Wax on, the Mammalian Way

Courtesy of Peggy Greb, ARS

Plants export wax from epidermal cells to their external surfaces through a lipid transporter similar to those present in mammalian cells, according to a study from the University of British Columbia.¹ "Up until now, we knew that plants produce this waxy coating on their cuticle … but no one knew how these highly hydrophobic molecules that are made in the cells get out," says BC's Lacey Samuels.

The group found an Arabidopsis thaliana mutant, cer5, which has a glossy, bright green stem phenotype caused by a reduced wax layer. "It had a very unusual cell structure," says Samuels, "with cytoplasmatic lipid inclusions I had never seen before." Samuels says the structures are identical to those present in patients with adrenoleukodystrophy, a genetic disorder associated with defects in an ATP-binding cassette (ABC) lipid transporter.

CER5, they discovered, encodes part of an ABC transporter that...