Genome-Wide Identification of CaGA20ox Gene Family Members Related to Floral Organ Development in Pepper (Capsicum annuum) at Different Temperatures

Environmental temperature significantly affects plant growth and development, particularly flower development. In pepper (Capsicum annuum), the molecular mechanisms underlying temperature-mediated floral organ development remain unclear. Gibberellins (GAs) are key plant hormones regulating growth and development, including flower development, and the CaGA20ox gene family may play a crucial role in this process due to its involvement in GA biosynthesis. In this study, we comprehensively analyzed the CaGA20ox gene family across six pepper genomes (‘Zhangshugang’, ‘Zunla’, ‘Chiltepin’, ‘CM334’, ‘Ca59’, and ‘T2T’) to explore their roles in flower development and temperature stress response, identifying five to six genes per genome. These genes exhibited distinct expression patterns across different tissues and developmental stages, with some members showing higher expression in specific floral organs, particularly pistils. Our results revealed that temperature significantly impacts pepper flower development and GA content, with lower temperatures enhancing antioxidant capacity and increasing GA levels. Specifically, the expression levels of four CazGA20ox genes (CazGA20ox1, CazGA20ox2, CazGA20ox4, and CazGA20ox6) were significantly influenced by temperature changes. Our systematic analysis of the role of the CaGA20ox gene family in temperature-mediated pepper flower development provides a foundation for further studies on the molecular mechanisms as well as the development of improved pepper varieties.