SKN1 , a novel plant defensin‐sensitivity gene in Saccharomyces cerevisiae , is implicated in sphingolipid biosynthesis

The antifungal plant defensin DmAMP1 interacts with the fungal sphingolipid mannosyl diinositolphosphoryl ceramide (M(IP) 2 C) and induces fungal growth inhibition. We have identified SKN1 , besides the M(IP) 2 C‐biosynthesis gene IPT1 , as a novel DmAMP1‐sensitivity gene in Saccharomyces cerevisiae . SKN1 was previously shown to be a KRE6 homologue, which is involved in β‐1,6‐glucan biosynthesis. We demonstrate that a Δ skn1 mutant lacks M(IP) 2 C. Interestingly, overexpression of either IPT1 or SKN1 complemented the skn1 mutation, conferred sensitivity to DmAMP1, and resulted in M(IP) 2 C levels comparable to the wild type. These results show that SKN1 , together with IPT1 , is involved in sphingolipid biosynthesis in S. cerevisiae .