GO:0019748 secondary metabolic process: Biosynthesis, Regulation, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0019748 secondary metabolic process describes the chemical reactions and pathways that produce compounds not strictly required for growth and maintenance, often unique to a taxon.
• Secondary metabolism spans plants, fungi, cyanobacteria, and Streptomyces, generating defense chemicals, antibiotics, pigments, and signaling molecules.
• These pathways are frequently organized in biosynthetic gene clusters and are tightly regulated by global and pathway-specific transcription factors.
• Flux balance analysis and metabolic flux phenotyping are key computational and experimental tools for mapping secondary metabolism.
• MicroRNAs and epigenetic mechanisms add layers of regulation in plant secondary metabolism.
• CRISPR-based knockout, base editing, and overexpression enable causal testing of secondary metabolism genes in diverse organisms.
Description
Secondary metabolic process (GO:0019748) encompasses the chemical reactions and pathways that produce compounds not necessarily required for growth and maintenance of cells, and which are often unique to a taxon. In multicellular organisms, secondary metabolism is generally carried out in specific cell types and may benefit the organism as a whole, while in unicellular organisms it is often used for antibiotic production or for the utilization and acquisition of unusual nutrients. These pathways are central to plant defense, fungal ecology, and microbial competition, and they represent a rich source of pharmaceuticals and bioactive molecules. Understanding secondary metabolic process is important because it bridges primary metabolism, ecological interactions, and human health. Plant secondary metabolites function as defenses, regulators, and even primary metabolites, blurring the functional trichotomy. In fungi, secondary metabolism is controlled by complex transcriptional and epigenetic networks that determine when and which metabolites are produced. In cyanobacteria and Streptomyces, secondary metabolism supports survival and antibiotic production, and metabolic modeling is increasingly used to predict and engineer these pathways. For researchers, GO:0019748 provides a structured framework to annotate genes, interpret omics data, and design experiments that test the function of biosynthetic gene clusters. The term is also a practical entry point for CRISPR-based functional genomics, where knockout, point mutation, knock-in, and overexpression models can reveal causal roles of candidate genes in secondary metabolite production.
secondary metabolic process At A Glance
| GO ID | GO:0019748 |
|---|---|
| GO term | secondary metabolic process |
| Ontology | biological_process |
| Synonym | secondary metabolism; secondary metabolite metabolic process; secondary metabolite metabolism |
| Major function | Production of taxon-specific compounds not required for growth and maintenance, including defense molecules, antibiotics, pigments, and signaling metabolites |
| Taxonomic scope | Plants, fungi, cyanobacteria, Streptomyces, and other organisms |
| Regulation | Controlled by global and pathway-specific transcription factors, epigenetic mechanisms, and microRNAs |
| Research methods | Metabolic flux phenotyping, flux balance analysis, CRISPR editing, transcriptomics, and metabolomics |
What Is GO:0019748?
In our own words, GO:0019748 secondary metabolic process refers to the chemical reactions and pathways that generate compounds which are not strictly essential for cell growth and maintenance, and which are often specific to a particular taxonomic group. In multicellular organisms, these processes typically occur in specialized cell types and can benefit the whole organism, while in unicellular organisms they frequently serve antibiotic production or the acquisition and use of unusual nutrients.
Why Is secondary metabolic process Important in Cell Biology?
Secondary metabolic process is important because it underlies the production of a vast array of bioactive compounds that shape ecological interactions, microbial competition, and human medicine. Plant secondary metabolites serve as defenses, regulators, and primary metabolites, making them central to plant survival and adaptation. Fungal secondary metabolism produces mycotoxins, antibiotics, and pigments that affect agriculture and health. Cyanobacterial and Streptomyces secondary metabolism is a major source of antibiotics and other pharmaceuticals, and metabolic modeling is increasingly used to optimize production. Understanding GO:0019748 therefore supports drug discovery, crop protection, and synthetic biology.
• Plant secondary metabolites act as defenses against herbivores and pathogens, and also regulate plant development and stress responses.
• Fungal secondary metabolism generates clinically important antibiotics and toxins, and is controlled by complex regulatory networks.
• Cyanobacteria use secondary metabolism for nutrient acquisition and production of bioactive compounds, which can be studied by metabolic flux phenotyping.
• Streptomyces secondary metabolism is a major source of antibiotics, and systems metabolic engineering aims to improve yields.
• Flux balance analysis provides a computational framework to model and predict secondary metabolite production.
• MicroRNAs regulate plant secondary metabolism, adding a post-transcriptional layer of control.
• Base editing enables facile inactivation of global regulators to perturb secondary metabolism across Streptomyces species.
