Plant Gene and Trait 2025, Vol.16, No.5, 194-205 http://genbreedpublisher.com/index.php/pgt 202 deliver floral displays which are both aesthetically reliable and stable. The case demonstrates that the application of molecular and physiological research to public garden management produces dependable results. The case places botanical gardens as bridges between science and society. 7 Genetic and Molecular Basis of Flowering Control 7.1 Key genes: RcCO, RcFT, RcSOC1, FLC-like, PIFs The flowering of Rosa chinensis depends on multiple environmental cues which activate or repress specific transcription factors that control gene expression. The plant uses a network similar to Arabidopsis which involves RcCO, RcFT, RcSOC1, FLC-like repressors, and RcPIFs. RcCO activates RcFT whose expression determines floral transition (Lu et al., 2020). RcSOC1 integrates light and thermal and hormonal signals and expresses highly under long-day and moderate temperatures to drive flowering (Sun et al., 2021). The FLC-like genes in roses act as repressors of flowering though their mechanisms differ from Arabidopsis. They do not depend on long-term vernalization but instead link to environmental stress and epigenetic modifications (Yu et al., 2023). RcPIF4 and RcPIF5 suppress RcCOand RcFT under high temperature and low light. They also function in photomorphogenesis and thermal responses which makes them potential breeding targets (Sun et al., 2021; Yu et al., 2023; Lu et al., 2024; Kang et al., 2024). 7.2 Transcriptional regulatory networks integrating light and temperature signals Genomic and transcriptomic studies show that these flowering regulators belong to a broader network which contains feedback loops and convergence points. RcCO expression follows circadian rhythms but its amplitude depends on phytochrome light quality. RcPIFs respond to temperature and serve as downstream effectors of heat shock factors. The transcriptome sequencing of Rosa chinensis under heat stress reveals coexpression relationships between RcPIF4, RcHSP70, and RcFT which suggests coordinated regulation of thermotolerance and flowering (Wang et al., 2024). Research also highlights the importance of noncoding RNAs. Long noncoding RNAs such as lncWD83 regulate flowering by altering post-translational states of MYC2 proteins (Chen et al., 2023). Epigenetic regulation also plays a major role. The expression of RcFT and FLC-like loci depends on histone modifications and DNA methylation which respond dynamically to environmental stresses. The rose plant adjusts flowering timing by modulating these marks which enables plasticity for survival (Yu et al., 2023). 7.3 Breeding applications: marker-assisted selection and CRISPR editing strategies The genomic studies of Rosa chinensis support new breeding methods. Molecular markers for RcFT, RcCO, RcSOC1, and RoKSN allow rapid identification of traits such as continuous flowering, floral uniformity, and thermotolerance which accelerates breeding cycles (Soufflet-Freslon et al., 2021). Transcriptome-wide association studies (TWAS) and expression QTL mapping identify critical regulators. Epigenetic selection appears promising because heritable DNA methylation at FLC-like genes influences flowering under stress (Yu et al., 2023). CRISPR/Cas9 genome editing now applies in rose breeding. Researchers target RcPIF4, RcCO, RcFT, and remove repressors like RoKSN to produce early-flowering and repeat-flowering plants which resemble domesticated cultivars. The technology faces limitations such as low tissue regeneration efficiency. Scientists improve success by adjusting hormone levels and using somatic embryogenesis. Non-transgenic editing methods such as ribonucleoprotein delivery and base editing increase acceptance. Regulatory frameworks vary. The United States and Japan permit fast approval for non-transgenic edited crops while the European Union applies GMO regulations. Consumer perception matters for commercialization. High-value ornamental markets demand aesthetic traits which gene editing can deliver. The integration of marker-assisted selection, high-throughput genotyping, and CRISPR will transform rose breeding by producing cultivars adapted to climates and cultivation systems.
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