Isolation and characterization of a Solanum tuberosum subtilisin- like protein with caspase- 3 activity (StSBTc-3)

FERNÁNDEZ, MARÍA BELÉN; DALEO, GUSTAVO RAÚL; GUEVARA, MARÍA GABRIELA

PLANT PHYSIOLOGY AND BIOCHEMISTRY

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

Lugar: Paris; Año: 2015 vol. 86 p. 137 - 146

0981-9428

Plant proteases with caspase-like enzymatic activity have been widely studied during the last decade. Previously, we have reported the presence and induction of caspase- 3 like activity in the apoplast of potato leaves, during S. tuberosum- P. infestans interaction. In this work we have purified and identified a potato extracellular protease with caspase- 3 like enzymatic activity from potato leaves infected with P. infestans. Results obtained from the size exclusion chromatography show that the isolated protease is a monomeric enzyme with an estimated molecular weight of 70 kDa approximately. Purified protease was analyzed by MALDI-TOF MS, showing a 100% of sequence identity with the deduced amino acid sequence of a putative subtilisin- like protease from S. tuberosum (Solgenomics protein ID: PGSC0003DMP400018521). For this reason the isolated protease was named as StSBTc- 3. This report constitutes the first evidence of isolation and identification of a plant subtilisin- like protease with caspase- 3 like enzymatic activity. In order to elucidate the possible function of StSBTc- 3 during plant pathogen interaction, we demonstrate that like animal caspase- 3, StSBTc- 3 is able to produce in vitro cytoplasm shrinkage in plant cells and to induce plant cell death. This result suggest that, StSBTc- 3 could exert a caspase executer function during potato- P. infestans interaction, resulting in the restriction of the pathogen spread during plant- pathogen interaction.