Journal of Tea Science Research, 2024, Vol.14, No.5, 285-292 http://hortherbpublisher.com/index.php/jtsr 289 Comparative transcriptome analysis has revealed a significant expansion of stress-related genes in C. taliensis, which can be utilized to enhance the stress resistance of cultivated tea varieties. In addition, the CsAFS2 gene identified in tea plants intercropped with chestnut trees has been shown to improve cold and pest resistance, demonstrating the potential of integrating wild tea genes into breeding programs (Li et al., 2023). For example, a research team from Qingdao Agricultural University spent 14 years using single-plant selection methods on the offspring of the Huangshan tea population, successfully developing new cultivars such as Lu Tea 6, Lu Tea 7, and Lu Tea 17. These varieties exhibit strong growth potential, enhanced resistance to cold, drought, and pests, and broad adaptability, making them suitable for cultivation in both northern and southern tea-growing regions. Furthermore, Professor Huang Yahui's team at South China Agricultural University conducted a survey of wild tea resources across Guangdong, Guangxi, Yunnan, and Hainan, identifying numerous unique genetic resources. Utilizing these resources, they spent 12 years selecting a new tea cultivar, Huanong 181, from the Lianzhou tea population in northern Guangdong, which was granted plant variety protection in 2020. This cultivar exhibits strong growth vigor, high resistance and adaptability, excellent quality, and significant market potential (Li et al., 2023). 5 Challenges and Opportunities in Stress-Resistant Tea Breeding 5.1 Conservation and utilization of wild tea germplasm resources The conservation and utilization of wild tea germplasm resources present both challenges and opportunities for breeding stress-resistant tea varieties. Wild relatives of cultivated tea, such as Camellia taliensis, offer valuable genetic resources due to their extensive abiotic tolerance and biotic resistance, which can be harnessed for genetic improvement of cultivated tea trees (Zhang et al., 2022). However, the large and complex genome of these wild species poses a challenge in terms of genetic information availability and resource management. Additionally, the integration of advanced technologies like hyperspectral machine-learning models can facilitate the non-destructive screening of drought-tolerant germplasm, offering a new avenue for evaluating and utilizing these resources effectively (Zheng et al., 2015). 5.2 Challenges in the genetic improvement of stress resistance traits Genetic improvement of stress resistance traits in tea plants is hindered by several factors. The recalcitrance of tea plants to genetic transformation, due to issues like phenolic oxidation and bactericidal effects of tea polyphenols, complicates the genetic engineering processes (Ramakrishnan et al., 2023). Moreover, the identification and manipulation of key genes involved in stress responses, such as those related to salt and cold stress, require comprehensive transcriptomic and genomic analyses. Despite these challenges, the identification of differentially expressed genes and transcription factors involved in stress responses provides a foundation for future genetic engineering efforts (Alagarsamy et al., 2018). 5.3 Prospects of emerging technologies in tea breeding Emerging technologies hold significant promise for advancing tea breeding programs. The integration of RNA-Seq and sRNA-Seq technologies has enabled the identification of key molecular players and pathways involved in stress responses, such as those related to cold stress. Additionally, the use of deep learning and image processing techniques for stress detection at the canopy level offers a non-invasive method to monitor and manage plant health, which is crucial for breeding disease-resistant varieties. These technologies, combined with traditional breeding methods, can accelerate the development of stress-resistant tea varieties by providing detailed insights into the genetic and phenotypic traits associated with stress tolerance (Wan et al., 2018). 6 Advances in Stress-Resistant Tea Breeding 6.1 In-depth analysis of stress resistance gene regulatory networks Recent studies have significantly advanced our understanding of the gene regulatory networks involved in stress resistance in tea plants. For instance, the expression of key genes such as CsCBF1 and CsDHNs has been linked to enhanced cold resistance, highlighting the importance of these genes in the regulatory networks that confer stress tolerance (Wang et al., 2023). Additionally, the CsAFS2 gene has been identified as playing a crucial role in both
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