Genome-wide identification and expression profiling of PIN-PILS family genes in barley reveal potential role in spikelet abortion and abiotic stress tolerance

Abstract

Abstract Auxin profoundly shapes plant growth and development, directing morphogenesis and adaptive responses. PIN and PILS family genes facilitate auxin transport, influencing its movement between plant cells and intracellular accumulation. However, systematic studies on PIN and PILS genes in barley are lacking. Here, we identified 14 PIN and 7 PILS genes in Hordium vulgare, establishing their evolutionary relationships with Arabidopsis, Brachypodium, maize, rice and wheat. Through analysis, we explored the physical properties, motifs, cis-regulatory elements, chromosomal location, collinearity, protein interactions, miRNA targets, and expression patterns of HvPIN-PILS genes across tissues, spikelet abortion, and stresses. We discovered cis-regulatory elements in the promoter region associated with plant development and stress, highlighting their potential roles. Moreover, our network analysis revealed interactions between HvPIN-PILS proteins and auxin signaling pathway components, underlining their critical regulatory functions in barley's growth and stress management. Our results indicated that mostly HvPIN-PILS genes highly expressed in Morex genotype during apical spikelet abortion stages. These findings pave the way for future research to enhance growth and stress tolerance in barley and related species by exploring the functions of PIN-PILS genes.