AgreenSkills session, year: 1st session, 2012
Receiving laboratory: LIPM Plant-Microbe Interactions Toulouse, France
Country of origin : Argentina
cAMP signalling and infection in the Medicago symbiont, Sinorhizobium meliloti
A currently active area of rhizobium-legume symbiosis research is the identification of the mechanisms that sustain the mutualistic character of the interaction between the plant and bacteria partners. Jacques Batut’s laboratory recently showed that rhizobia play an active role during the symbiosis in preventing excessive epidermal infection thread (IT) formation and in coordinating IT formation and nodulation, hereby contributing to optimization of infection. This process involves the first ever-characterized cAMP signaling cascade in rhizobia consisting of three receptor-like adenylate cyclases, a Crp-like regulator, and a target gene of unknown function which is specifically activated by an unknown signal synthesized by the legume M. truncatula during nodule organogenesis.
My aim is to identify the plant signal that activates the signaling cascade in Sinorhizobium meliloti and to elucidate the mode of perception and transduction of this signal by rhizobial adenylate cyclases. For signal identification, complementary strategies will be applied in parallel. Preliminary biochemical information indicates that the signal may be a labile peptide or small protein. In collaboration with Véréna Poinsot (IMRCP Université Paul Sabatier, Toulouse) we plan to purify and determine the structure of the plant signal. In a genetic approach, a set of M. truncatula symbiotic mutants will be systematically screened aiming to find plants unable to activate the rhizobial signaling cascade, allowing us to determine at which level of the plant symbiotic program the signal is synthesized. Finally, in order to explore signal perception and transduction by the rhizobia, we will use S. meliloti mutants displaying alterations in cascade signaling patterns.
I have a Microbiology Degree (5 years) from Universidad Nacional de Rio Cuarto (UNRC), Argentina. I did my final research project with Dr. Elizabeth Agostini, using transformed hairy roots cultures as a tool for biotransformations of natural products. I did my PhD under the direction of Dr. Walter Giordano (UNRC) working with Sinorhizobium meliloti, an alfaproteobacterium that fixes nitrogen in symbiosis with Medicago plants. I focused on the role of extracellular and surface macromolecules important in cell-cell and cell-surface adhesion in planktonic cells and biofilms. As a result of an ASM (American Society for Microbiology) fellowship I explored similar aspects in plant symbiotic beta-proteobacteria with Dr. Ann Hirsch at UCLA. I was also actively involved in teaching (chemistry, biochemistry, biophysics and molecular biology) for undergraduate students. I have been always interested in a broad range of subjects out of my research area, so during the last period of my PhD I took two intensive courses (one summer school) on marine microbiology/ecology in Chile. In 2012, I joined Nora Ausmees Lab (Lunds Universitet, Sweden) as a postdoc to work in an exciting project involving the development of a novel approach to unravel the molecular mechanisms of polar growth and the role of cytoskeleton in cellular differentiation in Streptomyces coelicolor. In september 2013, as a result of being awarded with the AgreenSkills fellowship, I moved to Jacques Batut Lab (Toulouse, France) to work again with S. meliloti, exploring a newly discovered instance of signal exchange during the legume-bacteria symbiosis.
1- Bogino, P.C.; Oliva, M.M.; Sorroche, F.G.; Giordano, W. (2013). The Role of Bacterial Biofilms and Surface Components in Plant-Bacterial Associations. Int. J. Mol. Sci. 14:15838-15859.
2– Sorroche, F. G., Spesia, M., Zorreguieta, A., Giordano, W. (2012). A positive correlation between bacterial autoaggregation and biofilm formation in native Sinorhizobium meliloti isolates from Argentina. Appl Environ Microbiol. 70(12): 4092-4101
3- Nievas, F., Bogino, P., Sorroche, F. Giordano, W. (2012). Detection, characterization, and biological effect of quorum-sensing signaling molecules in peanut-nodulating bradyrhizobia. Sensors (12):2851-2873.
4- Sorroche, F. G. & Giordano, W. (2012). PCR Analysis of expR Gene Regulating Biosynthesis of Exopolysaccharides in Sinorhizobium meliloti. Biochem Mol Biol Ed 40(2): 108–111.
5- Sorroche, F. G., Rinaudi, L., Zorreguieta, A., Giordano, W. (2010). EPS II-dependent Autoaggregation of Sinorhizobium meliloti planktonic cells. Curr Microbiol. 61(5):465-470.
6- Rinaudi, L., Sorroche, F. G., Zorreguieta, A., Giordano, W (2009). Analysis of mucR gene regulating the biosynthesis of exopolysaccharides: implications for biofilm formation in Sinorhizobium meliloti Rm1021. FEMS Microbiology Letters. 302(1):15-21.
2012. AgreenSkills Mobility Award.
2010. American Society for Microbiology (ASM) International Fellowship Award.
2005. Córdoba Ministry of Education Award to the Highest Average Grade in Microbiology (class 2005) at Universidad Nacional de Río Cuarto.
2005. Río Cuarto National University Award to the Second Highest Average grade of the School of Exact, Physical-Chemical and Natural Sciences
2000. Ministry of Education of the Argentinean Republic. Distinction with silver medal for participation in IBO 2000 (International Biology Olympiad). Antalya, Turkey (2000).
2000. San Rafael Council of Commerce, Industry and Agriculture. Distinction with medal. Best Oenologist and Agriculture Technician Award, class 2000. San Rafael, Mendoza, Argentina.
2000. Pascual Iaccarini Oenology and Agriculture School Award to the Highest Average Grade and Best Oenologist.