Plant Gene and Traits 2024, Vol.15, No.3, 108-117 http://genbreedpublisher.com/index.php/pgt 115 could also facilitate the identification of novel regulatory mechanisms and metabolic bottlenecks, which could be addressed through targeted breeding or genetic modification (Saithong et al., 2013). 7 Concluding Remarks The systematic review has highlighted significant advancements in understanding the biochemical pathways of starch synthesis in cassava (Manihot esculenta Crantz), which is a staple food and industrial crop in tropical and sub-tropical regions. A total of 45 genes have been identified as participants in the starch biosynthesis pathway, including key enzymes such as ADPG pyrophosphorylase (AGPase), granule bound starch synthase (GBSS), starch synthase (SS), starch branching enzyme (SBE), de-branching enzyme (DBE), and glucan, water dikinase (GWD). The expression patterns of these genes vary across different organs and developmental stages, with a higher activity toward the development of mature storage roots. Additionally, 110 quantitative trait loci (QTLs) associated with starch content and pasting properties have been identified, which are crucial for the improvement of starch quality through biotechnologies like transgenic breeding and molecular marker-assisted selection. Transgenic approaches have successfully increased starch production in cassava by enhancing the sink strength for carbohydrate through the expression of a modified bacterial AGPase gene. Furthermore, the regulation of the AGPase gene by transcription factors such as MeSAUR1 has been elucidated, providing insights into the molecular mechanisms of starch accumulation. The onset of storage root formation has been associated with specific gene expressions, including sulfite reductase and calcium-dependent protein kinase, which may play roles in signaling pathways and sulfur-containing protein biosynthesis. Future research should focus on the integration of omics data to further elucidate the dynamic regulation of starch biosynthesis in cassava. This includes the use of transcriptomic, proteomic, and metabolomic approaches to understand the complex interactions between genes, proteins, and metabolites during root development. Additionally, the role of postharvest physiological deterioration (PPD) in starch metabolism warrants further investigation, as it has implications for the shelf-life and commercial value of cassava. The exploration of natural genetic variation and the identification of novel SNPs in starch pathway genes could also provide new opportunities for breeding cassava varieties with improved starch quality and yield. The findings from this review have profound implications for food security, economic development, and sustainable agricultural practices. Cassava is a vital source of calories for millions of people, and improvements in starch quality and yield can significantly enhance the nutritional status and livelihoods of subsistence farmers. The development of cassava varieties with higher starch content and better resistance to PPD can reduce postharvest losses, increase the shelf-life of cassava products, and expand their use in the food and industrial sectors. Moreover, understanding the genetic bases of starch synthesis can facilitate the breeding of cassava varieties that are better adapted to climate change, thereby contributing to the sustainability of agricultural systems in vulnerable regions. Acknowledgments I am grateful to Dr. Fang for reviewing this manuscript and providing valuable suggestions. I also thank the two anonymous peer reviewers for their helpful questions and recommendations Funding This research is funded by the CRO research project "Genetic Improvement and Comprehensive Utilization of Cassava Resources" supported by the Hainan Institute of Tropical Agricultural Resources (Project No. H20230200). Conflict of Interest Disclosure The author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.
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