INGEBI   02650
INSTITUTO DE INVESTIGACIONES EN INGENIERIA GENETICA Y BIOLOGIA MOLECULAR "DR. HECTOR N TORRES"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
R3a resistance protein mutants with extended effector recognition specificity
Autor/es:
SEGRETIN M.E. AND S. KAMOUN
Lugar:
Dundee, Escocia
Reunión:
Conferencia; 7th Solanaceae Conference SOL2010; 2010
Institución organizadora:
SOL network
Resumen:
Phytophthora infestans is one of the most devastating pathogens affecting potato production worldwide. One strategy to generate resistant cultivars is the introduction of resistance genes that are able to recognize P. infestans effector proteins with avirulence activities. R3a, a resistance protein discovered in potato, can trigger an hypersentive response upon the recognition of the avirulence effector AVR3aKI from P. infestans but cannot recognize AVR3aEM, the product of another allele that is predominant in pathogen populations. To date, all the characterized P. infestans strains in nature carry at least one of these AVR3a proteins. The objective of this work is to extend R3a recognition specificity to AVR3aEM. To accomplish this, we generated a library of R3a mutant variants obtained by random mutagenesis. We screened the mutant clones by co-agroinfiltration with AVR3aEM in Nicotiana benthamiana plants, and evaluated the presence of HR-like phenotypes. Of approximately 2200 evaluated clones, 20 triggered different degrees of HR-like responses in different infiltration experiments. In parallel, the candidate clones were co-infiltrated with AVR3aKI and with a negative control plasmid to investigate the conservation of the original R3a recognition specificity and also to eliminate auto-active R3a mutants. In total, 17 clones were sequenced, most of them harboring multiple mutations. To investigate the contribution of the different mutations to the observed phenotypes chimeric clones were constructed, showing that depuration of individual mutations in R3a structure could lead to enhance recognition of AVR3aEM. This work highlights how knowledge of pathogen effectors can be exploited for engineering novel resistance genes.