New insights on the role of polyamines and polyaminooxidases in plant defense against pathogenic microorganisms

MARINA M; GONZALEZ ME; ROSSI FR; ROMERO FM; MAIALE SJ; GÁRRIZ A; BAUER, R; RUIZ OA; PIECKENSTAIN FL

Congreso; Structural Biology in the Bio Economy; 2012

Polyamines, natural polycationic compoundsessential for all living organisms, are involvedin a variety of physiological processes.Polyamines are positively charged atphysiological pH, thus interacting withnegatively charged macromolecules such asnucleic acids and proteins. Plant polyaminemetabolism is affected by a number ofstresses, including pathogen infection.Recently, the use of model plants such asNicotiana tabacum and Arabidopsis thaliana,as well as novel inhibitors of polyaminecatabolism, increased our knowledge on therole of PAs in plant defense. Diamino andpolyaminooxidases, which catabolizepolyamines and release hydrogen peroxide,were shown to contribute to tobaccoresistance to pathogenic bacteria, fungi andviruses. Modifications of plant sperminelevels by different experimental approachesdemonstrated that this tetraamine contributesto A. thaliana resistance to the biotrophicbacterium Pseudomonas viridiflava andcucumber mosaic virus. Interestingly, inplanta spermine accumulation led to a varietyof transcriptional changes related to plantdefense. Further elucidation of PA-mediatedchanges in the expression of defense-relatedgenes is a challenge for molecular plantpathologists