Genome-Wide Identification and Expression Analysis of the CmHAK Gene Family in Melon (Cucumis melo L.)

Abstract

(1) Background: As the largest family of potassium transporters in plants, KT/HAK/KUP plays an important function in plant growth, development, and stress, especially for potassium-loving plants such as melon. (2) Methods: The members of the KT/HAK/KUP gene family in the melon genome were identified by bioinformatics technology. The gene structure, chromosome location, phylogeny, and expression analysis were comprehensively and systematically analyzed. (3) Results: The results showed that there are 14 members of the KT/HAK/KUP gene family in melon, which are distributed on seven chromosomes. Each member contains 3–11 introns and 4–12 exons, and could be divided into three distinct branches in phylogeny. The number of amino acid residues encoded by each member varies between 610 and 878. In terms of expression, after 12 h of chilling stress, most of the CmHAK genes were expressed in two melon varieties with different chilling resistances. The expression levels of CmHAK6 and CmHAK8 were downregulated in chilling-resistant varieties, but there was no significant change in chilling-sensitive varieties, indicating that CmHAK6 and CmHAK8 genes may play a negative regulatory role in chilling-resistant varieties. (4) Conclusions: The study provides a theoretical basis for in-depth analysis of the functions of KT/HAK/KUP gene family and cultivation of high-potassium stress-resistant melon varieties.