Bioscience Methods 2024, Vol.15, No.4, 149-161 http://bioscipublisher.com/index.php/bm 152 of photosynthetic genes (Borba et al., 2018). Moreover, the construction of gene regulatory networks has identified several TF families, including DOF and MADS-domain TFs, as key regulators of diurnal fluctuations in C4 gene expression (Borba et al., 2023). The integration of transcriptome data with TF binding motifs has further elucidated the complex regulatory networks controlling photosynthesis (Dai et al., 2021). 3.4 Post-translational modifications and their impact on photosynthetic efficiency Post-translational modifications (PTMs) significantly impact photosynthetic efficiency in maize. Although the detailed mechanisms of PTMs in photosynthesis are not fully understood, it is known that PTMs can modulate the activity of photosynthetic proteins and enzymes, thereby influencing overall photosynthetic performance. For example, the regulation of photosynthesis by transcription factors often involves PTMs that affect their stability, localization, and interaction with other proteins (Halpape et al., 2023). 3.5 Impact of epigenetic modifications on photosynthetic genes Epigenetic modifications, such as DNA methylation and histone modifications, play crucial roles in the regulation of photosynthetic genes in maize. Chromatin accessibility and epigenetic features, including H3K27me3 modification and CHH methylation, coordinate to regulate cell type-specific gene expression in bundle sheath and mesophyll cells (Dai et al., 2021). These epigenetic modifications ensure the proper expression of key C4 genes, thereby optimizing photosynthetic efficiency. Additionally, the integration of epigenetic data with gene expression profiles has identified potential key C4 genes and provided insights into the regulatory mechanisms of C4 photosynthesis (Dai et al., 2021). In summary, the molecular regulation of photosynthesis in maize involves a complex interplay of gene expression profiles, light and circadian rhythms, transcription factors, post-translational modifications, and epigenetic modifications. Understanding these regulatory mechanisms is essential for improving photosynthetic efficiency and crop productivity. 4 Genetic and Biotechnological Approaches to Enhancing Photosynthesis in Maize 4.1 Genetic variability in photosynthetic traits in maize Genetic variability in photosynthetic traits is a crucial factor for improving maize yield and resilience. Large germplasm collections, including historical collections of crop species and their wild relatives, offer a wealth of opportunities to find novel allelic variations in key photosynthetic processes. These genetic resources can be selectively targeted to enhance photosynthetic efficiency through modern breeding programs (Figure 2) (Sharwood et al., 2022). Additionally, genome-wide association studies (GWAS) have identified significant genetic variations in photosynthesis-related traits, such as leaf net photosynthesis and stomatal conductance, which are promising targets for breeding programs (Yi et al., 2023). 4.2 Molecular breeding for improved photosynthetic efficiency Molecular breeding techniques, including genomic selection and marker-assisted selection, have been employed to enhance photosynthetic efficiency in maize. The integration of high-throughput phenotyping with genomic data allows for the dissection of complex traits and the identification of novel genes associated with photosynthesis. This approach facilitates the development of maize cultivars with improved photosynthetic efficiency and yield potential (Bezouw et al., 2019). The use of quantitative trait loci (QTL) mapping has also been instrumental in identifying minor QTLs associated with photosynthesis-related traits, providing valuable targets for molecular breeding (Yi et al., 2023). 4.3 CRISPR-Cas9 and other gene editing techniques CRISPR-Cas9 has emerged as a powerful tool for precise genome editing in maize, enabling targeted deletions, additions, and corrections in the genome. This technology has been successfully applied to edit multiple genes associated with agronomic traits, including photosynthesis. For instance, high-throughput CRISPR/Cas9 mutagenesis has streamlined trait gene identification, allowing for the rapid validation of important agronomic genes (Liu et al., 2020). Additionally, promoter editing of CLE genes using CRISPR-Cas9 has engineered quantitative variation for yield-related traits, demonstrating the potential of this technology in crop enhancement
RkJQdWJsaXNoZXIy MjQ4ODY0NQ==