Genome-wide analysis and expression of the Plasma membrane intrinsic gene family in Caragana korshinskii Kom

Plasma membrane intrinsic proteins (PIPs), as essential plant channel proteins located on the plasma membrane, play pivotal roles in the transfer of water, CO₂, and small uncharged solutes across the plasma membrane. Although the molecular mechanisms of PIPs have been extensively studied in model species, their characteristics and functions remain poorly characterized in Caragana korshinskii . Here, 13 CkPIP genes were identified through genome-wide analysis. CkPIPs were clustered into PIP1 (seven members) and PIP2 (six members) subfamilies, exhibiting conserved physicochemical properties, cis-acting elements that respond to abiotic stresses and phytohormones, and evidence of segmental duplication under purifying selection. Phylogenetic, structural, and expression analyses (RNA-seq and RT-qPCR) were performed to explore their evolutionary patterns and responses to drought stress. Under drought stress, CkPIPs exhibited tissue-specific expression dynamics: CkPIP1;1 , CkPIP1;2 , and CkPIP2;2 was prominently upregulated, suggesting their key roles in drought adaptation. This study expands our understanding of CkPIP family characteristics and provides valuable molecular insights for drought-resistance research and forage improvement.