Mining of key O-methyltransferase genes and UDP-glucosyltransferase genes for ginkgotoxin and ginkgotoxin-5'-glucoside synthesis based on transcriptome sequencing analysis.

Abstract

Ginkgo biloba seeds contain toxic 4'-O-methylpyridoxine (MPN) and 4'-O-methylpyridoxine-5'-glucoside (MPNG), but their biosynthetic genes are poorly understood. To identify these genes, we performed multistage transcriptome sequencing, differentially expressed gene screening, weighted gene co-expression network analysis (WGCNA), and enrichment analysis during seed development. MPNG accumulation predominated in mature seeds, correlating with gene expression dynamics. We identified 25 O-methyltransferase (OMT) and 40 uridine diphosphate (UDP)-glucosyltransferase (UGT) candidates. Among these, 7 OMTs (e.g. Gb_35680 and Gb_01186) and 8 UGTs (e.g. Gb_34745 and Gb_37494) were significantly upregulated during maturation, confirmed by quantitative real-time polymerase chain reaction (qRT-PCR). WGCNA revealed four gene modules strongly correlated with MPN/MPNG accumulation, enriched in methylation, glycosylation, and secondary metabolite biosynthesis. This study integrates dynamic transcriptome and coexpression analyses to pinpoint key regulatory nodes in ginkgotoxin biosynthesis, providing novel genetic targets for developing low-toxicity cultivars through molecular breeding.