Genome-Wide Analysis and Expression Profiling of Glyoxalase Gene Families Under Abiotic Stresses in Cucumber (Cucumis sativus L.)

The glyoxalase pathway, consisting of glyoxalase I (GLYI) and glyoxalase II (GLYII), is an enzymatic system that converts cytotoxic methylglyoxal to non-toxic S-D-lactoylglutathione. Although the <i>GLY</i> gene family has been analyzed in <i>Arabidopsis</i>, rice, grape, cabbage, and soybean, cucumber studies are lacking. Here, we analyzed the cucumber <i>GLY</i> gene family, identifying 13 <i>CsGLYI</i> and 2 <i>CsGLYII</i> genes. Furthermore, we investigated the physicochemical properties, phylogenetic relationships, chromosomal localization and colinearity, gene structure, conserved motifs, <i>cis</i>-regulatory elements, and protein-protein interaction networks of the CsGLY family. They were primarily localized in the cytoplasm, chloroplasts, and mitochondria, with a minor presence in the nucleus. The classification of <i>CsGLYI</i> and <i>CsGLYII</i> genes into five classes closely resembled the homologous genes in <i>Arabidopsis</i> and soybean. Additionally, hormone-responsive elements dominated the promoter region of <i>GLY</i> genes, alongside light- and stress-responsive elements. The predicted interaction proteins of CsGLYIs and CsGLYIIs exerted a significant role in cellular respiration, amino acid synthesis, and metabolism, as well as methylglyoxal catabolism. In addition, the expression profiles of <i>GLY</i> genes were distinct in different tissues of cucumber as well as under diverse abiotic stresses. This study is conducive to the further exploration of the functional diversity among glyoxalase genes and the mechanisms of stress responses in cucumber.