Identification of Endophytic Bacteria and their Characterization as Biocontrol Agents against Tomato Southern Blight DiseaseClaudia Mónica Ribaudo*, Daniela Soledad Riva, Juan Ignacio Gori, José Ignacio Zaballa and Catalina Molina
Facultad de Agronomía, Universidad de Buenos Aires, Cátedra de Bioquímica, Avenida San Martín 4453, C1417DSE Buenos Aires, Argentina
- Corresponding Author:
- Claudia Mónica Ribaudo
Facultad de Agronomía, Universidad de Buenos Aires
Cátedra de Bioquímica, Avenida San Martín 4453, C1417DSE Buenos Aires, Argentina
Tel: +54 11 4524 8087
E-mail: [email protected]
Received Date: August 24, 2016; Accepted Date: October 04, 2016; Published Date: October 05, 2016
Citation: Ribaudo CM, Riva DS, Gori JI, Zaballa JI, Molina C (2016) Identification of Endophytic Bacteria and their Characterization as Biocontrol Agents against Tomato Southern Blight Disease. Appli Micro Open Access 2:123. doi:10.4172/2471-9315.1000123
Copyright: © 2016 Ribaudo CM, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Objectives: The purpose of the present study was to characterize the endophytic bacterium PAC BNM0522 and to evaluate its role in the ethylene signaling pathway in the development of southern blight disease (caused by the necrotrophic fungus Sclerotium rolfsii) in tomato plants. Methods: In this study, biochemical tests, 16S rRNA gene sequencing, and amplification of the ACCD gene (acdS) were performed on the isolate obtained from pruning compost. This isolate was also screened for antibiotic production and competition for nutrients and evaluated its role in the ethylene signaling pathway by analysis of the expression of genes involved in ethylene biosynthesis by PCR and ethylene content by GC. Results: The analysis of the 16S rRNA gene partial sequence and biochemical test placed this bacterium within the genus Pseudomonas and revealed that it belongs to the group of PGPR with multiple plant growth-promoting traits. This rhizobacterium was able to promote host growth through direct antagonism to the fungal pathogen. The in vivo experiments showed that PAC BNM0522 inoculation controlled the disease caused by S. rolfsii. The ethylene level was enhanced in tomato plants infected with the fungus and decreased by inoculation of the rhizobacterium. The expression of the Sl-ACS2 isoform was induced by the presence of the pathogen and strongly repressed in PAC BNM0522-primed plants. The accumulation of the Sl-ACO1 messenger was down-regulated in deaminaseproducing PAC BNM0522-inoculated plants. Conclusion: Our results indicate that ACCD-containing PAC BNM0522 generated protection of tomato plants under pathogenic stress and alleviated ethylene-induced damage, by regulating the expression of genes involved in the ethylene pathway. PAC BNM0522 may be used as an alternative ecological approach to control soil-borne fungi.