Journal of Tea Science Research, 2024, Vol.14, No.5, 285-292 http://hortherbpublisher.com/index.php/jtsr 287 growth and development under stress conditions (Wang et al., 2024). Furthermore, the HD-Zip transcription factors are implicated in various abiotic stress responses, suggesting a broad regulatory role in stress adaptation. 3 Stress Resistance Traits and Genetic Diversity of Wild Tea Plants Wild tea plants exhibit rich genetic diversity, which provides a crucial foundation for their stress resistance under various environmental conditions. Compared to cultivated varieties, wild tea plants often demonstrate stronger tolerance to drought, cold, salinity, and diseases, primarily due to the accumulation of advantageous stress-resistant genes through long-term natural selection. Studies have shown that stress-responsive gene families, such as bZIP, MYB, and SOD, exhibit higher expression levels in wild tea plants under adverse conditions, enhancing their resilience to drought, low temperatures, and oxidative stress. Additionally, the high genetic variability of wild tea plants allows them to adapt to complex and changing ecological environments, making them valuable genetic resources for tea breeding and the development of stress-resistant cultivars. 3.1 Major wild tea species and their ecological distribution Wild tea species, primarily Camellia sinensis, are distributed across diverse ecological regions, which contribute to their varied stress resistance traits. These species are often found in environments that expose them to a range of abiotic stresses such as drought, cold, and heat, which have driven the evolution of unique adaptive mechanisms. The ecological distribution of these species plays a crucial role in their genetic diversity, providing a rich resource for breeding stress-resistant tea varieties (Han et al., 2022). 3.2 Analysis of stress resistance traits in wild tea plants Wild tea plants exhibit several stress resistance traits that are crucial for their survival in harsh environments. For instance, in Shen et al. (2019), it was noted that CsAFS2 genes in tea trees enhance resistance to low temperature and pest stress by increasing protective enzyme activity and upregulating stress-related genes. Cold-resistant traits have been linked to the accumulation of sucrose and the expression of specific genes like CsCBF1 and CsDHNs, which are crucial for cold acclimation (Shen et al., 2019). Additionally, alternative splicing of genes in response to drought and heat stresses increases transcriptome diversity, enhancing the plant's ability to adapt to these conditions. These traits are vital for developing stress-resistant tea cultivars (Ban et al., 2017; Rahimi et al., 2018). 3.3 Molecular studies on the genetic diversity of wild tea plants Molecular studies have revealed significant genetic diversity among wild tea plants, which is essential for their adaptability to various stresses. The identification of differentially expressed genes (DEGs) and transcription factors involved in stress responses highlights the complex genetic networks that confer stress tolerance. For example, the CsABF gene family plays a significant role in drought tolerance through the ABA signaling pathway, with specific genes like CsABF2 and CsABF11 being key regulators. Furthermore, the genetic diversity observed in wild tea species provides a valuable genetic pool for breeding programs aimed at enhancing stress resistance in cultivated tea varieties (Yolcu et al., 2020; Zhang et al., 2023). 4 Application of Wild Tea Resources in Breeding Stress-Resistant Varieties The integration of wild tea resources into breeding programs through molecular and gene editing technologies offers promising opportunities to develop stress-resistant tea varieties. These approaches address the limitations of traditional breeding and leverage the genetic diversity of wild relatives to enhance the resilience of tea plants against environmental stresses. 4.1 Traditional breeding methods for tea plants and their limitations Traditional breeding methods for tea plants primarily involve selection and cross-breeding to enhance desirable traits such as yield and quality. However, these methods are often slow and limited by genetic bottlenecks, as they rely heavily on existing genetic diversity within cultivated varieties. The low cross-compatibility and genetic drag from undesirable alleles further constrain the use of wild relatives in traditional breeding, making it challenging to introduce new traits such as stress resistance (Zhao et al., 2022) (Figure 2).
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