REVIEW Caspases in plants: metacaspase gene family in plant stress responses David Fagundes 1 & Bianca Bohn 1 & Caroline Cabreira 2 & Fábio Leipelt 1 & Nathalia Dias 1 & Maria H. Bodanese-Zanettini 2 & Alexandro Cagliari 1 Received: 22 April 2015 /Revised: 22 July 2015 /Accepted: 24 July 2015 # Springer-Verlag Berlin Heidelberg 2015 Abstract Programmed cell death (PCD) is an ordered cell suicide that removes unwanted or damaged cells, playing a role in defense to environmental stresses and pathogen inva- sion. PCD is component of the life cycle of plants, occurring throughout development from embryogenesis to the death. Metacaspases are cysteine proteases present in plants, fungi, and protists. In certain plant–pathogen interactions, the PCD seems to be mediated by metacaspases. We adopted a com- parative genomic approach to identify genes coding for the metacaspases in Viridiplantae. We observed that the metacaspase was divided into types I and II, based on their protein structure. The type I has a metacaspase domain at the C-terminus region, presenting or not a zinc finger motif in the N-terminus region and a prodomain rich in proline. Metacaspase type II does not feature the prodomain and the zinc finger, but has a linker between caspase-like catalytic domains of 20 kDa (p20) and 10 kDa (p10). A high conser- vation was observed in the zinc finger domain (type I proteins) and in p20 and p10 subunits (types I and II proteins). The phylogeny showed that the metacaspases are divided into three principal groups: type I with and without zinc finger domain and type II metacaspases. The algae and moss are presented as outgroup, suggesting that these three classes of metacaspases originated in the early stages of Viridiplantae, being the absence of the zinc finger domain the ancient con- dition. The study of metacaspase can clarify their assignment and involvement in plant PCD mechanisms. Keywords Programmed cell death . Metacaspase gene family . Biotic and abiotic stress responses David Fagundes, Bianca Bohn and Caroline Cabreira contributed equally to this work. Electronic supplementary material The online version of this article (doi:10.1007/s10142-015-0459-7) contains supplementary material, which is available to authorized users. * Alexandro Cagliari alexandro-cagliari@uergs.edu.br David Fagundes dsanttos007@hotmail.com Bianca Bohn biabohn@hotmail.com Caroline Cabreira carol.cabreira@yahoo.com.br Fábio Leipelt fabioleipelt@hotmail.com Nathalia Dias nat112006@yahoo.com.br Maria H. Bodanese-Zanettini mhbzanettini@yahoo.com.br 1 Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50 Santa Cruz do Sul, RS, Brazil 2 Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil Funct Integr Genomics DOI 10.1007/s10142-015-0459-7