Genome-Wide Identification, Characterization, and Expression Analysis of the Geranylgeranyl Pyrophosphate Synthase (GGPPS) Gene Family Reveals Its Importance in Chloroplasts of Brassica oleracea L.

Abstract

GGPPS (geranylgeranyl pyrophosphate synthase) is a crucial enzyme in the terpene biosynthesis pathway. Terpenoids play essential roles in chlorophyll biosynthesis and the development of cabbage (Brassica oleracea L. var. capitata L.), a major cruciferous vegetable worldwide. However, limited information is available regarding B. oleracea GGPPS genes. In this study, we examined 10 BoGGPPS genes from the B. oleracea genome. The subcellular localization prediction suggests that BoGGPPS proteins are mainly expressed in chloroplasts and plastids. Similar BoGGPPS genes exhibited a similar structure and motif. Distribution, collinearity, and Ka/Ks analysis revealed multiple duplication events within the BoGGPPS gene family. Cabbage BoGGPPS may participate in light and hormone responses via analysis of cis-acting elements. Three-dimensional structure analysis demonstrated the abundance of α-helices and random coils among BoGGPPS members, suggesting their important functions. Based on qRT-PCR, we observed notable differences in the transcript levels of BoGGPPS genes between leaves and siliques. Bol028967 exhibited significantly higher transcript levels in WT (Wild-type) siliques compared to in Boas1 (Brassica oleracea albino silique 1), and subcellular localization analysis confirmed its expression in chloroplasts, implying its essential role in chloroplast synthesis. These findings lay the groundwork for further exploration and in-depth functional analysis of BoGGPPS genes and their relationship with terpenoids in the context of chlorophyll synthesis in B. oleracea.