BIANNUALREPORT2012-2013

Group Structure

Group Leaders: María Coca (CSIC Assistant professor), Belen López-García (until September 2013), Blanca San Segundo (CSIC Research Professor).
Postdoctoral Researchers: Lidia Campos-Soriano, Mauricio Soto-Suárez.
PhD Students: Marcelo Alborno-Jover, Patricia Baldrich, Mireia Bundó, Rosany Camargo (since March 2013), Cristina Peris-Peris, Aarón Rebollar.
Undergrad or Master Students: Marcel Bach (since May 2013), Lieke Kristensen (since November 2013)

Summary

Plants have evolved an innate immune system to counteract pathogen infection. The group’s main interests are to identify and functionally characterize components and signal transduction pathways controlling the plant defense response to pathogen infection. More specifically, we explore the regulatory roles of microRNAs (miRNAs) and Calcium-dependent Protein Kinase (CPK) genes in plant innate immunity, using rice and Arabidopsis as the model systems (representative species for monocotyledoneous and dicotyledoneous plants). The discovery of distinct miRNAs and CPKs playing a role in plant immunity, including their potential role in cross-talking between biotic and abiotic stress, offers new opportunities to understand mechanisms controlling disease resistance while providing useful toos in breeding programmes for crop protection. We also investigate the impact of the arbuscular mycorrhizal (AM) symbiosis on the plant response to biotic/abiotic stress and the molecular mechanisms governing the symbiotic interaction.

Progress during 2012-2013 includes the identification of a novel miRNA from rice, miR7695, that represents a recently evolved miRNA that experienced natural and/or domestication selection during rice evolution. We demonstrated that miR7695 targets an alternatively spliced transcript of the Nramp6 (Natural resistance-associated macrophage protein 6) gene. Most importantly, miR7695 overexpression in rice confers pathogen resistance supporting that this particular miRNA is a positive regulator of rice defense responses.

Additionally, during these years we developed and evaluated two different production systems of antimicrobial peptides based on the use of rice seeds as biofactories. Both systems have proven suitable for most of the antimicrobial peptides tested, representing an important step forward to bring these high-value compounds to the market.

Moreover, we have developed novel non-toxic targeted antimicrobial peptides, focusing on their potential application to plant protection. In particular, we have designed and identified new peptides based on their activity blocking a specific infection-related process, the appressorium formation of the phytopathogenic fungi Magnaporthe oryzae which is required to penetrate the host surface.

Research Projects

• Identification and functional validation of novel pathogen-related miRNAs from rice.
• Molecular evolution of rice miRNAs.
• Functional characterization of CPK genes in the rice defense response.
• Performance of rice and maize plants during interaction with arbuscular mycorrhizal fungi: disease resistance and alleviation of abiotic stress (drought).
• Development of production systems of antimicrobial peptides based in rice seeds as biofactories
• Identification, functional characterization and application of novel antimicrobial peptides to control blast rice disease

Selected Publications

Campo S., Peris-Peris C., Montesinos L., Penas G., Messeguer J., San Segundo B.
Expression of the maize ZmGF14-6 gene in rice confers tolerance to drought stress while enhancing susceptibility to pathogen infection
(2012) Journal of Experimental Botany, vol. 63 (2), pp. 983-999

Campos-Soriano L., Garcia-Martinez J., Segundo B.S.
The arbuscular mycorrhizal symbiosis promotes the systemic induction of regulatory defence-related genes in rice leaves and confers resistance to pathogen infection
(2012) Molecular Plant Pathology, vol. 13 (6), pp. 579-592

López-García B., San Segundo B., Coca M.
Antimicrobial peptides as promising alternative to plant disease protection.
(2012) In Small wonders: peptides for disease control. ACS Books, ACS Symposium (Rajesaran K., Cary J.W., Jaynes J., Montesinos E. Eds). Chapter 13, pp. 163-194.

Carmona L., Gandia M., López-García B., Marcos J.F.
Sensitivity of Saccharomyces cerevisiae to the cell-penetrating antifungal peptide PAF26 correlates with endogenous nitric oxide (NO) production
(2012) Biochem. Biophys. Res. Comm., vol. 417, pp. 56-61

López-García B., Hernández M., San Segundo B.
Bromelain, a cysteine protease from pineapple (Ananas comosus) stem, is an inhibitor of fungal plant pathogens
(2012) Lett. Appl. Microbiol., vol. 55, pp. 62-67

Campo S., Peris-Peris C., Sire C., Moreno A.B., Donaire L., Zytnicki M., Notredame C., Llave C., San Segundo B.
Identification of a novel microRNA (miRNA) from rice that targets an alternatively spliced transcript of the Nramp6 (Natural resistance-associated macrophage protein 6) gene involved in pathogen resistance
(2013) New Phytologist, vol. 199 (1), pp. 212-227

Campos-Soriano L., Vale G., Lupotto E., San Segundo B.
Investigation of rice blast development in susceptible and resistant rice cultivars using a gfp-expressing Magnaporthe oryzae isolate
(2013) Plant Pathology, vol. 62 (5), pp. 1030-1037

Schmidt R., Mieulet D., Hubberten H.-M., Obata T., Hoefgen R., Fernie A.R., Fisahn J., San Segundo B., Guiderdoni E., Schippers J.H.M., Mueller-Roebera B.
SALT-RESPONSIVE ERF1 regulates reactive oxygen species-dependent signaling during the initial response to salt stress in rice
(2013) Plant Cell, vol. 25 (6), pp. 2115-2131

Rebollar A., López-García B.
PAF104, a synthetic peptide to control the rice blast disease by blocking the appressorium formation in Magnaporthe oryzae
(2013) Mol. Plant Microbe Interact., vol. 26, pp. 1407-1416