blt4 is a barley gene which, as measured by steady state mRNA levels, is induced by a low positive temperature treatment of shoot meristems. The gene is also induced in shoot meristems by drought stress. We now report the response of this gene to foliar applications of abscisic acid. The striking similarity between the predicted amino acid sequence of blt4 and two maize phospholipid transfer proteins indicates a biochemical function for the blt4 gene product. This homology also demonstrates the hitherto unreported environmental regulation of expression of a phospholipid transfer protein which may involve abscisic acid in the signal transduction pathway.