CrERF5, an AP2/ERF Transcription Factor, Positively Regulates the Biosynthesis of Bisindole Alkaloids and Their Precursors in Catharanthus roseus

Abstract

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.

The regulation of ZCT1, a transcriptional repressor of monoterpenoid indole alkaloid biosynthetic genes in Catharanthus roseus

“…A crucial regulatory mechanism in specialized metabolism is the transcriptional regulation of biosynthetic genes. Several transcription factors (TFs) involved in MIA regulation have been identified in Catharanthus , including the octadecanoid‐responsive Catharanthus AP2‐domain (ORCA) TF family and the zinc finger Catharanthus (ZCT) TF family described below (Menke et al, ; Van der Fits & Memelink, ; Van der Fits, Zhang, Menke, Deneka, & Memelink, ; Sibéril et al, ; Chatel et al, ; Pauw et al, ; Vom Endt, Soares e Silva, Kijne, Pasquali, & Memelink, ; Zhang et al, ; Suttipanta et al, ; Van Moerkercke et al, , ; Paul et al, ; Liu et al, ; Liu, Patra, Pattanaik, Wang, & Yuan, ; Patra, Pattanaik, Schluttenhofer, & Yuan, ; Pan et al, ). Three characterized members ( ZCT1 , ZCT2, and ZCT3 ) of the Cys 2 /His 2 ‐type (C 2 H 2 ) zinc finger family are expressed by the stress‐induced phytohormone jasmonate (Goklany, Rizvi, Loring, Cram, & Lee‐Parsons, ; Pauw et al, ).…”

Genomic Characterization of WRKY Transcription Factors Related to Andrographolide Biosynthesis in Andrographis paniculata

“…As the demand for andrographolide has grown over the past years, obtaining higher contents of andrographolide by controlling the biosynthesis pathway of andrographolide has attracted researchers' attention. Transcription factors are important regulators that can activate biosynthetic enzyme genes at the transcription level to promote active compound production (Bai et al, 2018 ; Cao et al, 2018 ; Pan et al, 2019 ). In A. paniculata , transcription factors have rarely been studied.…”

Metabolic Engineering Strategies of Industrial Hemp (Cannabis sativa L.): A Brief Review of the Advances and Challenges

“…The manipulation of genes that are linked though transcription factors provides a means to upregulate a pathway, but circumventing the signal transduction that precedes coordinated regulation such as a pathogen defense response. This strategy has been applied to many plant secondary metabolites, including anthocyanins in Arabidopsis ( Liu et al, 2018 ; Outchkourov et al, 2018 ), flavonoids in tomato ( Stracke et al, 2007 ; Luo et al, 2008 ), and alkaloids in Catharanthus roseus ( Van Moerkercke et al, 2015 ; Pan et al, 2019 ) by upregulation of transcription factors. In Cannabis , van Bakel et al (2011) identified several dozen transcription factors that are likely to play roles in the regulation of the THC synthesis pathway.…”