In silico genome-wide analysis of Citrus sinensis (L.) Osbeck NHX and KEA genes and their roles in abiotic stress

Abstract

Citrus sinensis (L.) Osbeck is a valuable plant belonging to the Rutaceae family. Stress is induced in plants by abiotic factors such as drought, salinity, and temperature. The monovalent cation proton antiporter (CPA) superfamily, which includes the K⁺ efflux antiporter (KEA) and Na⁺/H⁺ exchanger (NHX) genes, plays a crucial role in the regulation of physiological events. This study aims to identify the KEA and NHX genes of C. sinensis and elucidate the roles of these genes in the response to abiotic stress. For this purpose, phylogenetic structure, distribution of chromosomes, gene duplications, gene and protein structures, cis-acting elements, functional gene ontologies, targeted miRNAs, and in silico PCR primer searches were performed using CsNHX and CsKEA sequences. Two KEA and fifty-five NHX were identified as a result of the analysis. Nine of the fifty-five genes (CsNHX5, CsNHX11, CsNHX12, CsNHX17, CsNHX27, CsNHX28, CsNHX47,CsNHX48, and CsNHX55) have been identified as playing a role in the stress response. On the phylogenetic tree, NHX genes were observed to be divided into three distinct clusters. The existence of multiple segmental and tandem duplications in the CsNHX genes has been demonstrated. Stress-related motifs were identified in the promoter regions of CsKEA and CsNHX by cis-acting element analysis, while stress-related miRNAs were identified by miRNA analysis. Consequently, KEA genes are responsible for transport, but they may also play a role in abiotic stress, as they contain cis-acting elements involved in the stress response and are targeted by miRNAs associated with stress. In addition, it has been determined that CsNHX5, which plays a role in the stress response, has the potential to be used in future transgenic plant production studies as it satisfies the PCR in silico criteria.