Saltar al contenido
Portada » ALVAREZ, M. Elena

ALVAREZ, M. Elena

Investigadora Principal de CONICET / Profesora Titular – UNC
Teléfono: +54 351 5353855 x 3422
E-mail: maria.elena.alvarez@unc.edu.ar

Tema de Investigación

Bases moleculares de la resistencia a patógenos microbianos en Arabidopsis

Plants infected with microbial pathogens trigger a wide array of cellular alterations. At the apoplastic level, they induce a rapid oxidative burst resulting from activation of the plasma membrane-associated enzyme NADPH oxidase. This response is coordinated with other intracellular redox changes that are currently being studied. At the nuclear level, infected cells display severe epigenetic and chromatin changes that may affect the expression of defense genes. We are studying two responses in the Arabidopsis-Pseudomonas syringae pv. tomato (Pst) model.

a) Metabolism of L-proline (Pro): We provided the first evidence that leaves infected with Pst stimulate Pro catabolism or Pro synthesis in infected or peripheral tissues, respectively. At the infection site, proline dehydrogenase (ProDH) is required for proper activation of NADPH oxidase. ProDH normally couples with P5C dehydrogenase (P5CDH) converting Pro into P5C, and P5C into Glu, respectively, at mitochondria. However, during Pst-induced ROS generation, ProDH uncouples from P5CDH and P5C does not accumulate but would be reconverted to Pro through the Pro/P5C cycle. We are investigating whether under this condition ProDH affects the redox balance of mitochondria, cytosol, or chloroplast and thus modulates NADPH oxidase. In addition, we are studying the coordination of ProDH with enzymes controlling the redox state of the cytosol.

b) Epigenetic and chromatin modifications: We have reported that Pst infection triggers genome hypomethylation and decondensation of chromocenters containing pericentromeric heterochromatin. These changes occur without DNA replication, so they could derive from active DNA demethylation. Pericentromeric TEs become transiently activated after Pst-infection but then are re-silenced by the RdDM mechanism using small RNAs (RNAs). Curiously, these sRNAs also map to distal PRR/NLR receptor genes and could co-regulate both types of loci in trans. We are investigating which enzymes and mechanisms generate DNA hypomethylation, chromocenter relaxation, and transient activation of pericentromeric TEs, in tissues infected with Pst.

Becarios Integrantes del Grupo

Publicaciones Seleccionadas

Colaboraciones

  • Dr. László Szabados, Biological Research Centre, Hungarian Academy of Sciences, Institute of Plant Biology, Hungary.
  • Dr. Christine Foyer; Centre for Plant Sciences, University of Leeds, UK.
  • Dr. Loreto Holuigue; Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Chile.
  • Dr. Mohammad-Reza Hajirezaei; Institute of Plant Genetics and Crop Plant Research Gatersleben, Germany.
  • Dr. Arnould Savouré; Sorbonne Université, Institute of Ecology and Environmental Sciences of Paris, Paris, France.

Breve Currículum Vitae

Educación y Formación

  • Bioquímica. Facultad Ciencias Químicas, Universidad Nacional de Córdoba. 1985.
  • Doctora en Ciencias Químicas. Universidad Nacional de Córdoba. 1992.
  • Posdoctorado. Plant Biology Laboratory, Salk Institute, San Diego, USA.1994-1997.

Investigación

Biología Molecular de Plantas. Fitopatología. Estudio de mecanismos de defensa contra patógenos biótrofos y necrótrofos en Arabidopsis.

