Genomics and Applied Biology 2024, Vol.15, No.6, 285-295 http://bioscipublisher.com/index.php/gab 286 2 Overview of Photosynthesis in Sweet Potato Sweet potato (Ipomoea batatas) is a significant crop known for its high starch content and adaptability to various environmental conditions. Photosynthesis in sweet potato, like in other plants, involves the conversion of light energy into chemical energy, which is then used to produce carbohydrates. This process is crucial for the growth and yield of sweet potato, particularly in its storage roots, which are the primary sink organs for photoassimilates and energy (Fan et al., 2021). 2.1 Photosynthetic pathways and efficiency in sweet potato Photosynthesis in sweet potato involves both the light-dependent reactions and the Calvin cycle. The efficiency of these pathways can be influenced by various genetic and environmental factors. For instance, the overexpression of the H+-pyrophosphatase gene (IbVP1) in sweet potato has been shown to enhance photosynthetic ability and sucrose content in source leaves, leading to increased starch content and yield in storage roots (Fan et al., 2021). Additionally, transcription factors such as BBX21 have been found to improve photosynthetic rates and water use efficiency under both optimal and drought conditions, further highlighting the genetic regulation of photosynthetic efficiency (Crocco et al., 2018; Ocampo et al., 2021). 2.2 Key components and enzymes involved in photosynthesis Several key components and enzymes are involved in the photosynthetic process in sweet potato. These include chlorophyll-binding proteins, photosystem I and II, and enzymes involved in the Calvin cycle. The expression of genes encoding these components can be regulated by various transcription factors. For example, the transcription factor StABI5 has been shown to negatively regulate chloroplast development and photosynthesis by downregulating genes involved in photosynthesis and carbon fixation (Zhu et al., 2020). Similarly, the overexpression of IbBBX29 has been linked to increased flavonoid accumulation and improved leaf development, which can indirectly affect photosynthetic efficiency (Gao et al., 2022). 2.3 Genetic factors influencing photosynthetic performance Genetic factors play a crucial role in determining the photosynthetic performance of sweet potato. Variations in transcription factors and photosynthesis-related genes can significantly impact photosynthetic traits. For instance, genetic variation in transcription factors and light-reaction genes has been shown to regulate photosynthetic traits by affecting the expression of multiple genes involved in the photosynthetic pathway (Wang et al., 2018). Additionally, the overexpression of genes such as IbMIPS1 and IbNAC43 has been found to influence photosynthetic performance by modulating stress responses and leaf development, respectively (Zhai et al., 2016; Sun et al., 2023). Furthermore, the identification of genetic variations in starch biosynthesis and sucrose metabolism genes provides insights into the molecular mechanisms regulating photosynthesis and carbohydrate metabolism in sweet potato (Zhang et al., 2020). In summary, the genetic regulation of photosynthesis in sweet potato involves a complex interplay of various transcription factors, enzymes, and genetic variations. Understanding these regulatory mechanisms can provide valuable insights into improving photosynthetic efficiency and crop yield in sweet potato. Further research in this area can lead to the development of genetically engineered sweet potato cultivars with enhanced photosynthetic performance and stress tolerance. 3 Genetic Regulation of Photosynthesis 3.1 Regulatory genes and transcription factors The genetic regulation of photosynthesis in sweet potato involves several key genes that influence various aspects of the photosynthetic process. For instance, the H+-pyrophosphatase gene (IbVP1) has been shown to enhance photosynthesis and sucrose content in source leaves, thereby increasing starch content and yield in storage tissues (Fan et al., 2021). Additionally, the IbMIPS1 gene, which is involved in myo-inositol biosynthesis, has been found to upregulate genes related to photosynthesis and stress responses, thereby improving photosynthetic efficiency under stress conditions (Zhai et al., 2016).
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