Plant Gene and Trait 2025, Vol.16, No.3, 92-103 http://genbreedpublisher.com/index.php/pgt 97 light-harvesting system more flexible: it can gather when it should, and relax when it should, and it can cope with various tosses of strong light, weak light, and variable light (Johnson et al., 2011; Allahverdiyeva et al., 2015). 5.3 Genes controlling chlorophyll biosynthesis and light harvesting complexes How light energy is captured and how it is distributed after being captured is actually controlled by genes. Genes like LHCB1 are specifically responsible for producing the main protein in the light-harvesting complex, and the core of the trimer LHCII depends on it. Once this gene has a problem, the chlorophyll content will drop, and even the structure of the thylakoid will be messed up, which will directly affect the light-harvesting process (Vayghan et al., 2021). The light-harvesting system is not a stereotyped template. It has a variety of possible structural changes and can flexibly switch between the two states of “capturing light” or “dissipating energy”. Behind these “strategy switches” is the expression regulation of genes related to the light system, which not only affects the photosynthetic efficiency of plants, but also determines whether they can survive under strong light stress (Mascoli et al., 2019; Li et al., 2020). 6 Biotechnological Advances for Improving Photosynthetic Traits 6.1 Use of CRISPR/Cas9 and RNAi to modify key photosynthetic genes In the field of plant genetic modification, the emergence of CRISPR/Cas9 is indeed a breakthrough. This system can use gRNA to bring Cas9 to the specified DNA location, and then perform “surgery” on that gene, deleting what needs to be deleted and modifying what needs to be modified. Now many studies are using it to modify traits such as nutrition and resistance, and photosynthesis has of course become one of the goals. If those key regulatory genes or enzyme genes can be regulated, photosynthetic efficiency may be pulled up. But then again, the old technology of RNAi has not left the stage, and it is still good at “downregulating” gene expression. Many studies still rely on it to find out what photosynthetic genes are responsible for (Arora and Narula, 2017). 6.2 Transgenic approaches to enhance enzyme activity and carbon assimilation Not all ideas for improving photosynthetic efficiency rely on “knockout” or “silencing”. Sometimes, it is more effective to “stimulate” key enzymes. For enzymes such as PEPC, NADP-ME, and PPDK that participate in the C4 and Calvin cycles, researchers have overexpressed or optimized their structures through transgenic methods, with the goal of increasing the carbon dioxide fixation capacity. These operations are not new, but as CRISPR/Cas9 becomes more mature, it has become more feasible to modify multiple genes at the same time and selectively activate or inhibit certain genes. Moreover, more precise delivery methods such as ribonucleoprotein complexes (RNPs) have also reduced the probability of “editing errors” (Filippova et al., 2019). 6.3 Omics-driven strategies (genomics, transcriptomics, proteomics, metabolomics) for gene discovery Without the support of omics technology, many photosynthetic regulatory factors hidden deep in the genome may not be easy to discover. From genes to proteins, and then to the metabolic level, these high-throughput methods can capture everything that happens in plants under different growth conditions. Whose expression level is changing? Which type of metabolite suddenly increased? These data are integrated like a map, pointing out the direction for genetic engineering or breeding. CRISPR is now increasingly used in conjunction with these omics tools, and technologies such as NGS have become routine operations. In this way, which alleles have the potential to improve photosynthesis can also be screened out and verified more quickly (Saini et al., 2023). 7 Environmental and Developmental Factors Influencing Gene Expression 7.1 Effects of temperature, light intensity, and water availability Plants react to changes in the environment, especially in the expression of photosynthetic genes. Light, as the number one “conductor”, has long been proven to regulate many genes through photoreceptors, and can even affect multiple links of transcription and post-transcription (Rasmusson and Escobar, 2007). However, light is not the only variable. Changes in temperature are also quite “capable”, directly affecting the level of transcription factors, RNA polymerase activity, and even rewriting the alternative splicing method. When low temperature is combined with light, some genes will be specifically activated - most of these genes are related to antioxidants, pigment synthesis or hormone (such as abscisic acid) production, and are closely linked to plant adaptability.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==