Publicaciones (últimos 15 años)

  • Fabro G, Di Rienzo JA, Voigt C, Somerville S, Savchenko T, Dehesh K and Alvarez ME. “Genome-wide expression profiling Arabidopsis thaliana at the stage of Golovinomyces cichoracearum haustorium formation”. 2008. Plant Physiology 146: 1421-39.
  • Cecchini N, Monteoliva M, Blanco F, Holuigue L and Alvarez ME. “Features of basal and race-specific defences in photosynthetic Arabidopsis thaliana suspension cultured cells”. 2009. Mol. Plant Pathol. 10:305-310.
  • Blanco F, Salinas P, Cecchini N, Jordana X, Van Hummelen P, Alvarez ME, Holuigue L. «Early genomic responses to salicylic acid in Arabidopsis» 2009. Plant Mol. Biol. 70: 79-102.
  • Alvarez ME, Nota F and Cambiagno D. “Epigenetic control of plant immunity”. 2010. Mol. Plant Pathol. 11, 563–576. • Cecchini NM, Monteoliva MI and Alvarez ME. “Proline dehydrogenase contributes to pathogen defence in Arabidopsis”. 2011. Plant Physiology 155, 1947-1959.
  • Cecchini NM, Monteoliva MI and Alvarez ME. “Proline dehydrogenase is a positive regulator of cell death in different kingdoms”. 2011 Plant Signal Behav 6(8).
  • Fabro G and Alvarez ME. “Loss of compatibility might explain resistance of the Arabidopsis thaliana accession Te-0 to Golovinomyces cichoracearum”. 2012. BMC Plant Biology 12(1): 143. doi: 10.1186/1471-2229-12-143.
  • Armijo G, Salinas P, Monteoliva MI, García C, Seguel A, Song W, van der Krol AR, Alvarez ME and Holuigue L. “A salicylic acid-induced lectin-like protein plays a positive role in the Effector-Triggered Immunity response of Arabidopsis thaliana to Pseudomonas syringae Avr-Rpm1”. 2013. Molec. Plant-Microbe Interact. 26:1395-406. 10.1094/MPMI-02-13-0044-R.
  • Monteoliva MI, Rizzi YS, Cecchini NM, Hajirezaei MR, Alvarez ME. «Context of action of Proline Dehydrogenase (ProDH) in the Hypersensitive Response of Arabidopsis». 2014. BMC Plant Biology 14(1):21.
  • Nota F, Cambiagno DA, Ribone P, Alvarez ME. Expression and function of AtMBD4L, the single gene encoding the nuclear DNA glycosylase MBD4L in Arabidopsis». 2015. Plant Sci 235:122-129. doi: 10.1016/j.plantsci.2015.03.011.
  • Cambiagno DA, Lonez, C, Ruysschaert JM, Alvarez ME. The synthetic cationic lipid diC14 activates a sector of the Arabidopsis defence network requiring endogenous signalling components. 2015. Mol. Plant Pathol. 16:963-972. doi: 10.1111/mpp.12252.
  • Rizzi YS, Monteoliva, MI, Fabro G, Grosso C, Laróvere LE, Alvarez ME. P5CDH affects the pathways contributing to Pro synthesis after ProDH activation by biotic and abiotic stress conditions. 2015. Front. Plant Sci. 6, 572. doi: 10.3389/fpls.2015.00572.
  • Fabro G, Rizzi YS, Alvarez ME. Arabidopsis proline dehydrogenase contributes to flagellin-mediated PAMP-Triggered Immunity by affecting RBOHD. 2016. Mol Plant Microbe Interact. 29:620-8. doi: 10.1094/MPMI-01-16-0003-R. • D’Ambrosio JM, Couto D, Fabro G, Scuffi D, Lamattina L, Munnik T, Andersson MX, Alvarez ME, Zipfel C, Laxalt AM. Phospholipase C2 Affects MAMP-Triggered Immunity by Modulating ROS Production. 2017. Plant Physiol. 175:970-981. doi: 10.1104/pp.17.00173.
  • Rizzi YS, Cecchini NM, Fabro G, Alvarez ME. Differential control and function of Arabidopsis ProDH1 and ProDH2 genes upon infection with biotrophic and necrotrophic pathogens. 2017. Mol Plant Pathol. 18:1164-1174. doi: 10.1111/mpp.12470.
  • Beltramino M, Ercoli MF, Debernardi JM, Goldy C, Rojas A, Nota F, Alvarez ME, Vercruyssen L, Inzé D, Palatnik JF, Rodriguez RE. Robust stimulation of leaf growth by AtGRF3-like trancription factors under different growth conditions. 2018. Sci Rep. 8:13447. doi: 10.1038/s41598-018-29859-9.
  • Cambiagno DA, Nota F, Zavallo D, Rius S, Casati P, Asurmendi S, Alvarez ME. Immune receptor genes and pericentromeric transposons as targets of common epigenetic regulatory elements. 2018. Plant Journal 96:1178-1190. doi:10.1111/tpj.14098.
  • Fabro G, Cislaghi AP, Condat F, Deza Borau G, Alvarez ME. The N-terminal domain of Arabidopsis proline dehydrogenase affects enzymatic activity and protein oligomerization. 2020. Plant Physiol and Biochem 154:268-276. https://doi.org/10.1016/j.plaphy.2020.04. 019.
  • Mencia R, Céccoli G, Fabro G, Torti P, Colombatti F, Ludwig-Müller J, Alvarez ME, Welchen E. OXR2 Increases Plant Defense against a Hemibiotrophic Pathogen via the Salicylic Acid Pathway. 2020. Plant Physiol 184:1112-1127. doi: 10.1104/pp.19.01351. •
  • Harris JM, Balint-Kurti P, Bede JC, Day B, Gold S, Goss EM, Grenville-Briggs LJ, Jones KM, Wang A, Wang Y, Mitra RM, Sohn KH, Alvarez ME. What are the Top 10 Unanswered Questions in Molecular Plant-Microbe Interactions? 2020. Mol Plant Microbe Interact. 33(12):1354-1365. doi: 10.1094/MPMI-08-20-0229-CR.
  • Alvarez ME, Savouré A, Szabados L. Proline metabolism as regulatory hub. 2021. Trends in Plant Science. https://doi.org/10.1016/j.tplants.2021.07.009
  • Cambiagno DA, Torres JR, Alvarez ME. Convergent epigenetic mechanisms avoid constitutive expression of immune receptor gene subsets. 2021. Front Plant Sci. 12:703667. doi: 10.3389/fpls.2021.703667.
  • Cecchini NM, Torres JR, Lescano López I, Cobo S, Nota F, Alvarez ME. Alternative splicing of an exitron determines the subnuclear localization of the Arabidopsis DNA-glycosylase MBD4L under heat stress.Plant J. 2022 Jan 21. doi: 10.1111/tpj.15675.

