Abstract
HvLsi2 is a homolog of rice efflux silicon transporter OsLsi2 in barley. They share 86% identity. Our previous study showed that HvLsi2 is also able to transport Si out of the cell in Xenopus oocyte. HvLsi2 was mainly expressed in the roots and positive correlation was found between the HvLsi2 expression level and Si uptake in different cultivars. In this study, we further conducted functional analysis of this transporter. To examine the subcellular localization of HvLsi2, we prepared microsome from barley roots and fractionated by sucrose gradient. Western analysis showed that HvLsi2 was in the same fraction as plasma membrane marker HvPIP2;1. Immunostaining showed that HvLsi2 was localized on the endodermis, but did not show polar localization. When HvLsi2 was introduced into rice lsi2 mutant under the control of OsLsi2 promoter, the Si uptake was recovered to the level of wild-type rice. Interestingly, HvLsi2 showed polar localization in rice.
