Genome-wide identification of glutathione peroxidase (GPX) gene family and their response to abiotic stress in cucumber.

Plant glutathione peroxidases (GPXs) are non-heme thiol peroxidases that play vital roles in maintaining HO homeostasis and regulating plant response to abiotic stress. Here, we performed a comparative genomic analysis of the gene family in cucumber (). As a result, a total of 6 genes were identified, which were unevenly located in four out of the seven chromosomes in cucumber genome. Based on the phylogenetic analysis, the genes of cucumber, Arabidopsis and rice could be classified into five groups. Analysis of the distribution of conserved domains of GPX proteins showed that all these proteins contain three highly conserved motifs, as well as other conserved sequences and residues. Gene structure analysis revealed a conserved exon-intron organization pattern of these genes. Through analyzing the promoter regions of genes, many hormone-, stress-, and development-responsive -elements were identified. Moreover, we also investigated their expression patterns in different tissues and developmental stages as well as in response to abiotic stress and x acid (ABA) treatments. The qRT-PCR results showed that the transcripts of genes varied largely under abiotic stress and ABA treatments at different time points. These results demonstrate that cucumber gene family may function in tissue development and plant stress responses.