A strain of Bacillus subtilis subsp. subtilis shows a specific antagonistic activity against the soil-borne pathogen of onion Setophoma terrestris

Authors
Albarracín Orio, Andrea Georgina; Brücher, Elsa; Ducasse, Daniel Adrian
Publication Year
2015
Language
English
Format
article
Status
Published version
Description
Pink Root is among the major diseases of onion and its causal agent, Setophoma terrestris, is one of the most severe pathogens in soils of tropical and subtropical climates. The management of Pink Root is difficult and the strategies currently used are ineffective. Although, there are some varieties resistant to S. terrestris, they are not resistant to every isolate of the pathogen and it is not unusual to find isolates that break that resistance. Moreover, chemical control is not technically or economically feasible. So, we decided to address biocontrol as a mean to manage the main onion disease in Argentina.We tested the efficiency of a strain of Bacillus subtilis subsp. subtilis isolated from the rhizosphere of onion plants to inhibit the growth of S. terrestris in vitro. Our strain of Bacillus subtilis showed a strong capacity of growth inhibition of S. terrestris. No antagonistic activity against two other onion pathogens, Fusarium oxysporum f. sp. cepae and F. proliferatum, was observed. Interestingly, we found a high growth inhibition of S. terrestris on plates containing cell-free supernatant of B. subtilis previously grown in the presence of the fungus. No significant differences in the fungal growth were obtained between control plates and plates containing cell-free supernatant from B. subtilis grown without previous contact with S. terrestris. Electron microscopy of S. terrestris from co-cultures plates revealed thickened, tortuous or coiledfungal hyphae, with granules and globular like terminations. These results suggested that the strain of B. subtilis under study has a strong biocontrol activity against S. terrestris and that it would be acting diffusible bacterial inhibitory compounds specifically induced by this pathogen.
Instituto de Patología Vegetal
Fil: Albarracín Orio, Andrea Georgina. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; Argentina
Fil: Brücher, Elsa. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; Argentina
Fil: Ducasse, Daniel Adrian. INTA. Instituto de Patología Vegetal; Argentina. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias. Laboratorio de Biología Molecular; Argentina
Source
European journal of plant pathology 144 (1) : 217–223. (January 2016)
Subject
Bacillus Subtilis
Control Biológico
Cebolla
Allium Cepa
Organismos Transmitidos por Suelo
Soilborne Organisms
Onions
Biological Control
Setophoma Terrestris
Access level
Restricted access
License
Repository
INTA Digital (INTA)
Institution
Instituto Nacional de Tecnología Agropecuaria
OAI Identifier
oai:localhost:20.500.12123/2596