Extracellular subtilisin/like protein from Colletotrichum spp. induces defense response in plants

CHALFOUN NADIA R.; GRELLET BOURNONVILLE CARLOS F.; DI PETO, PÍA

San Miguel de Tucumán

Congreso; XLV Reunión Anual de SAIB; 2009

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

We have earlier reported that the avirulent isolate M23 of C. fragariae protects the cv Pájaro of strawberry against anthracnose and that culture supernatant derived from that strain induced HR, autofluorescence, oxidative burst, accumulation of salicylic acid and callose deposition. Analysis of the active fraction indicated that the defense inducing agent consists in a 37 kDa protein. The aim of this work is to characterize the protein secreted by the isolate M23 and to study its activity in other strawberrry cultivars and in Arabidopsis thaliana. The purified protein was separated by SDS-PAGE and electroblotted in 10 mM CAPS (pH 11). The band excised was subjected to Edman gas-phase microsequencing. Each amino acid sequence obtained was compared to annotated sequences using psi-BLASTP. Partial sequence of the purified protein revealed that it belongs the family of the subtilisin-like serin-proteases and the mature protein lacks the N-terminal protease inhibiting domains found in homologous proteins. Phytopathological experiments showed that defense eliciting protein exhibits the ability to confer resistance to other strawberry cultivars in different degrees. Experiments also showed that the purified protein could also induce the accumulation of hydrogen peroxide (H2O2), superoxide anion (O2.-) and callose deposition in Arabidopsis thaliana.