Tree Genetics and Molecular Breeding 2024, Vol.14, No.2, 57-68 http://genbreedpublisher.com/index.php/tgmb 59 MYB, NAC, etc., showing the interactions and connections between them. Larger nodes and thicker lines indicate the central role or strong interactions of transcription factors in responding to these stress conditions, revealing the complex regulatory mechanisms of plant response to environmental stress. 3.2 Case studies: genetic adaptations to drought conditions Several case studies have demonstrated the genetic adaptations of trees to drought conditions. In Populus euphratica, three stress-responsive NACtranscription factors (PeNAC034, PeNAC045, and PeNAC036) have been shown to differentially regulate drought tolerance (Francescantonio et al., 2020). Overexpression of PeNAC036 in Arabidopsis increased tolerance to drought, while PeNAC034 overexpression led to increased sensitivity, indicating the complex regulatory roles of these genes (Lu et al., 2018). Another study on Populus euphratica identified a calcium-dependent protein kinase gene, PeCPK10, which conferred enhanced drought tolerance when overexpressed in Arabidopsis, suggesting its potential role as a positive regulator of drought stress response (Chen et al., 2013). Furthermore, the WRKY8 transcription factor in tomato has been shown to alleviate drought-induced wilting and chloROSis, demonstrating its role in enhancing drought resistance through the regulation of osmotic substances and antioxidant enzyme activities (Jia et al., 2016). Figure 1 Network analysis of differentially expressed genes encoding transcription factors detected in salt and drought stresses (Adopted from Ghorbani et al., 2019) 3.3 Technological advances in drought resistance research Technological advances have significantly contributed to the understanding and improvement of drought resistance in trees. Transcriptome meta-analysis has emerged as a powerful tool to unravel the stress-responsive molecular networks in crops. For example, a meta-analysis of transcriptome studies in cotton has identified key regulatory hub genes and pathways associated with drought stress, providing potential candidate genes for further functional studies (Bano et al., 2022). Similarly, microarray expression profile analysis in Arabidopsis has revealed the central role of transcription factors and differentially expressed genes in drought stress response, offering insights into the molecular mechanisms underlying drought tolerance (Ghorbani et al., 2019). Additionally, the use of virus-induced gene silencing (VIGS) and overexpression techniques in cotton and N. benthamiana has facilitated the functional characterization of genes like GhRaf19, which negatively regulates drought tolerance by modulating reactive oxygen species (ROS) (Jia et al., 2016). These technological advancements are paving the way for the development of genetically improved tree genotypes with enhanced drought resistance.
RkJQdWJsaXNoZXIy MjQ4ODYzMg==