Soybean BRU1 encodes a functional xyloglucan endotransglycosylase that is highly expressed in inner epicotyl tissues during brassinosteroid-promoted elongation

Abstract

Brassinosteroids promote soybean epicotyl elongation and regulate expression of BRU1, a gene with homology to xyloglucan endotransglycosylases (XETs). Recombinant BRU1 protein possesses XET activity and in situ hybridization reveals highest BRU1 transcript accumulation in inner epicotyl tissue, particularly the phloem and paratracheary parenchyma cells. These results suggest a role for BRU1 in vascular development in addition to cell elongation.