Terpene trilactones (TTLs) have important medicinal value, but their low content in Ginkgo biloba leaves makes their exploitation extremely costly, thereby limiting the development of TTL-related industries. It was found that exogenous methyl jasmonate (MeJA) treatment increased the accumulation of TTLs, but the molecular mechanism is still unclear. Here, we identified two bHLH transcription factors in G. biloba, with the protein subcellular localizations in the nucleus. Expression of GbMYC2s was strongly induced by MeJA treatment, and the interactions between GbJAZs and GbMYC2s were demonstrated by yeast two-hybrid and bimolecular fluorescence complementation experiments. Overexpression of GbMYC2_4 and GbMYC2_5 enhanced Arabidopsis root sensitivity and significantly increased TTL content. In addition, GbGGPPS was found to be a common target of GbMYC2_4 and GbMYC2_5 by yeast one-hybrid, electrophoretic mobility shift, and dual-luciferase reporter assays and DAP-seq, and they achieved regulation of GbGGPPS by binding to the G-box. Further findings revealed that GbMYC2_4 and GbMYC2_5 bind the G-box not universally but selectively. Our study revealed that jasmonic acid signaling mediates TTL biosynthesis through the GbJAZ–GbMYC2–GbGGPPS module, which enriches the terpenoid biosynthesis regulatory networks and provides a research basis and target genes for enhancing TTL content through genetic engineering.

Carotenoids are naturally occurring tetraterpenoids that play a key role in fruit coloration, and yellow peaches are one of the best sources of carotenoid intake. MYB transcription factors are one of the largest families in plants and play an important role in the regulation of plant secondary metabolite biosynthesis. However, peach MYB family genes have not been fully analyzed, and in particular, MYBs that regulate carotenoid biosynthesis have not been fully characterized. In this study, 190 peach MYB genes, containing 68 1R-MYBs, 118 2R-MYBs, 3 3R-MYBs, and 1 4R-MYB, were identified at the genome level using bioinformatics methods. These 190 MYBs were classified into 27 subfamilies based on their phylogenetic relationships with Arabidopsis thaliana MYB family members, and they were unevenly distributed across eight chromosomes. MYB genes of the same subfamily exhibit similar but not identical gene structures and conserved motifs. The promoter regions contain cis-acting elements associated with stress response, hormone response, and plant growth and development. There were 54 collinear pairs of MYB genes in the peach genome, compared with 233 and 221 collinear pairs with Rosa chinensis and Arabidopsis, respectively. Thirteen differentially expressed genes in the carotenoid biosynthesis pathway in yellow peach were identified by transcriptome sequencing and contained MYB binding sites on their promoters. Based on a phylogenetic analysis, we identified 13 PpMYBs that may be involved in carotenoid biosynthesis, and a correlation analysis revealed that they regulate carotenoid accumulation by positively or negatively regulating the expression of carotenoid biosynthetic genes. Further degradome sequencing screened that mdm-miR858 was able to target PpMYB17 and PpMYB126 involved in the regulation of carotenoid biosynthesis. Our findings provide new insights into the potential role of MYB transcription factors in carotenoid biosynthesis and provide a theoretical basis for their molecular mechanisms.

Zanthoxylum armatum (Z. armatum) is a significant economic tree species known for its medicinal and edible properties. However, the presence of prickles on Z. armatum poses a considerable challenge to the advancement of its industry. Numerous studies have indicated that the C2H2 zinc finger protein (C2H2-ZFPs) families are crucial in the development of plant trichomes or prickles. This study identified 78 ZaC2H2 genes from the Z. armatum genome, categorizing them into three groups and analyzing their protein physicochemical properties, chromosomal locations, conserved domains, and gene structures. The evolutionary analysis indicates that the amplification of ZaC2H2 genes primarily results from whole-genome duplication or segmental duplication, and these genes have undergone strong purifying selection pressure throughout their evolutionary history. The analysis of cis-acting elements revealed that they contain various hormone response elements, such as ABRE, AuxRR, the CGTCA motif, GARE motifs, and TCA elements, which are responsive to ABA, IAA, MeJA, GA, and SA signals. RT-qPCR was employed to assess the expression levels of the candidate genes ZaC2H2-45, ZaC2H2-46, ZaC2H2-49, and ZaC2H2-55 under the treatment of five hormones. The results indicated that the expression levels of the ZaC2H2-46 and ZaC2H2-55 genes were significantly up-regulated under NAA, SA, and MeJA treatments. These results will help to further understand the characteristics of the ZaC2H2 gene family and provide a theoretical basis for studying the development of prickles.