Next-Generation Metabolic Engineering of Capsaicinoids Biosynthesis in Chilli Pepper: Bridging Genomic Insights to...

Chilli peppers (Capsicum species) have been widely used around the world because of their economic value and distinctive sensory characteristics. They contain abundant functional metabolites, especially a group of vanillylamide compounds belonging to the family of capsaicinoids, which have been exploited for medicinal, nutritional, agricultural, and cosmetic uses. The demand for capsaicinoid molecules is increasing day by day due to their high economic value and wide range of applications. Therefore, increasing bioactive metabolites, especially capsaicinoids in chilli peppers, is a major priority in the current scenario. Multi-omics approaches such as genomics, transcriptomics, proteomics, and metabolomics have substantially contributed to understanding the complex regulatory networks governing capsaicinoid biosynthesis. Key structural genes, transcription factors, and signaling pathways involved in the phenylpropanoid and branched-chain fatty acid pathways have been identified, providing valuable targets for metabolic engineering in chilli pepper. Despite these advances, the integration of genetic modification approaches for the targeted enhancement of capsaicinoid production remains limited in chilli pepper. Recent developments in biotechnology, particularly CRISPR/Cas-mediated genome-editing, enable the precise genetic modification of metabolic pathways and regulatory networks in plants. Therefore, it can contribute to the precise modification of key genes involved in the capsaicinoid biosynthesis pathway, offering potential strategies to enhance the capsaicinoid content in chilli pepper. However, CRISPR/Cas-mediated genome editing in chilli pepper is still in its early stages. There are currently no reports available on the successful enhancement of capsaicinoid content in chilli peppers through CRISPR/Cas-mediated genome editing. To date, no comprehensive review has evaluated the CRISPR-Cas-mediated genome-editing approaches for capsaicinoid metabolic engineering in chilli pepper. This review critically evaluates the recent advances in CRISPR/Cas-mediated metabolic engineering in chilli peppers, with particular emphasis on regulatory genes involved in capsaicinoid biosynthesis. Furthermore, multi-omics approaches are expected to complement these strategies by enabling the identification of key regulatory genes, the optimization of genome-editing targets, and the prediction of metabolic outcomes for enhanced capsaicinoid production. Overall, this review provides insights into improving capsaicinoid accumulation in chilli peppers through advanced genome-editing technologies.