Does phosphite trigger the defense response in Fusarium infected tubers?.

LOBATO MC; MACHINANDIARENA MF; FELDMAN ML; DALEO GR; OLIVIERI FP; ANDREU AB

Villa Carlos Paz,Córdoba, Argentina

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular. SAIB.; 2008

Sociedad Argentina de Investigaciones Bioquimicas-SAIB

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 foliage protects tubers against Fusarium solani. In order to correlate the protection extent with the fungal invasion, the activities of two fungal enzymes were measured: FESP (Fusarium extracellular serine protease) and polygalacturonases (PG). Potato tubers (cv Bannock Russet) from treated plants and infected with F. solani showed reduced FESP and PG activities. These results were correlated with a low degree of infection. The activity of two enzymes related to defense, peroxidases and polyphenoloxidases were quantified. Both activities also decreased.By using antibodies against different PRPs, the accumulation of these proteins in potato tubers from treated plants and infected were analyzed. The chitinase accumulation increased while glucanase content clearly decreased.Proteinase inhibitor and polygalacturonase inhibiting protein contents were increased by KPhi treatment both in infected and non infected tubers.These results suggest that all these proteins are involved in the mechanism by which KPhi protects tubers against F. solani during the infection process. Supported by UNMdP, CONICET, ANPCyT, McCain Argentina SA. and AgroEmcodi SA