Genome-Wide Identification and Expression Analysis of the Casparian Strip Membrane Domain Protein-like Gene Family in Peanut ( Arachis hypogea L.) Revealed Its Crucial Role in Growth and Multiple Stress Tolerance.

Casparian strip membrane domain proteins (CASPs), regulating the formation of Casparian strips in plants, serve crucial functions in facilitating plant growth, development, and resilience to abiotic stress. However, little research has focused on the characteristics and functions of AhCASPs in cultivated peanuts. In this study, the genome-wide identification and expression analysis of the AhCASPs gene family was performed using bioinformatics and transcriptome data. Results showed that a total of 80 AhCASPs members on 20 chromosomes were identified and divided into three subclusters, which mainly localized to the cell membrane. Ka/Ks analysis revealed that most of the genes underwent purifying selection. Analysis of cis elements suggested the possible involvement of AhCASPs in hormonal and stress responses, including GA, MeJA, IAA, ABA, drought, and low temperature. Moreover, 20 different miRNAs for 37 different AhCASPs genes were identified by the psRNATarget service. Likewise, transcriptional analysis revealed key AhCASPs responding to various stresses, hormonal processing, and tissue types, including 33 genes in low temperature and drought stress and 41 genes in tissue-specific expression. These results provide an important theoretical basis for the functions of AhCASPs in growth, development, and multiple stress resistance in cultivated peanuts.