Identification and Characterization of Rice Variants.

In rice, the high-affinity K transporter, , functions as a Na-selective transporter. mRNA variants of have been reported previously, but their functions remain unknown. In this study, five variants () were identified from japonica rice (Nipponbare) in addition to . Absolute quantification qPCR analyses revealed that the transcript level of was significantly higher than other variants in both the roots and shoots. Expression levels of , and some variants, increased after 24 h of salt stress. Two electrode voltage clamp experiments in a heterologous expression system using oocytes revealed that oocytes expressing OsHKT1;3_FL and all of its variants exhibited smaller Na currents. The presented data, together with previous data, provide insights to understanding how family members are involved in the mechanisms of ion homeostasis and salt tolerance in rice.