• Secondary metabolic pathways are often encoded in biosynthetic gene clusters, making them tractable targets for CRISPR-based functional genomics.
• Understanding secondary metabolism supports the discovery of new drugs, agrochemicals, and bioproducts.
• Secondary metabolism is a key area for systems biology, integrating genomics, metabolomics, and flux modeling.
What Happens During secondary metabolic process?
Precursor supply from primary metabolism
In simple terms: Secondary metabolism borrows building blocks from primary metabolism to make specialized compounds.
Secondary metabolic pathways often start from primary metabolites such as amino acids, acetyl-CoA, and sugars, which are diverted into specialized branches. In plants, the blurring between primary and secondary metabolism means that some compounds serve both growth-related and defense-related roles. In fungi and bacteria, precursor supply is a key determinant of secondary metabolite yields, and metabolic modeling can predict flux distributions.
Biosynthetic gene cluster expression
In simple terms: Genes for a secondary metabolite are often grouped together and switched on as a unit.
Many secondary metabolic pathways are encoded by biosynthetic gene clusters, which contain the enzymes, regulators, and transporters needed for production. In Streptomyces, global regulators control the expression of multiple clusters, and base editing can inactivate these regulators to perturb secondary metabolism across species. In fungi, cluster expression is governed by pathway-specific and global transcription factors.
Enzymatic assembly and tailoring
In simple terms: Enzymes build the core molecule and then decorate it with chemical modifications.
After precursor activation, enzymes such as polyketide synthases, nonribosomal peptide synthetases, and terpene synthases assemble the core scaffold, which is then tailored by oxidases, methyltransferases, and glycosyltransferases. In cyanobacteria, metabolic flux phenotyping has been used to trace how carbon and nitrogen flow into secondary metabolites. The order and efficiency of these enzymatic steps strongly influence the final metabolite profile.
Regulation by transcription factors and small RNAs
In simple terms: The cell decides when to make secondary metabolites using dedicated control proteins and small RNA molecules.
Secondary metabolism is regulated by global and pathway-specific transcription factors, and in plants by microRNAs that target biosynthetic or regulatory genes. In fungi, epigenetic modifications and chromatin remodeling also influence cluster expression. In Streptomyces, inactivation of a global regulator using base editing can broadly perturb secondary metabolism, demonstrating the importance of regulatory hierarchies.
Transport, storage, and ecological function
In simple terms: Once made, secondary metabolites are moved, stored, or released to perform their roles.
Secondary metabolites may be transported out of the cell, stored in vacuoles or vesicles, or secreted to mediate interactions with other organisms. In plants, specific cell types often carry out secondary metabolism, and the products can act as defenses or signals. In unicellular organisms, secondary metabolites such as antibiotics can inhibit competitors or help acquire unusual nutrients.
Key Genes Involved in GO:0019748 secondary metabolic process
The following genes and gene families are representative of secondary metabolic process across plants, fungi, cyanobacteria, and Streptomyces, based on the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PKS (polyketide synthase) | Assembles polyketide scaffolds | Core biosynthetic enzyme in many secondary pathways |
| NRPS (nonribosomal peptide synthetase) | Produces peptide secondary metabolites | Target for engineering antibiotics and peptides |
| Terpene synthase | Generates terpenoid scaffolds | Key enzyme in plant and fungal volatile and defense compounds |
| Global regulator (e.g., Streptomyces global regulator) | Controls multiple biosynthetic gene clusters | Base editing target to perturb secondary metabolism |
| Pathway-specific transcription factor | Activates a single biosynthetic gene cluster | Used to study cluster regulation in fungi |
| MicroRNA (plant) | Post-transcriptional regulator of secondary metabolism | Modulates biosynthetic gene expression in plants |
| Cytochrome P450 | Tailoring enzyme for oxidation | Diversifies secondary metabolite structures |
| Methyltransferase | Adds methyl groups to secondary metabolites | Affects bioactivity and stability |
| Glycosyltransferase | Glycosylates secondary metabolites | Influences solubility and transport |
| ABC transporter | Exports secondary metabolites | Affects production and resistance |
| MFS transporter | Efflux of secondary metabolites | Contributes to secretion and self-resistance |
| Sigma factor | Coordinates stress and secondary metabolism | Links environmental signals to cluster expression |
| Histone deacetylase | Epigenetic regulator of secondary metabolism | Modulates cluster accessibility in fungi |
| Histone acetyltransferase | Epigenetic activator of secondary metabolism | Influences cluster expression |
| Two-component system sensor | Senses environmental cues | Connects external signals to secondary metabolism |
| Quorum-sensing regulator | Coordinates population-level secondary metabolism | Controls antibiotic production in bacteria |
| Ribosomal protein (indirect) | Supports protein synthesis for biosynthetic enzymes | Provides capacity for secondary metabolism |
How Is secondary metabolic process Regulated?
