JA-induced JAZ8 degradation releases and activates the TCP14-ORA complex in enhancing artemisinin biosynthesis in Artemisia annua .

Catharanthus roseus contains a variety of monoterpenoid indole alkaloids (MIAs), among which bisindole alkaloids vinblastine and vincristine are well-known to have antitumor effects and widely used in clinical treatment. However, their contents in C. roseus is extremely low and difficult to meet market demands. Therefore, it is of great significance to study the transcriptional regulation mechanism of MIAs biosynthesis for high yielding of bisindole alkaloids in C. roseus. Studies have shown that MIAs biosynthesis in C. roseus has complex temporal and spacial specificity and is under tight transcriptional regulation, especially bisindole alkaloids. In this study, an AP2/ERF transcription factor CrERF5 was selected by RNA-seq of C. roseus organs, and its full-length sequence was cloned and characterized. CrERF5 responds to both ethylene and JA signals and is localized in the nucleus. CrERF5 could activate the transcriptional activity of the TDC promoter. Transient overexpressing CrERF5 in C. roseus petals caused a significant increase of the expression levels of key genes in both the upstream and downstream pathways of MIAs biosynthesis while silencing CrERF5 resulted in a decrease of them. Accordingly, the contents of bisindole alkaloids anhydrovinblastine and vinblastine, monoindole alkaloids ajmalicine, vindoline and catharanthine were strongly enhanced in CrERF5-overexpressing petals while their contents decreased in CrERF5-silenced plants. These results suggested that CrERF5 is a novel positive ethylene-JA-inducible AP2/ERF transcription factor upregulating the MIAs biosynthetic pathway leading to the bisindole alkaloids accumulation.

Artemisia japonica Thunb is an important perennial herb containing abundant chemical compounds utilized in conventional medicine for the treatment of malaria, hepatitis, hypertension, and inflammation. The protoplasts-based transient transform...

Catharanthus roseus contains nearly 200 bioactive monoterpenoid indole alkaloids (MIAs) that are effective in treating cancer and other diseases. Ethylene plays a significant role in enhancing MIA biosynthesis, and we have found that it greatly induces the accumulation of anhydrovinblastine. However, the regulatory mechanisms underlying this process are not yet fully understood. In this study, a comprehensive analysis of the metabolome and transcriptome of C. roseus was conducted to identify two EIN3/EIL transcription factors, CrEIN3 and CrEIL1, which act as key components mediating the ethylene signal to upregulate MIA biosynthesis. Both CrEIN3 and CrEIL1 were found to upregulate the expression of MIA biosynthetic genes and the activator gene ORCA3, while repressing the expression of repressor genes GBF1 and ZCT1, resulting in increased vinblastine production in C. roseus . CrEIN3 directly binds to the SGD promoter, while CrEIL1 interacts with JA‐induced BIS2 to enhance upregulation of the iridoid pathway, thereby further promoting downstream MIA biosynthesis and strengthening the accumulation of bisindole MIAs. Our findings reveal an ethylene‐activated regulatory model consisting of CrEIN3 and CrEIL1 that integrates JA‐induced BIS2 to cooperatively regulate MIA production in C. roseus , shedding light on the mechanism of ethylene signal regulating MIA biosynthesis. This research provides a foundation for understanding plant hormone regulation of alkaloid metabolism, which will contribute to future efforts in developing high‐yielding MIAs in plant or yeast‐based platforms.