Localisation of expression of a high-affinity sulfate transporter in barley roots

Abstract.

The tissue-specific expression pattern of the gene encoding the high-affinity sulfate transporter, HvST1, was examined in sections of barley (Hordeum vulgare L.) roots by in-situ hybridisation. The results showed expression in all cell layers close to the root tip, with increased expression under conditions of sulfate stress. In mature roots, HvST1 was not expressed in sulfate-sufficient conditions, but under sulfate stress, transcripts were detected in the xylem parenchyma, pericycle and endodermis. This pattern of expression is consistent with a role in sulfate uptake and may indicate that the majority of sulfate uptake occurs close to the root tip. In low-sulfate conditions, HvST1 may have an additional role in scavenging sulfate lost during transport.