Non race- specific resistance of potato to Phytophthora infestans involves DEVDase activity

FERNÁNDEZ, MB; DALEO, GR; GUEVARA, MG

Congreso; 47 Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2011

During S. tuberosum- P. infestans (Pi) interaction, two forms of genetic resistance have been characterized: race- or non race-specific. The latter is due to the expression of quantitative loci and thus, its field durability is greater than in race specific resistance. In the last years, plant caspase- like activities have been described in Solanaceae: caspase-1 (after viral infection in tobacco leaves) and caspase-3 and 9 (after heat shock in tomato fruit). The aim of this work was to analyze caspase-3 like activity (DEVDase) in potato cultivars with non race specific resistance to Pi. Protein extracts from potato leaves from cv. Pampeana (moderately resistant) and cv. Bintje (susceptible) infected with Pi for 0, 1, 6, 12, 24 and 48hs were prepared. DEVDase activity was detected after 24 and 48h of infection in the resistant cv. but not in the susceptible one. Biochemical characterization of DEVDase activity exhibited inhibition by PMSF and caspase-3 inhibitor (DEVD-CHO) and sensitiveness to Ca+2 and Zn+2 ions. Pre-treatment of Pampeana leaves with DEVD-CHO or the general caspase inhibitor VAD-FMK showed a greater Pi disease development compared to control condition. However, plant cell death was decreased in caspase inhibitors treated leaves. Finally, we conclude that caspase- 3 like activity is involved in partial nonrace specific resistance of S. tuberosum leaves to P. infestans.