SABATH methyltransferase can methylate small-molecule metabolites of plants to generate different products, and it plays a crucial role in plant growth and development as well as stress response. In this study, 13 SABATH genes distributed on five chromosomes of cucumbers were identified, and the synergistic effects among their domains, gene structures, conserved motifs, phylogenetic relationships, collinearity analysis, cis-acting elements, expression patterns, and plant growth-promoting rhizosphere bacteria (PGPR) were analyzed. The gene structure and conserved motifs of the same group of CsSABATH have similar intron numbers and conserved motifs. We detected 10 cis-elements in the promoter of the CsSABATH gene, indicating that they may be involved in different signaling pathways. qRT-PCR revealed the tissue-specific, drought and salt stress-responsive expression of the SABATH gene in cucumbers. Furthermore, we also verified that the expression level of CsaV3_6G046510 after inoculation with PGPR-GD17 bacteria under drought and salt stress was significantly lower than normal drought and salt dress, indicating that this gene may respond to PGPR and in abiotic stress play an important role. This study provides valuable insights into the molecular characteristics and evolutionary history of the SABATH gene family in cucumbers, laying a foundation for further analysis of the function of the CsSABATH gene in cucumbers.

Glycerophosphate diester phosphodiesterase (GDPD) catalyzes the decomposition of glycerophosphate diester into sn-glycerol-3-phosphate and corresponding alcohols. In this study, six GDPD genes were identified in the cucumber genome, named CsGDPD1 to CsGDPD6, and distributed on chromosomes 1, 3, 4, 5, 6, and 7. All six proteins exhibited similar predicted three dimensional structures, suggesting conserved biochemical functions. Phylogenetic and dN/dS selection pressure analyses revealed that CsGDPD genes are evolutionarily close to their Arabidopsis homologs and have evolved under purifying selection, indicating functional conservation. Synteny analysis identified five collinear gene pairs between cucumber and Arabidopsis, but no synteny with rice. Promoter cis-acting element analysis showed the presence of multiple stress- and hormone-responsive elements. Tissue-specific expression profiling demonstrated that CsGDPD1, CsGDPD2, and CsGDPD6 are broadly expressed across tissues, whereas CsGDPD4 and CsGDPD5 show preferential expression in reproductive organs. qRT-PCR under drought and salt stress, with or without the plant growth promoting rhizobacterium GD17, revealed that drought alone upregulates all CsGDPD genes; PGPR-GD17 alone (+PGPR) suppresses their expression; and combined PGPR + Drought leads to synergistic suppression. Under salt stress, CsGDPD5 was dramatically upregulated (20-fold), and PGPR-GD17 partially reversed salt induced changes. These results provide a comprehensive foundation for understanding the evolutionary and functional roles of the GDPD gene family in cucumber stress responses.

Photoperiod sensitivity significantly affects the reproductive process of plants. The CONSTANS, CONSTANS-LIKE, and TOC1 (CCT) genes play pivotal roles in photoperiod sensitivity and regulating flowering time. However, the function of the CCT gene in regulating flowering varies among different species. Further research is needed to determine whether it promotes or delays flowering under long-day (LD) or short-day (SD) conditions. CCT MOTIF FAMILY (CMF) belongs to one of the three subfamilies of the CCT gene and has been proven to be involved in the regulation of circadian rhythms and flowering time in cereal crops. In this study, 60 CCT genes in Chinese cabbage were genome-wide identified, and chromosomal localization, gene duplication events, gene structure, conserved domains, co-expression networks, and phylogenetic tree were analyzed by bioinformatics methods. The specific expression patterns of the BrCMF gene in different tissues, as well as the transcriptome and RT-qPCR results under different photoperiodic conditions, were further analyzed. The results showed that BrCMF11 was significantly upregulated in ebm5 under LD conditions, suggesting that BrCMF11 promoted flowering under LD conditions in Chinese cabbage. These findings revealed the function of the BrCCT gene family in photoperiod flowering regulation and provided a prominent theoretical foundation for molecular breeding in Chinese cabbage.