Abstract:

Class III peroxidases（PRX）play an important role in plant growth and development and stress response. In this study, the class III PRX gene family of cabbage was identified by bioinformatics, its function and structure were predicted, and the expression patterns of PRX gene under different abiotic stresses were analyzed, aiming to clarify the functional and evolutionary relationship of PRX gene family in cabbage genome. The results showed that a total of 125 BoPRX gene family members were identified in the cabbage genome, and were unevenly distributed on 9 chromosomes, the encoded 173-488 amino acids, and most were hydrophilic. Subcellular localization predicted that most BoPRX genes were located in chloroplasts. Phylogenetic analysis showed that the members of PRX family genes in the cabbage were classified into 5 groups, and members of each group had similar exon/intron structures and protein-conserved motifs. Promoter region analysis revealed that the BoPRX promoter sequence contained a variety of cis-regulatory elements related to abiotic stress responses such as hormones and stress. Heat map analysis of transcriptome data demonstrated that BoPRXs expression was the highest in chloroplasts. Fluorescence quantitative PCR analysis showed that 6 BoPRX genes were induced to be up-regulated by NaCl and PEG. Under ABA stress, except for BoPRX100, the expressions of the remaining genes were inhibited at most time, the expressions of the BoPRXs were all differentially regulated by ABA, indicating that they were all involved in the ABA signaling pathway. These findings reveal a complex regulation of PRXs that is dependent on the type of PRX, and the signaling molecule. It provides valuable information for further analysis of the functions of key members of the PRX family of cabbage.

Key words: cabbage, PRX gene, abiotic stress, expression analysis