Expression levels of inositol phosphorylceramide synthase modulate plant responses to biotic and abiotic stress in Arabidopsis thaliana. Expression levels of inositol phosphorylceramide synthase modulate plant responses to biotic and abiotic stress in Arabidopsis thaliana

This research was undertaken to investigate the global role of inositol phosphorylceramide synthase (IPCS) activity in plants and reveal its potential as a herbicide target. The non-mammalian enzyme is a key component in the plant sphingolipid biosynthetic pathway and is shown here to be a possible herbicide target. RNA-Seq analyses demonstrated that over-expression of inositol phosphorylceramide synthase isoforms AtIPCS1, 2 or 3 in Arabidopsis thaliana resulted in the down-regulation of genes involved in plant response to pathogens. In addition, genes associated with the abiotic stress response to salinity, cold and drought were found to be similarly down-regulated. Detailed analyses of transgenic lines over-expressing AtIPCS1-3 at various levels revealed that the degree of down-regulation is specifically correlated with the level of IPCS expression. Singular enrichment analysis of these down-regulated genes showed that AtIPCS1-3 expression affects biological signaling pathways involved in plant response to biotic and abiotic stress. The up-regulation of genes involved in photosynthesis and lipid localization was also observed in the over-expressing lines. Overall design: Two biological replicates were analyzed for each AtPCS isoform (three IPCS isoforms; two levels of AtIPCS expression per isoform)