Multiomics analysis of gibberellin involved in far-red light-regulated internode elongation in cucumber seedlings

GA participates in FR light-induced internode elongation of cucumber by regulating the expression of genes/proteins related to aquaporins, expansins, cell wall biosynthesis, hormone metabolism, and signal transduction. This study investigated the effects of the interaction between far-red (FR) light and gibberellin (GA) on the internode elongation of cucumber (Cucumis sativus L. 'Zhongnong No. 26') seedlings through combined physiological, biochemical, transcriptomic, and proteomic analyses. The results revealed that FR light and GA significantly promoted internode elongation in cucumber seedlings, whereas a GA biosynthesis inhibitor (PAC) inhibited the promoting effect of FR light. Hormone content determination revealed that FR light and GA decreased the contents of abscisic acid (ABA), indole-3-acetic acid (IAA), cytokinin (CTK), and jasmonate (JA) in cucumber seedling internodes. Bioinformatics analysis revealed that the expression patterns of the Co-DEGs and Co-DEPs were consistent in the FR (WL combined with FR light) and WLG (WL, in which plants were sprayed GA) groups, as well as in the FRP (FR, in which plants were sprayed PAC) and WL (full-spectrum LED white light) groups, suggesting that the mechanisms of FR and GA were similar in these Co-DEGs and Co-DEPs. Further analysis of these Co-DEGs and Co-DEPs revealed that they were involved mainly in cell wall biosynthesis and modification, lignin synthesis, hormone metabolism, and signal transduction pathways. In conclusion, this study revealed the important role of GA in FR light-induced internode elongation in cucumber seedlings, and this promoting effect was achieved mainly through the regulation of aquaporins, expansins, hormone metabolism, and signal transduction-related genes/proteins. This study provides new insights into the molecular mechanism of FR light-induced internode elongation in cucumber seedlings.