Abstract
Silicon is a beneficial element for plant growth, which helps plant to overcome various stresses such as pest, pathogen, drought and heavy-metal toxicity. Our goal is to understand the silicon uptake mechanism in barley by physiological and molecular biological approaches. Kinetics analysis indicated that the concentrations in symplast and xylem were always higher than that in the external solution and saturated at higher concentrations, suggesting that the radical transport of silicon from the external solution and the xylem loading are actively mediated by transporter(s). HvLsi1 and HvLsi2 were then isolated as homologous genes to rice silicon transporters. Both genes were specifically expressed in the roots. HvLsi1 showed silicon influx transporter activity in Xenopus oocytes. Immunostaing showed that HvLsi1 is localized on the distal side of outer cortex cells, which is slightly different from the localization of Lsi1 in rice. Characterizations of HvLsi2 will be reported as well.
