Abstract
BACKGROUND: The peroxidase (PRX) gene family plays important roles in plant growth and development, antioxidant defense, immune response, cell wall synthesis, and environmental stress response. However, the genome-wide identification and analysis of PRX in castor bean (Ricinus communis L.) have not been comprehensively analyzed. RESULTS: Based on the data, the PRX gene family in castor bean genome was identified genome-wide and analyzed by bioinformatics methods. Sixty-three members of the PRX gene family were identified in castor bean. These genes were unevenly distributed on 10 chromosomes. Phylogenetic analysis showed that the RcPRX family members were grouped into five clusters, most of which were closely related to Arabidopsis thaliana. Analysis of cis-acting elements in the promoters showed that RcPRX promoters contained the highest number of antioxidant responsive elements and abscisic acid responsive elements, and these genes may mediate oxidative and osmotic stress responses. In addition, transcriptome analysis showed that the high expression of RcPRX genes in castor bean roots may promote root growth and development and enhance plant adaptation to adverse stress. Meanwhile, qRT-PCR expression analysis revealed that most of the RcPRX genes were significantly up-regulated under salt stress, drought stress. A plausible explanation for the observed differential stress resilience among tissues with cotyledons exhibiting comparatively enhanced tolerance to salt and drought stress relative to roots and true leaves may reside in their distinct physiological and biochemical profiles. CONCLUSIONS: These findings provide new insights into the composition, evolution, and function of the castor RcPRX gene family and provide a basis for subsequent exploration of gene function.