Genome-wide analysis of HAK/KUP/KT potassium transporter genes in banana (Musa acuminata L.) and their tissue-specific expression profiles under potassium stress

Siwen Liu,Bangting Wu,Jianghui Xie,Yanling Xie,Chunyu Li,Wei Wang,Sijun Zheng,Dandan Xiang

doi:10.1007/s10725-021-00793-7

Abstract

Potassium is one of the most essential inorganic cations for plant growth and development. The high affinity K+ (HAK)/K+ uptake (KUP)/K+ transporter (KT) family plays essential roles in the regulation of cellular K+ levels and the maintenance of osmotic balance. However, the roles of these genes in the responses of bananas to low-potassium stress are unclear. In this study, 24 HAK/KUP/KT (MaHAK) genes were identified from banana. These genes were further classified into four groups based on phylogenetic analysis, gene structure and conserved domain analysis. Segmental duplication events played an important role in the expansion of the MaHAK gene family. Transcriptome analysis revealed the expression patterns of MaHAKs in various tissues under different K+ conditions. MaHAK14b was upregulated under both short- and long-term K+-deficient conditions, suggesting that it plays crucial roles in K+ uptake at low K+ concentrations. Furthermore, MaHAK14b mediated K+ uptake when it was heterologously expressed in the yeast mutant R5421 on low K+ medium. Collectively, these findings provide a foundation for further functional analysis of MaHAK genes, which may be used to improve potassium stress resistance in bananas.

Highlights

Potassium ions (K+) are one of the most essential plant macronutrients and are involved in various plant physiological and biochemical processes, such as osmoregulation, enzyme activation, stomatal regulation, and maintenance of pH (Hasanuzzaman et al 2018)
Potassium transporters in plants can be classified into four families: the high affinity K+ (HAK)/K+ uptake (KUP)/K+ transporter (KT) family, the Trk/Ktr/HKT family, the K+ efflux antiporter (KEA) family, and the cation/H+ exchanger (CHX) family (Maser et al 2001; Gierth and Maser 2007)
The HAK/KUP/KT gene family has been largely investigated in many plants, e.g., Arabidopsis thaliana (Maser et al 2001), Oryza sativa (Gupta et al 2008), Zea mays (Zhang et al 2012), Prunus persica (Song et al 2015), Cicer arietinum (Azeem et al 2018), Manihot esculenta (Ou et al 2018), and Triticum aestivum (Cheng et al 2018)

Summary

Introduction

Potassium ions (K+) are one of the most essential plant macronutrients and are involved in various plant physiological and biochemical processes, such as osmoregulation, enzyme activation, stomatal regulation, and maintenance of pH (Hasanuzzaman et al 2018). The HAK/KUP/KT gene family has been largely investigated in many plants, e.g., Arabidopsis thaliana (Maser et al 2001), Oryza sativa (Gupta et al 2008), Zea mays (Zhang et al 2012), Prunus persica (Song et al 2015), Cicer arietinum (Azeem et al 2018), Manihot esculenta (Ou et al 2018), and Triticum aestivum (Cheng et al 2018). The expression profiles of HAK/KUP/KT genes in response to different abiotic stresses have been investigated in many plant species (Cheng et al 2018)

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Conclusion