Isolation and functional determination of inward‐rectifier K ⁺ channel PbrAKT1 in pear

ABSTRACT Potassium (K + ) is essential to plant growth and development. The absorption and transport of K + by plant roots occurs mainly through K + channels or transporters. In this study, an AKT1‐type channel named PbrAKT1 was successfully cloned and characterised by a series of detailed procedures, including protein sequence alignment, expression and subcellular localisation analysis, as well as functional verification by heterologous expression function validation in yeast mutant R5421 , Arabidopsis akt1 mutant, and Xenopus oocytes. The results showed that PbrAKT1 is preferentially expressed in pear roots and exhibits plasma membrane localisation, but its expression is unaffected by low K + treatment. PbrAKT1 exhibits the function of an inwardly‐rectifying K + channel, and its activity is autonomously regulated when expressed in Xenopus oocytes. In addition, a series of heterologous expression experiments confirmed that PbrAKT1 plays an indispensable role in the processes of K + transport, as well as alleviating the low‐K + ‐sensitive phenotype of yeast mutant R5421 and Arabidopsis akt1 mutant. In summary, PbrAKT1 plays an indispensable role in the processes of K + transport and provide new information on the molecular mechanism of K + absorption in pear roots.