Transcriptional Regulation of Alkaloid Biosynthesis in Tobacco Plants

The tobacco plant produces a suite of structurally diverse alkaloids, chief among them nicotine, predominantly synthesised in root tissues and sequestered in leaf vacuoles. This biosynthetic sequence comprises a series of enzymatic steps assembling pyridine and pyrrolidine moieties, regulated at the transcriptional level by networks of transcription factors and phytohormonal signals. Central to this control are jasmonate-induced transcriptional cascades, featuring Ethylene Response Factor (ERF) and MYC2 families that bind cognate cis-elements upstream of biosynthetic genes. Clusters of ERF genes within loci such as NIC2 act redundantly and divergently to fine-tune pathway flux, while downstream enzymes, including berberine bridge enzyme-like proteins, influence product stereochemistry. Advances in genomic resources, transcriptomic profiling, gene editing and chemical treatments have illuminated the dynamic interplay between environmental stimuli, hormonal cues and transcriptional regulators, enabling targeted manipulation of alkaloid content for both fundamental research and applied crop improvement.

Research from Nature Portfolio

High-quality draft genomes for multiple Nicotiana tabacum varieties have provided a comprehensive inventory of gene models underpinning alkaloid biosynthesis, revealing ancestral origins of key regulatory clusters and enabling map-based cloning of homeologous loci with roles in nitrogen use and defence metabolism. Global RNA-sequencing analyses of topping and subsequent suckercide treatments have elucidated the early transcriptional responses in roots and aerial tissues, identifying gene cohorts related to wounding, phytohormone metabolism and secondary metabolite production, and highlighting promoters inducible by agronomic practices for potential chemical-free control strategies.

Transcriptional Regulation of Alkaloid Biosynthesis in Tobacco Plants publication trend

The graph below shows the total number of articles in transcriptional regulation of alkaloid biosynthesis in tobacco plants across all publications each year (not limited to Nature Index journals).

Technical terms

Jasmonate: A plant hormone that mediates defence responses and activates secondary metabolism, including alkaloid biosynthesis.

Ethylene Response Factor (ERF): A family of transcription factors that bind specific cis-elements to regulate gene expression in response to ethylene and jasmonate.

Berberine Bridge Enzyme-like proteins (BBLs): Oxidase-like enzymes catalysing late steps in pyridine alkaloid synthesis and influencing product stereochemistry.

Transcriptome: The complete set of RNA transcripts expressed in a cell or tissue under specific conditions.

CRISPR/Cas9: A genomic editing system enabling precise disruption or modification of target genes in plants.

References

1. An improved Nicotiana benthamiana bioproduction chassis provides novel insights into nicotine biosynthesis. New Phytologist (2023).
2. Genetic regulation and manipulation of nicotine biosynthesis in tobacco: strategies to eliminate addictive alkaloids. Journal of Experimental Botany (2023).
3. A reference genome for Nicotiana tabacum enables map-based cloning of homeologous loci implicated in nitrogen utilization efficiency. BMC Genomics (2017).
4. RNA-sequencing Reveals Global Transcriptomic Changes in Nicotiana tabacum Responding to Topping and Treatment of Axillary-shoot Control Chemicals. Scientific Reports (2015).
5. Transcriptome analysis reveals key genes involved in the regulation of nicotine biosynthesis at early time points after topping in tobacco (Nicotiana tabacum L.). BMC Plant Biology (2020).
6. Clustered Transcription Factor Genes Regulate Nicotine Biosynthesis in Tobacco. The Plant Cell (2010).
7. Transgenic and Mutation-Based Suppression of a Berberine Bridge Enzyme-Like (BBL) Gene Family Reduces Alkaloid Content in Field-Grown Tobacco. PLOS ONE (2015).