Genome-Wide Identification, Molecular Evolution, and Expression Divergence of CLC, ALMT, VDAC, and MSL Gene Family in Barley

Organic and inorganic nutrients, osmotic components, associated protein cofactors, and signaling molecules regulate biotic and abiotic stresses in plants. Earlier reports suggest that plant cells activate anion channels and induce the efflux of anions at the plasma membrane under drought. Herein, CHLORIDE CHANNEL (CLC), ALUMINUM-ACTIVATED MALATE TRANSPORTER (ALMT), VOLTAGE-DEPENDENT ANION CHANNEL (VDAC), and MECHANOSENSITIVE CHANNEL of SMALL CONDUCTANCE-LIKE (MscS-like, MSL) gene family were reported in barley. Totally, 43 anion channel proteins were identified in barley at the genome-wide level. Expression profiles of anion channel genes were obtained from public databases and verified by qRT-PCR. In addition, the expression pattern of the anion channel gene family in multiple tissues among ten land plants showed the organs in which it is actively expressed, and 43 anion channel genes were expressed in diverse tissues, such as tillers, epidermal strips, inflorescences, and grain in barley. The expression of anion channel genes was performed in ten different cultivars and wild barley, of which 17 genes were confirmed by qRT-PCR under drought treatment, suggesting that different cultivars have diverse anion channel genes in response to drought stress. The plants with high transcripts of these genes demonstrated stronger tolerance to drought stress and element content (e.g., potassium, calcium). The results might help to further elucidate the molecular mechanism of anion channels related to stress and provide a toolkit for enhancing the drought tolerance of barley.