INVESTIGADORES
GARRIZ Andres
congresos y reuniones científicas
Título:
Role of a polyamine oxidase gene in the defense of Lotus japonicus against Pseudomonas syringae
Autor/es:
BORDENAVE C; BABUIN, MARIA FLORENCIA; CAMPESTRE MP; ROCCO R; CALZADILLA P; MENENDEZ AB; SANTIAGO J. MAIALE; MARÍA MARINA; OA RUIZ; ANDRÉS GÁRRIZ
Lugar:
Buenos Aires
Reunión:
Simposio; International Symposium of Forage Breeding; 2015
Resumen:
Polyamines are organic polycations that have proven to be essential for normal growth anddevelopment in all living organisms. In plants, changes in the metabolism ofthese compounds have been described to occur in response to both pathogenic andbeneficial microbes. In this trend, several lines of evidences suggest that theoccurrence of these changes determines the outcome of the interactions between plantsand microbes. In a previous work, we analyzed global gene expression in twoecotypes of the model legume Lotusjaponicus during the infections caused by the phytopathogenic bacteria Pseudomonas syringae DC3000 pv. tomato. Theseecotypes differ in their tolerances to the bacteria, and accordingly they alsoshow overlapping but distinct gene regulation profiles. Among all the transcriptswhose expression was most significantly modulated, we identified a gene codingfor a putative polyamine oxidase, one of the key enzymes involved in polyaminecatabolism. This enzyme oxidizes higher polyamines as spermidine and sperminewith the production of H2O2, and it is believed to participatein the induction of several defense mechanisms during plant pathogeninteractions. In this work, we assessed the phenotype of a mutant line of L. japonicus with a LORE-1 insertion inthe polyamine oxidase gene locus. Our data show that the absence of this enzymeremarkably increases the tolerance of the plant, reducing bacteriamultiplication as well as the generation of necrosis in infiltrated tissues. Thisis accompanied by a notably reduction in the production of radical oxygenspecies and mild effects on the photosynthetic rate at the infection site. Theimportance of polyamine oxidation for plant defense and the similarities withpreviously published reports are discussed.