A Novel High-Affinity Potassium Transporter Gene Enhances Low-Potassium Tolerance in Transgenic Roots of Sweet Potato ( (L.) Lam.).

The high-affinity potassium transporters (HKT) mediate K-Na homeostasis in plants. However, the function of enhancing low-potassium tolerance in sweet potato [ (L.) Lam.] remains unrevealed. In this study, a novel HKT transporter homolog gene was cloned from sweet potato, which was significantly induced by potassium deficiency stress. overexpressing transgenic roots were obtained from a sweet potato cultivar Xuzishu8 using an -mediated root transgenic system in vivo. Compared with the CK, whose root cells did not overexpress the gene, overexpression of the gene protected cell ultrastructure from damage, and transgenic root meristem cells had intact mitochondria, endoplasmic reticulum, and Golgi dictyosomes. The steady-state K influx increased by 2.2 times in transgenic root meristem cells. Overexpression of the gene also improved potassium content in the whole plant, which increased by 63.8% compared with the CK plants. These results could imply that the gene, as a high-affinity potassium transporter gene, may play an important role in potassium deficiency stress responses.