DSH5, a dihydrosphingosine C4 hydroxylase gene family member, shows spatially restricted expression in rice and is lethal when expressed ectopically.

Dihydrosphingosine C4 hydroxylase (DSH), a diiron-binding membrane enzyme, catalyzes the hydration of dihydrosphingosine and acyl-sphinganine to produce phytosphingosine and phytoceramide, respectively. Rice has two types of DSH homologs: general DSHs, namely DSH1, DSH2 and DSH4, and others that show spatial expression profiles, namely DSH3 and DSH5. The general DSHs exist in many plant species.