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 show expanded recognition specificity towards several Phytophthora species effectors
Autor/es:
MARÍA E. SEGRETIN, M. PAIS AND S. KAMOUN
Lugar:
La Habana
Reunión:
Congreso; Congreso Internacional Biotecnología Habana 2011: Agro-Biotecnología, contribuyendo a enfrentar los retos globales; 2011
Institución organizadora:
CIGB
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 main objective of this work is to extend R3a recognition specificity to AVR3aEM. We generated a library of R3a mutant variants obtained by random mutagenesis and we screened the mutant clones by co-agroinfiltration with AVR3aEM in Nicotiana benthamiana plants, looking for the presence of HR-like phenotypes. Of approximately 2200 evaluated clones, 20 consistently triggered different degrees of HR-like responses, not observed when infiltrated with a truncated GFP construct. From these, 17 clones (?R3a+?) were sequenced, most of them harbouring multiple mutations. To investigate the contribution of the different mutations to the observed phenotypes, new mutant clones were constructed. So far, we identified 6 single mutations that can expand R3a recognition specificity to AVR3aEM. We also decided to investigate if R3a+ clones could recognize not only AVR3aEM from P. infestans but also AVR3a homologues from other Phytophthora species. After co-infiltration experiments in N. benthamiana, we identified a few R3a+ clones that also recognize P. capsici AVR3a11 and P. sojae AVR1b. We are generating transgenic plants to test if expression of selected R3a+ clones can protect them from Phytophthora sp. infection. This work highlights how knowledge of pathogen effectors can be exploited for engineering novel resistance genes.