Abc1kN is involved in glucosinolate metabolism and stress response during seed development in Arabidopsis thaliana

The activity of bc1 complex kinases is a group of proteins that share a highly conserved ABC1 domain (that is not related to the ATP-Binding Cassette – ABC – transporter proteins) widespread among living organisms. Homologous proteins are grouped into an interesting protein family, ABC1Ks, that, although showing the typical kinase domain(s), lacks many of the features of eukaryotic protein kinases. Members of the family have been isolated from mitochondria, chloroplasts, and the sub-plastidial plastoglobule vesicles, which points to the wide distribution of members of this family among archaea, eubacteria and eukaryotes. In our work, we describe the characterization of the knock-out mutant lines on one of these Abc1k genes of the Arabidopsis thaliana genome, that we termed Abc1kN. The gene seems to be expressed mainly during embryogenesis, as proven by blue colour of embryos in transgenic plants adopted for GUS assay driven by the native promoter. Moreover, mRNA is not detectable in leaves, shoots or roots, by Real Time PCR. Mutant lines have been analysed, and although the lack of the gene function does not influence the overall plant fitness, development and reproduction, mutant seeds show a different colour and size, reduced ABA accumulation and anomalous glucosinolate modifications. Also germination is affected as well as abiotic stress response of germination. An RNA-seq approach was conducted on siliques, highlighting differences in expression of genes involved in abiotic stress response.