Genome-wide characterization and expression analysis of HAK K+ transport family in Ipomoea

The potassium transporter high-affinity K + transporter/K + uptake permease/K + transporter (HAK/KUP/KT) family plays a vital role in potassium uptake, and potassium ion (K + )-mediated environmental stress. In the present study, we identified 22 IbHAK/KUP/KT ( HAK ) genes in sweet potato [ Ipomoea batata (L.) Lam] and the same number of HAK genes from sweet potato wild relative Ipomoea trifida . Phylogeny analysis indicated that the HAKs can be divided into five clades. Chromosomal distribution and genome synteny analyses revealed two tandem-duplicated gene pairs IbHAK16/17 and IbHAK17/18 on chromosomes 13 and eight segmental-duplicated gene pairs on chromosomes 1, 3, 5, 8, 10, 12, 14 among the IbHAK gene family. Eleven orthologous HAK gene pairs between I. batata and I. trifida were involved in the duplication of genomic blocks based on comparative genomic analysis. The Ka/Ks ratios of these IbHAK genes ranged from 0.02 to 0.55(