Microorganisms of agronomical and environmental interest

Summary

In our laboratory we study the interaction between plants and microorganisms in order to understand the molecular mechanisms that determine the interaction between them. Our main study model is the disease called citrus canker caused by bacteria of the genus Xanthomonas.

Research Lines

Molecular characterization of the phytopathogen Xanthomonas axonopodis pv. citri, responsible for citrus canker.

We investigate plant-pathogen interaction and in particular the interaction between the phytopathogen Xanthomonas axonopodis pv. citri and citrus plants. Our efforts are aimed to the understanding the pathogenicity factors of this bacteria such as proteins involved in adhesion, molecules responsible for biofilm formation and effector proteins involved in virulence. We also study an eukaryotic protein acquired by the bacteria that is able to mimic plant natriuretic peptides and doing so, regulate the plant cell homeostasis to its own benefit.

Environmental biotechnology

Principal Investigator: Natalia Gottig.   gottig@ibr-conicet.gov.ar

Our research group performs the isolation and characterization of environmental microorganisms in order to use them or even the enzymesderived from them in bioremediation processes. Particularly, a problem widely distributed in Argentina, is the presence of iron (Fe) andmanganese (Mn) in groundwater. These metals affect the quality of waterfor human consumption from the point of view of acceptability, operationaland health. In recent years methods of biological removal of metals fromthese waters were developed, which offer a low-cost and high efficiency,without presenting negative environmental impact. This process is done by installing water treatment plants which consist of a double filtrationsystem where metals are oxidized by naturally occurring bacteria.Bacterial biofilms that form on these sand filters, act as chemicalbuffers immobilizing metals and biological oxidation products thereof.With this methodology, Fe oxides obtained are retained and are filteredand removed from the water quickly. However, Mn removal times are veryslow and not suited to the water requirements of the population.Therefore, one objective of our group is isolate and select bacteria thatcan perform a high efficient Mn oxidation and with a great capacity ofbiofilm formation. These bacteria may allow the development of mixedbacterial inoculants suitable for bioremediation processes of Mn. Anotherkey objective is to study the molecular mechanisms involved in Mnoxidation process, its physiological role and if this process providessome adaptive advantage to bacteria. All results obtained from theseanalyses will extend the basic knowledge of the Mn biogeochemistry, themolecular mechanisms used by bacteria to oxidize metals and adapt to theirpresence and will improve several bioremediation processes.

Improvement of  bacterial inoculants used in crops of agronomic interest.

Principal Investigator: Jorgelina Ottado: ottado@ibr-conicet.gov.ar

Our group is also interested in improving bacterial strains used as inoculants for agronomic crops. These bacteria naturally present in sol are able to interact with plants roots promotingplant growth and development, without drawing up excessive use of fertilizers, that long-term damage the soil and pollute the environment. The improvement is based on the introduction of new genes that provide overcoming characteristics regarding bacterial resistance to environmental stresses. These advantages result in increased production and the ability to cover a larger cultivation area using less favorable soils.

Selected Publications

- Garavaglia, B.S., Zimaro, T., Abriata, L.A., Ottado, J.*, Gottig, N. *(2016). XacFhaB adhesin, an important Xanthomonas citri subsp. citri virulence factor, is recognized as a pathogen-associated molecular pattern. Mol Plant Pathol. Jan 2. doi: 10.1111/mpp.12364.

- Ficarra, F.A., Garofalo, C.G., Gottig, N., Ottado, J. (2015). The Amino Acid Arginine 210 of the Response Regulator HrpG of Xanthomonas citri subsp. citri Is Required for HrpG Function in Virulence. PLoS One. May 11;10(5):e0125516.

- Piazza, A., Zimaro, T., Garavaglia, B.S., Ficarra, F.A., Thomas, L., Marondedze, C., Feil, R., Lunn, J.E., Gehring, C., Ottado, J., Gottig, N. (2015). The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses.J Exp Bot. 2015 May;66(9):2795-811.

- Zimaro, T., Thomas, L., Marondedze, C., Sgro, G.G., Garofalo, C.G., Ficarra, F.A., Gehring, C., Ottado, J., Gottig, N. (2014). The type III protein secretion system contributes to Xanthomonas citri subsp. citri biofilm formation. BMC Microbiol. Apr 18;14:96.

- Zimaro, T., Thomas, L., Marondedze, C., Garavaglia, B.S., Gehring, C., Ottado, J., Gottig, N. (2013) Insights into xanthomonas axonopodis pv. citri biofilm through proteomics. BMC Microbiol., 13, 186.

- Sgro, G.G., Ficarra, F.A., Dunger, G., Scarpeci, T.E., Valle, E.M., Cortadi, A., Orellano, E.G., Gottig, N., Ottado, J. (2012) Contribution of a harpin protein from Xanthomonas axonopodis pv. citri to pathogen virulence. Mol Plant Pathol., 13, 1047-59.

- Dunger, G., Garofalo, C.G., Gottig, N., Garavaglia, B.S., Rosa, M.C., Farah, C.S., Orellano, E.G, Ottado, J. (2012) Analysis of three Xanthomonas axonopodis pv. citri effector proteins in pathogenicity and their interactions with host plant proteins. Mol. Plant Pathol., 13, 865-76.

- Garavaglia, B.S., Thomas, L., Gottig, N., Dunger, G., Garofalo, C.G., Daurelio, L.D., Ndimba, B., Orellano, E.G., Gehring, C., Ottado, J. (2010) A eukaryotic-acquired gene by a biotrophic phytopathogen allows prolonged survival on the host by counteracting the shut-down of plant photosynthesis. PLoS ONE, 5, e8950.

- Garavaglia, B.S., Thomas, L., Zimaro, T., Gottig, N., Daurelio, L.D., Ndimba, B., Orellano, E.G., Ottado, J., Gehring, C. (2010) A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host. BMC. Plant Biol., 10, 51.

- Gottig, N., Garavaglia, B.S., Garofalo, C.G., Orellano, E.G., Ottado, J. (2009) A filamentous hemagglutinin-like protein of Xanthomonas axonopodis pv. citri, the phytopathogen responsible for citrus canker, is involved in bacterial virulence. PLoS. ONE, 4, e4358.

- Gottig, N., Garavaglia, B.S., Daurelio, L.D., Valentine, A., Gehring, C., Orellano, E.G., Ottado, J. (2008) Xanthomonas axonopodis pv. citri uses a plant natriuretic peptide-like protein to modify host homeostasis. Proc. Natl. Acad. Sci. U. S. A, 105, 18631-18636.

Collaborators

- Chris Gehring – King Abdullah University of Science and Technology (KAUST), Arabia Saudita.
- John E. Lunn– Max Planck Institute of Molecular Plant Physiology, Germany.

Grants

-Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT). PICT2013.
-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). PIP2014-2016.

Director

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Ottado, Jorgelina
Core CCT
Email: ottado@ibr-conicet.gov.ar
Phone: +54 341 4237070
Office Extension: 633
Laboratory Extension: 625

Researchers

  • Natalia Gottig
  • Betiana Garavaglia

Postdoctoral fellows

  • Cecilia Vranych

Doctoral fellows

  • María Victoria Barcarolo
  • Ainelén Piazza
  • Lucila Ciancio
  • Masotti Firella