Genome-Wide Analysis of Potassium Channel Genes in Rice: Expression of the OsAKT and OsKAT Genes under Salt Stress

Abstract

Potassium (K+), as a vital element, is involved in regulating important cellular processes such as enzyme activity, cell turgor, and nutrient movement in plant cells, which affects plant growth and production. Potassium channels are involved in the transport and release of potassium in plant cells. In the current study, three OsKAT genes and two OsAKT genes, along with 11 nonredundant putative potassium channel genes in the rice genome, were characterized based on their physiochemical properties, protein structure, evolution, duplication, in silico gene expression, and protein–protein interactions. In addition, the expression patterns of OsAKTs and OsKATs were studied in root and shoot tissues under salt stress using real-time PCR in three rice cultivars. K+ channel genes were found to have diverse functions and structures, and OsKATs showed high genetic divergence from other K+ channel genes. Furthermore, the Ka/Ks ratios of duplicated gene pairs from the K+ channel gene family in rice suggested that these genes underwent purifying selection. Among the studied K+ channel proteins, OsKAT1 and OsAKT1 were identified as proteins with high potential N-glycosylation and phosphorylation sites, and LEU, VAL, SER, PRO, HIS, GLY, LYS, TYR, CYC, and ARG amino acids were predicted as the binding residues in the ligand-binding sites of K+ channel proteins. Regarding the coexpression network and KEGG ontology results, several metabolic pathways, including sugar metabolism, purine metabolism, carbon metabolism, glycerophospholipid metabolism, monoterpenoid biosynthesis, and folate biosynthesis, were recognized in the coexpression network of K+ channel proteins. Based on the available RNA-seq data, the K+ channel genes showed differential expression levels in rice tissues in response to biotic and abiotic stresses. In addition, the real-time PCR results revealed that OsAKTs and OsKATs are induced by salt stress in root and shoot tissues of rice cultivars, and OsKAT1 was identified as a key gene involved in the rice response to salt stress. In the present study, we found that the repression of OsAKTs, OsKAT2, and OsKAT2 in roots was related to salinity tolerance in rice. Our findings provide valuable insights for further structural and functional assays of K+ channel genes in rice.

Magnesium transporter Gene Family: Genome-Wide Identification and Characterization in Theobroma cacao, Corchorus capsularis, and Gossypium hirsutum of Family Malvaceae

“…Moreover, sub-groups of MGTs in the three studied plants showed diversity in the predicted pocket sites in the 3D structure. Overall, our findings suggest that PHE, GLU, LEU, GLY, and ILE, as the key binding sites, are associated with the function and interaction of MGTs in response to environmental stimuli and changes in ion/Mg concentration [54,75,76].…”

“…Notably, a gene cluster of three MRS2/TcMGT genes, namely TcMGT013, TcMGT14, and TcMGT15, was observed in chromosome 6, providing an avenue for further molecular investigations in cacao. In addition, the K a /K s ratios in most duplicated genes were less than one, suggesting that MGTs have evolved slowly under a purifying selection [54,71]. The comparisons between structures of MGT proteins revealed that NIPA proteins include the conserved structures with more transmembrane regions.…”

“…The MGT genes with more than 85% identity in each species were selected as duplicated genes [54]. Then, the location diagram of duplicated genes in cacao and G. hirsutum were constructed using TBtools [55].…”

Rice Potassium Transporter OsHAK8 Mediates K+ Uptake and Translocation in Response to Low K+ Stress

“…However, comparing with Arabidopsis , much less is known about the mechanism underlying K + absorption and translocation in rice plants. Although OsAKT1 and OsHAK5, like AtAKT1 and AtHAK5, mediate K + uptake in rice roots ( Li et al, 2014 ; Yang et al, 2014 ), K + channels such as OsKATs and OsAKTs may be involved in K + accumulation in the cytoplasm in response to salt stress ( Musavizadeh et al, 2021 ). Thus, more transporters related to K + absorption and translocation need to be explored.…”

Hormone Profiles and Antioxidant Activity of Cultivated and Wild Tomato Seedlings under Low-Temperature Stress

“…The change in membrane conformation that results in a decrease in membrane fluidity is one of the first structural changes related to low-temperature stress [5]. Furthermore, the alteration of membrane conformation can cause oxidative stress by rapidly inducing reactive oxygen species (ROS), and then, the concentration of cryoprotective compounds increases in the cytoplasmic matrix [2,6,7]. However, plants use various mechanisms, including morphological and structural modifications, as well as biochemical mechanisms to modulate cellular homoeostasis to reduce low, nonfreezing temperature-induced damage [2,8,9].…”