Potassium is an essential mineral nutrient for citrus growth and stress response. In this study, the
HAK/KUP/KT gene family was identified from the genome of trifoliate orange (
Poncirus trifoliata). The physical and chemical properties, chromosomal location, gene structure, evolutionary relationship, conserved
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Potassium is an essential mineral nutrient for citrus growth and stress response. In this study, the
HAK/KUP/KT gene family was identified from the genome of trifoliate orange (
Poncirus trifoliata). The physical and chemical properties, chromosomal location, gene structure, evolutionary relationship, conserved motifs, and tissue expression characteristics were analyzed. The expression characteristics under low potassium and salt stress were analyzed by fluorescence quantitative PCR. The function of
PtKUP10 was investigated by heterologous expression in
Arabidopsis thaliana. The results showed that at least 18
PtKUPs were distributed in seven chromosomes. Phylogenetic analysis showed that four
PtKUPs clustered in clade I, which mediated the high-affinity potassium absorption. Gene expression analysis showed that four
PtKUPs were highly expressed in root, seven
PtKUPs were up-regulated by low potassium stress, and nine
PtKUPs were up-regulated by salt stress. The
cis-acting elements on the promoter of
PtKUPs were predominantly involved in stress and hormone responses. Overexpression of
PtKUP10 in
Arabidopsis thaliana could enhance salt tolerance by accumulating more potassium in the shoot and reducing sodium content in the shoots and roots. These results indicated that
PtKUPs play important roles in potassium absorption and salt stress response, and
PtKUP10 might enhance salt tolerance by maintaining potassium and sodium homeostasis.
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