Genome-wide analysis of the HAK potassium transporter gene family reveals asymmetrical evolution in tobacco (Nicotiana tabacum)

Being an essential mineral nutrient, potassium (K+) plays numerous important roles in plant growth and development and determines the yield and quality of crop products. The cellular level of K+ is controlled to a large extent by the potassium transporter which belongs to the KT/HAK/KUP (HAK) family. However, little is known about these genes in tobacco. In this study, we surveyed the tobacco genome and identified forty-one putative NtHAK genes (NtHAKS1-NtHAKS21 and NtHAKT1-NtHAKT20). Investigation of the cis-elements in upstream regions of these NtHAKs suggests that members of this family respond to environmental clues and phytohormones. Expression data mining reveals that NtHAKs showed clear sub-genome dominance. In all, these results will provide molecular insights into the potassium transporter research in tobacco.