Bioscience Methods 2025, Vol.16, No.6, 289-298 http://bioscipublisher.com/index.php/bm 290 genetic mechanism of biological stress resistance in tea plants, evaluate the effectiveness of emerging genetic tools, and point out the research gaps and future directions for the sustainable improvement of tea plants. By integrating insights from molecular biology, genomics, and plant-microbial interactions, this study aims to inform breeding strategies and support the cultivation of adaptable tea tree varieties to achieve a sustainable global tea industry. 2 Genetic Basis of Tea Plant Resistance to Biotic Stress 2.1 Types and functional characteristics of resistance-related genes in tea plants The disease and pest resistance of tea plants is not achieved through a single mechanism, but rather through the "division of labor and cooperation" of multiple different types of genes. Some genes are responsible for regulating transcription factors such as WRKY, FHY3/FAR1, and JAZ; Some genes themselves are involved in metabolic processes, such as laccase and hydroxycinnamoyltransferase; There are also some genes, such as members of the PYL family, that are important components of plant hormone signaling. Under different circumstances, these genes do not always function simultaneously. Like CsWRKY48, CsFHY3/FAR1, CsCBF, etc., they are involved in regulating a series of defense-related genes and also interact with other transcription factors (such as MYC, MYB), corresponding to different stress responses (Liu et al., 2021; Wang et al., 2024). Enzyme genes such as CsHCTs and CsLACs, which are related to the synthesis of lignin and flavonoids, are usually more active when plants "build walls for self-protection" (Chen et al., 2021). However, JAZ genes are also quite unique. As members of the TIFY family, they are upregulated in the face of insect or fungal attacks, indicating that they are closely related to the defense mechanism of JA signaling. Furthermore, genes that process reactive oxygen species, such as SOD, also play a role in reducing cellular damage during the stress response, and the related miRNA regulatory mechanisms have begun to be revealed. The PYL gene in the ABA signaling pathway seems more like a "coordinator", determining whether plants should defend or save water based on environmental conditions. 2.2 Genetic inheritance and sources of variation in resistance traits The trait of resistance is not always simply "present" or "absent"; its manifestations among groups are highly diverse. One of the reasons for this diversity is the accumulation of genetic variations during natural selection, and another reason may not be so intuitive - the replication and expansion of gene families. Some genes, such as BZR1, HD-Zip, and SAT, not only exist in cultivated varieties but also have different versions in many wild tea varieties. The differences among these "family members" precisely shape the complexity of traits (An et al., 2023; Li et al., 2023). Genome-wide association studies (GWAS) have helped researchers identify some significant SNP loci related to resistance. For instance, CsNCED1 is a representative one (Deng et al., 2025). Gene expansion methods such as fragment replication and tandem duplication are actually silently promoting the diversified development of resistance genes, providing many "alternative options" waiting to "take up their positions" in stressful environments (Figure 1) (Liu et al., 2021). 2.3 Regulatory mechanisms of gene expression in response to biotic stress When it comes to the regulation of gene expression, the response mechanism of tea plants is not static. It is actually a multi-level and multi-channel dynamic process. For example, when attacked by pathogens, some transcription factors will be rapidly activated, such as WRKY, CBF, HD-Zip, etc., which respond very quickly in initiating the expression of defense genes (Hu et al., 2020; Wang et al., 2024; Luo et al., 2025). However, such reactions are not "fully activated upon activation", as the hormones within the plant are also constantly competing with each other. The mutual restraint or promotion among salicylic acid, jasmonic acid, abscisic acid and gibberellin will adjust the reaction direction according to the type of stress. For example, if ABA is elevated, it may inhibit SA signaling, thereby making plants more likely to "fail" when facing pathogens (Deng et al., 2025).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==