria

sugarcane

heterologous expression

PÁGINAS: 90
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Fisiologia de Plantas Cultivadas
RESUMO:

Gluconacetobacter diazotrophicus (PAL5), an endophytic diazotrophic bacterium with recognized plant growth potential, may expand its application potential for the production of bacteriocins. The present study aimed to optimize the production and purification of bacteriocin gluconacin and to evaluate its spectrum of action on phytopathogens and beneficial bacteria of importance for sugarcane and tomato crops. Evaluations were performed to elucidate the mechanism of action of this antimicrobial peptide, as well as to verify its stability against physical and chemical changes. The biotechnological potential of bacteriocin was tested in vivo in tomato plants in protection against Xanthomonas perforans, causal agent of the bacterial spot. The results demonstrated that bacteriocin was expressed and purified satisfactorily. This antimicrobial agent demonstrated a broad spectrum of action, inhibiting the growth of all bacterial phytopathogens evaluated. In addition, bacteriocin gluconacin has also shown antagonism against some beneficial strains belonging to Bacillus species and other strains of G. diazotrophicus. X. albilineans cells (model microorganism) treated with bacteriocin showed loss of inorganic phosphate and UV absorbing materials. Scanning microscopy analyzes demonstrated that cells were fully lysed after treatment, suggesting that bacteriocin alters the integrity of the membrane and increases its permeability, resulting in complete cell lysis. The results of physicochemical characterization indicated that bacteriocin gluconacin showed stability at high temperatures and acid pHs, while a reduction in inhibitory activity was observed after treatment with some proteases and surfactants. Greenhouse evaluations showed a significant reduction of bacterial spot symptoms in plants treated with antimicrobial peptide, suggesting great biotechnological potential.

MEMBROS DA BANCA:
Presidente - 538.864.458-87 - JOSE IVO BALDANI - UFRRJ
Interno - 1213072 - MARGARIDA GORETE FERREIRA DO CARMO
Externo ao Programa - 1681790 - CRISTIANE MARTINS CARDOSO DE SALLES
Externo à Instituição - STEFAN SCHWAB - EMBRAPA
Externo à Instituição - LUIS HENRIQUE DE BARROS SOARES - EMBRAPA