Tree Genetics and Molecular Breeding 2025, Vol.15, No.3, 89-97 http://genbreedpublisher.com/index.php/tgmb 92 4.3 High-throughput screening strategies (RNA-seq, WGCNA, GWAS) Nowadays, high-throughput technologies such as RNA-seq and WGCNA have been widely used to screen genes related to flowering in tea plants. Researchers analyzed transcriptome data of different developmental stages and different varieties and found that genes such as SOC1, LFY, GI and PRR7 showed obvious expression trends at the flower induction and flower bud differentiation stages (Liu et al., 2020a). Furthermore, differential expression analysis also identified hundreds of genes related to hormone synthesis and signal transduction, constituting a relatively complex hormone regulatory network. It is speculated that genes such as MYC, FT, SOC1 and LFY are the cores among them (Xu et al., 2022). Although GWAS methods are not widely used in tea plants, previous studies, through genome-wide association analysis combined with functional validation, have discovered genes like CsMADS27 that play an important role in the dormancy and germination processes of tea plants (Hao et al., 2024). 5 Key Gene Families Involved in Flowering Regulation 5.1 CONSTANS-like and FT/TFL1 family genes CONSTANS (CO) and FLOWERING LOCUS T (FT) are very important regulatory genes in the photoperiodic pathway. Research has found that in tea plants and their close relatives, these two genes and their similar genes play a key role in the regulatory network of circadian rhythms and photcycles, and can regulate flower bud differentiation and flowering time. For instance, Unigene0001842 (that is, CO) and Unigene0084708 (that is, FT) have been identified as the core genes regulating the flowering time of tea plants. They can also work together with genes such as GI and PRR that regulate circadian rhythms to help initiate flower bud differentiation (Guo et al., 2022). In addition, genes like HD3A in the FT/TFL1 family also occur during the flower development process of tea plants, while SOC1, as a downstream integration factor, plays a leading role throughout the flowering process (Xu et al., 2022). 5.2 MADS-box genes and floral integrators The MADS-box gene is also very important in the regulation of flowering in tea plants. CsFLC1 is a gene similar to FLC in the MADS-box family, and its expression level is very high when plants are dormant and preparing to flower in winter. It can affect the expression of flower-related genes such as SOC1, AGL42, SEP3 and AP3, and can also change the flowering time by regulating hormone signals (Liu et al., 2022). There is another key gene, CsMADS27, which also belongs to the MADS-box family. It can control the dormancy and germination of tea plants. This gene is regulated by CsCBF1 and CsZHD9, and controls the expression of downstream CsDJC23 (Hao et al., 2024). These MADS-box genes can also work together with transcription factors such as WRKY, MYB, and bHLH to jointly regulate flower development and secondary metabolism (Liu et al., 2017; Sun et al., 2019). 5.3 Circadian clock and vernalization-related genes The flowering of tea plants is also regulated by some genes in the circadian rhythm and vernalization pathway. Genes such as PRR7, GI and LHY are closely related to flower bud differentiation, and their expression levels increase under stress (Liu et al., 2020a; Guo et al., 2022). CsFLC1 can not only control flowering but also regulate the dormancy of tea plants in winter, indicating that the spring pathway also plays an important role in tea plants (Liu et al., 2022). Furthermore, flowering integration genes such as SOC1 and LFY, like an intersection point, can integrate various signals from photoperiod, hormones and vernalization, and ultimately precisely control when flowering occurs (Xu et al., 2022). 6 Regulatory Networks and Molecular Pathways 6.1 Integrative regulatory models in tea flowering When tea plants flower is determined by many levels of molecular mechanisms. These mechanisms include miRNA, transcription factors, hormone signals and energy metabolism, etc. miR156 and miR172 can control the expression of key genes such as SPL and AP2, thereby affecting the expression of SOC1. This forms two main pathways: miR156-SPL and miR172-AP2, which jointly participate in the regulation of flowering time (Wang, 2014; Fan et al., 2024). In addition, genes such as PRR, LHY, GI, CO and FT can receive light and temperature
RkJQdWJsaXNoZXIy MjQ4ODYzNA==