 

  • Tesis Doctorales dirigidas
  • Valeria Pavet. “Alteraciones moleculares y estructurales del genoma de Arabidopsis thaliana en el proceso de infección con Pseudomonas syringae”. 2005.
  • Georgina Fabro. “Caracterización molecular de señales de Arabidopsis que modulan la virulencia de patógenos fúngicos”. 2005.
  • Nicolás Cecchini. “Metabolismo de prolina en respuestas de defensa a patógenos en Arabidopsis”. 2010.
  • Mariela Monteoliva. “Contribución del catabolismo de prolina a la Respuesta Hipersensible”. 2012.
  • Florencia Nota. “Caracterización molecular y funcional del gen AtMBD4L, codificante de una nueva DNA glicosilasa de Arabidopsis thaliana”. 2014.
  • Damián Cambiagno. “ Alteraciones de la cromatina centromérica de Arabidopsis inducida por infección bacteriana y su efecto en la defensa”. 2016.
  • Yanina Rizzi. “Aportes de Prolina Deshidrogenasa a la defensa contra patógenos en Arabidopsis». 2017. •
  • José Roberto Torres. “Actividad in vivo de la ADN glicosilasa MBD4L de Arabidopsis en condiciones de estrés”. 2022.
  • Ana Paula Cislaghi. “Aportes de prolina deshidrogenasa (ProDH) a la señalización de defensas contra patógenos reguladas por desbalances redox en Arabidopsis”. En curso.