Genome-Wide Analysis of the GGPS Gene Family in Phoebe zhennan and Analysis of the Role of PzGGPS12 in Terpenoid Biosynthesis.

Geranylgeranyl diphosphate synthase (GGPS) is a key enzyme in terpenoid biosynthesis, but its role in Phoebe zhennan remains largely unknown. Here, 14 PzGGPS genes were identified and classified into three groups with conserved gene structures and motifs. Among them, PzGGPS12 was identified as a key gene for terpenoid biosynthesis, wood fragrance formation, and drought tolerance. Functional analyses showed that PzGGPS12 catalyzes the production of terpene precursors and promotes the accumulation of mono-, sesqui-, di-, and triterpenoids, thereby enhancing drought resistance through metabolic flux regulation. Furthermore, PzNAC6, PzWRKY12, and PzC3H8 were identified as major upstream transcription factors controlling the PzGGPS12 expression. These results reveal the regulatory network of PzGGPS12 and highlight its dual roles in wood fragrance formation and drought adaptation, providing new insights into terpenoid metabolism and molecular breeding of P. zhennan.