Genome-Wide Identification and Characterization of the Shaker-Type K Channel Genes in (L.) Batsch.

Shaker-type K channels are critical for plant K acquisition and translocation that play key roles during plant growth and development. However, molecular mechanisms towards K channels are extremely rare in fruit trees, especially in peach. In this study, we identified 7 putative shaker-type K channel genes from peach, which were unevenly distributed on 5 chromosomes. The peach shaker K channel proteins were classified into 5 subfamilies, I-V, and were tightly clustered with pear homologs in the phylogenetic tree. Various -acting regulatory elements were detected in the promoter region of the shaker-type K channel genes, including phytohormone-responsive, abiotic stress-responsive, and development regulatory elements. The peach shaker K channel genes were expressed differentially in distinct tissues, and was specifically expressed in the full-bloom flowers; and were predominantly expressed in the leaves, while , , and were majorly expressed in the roots. The peach shaker K channel genes were differentially regulated by abiotic stresses in that K deficiency, and ABA treatment mainly increased the shaker K channel gene expression throughout the whole seedling, whereas NaCl and PEG treatment reduced the shaker K channel gene expression, especially in the roots. Moreover, electrophysiological analysis demonstrated that PpSKOR is a typical voltage-dependent outwardly rectifying K channel in peach. This study lays a molecular basis for further functional studies of the shaker-type K channel genes in peach and provides a theoretical foundation for K nutrition and balance research in fruit trees.