Apoptotic chromatin condensation inducer in the nucleus: Genome-wide analysis in plants and expression profile during Cowpea Severe Mosaic Virus infection in Vigna unguiculata [L.] Walp

Apoptotic Chromatin Condensation Inducer in the Nucleus (ACIN1) is a scaffold protein that was first described as a complex component responsible for triggering apoptosis in human cells. In plants, ACIN1 participates in silencing of Flowering Locus C (FLC), involved in vernalization in Arabidopsis thaliana. Contrary to what has been observed for humans, there are no reports on ACIN1 linked to programmed cell death (PCD) in plants. Actually, the function of ACIN1 in plants is still poorly understood. In the present study, a genome-wide analysis of the ACIN1 gene family in plants identified 27 ACIN1 orthologs from 19 species belonging to 12 plant families. The phylogenetic relationships, physicochemical properties, gene structure, conserved motifs, promoter cis-elements, chromosomal localization, syntenic regions, and protein network were investigated. Altogether, these analyzes revealed highly conserved domains in the structure of the ACIN1 proteins, as well as putative metacaspase cleavage sites, which suggest that they play a conserved function probably associated with the programmed cell death in plants. For instance, differential expression pattern and modulation of ACIN1 were noticed after inoculation of cowpea with Cowpea severe mosaic virus (CPSMV). Therefore, this study was conducted to provide, for the first time, information on the evolutionary, structural, and functional characteristics of the ACIN1 gene family as an initial effort towards understanding the role of these proteins in studied plant development and stress responses.