TCP proteins are plant-specific transcription factors widely implicated in leaf morphogenesis and senescence, flowering, lateral branching, hormone crosstalk, and stress responses. However, the relationship between the transcription pattern of TCPs and organ development in cucumber has not been systematically studied. In this study, we performed a genome-wide identification of putative TCP genes and analyzed their chromosomal location, gene structure, conserved motif, and transcript expression. A total of 27 putative TCP genes were identified and characterized in cucumber. All 27 putative CsTCP genes were classified into class I and class II. Class I comprised 12 CsTCPs and Class II contained 15 CsTCPs. The 27 putative CsTCP genes were randomly distributed in five of seven chromosomes in cucumber. Four putative CsTCP genes were found to contain putative miR319 target sites. Quantitative RT-PCR revealed that 27 putative CsTCP genes exhibited different expression patterns in cucumber tissues and floral organ development. Transcript expression and phenotype analysis showed that the putative CsTCP genes responded to temperature and photoperiod and were induced by gibberellin (GA)and ethylene treatment, which suggested that CsTCP genes may regulate the lateral branching by involving in multiple signal pathways. These results lay the foundation for studying the function of cucumber TCP genes in the future.

Cucumber is one of the most important vegetables in the world. The C2H2 zinc finger protein (C2H2-ZFP) family plays an important role in the growth development and abiotic stress responses of plants. However, there have been no systematic studies on cucumber. In this study, we performed a genome-wide study of C2H2-ZFP genes and analyzed their chromosomal location, gene structure, conservation motif, and transcriptional expression. In total, 101 putative cucumber C2H2-ZFP genes were identified and divided into six groups (I–VI). RNA-seq transcriptome data on different organs revealed temporal and spatial expression specificity of the C2H2-ZFP genes. Expression analysis of sixteen selected C2H2-ZFP genes in response to cold, drought, salt, and abscisic acid (ABA) treatments by real-time quantitative polymerase chain reaction showed that C2H2-ZFP genes may be involved in different signaling pathways. These results provide valuable information for studying the function of cucumber C2H2-ZFP genes in the future.

Cucumber (Cucumis sativus) fruit spines are a classic material for researching the development of multicellular trichomes. Some key genes that influence trichome development have been confirmed to be associated with cuticle biosynthesis and secondary metabolism. However, the biological mechanisms underlying trichome development, cuticle biosynthesis, and secondary metabolism in cucumber remain poorly understood. CsTs, a C-type lectin receptor-like kinase gene, reportedly causes a tender trichome phenotype in cucumber when it mutates. In this study, the role of CsTs in cucumber fruit spines morphogenesis was confirmed using gene editing technology. Sectioning and cell wall component detection were used to analyse the main reason of tender fruit spines in the ts mutant. Subsequently, transcriptome data and a series of molecular biology experiments were used to further investigate the relationship between CsTs and cytoskeletal homeostasis in cucumber. CsTs overexpression partially compensated for the abnormal trichome phenotype of an Arabidopsis homolog mutant. Genetic hybridization and metabolic analysis indicated that CsTs and CsMict can affect trichome development and cuticle biosynthesis in the same pathway. Our findings provide important background information for further researching on the molecular mechanism underlying cucumber trichome development and contribute to understanding the biological function of C-type lectin receptor-like kinases.

Fruit spines constitute a critical protective barrier, and their density serves as a key determinant of appearance quality, directly influencing market value in cucumber (Cucumis sativus L.). Prior studies demonstrated that CsHMG9 (FS2), a high-mobility group (HMG) protein, regulates fruit spine density in cucumber. To elucidate the roles of the CsHMG in fruit spine density, we conducted comprehensive analyses of CsHMG family regarding their chromosomal localization, phylogeny, gene structures, conserved motifs, cis-acting elements and organ-specific expression patterns. Genome-wide identification revealed 17 CsHMGs in cucumber, with phylogenetic analysis classifying them into five distinct subfamilies. The subcellular localization of proteins varies among different CsHMG subfamilies. Reverse transcription quantitative PCR (RT-qPCR) analysis demonstrated differential gene expressions of CsHMGs under diverse treatments, indicating potential involvement in multiple signaling pathways. Furthermore, a Tnt1 retrotransposon insertion mutant of CsHMG9 exhibited significantly reduced fruit spine density. Allelic validation via genetic crossing between fs2-Tnt1 and fs2-EMS confirmed that CsHMG9 is the key regulator of fruit spine density in cucumber. Building on this, integrated approaches, including yeast one-hybrid (Y1H), dual-luciferase assays (Dual-LUC), RT-qPCR and genetic analyses, demonstrated that CsHMG9 acts downstream of key trichome regulators (Tril, Mict and TOE3), while feedback-regulating Tril expression to modulate fruit spine density in cucumber. This study clarified the function of CsHMG9 in fruit spine density and provided a foundational insight into CsHMG biology.