Secondary metabolic process is regulated at multiple levels. In fungi, global and pathway-specific transcription factors, chromatin modifiers, and environmental signals control biosynthetic gene cluster expression. In Streptomyces, global regulators coordinate multiple clusters, and base editing can inactivate these regulators to perturb secondary metabolism across species. In plants, microRNAs post-transcriptionally regulate secondary metabolism, adding another layer of control. Metabolic flux phenotyping and flux balance analysis further reveal how pathway flux is distributed and regulated under different conditions.
secondary metabolic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| Global regulator (Streptomyces) | Antibiotic production and resistance | Base editing knockout in Streptomyces |
| Pathway-specific transcription factor | Fungal virulence and mycotoxin production | Knockout in Aspergillus or Fusarium |
| MicroRNA (plant) | Plant defense and stress response | Overexpression or knockout in Arabidopsis |
| PKS/NRPS cluster | Antibiotic and anticancer compound production | Knock-in or overexpression in heterologous hosts |
| Cytochrome P450 | Secondary metabolite diversification and drug metabolism | Point mutation to alter substrate specificity |
Secondary metabolism and infectious disease
Fungal secondary metabolites include mycotoxins and virulence factors that contribute to plant and human infections, and understanding their regulation can inform antifungal strategies. Streptomyces secondary metabolites are a source of antibiotics, and engineering their production is important for combating infectious diseases.
Secondary metabolism and cancer
Plant and microbial secondary metabolites are a major source of anticancer drugs, and studying their biosynthetic pathways supports drug discovery and production. Metabolic modeling of secondary metabolism can help optimize yields of bioactive compounds with therapeutic potential.
Secondary metabolism and metabolic disorders
Some secondary metabolites influence human metabolism and can serve as leads for treating metabolic disorders, although the causal links require further study. Plant secondary metabolites also affect nutrient availability and gut microbiome interactions.
From secondary metabolic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is a candidate gene essential for secondary metabolite production? | CRISPR knockout in the native producer |
| Does a specific amino acid change alter enzyme activity? | Point mutation knock-in via CRISPR |
| Can a biosynthetic gene cluster be expressed in a heterologous host? | Knock-in of the entire cluster |
| Does overexpression of a regulator increase metabolite yield? | Overexpression of the regulator |
| How does a tagged enzyme localize during secondary metabolism? | Tagged knock-in with fluorescent protein |
| What is the flux distribution through a secondary pathway? | Metabolic flux phenotyping and flux balance analysis |
How to Study the secondary metabolic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Metabolic flux phenotyping | Flux through secondary pathways | Cyanobacterial secondary metabolism |
| Flux balance analysis | Predicted metabolic flux distributions | Microbial secondary metabolite production |
| RNA-seq | Transcript levels of biosynthetic genes | Cluster expression profiling |
| Small RNA-seq | MicroRNA expression | Plant secondary metabolism regulation |
| CRISPR knockout | Loss-of-function phenotype | Gene essentiality in secondary metabolism |
| Base editing | Single-nucleotide changes | Inactivation of global regulators |
| Metabolomics | Metabolite profiles | Detection of secondary metabolites |
| Heterologous expression | Production in a surrogate host | Biosynthetic gene cluster characterization |
Metabolic flux phenotyping
Metabolic flux phenotyping measures the flow of carbon and nitrogen through secondary metabolic pathways, often using isotope labeling and mass spectrometry. In cyanobacteria, this approach has been used to map secondary metabolism under different conditions.
Flux balance analysis
Flux balance analysis uses genome-scale metabolic models to predict flux distributions and identify bottlenecks in secondary metabolite production. It is widely applied to microbial secondary metabolism and can guide strain engineering.
Transcriptomics and microRNA profiling
RNA sequencing and small RNA sequencing reveal expression changes in biosynthetic gene clusters and regulatory microRNAs. In plants, microRNA profiling has been used to study secondary metabolism regulation.
CRISPR-based functional genomics
CRISPR knockout, base editing, and knock-in enable causal testing of genes in secondary metabolic pathways. Base editing has been used to inactivate global regulators in Streptomyces to perturb secondary metabolism.
How CRISPR Can Be Used to Study GO:0019748 secondary metabolic process
Knockout
CRISPR knockout is used to delete candidate genes within secondary metabolic pathways or their regulators, revealing whether they are required for metabolite production. In Streptomyces, knockout of global regulators can broadly perturb secondary metabolism. In fungi, knockout of pathway-specific transcription factors can abolish cluster expression.
