Integrative Analysis of Elicitor-Induced Camptothecin Biosynthesis in Camptotheca acuminata Plantlets Through a Combined Omics Approach

Abstract

Treatments with abiotic elicitors can efficiently induce the accumulation of specialized metabolites in plants. We used a combined omics approach to analyze the elicitation effects of MeJa, AgNO3, and PEG on camptothecin (CPT) biosynthesis in Camptotheca acuminata plantlets. Untargeted analyses revealed that treatments with MeJa, AgNO3, and PEG significantly inhibited the photosynthetic pathway and promoted carbon metabolism and secondary metabolic pathways. The CPT levels increased by 78.6, 73.3, and 50.0% in the MeJa, AgNO3, and PEG treatment groups, respectively. Using C. acuminata plantlets after elicitation treatment, we mined and characterized 15 new alkaloids, 25 known CPT analogs and precursors, 9 iridoid biosynthetic precursors, and 15 tryptamine biosynthetic precursors based on their MS/MS fragmentation spectra. Using 32 characterized genes involved in CPT biosynthesis as bait, we mined 12 prioritized CYP450 genes from the 416 CYP450 candidates that had been identified based on co-expression analysis, conserved domain analysis, and their elicitation-associated upregulation patterns. This study provides a comprehensive perspective on CPT biosynthesis in C. acuminata plantlets after abiotic elicitation. The findings enable us to elucidate the previously unexplored CYP450-mediated oxidation steps for CPT biosynthesis.

Integrated transcriptome and proteome analysis provides new insights into camptothecin biosynthesis and regulation in Camptotheca acuminata

“…The whole genomes of the both CPT‐producing plants have been sequenced and assembled (Kang et al, 2021; Rai et al, 2021; Zhao et al, 2017), which has boosted the discovery and characterization of genes involved in CPT biosynthesis. In addition, considerable effort has been directed at elucidating the CPT biosynthetic pathway from a multiomics perspective (Pu et al, 2020; Pu et al, 2022). For example, Pu et al identified a series of CPT analogues and found 12 candidate CYP450s possibly involved in the biosynthesis of CPT and its derivatives based on Illumina sequencing and metabolite analysis (Pu et al, 2020, Pu et al, 2022).…”

“…In addition, considerable effort has been directed at elucidating the CPT biosynthetic pathway from a multiomics perspective (Pu et al, 2020; Pu et al, 2022). For example, Pu et al identified a series of CPT analogues and found 12 candidate CYP450s possibly involved in the biosynthesis of CPT and its derivatives based on Illumina sequencing and metabolite analysis (Pu et al, 2020, Pu et al, 2022). It is thus clear that multiomics technologies play an important role in revealing the biosynthesis and regulation of CPT.…”

“…Subsequently, Yang et al confirmed that CaPSTR had STR activity, which catalyzes the condensation of secologanin with tryptamine to yield strictosidine (Yang et al, 2021). Several C. acuminata transcriptomes have been sequenced with the Illumina sequencing platform by different groups of researchers to identify more enzymes involved in CPT biosynthesis (Góngora‐Castillo et al, 2012; Pu et al, 2022). However, the molecular mechanism underlying CPT biosynthesis and its regulation remain largely unknown.…”

“…Several C. acuminata transcriptomes have been sequenced with the Illumina sequencing platform by different groups of researchers to identify more enzymes involved in CPT biosynthesis (G ongora-Castillo et al, 2012;Pu et al, 2022). However, the molecular mechanism underlying CPT biosynthesis and its regulation remain largely unknown.…”

Profiles of Metabolic Genes in Uncaria rhynchophylla and Characterization of the Critical Enzyme Involved in the Biosynthesis of Bioactive Compounds-(iso)Rhynchophylline

“…It indicates that TFs in MYB, WRKY, AP2/ERF and bHLH are likely to regulate spiroindole alkaloid production in U. rhynchophylla . In addition, the members of the CYP71 and CYP81 families are usually involved in indole alkaloid, flavonoid, and terpenoid metabolism [ 28 ]. The unigenes of the CYP71 and CYP81 families shown in Figure 9 are also possible candidates for spiroindole alkaloid biosynthesis.…”