Does Phosphite trigger the defense response in Fusarium infected tubers?

LOBATO MC; MACHINANDIARENA MF; FELDMAN ML; DALEO G.R; OLIVIERI FP; ANDREU AB

Villa Carlos Paz / Córdoba / Argentina

Congreso; XLIV Reunión Anual- Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

XX-XXX, DOES PHOSPHITE TRIGGER AN INCREASE IN DEFENSE RESPONSES IN POTATOES INFECTED WITH FUSARIUM? Lobato|||MC; Machinandiarena|||MF; Feldman|||ML; Daleo|||GR; Olivieri|||FP; Andreu|||AB Instituto de Investigaciones Biológicas, FCEyN, Universidad Nacional de Mar del Plata E-mail: mclobato@mdp.edu.ar Plants react against pathogens developing an array of responses that helps them to counteract this attack. Previous results in our group showed that potassium phosphite (KPhi) applied to potato plants protect tubers against Fusarium solani. In order to correlate the protection extent with fungus invasion, we measured the activity of two fungal enzymes: FESP (Fusarium extracellular serine protease) and polygalacturonases (PG). Tubers cv. Bannock Russet coming from KPhi treated plants (KPhi-T) infected with F. solani showed reduced FESP and PG activities indicating a lower degree of infection. We also quantified the activity of two enzymes related to defense, peroxidases and polyphenol oxidases, which also decreased.By using antibodies against different PRPs, we analyzed the accumulation of these proteins in potato tubers infected with F. solani. Chitinase accumulation increased in infected tubers coming from KPhi-T, while glucanase content decreased. Proteinase inhibitor and polygalacturonase inhibiting protein contents increased by KPhi treatment both in infected and non infected tubers.These results suggest that these proteins could be involved in the mechanism by which KPhi protect tubers against F. solani but at different stages of the infection process.Supported by UNMdP, CONICET, ANPCyT, McCain Argentina SA. and AGROEMCODI SA