CCCH Zinc Finger Genes in Barley: Genome-Wide Identification, Evolution, Expression and Haplotype Analysis

Abstract

Background: CCCH transcription factors are important zinc finger transcription factors involved in the response to biotic and abiotic stress and physiological and developmental processes. Barley (Hordeum vulgare) is an agriculturally important cereal crop with multiple uses, such as brewing production, animal feed, and human food. The identification and assessment of new functional genes are important for the molecular breeding of barley. Results: In this study, a total of 35 protein-encoding CCCH genes unevenly dispersed on seven different chromosomes were identified in barley. Phylogenetic analysis categorized the barley CCCH genes (HvC3Hs) into seven subfamilies according to their distinct features, and this classification was supported by intron–exon structure and conserved motif analysis. Despite the large genome size of barley, the lower number of CCCH genes in barley might be attributed to the low frequency of segmental and tandem duplication events. Furthermore, the HvC3H genes displayed distinct expression profiles for different developmental processes and in response to various types of stresses. The expression of HvC3H9 was significantly induced by multiple types of abiotic stress and/or phytohormone treatment, which might make it an excellent target for the molecular breeding of barley. Genetic variation of HvC3Hs was characterized using publicly available exome-capture sequencing datasets. Clear genetic divergence was observed between wild and landrace barley populations in HvC3H genes. For most HvC3Hs, nucleotide diversity and the number of haplotype polymorphisms decreased during barley domestication. Conclusion: Overall, our study provides a comprehensive characterization of barley CCCH transcription factors, their diversity, and their biological functions.