Point Mutation
Point mutations introduced by CRISPR base editing or homology-directed repair can alter enzyme active sites or regulatory phosphorylation sites, allowing fine mapping of function. Base editing has been used to inactivate a Streptomyces global regulator, demonstrating the utility of precise nucleotide changes in secondary metabolism research.
Knock-in
Knock-in of biosynthetic gene clusters or tagged enzymes enables heterologous production and localization studies. This approach is valuable for characterizing cryptic clusters and for engineering new secondary metabolites.
Overexpression
Overexpression of positive regulators or biosynthetic enzymes can increase secondary metabolite yields. In Streptomyces and fungi, overexpression of pathway-specific activators is a common strategy to boost production.
How EDITGENE Supports secondary metabolic process Research
Researchers studying secondary metabolic process-related genes often need to determine whether a candidate gene is causally involved in metabolite production, how specific mutations affect enzyme activity, and whether overexpression can enhance yields. EDITGENE provides CRISPR-based cell models and screening services to address these questions across plants, fungi, cyanobacteria, and Streptomyces.
Contact EDITGENE today to design your custom CRISPR model for secondary metabolic process research.
Frequently Asked Questions About secondary metabolic process
What is GO:0019748 secondary metabolic process?
GO:0019748 secondary metabolic process describes the chemical reactions and pathways that produce compounds not necessarily required for growth and maintenance, often unique to a taxon.
What genes are involved in secondary metabolic process?
Genes include polyketide synthases, nonribosomal peptide synthetases, terpene synthases, cytochrome P450s, methyltransferases, glycosyltransferases, transporters, and global or pathway-specific regulators.
Why is secondary metabolism important in plants?
Plant secondary metabolites act as defenses, regulators, and primary metabolites, and they mediate interactions with herbivores and pathogens.
How is fungal secondary metabolism regulated?
Fungal secondary metabolism is regulated by global and pathway-specific transcription factors, epigenetic modifiers, and environmental signals.
What methods are used to study secondary metabolism?
Methods include metabolic flux phenotyping, flux balance analysis, RNA-seq, small RNA-seq, metabolomics, and CRISPR-based editing.
Can CRISPR be used to study secondary metabolic pathways?
Yes, CRISPR knockout, base editing, knock-in, and overexpression enable causal testing of genes in secondary metabolic pathways.
What is the role of microRNAs in plant secondary metabolism?
MicroRNAs post-transcriptionally regulate genes involved in plant secondary metabolism, influencing metabolite production.
How does flux balance analysis help secondary metabolism research?
Flux balance analysis predicts metabolic flux distributions and identifies bottlenecks, guiding strain engineering for secondary metabolite production.
What are biosynthetic gene clusters?
Biosynthetic gene clusters are groups of genes encoding the enzymes, regulators, and transporters for a secondary metabolite, often coordinately regulated.
How can I engineer Streptomyces for higher secondary metabolite yields?
Strategies include base editing of global regulators, overexpression of activators, and systems metabolic engineering guided by metabolic models.
Conclusion
GO:0019748 secondary metabolic process is a fundamental biological process that spans plants, fungi, cyanobacteria, and Streptomyces, producing a vast array of bioactive compounds with ecological and medical importance. Understanding its regulation, biosynthesis, and flux control is essential for drug discovery, crop protection, and synthetic biology. CRISPR-based functional genomics, combined with metabolic modeling and multi-omics, provides powerful tools to dissect and engineer secondary metabolism for research and application.
References
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- 3. Eagan JL et al.. 2025. Fungal secondary metabolism.. Curr Biol 35(11):R503-R508 PMID: 40494304
- 4. Otsuka R et al.. 2026. Facile inactivation of a Streptomyces global regulator using a versatile base editing plasmid for secondary metabolism perturbation across multiple species.. J Biosci Bioeng 142(3):246-252 PMID: 42142957
- 5. Qiu S et al.. 2023. Flux balance analysis-based metabolic modeling of microbial secondary metabolism: Current status and outlook.. PLoS Comput Biol 19(8):e1011391 PMID: 37619239
- 6. Owusu Adjei M et al.. 2021. MicroRNAs Roles in Plants Secondary Metabolism.. Plant Signal Behav 16(7):1915590 PMID: 33938393
- 7. Yu W et al.. 2023. Molecular regulation of fungal secondary metabolism.. World J Microbiol Biotechnol 39(8):204 PMID: 37209190
- 8. Robertsen HL et al.. 2018. Toward Systems Metabolic Engineering of Streptomycetes for Secondary Metabolites Production.. Biotechnol J 13(1) PMID: 29076639
