Genome-Wide Identification, Characterization, and Comparison of C3HC4 Family Genes in Salt Tolerance Between Barley and Rice

Soil salinization constitutes a major constraint on global agricultural production, with marked divergence in salt adaptation strategies between salt-tolerant barley (<i>Hordeum vulgare</i>) and salt-sensitive rice (<i>Oryza sativa</i>). This study systematically investigated the evolution and functional specialization of the C3HC4-type RING zinc finger gene family, known to mediate abiotic stress responses through E3 ubiquitin ligase activity, in these contrasting cereal species. Through comparative genomics, we identified 123 <i>HvC3HC4</i> genes and 90 <i>OsC3HC4</i> genes, phylogenetically classified into four conserved subgroups. Differences in <i>C3HC4</i> genes in phylogenetic relationships, chromosomal distribution, gene structure, motif composition, gene duplication events, and <i>cis</i>-elements in the promoter region were observed between barley and rice. Moreover, <i>HvC3HC4s</i> in barley tissues preferentially adopted an energy-conserving strategy, which may be a key mechanism for barley's higher salt tolerance. Additionally, we found that <i>C3HC4</i> genes were evolutionarily conserved in salt-tolerant species. The current results reveal striking differences in salt tolerance between barley and rice mediated by the <i>C3HC4</i> gene family and offer valuable insight for potential genetic engineering applications in improving crop resilience to salinity stress.