Partial biochemical characterization of caspase 3-like activity involved in Solanum tuberosum-P. infestans interaction

FERNÁNDEZ MB, ; DALEO GR ; GUEVARA MG.

Congreso; American Phytopathological Society (APS) meeting; 2011

American Phytopathologycal Society

In plants, the induction of eight caspase- like activities has been described after stress conditions. The aim of this work was to determine the caspase- like activity during Solanum tuberosum- P. infestans (Pi) interaction. Results obtained show that, DEVDase activity was increased in a 70 % and 80% at 24 and 48h after Pi infection, respectively. In order to characterize the caspase like activity detected, the effect of a caspase inhibitors and general inhibitors was analyzed. Data obtained show that, only Ac-DEVD-CHO (50 µM), an specific caspase 3 inhibitor and PMSF, a serine protease inhibitor (2.5 mM) were able to reduce the DEVDase activity in a 95% and 50%, respectively. Additionally, the effect of several ions on the potato caspase 3-like activity was determined. We found that, this activity was reduced in a 30% and 40% in presence of CaCl2 100 and 500 mM, respectively. Contrary, this activity was induced 6 fold in presence of ZnCl2 10mM; and no effect was detected at all concentrations of NaCl assayed. Unlike animal caspases, potato caspase-3 like activity is not detected at neutral pH, however at acidic pHs (3-5), the maximal proteolytic values were determined. These results suggest a possible mitochondrial intermembrane and/or vacuolar and/or apoplastic localization for this/these enzyme/s. This work constitutes the first evidence and partial biochemical characterization of caspase 3- like activity induced during S. tuberosum- Pi interaction.