How Madagascar Periwinkle genes respond to stress and an essential amino acid

Jenn Hoskins
13th October, 2025

How Madagascar Periwinkle genes respond to stress and an essential amino acid

A: Control seedlings and B: Seedlings under drought stress of 40%.

Image adapted from: Yousefi et al. / CC BY (Source)

Key Findings

  • In Madagascar periwinkle plants, drought stress and tryptophan application boosted gene activity related to alkaloid production
  • Tryptophan treatment, especially combined with drought, increased levels of vinblastine and vincristine, valuable anti-cancer compounds, by up to 488%
  • The study found that tryptophan application improved overall plant health, doubling plant biomass and increasing protective antioxidants like phenols and flavonoids
Catharanthus roseus, commonly known as Madagascar periwinkle, is a plant of significant medicinal importance, primarily due to its production of the potent anti-cancer drugs vinblastine and vincristine[2]. However, obtaining these compounds is challenging as they are produced in very small quantities within the plant, prompting ongoing research into methods to boost their yield. Recent work from researchers at the University of Khuzestan, Lorestan University, and UNC Chapel Hill[1] investigated how environmental stresses, specifically drought and the addition of the amino acid tryptophan, affect the plant’s ability to produce these valuable alkaloids. The study focused on understanding how these factors influence the genes involved in the biochemical pathways responsible for creating these compounds. Plants naturally synthesize a vast array of molecules through complex pathways, and the production of vinblastine and vincristine relies on the terpenoid indole alkaloid (TIA) pathway[2]. The researchers used a controlled experiment, manipulating drought levels (moderate and severe) and tryptophan concentrations (with and without addition) over different time periods (24, 48, 72, and 168 hours). They then measured the activity of key genes in four relevant pathways: phenolic/flavonoid, indole, terpenoid, and alkaloid. The results revealed a complex interplay between stress, tryptophan, and gene expression. The Cm gene, involved in the production of phenolic and flavonoid compounds, consistently showed increased activity across all treatments, peaking after 168 hours when both drought stress and tryptophan were applied. Genes in the indole alkaloid pathway, As and Tdc, exhibited a different pattern, with highest activity at 24 hours, particularly under drought conditions. Genes in the terpenoid and alkaloid pathways showed an initial increase at 24 hours, followed by a decrease, and then a resurgence at 168 hours. Crucially, the accumulation of vinblastine and vincristine themselves significantly increased, especially under severe drought stress, aligning with the observed gene expression patterns. These findings build upon earlier research demonstrating that manipulating genes within the TIA pathway can have unpredictable effects on alkaloid production[3]. The previous study showed that overexpression of the AS gene, a rate-limiting enzyme in the TIA pathway, sometimes increased alkaloid levels, but other times decreased them, suggesting that altering a single gene can trigger wider, complex changes throughout the plant’s metabolism. ’s work expands on this by showing that external factors like drought and tryptophan can also act as triggers for these changes. The observed upregulation of genes in the JA biosynthesis pathway, as demonstrated in[3], is consistent with the overall stress response seen in the current study. Interestingly, the study also found that endophyte inoculation can increase vindoline content by 229-403%[4], and that this is linked to changes in the expression of key structural and regulatory genes of vindoline biosynthesis. This suggests that multiple pathways can be used to enhance alkaloid production, and that the plant's response to stress can be modulated by interactions with other organisms. Furthermore, the application of tryptophan doubled plant biomass compared to the control group, indicating a positive effect on overall plant health even under stressful conditions. The increased levels of non-enzymatic antioxidants, like phenols and flavonoids, also suggest that tryptophan helps protect the plant from the damaging effects of drought. The researchers conclude that a combination of drought stress and tryptophan application effectively modulates gene expression and metabolite production, offering a potential strategy for optimizing alkaloid biosynthesis in Catharanthus roseus under challenging environmental conditions.

AgricultureBiochemPlant Science

References

Main Study

1) Evaluation of the expression pattern of TIAs pathway genes in response to tryptophan amino acid treatment and drought stress in Catharanthus roseus

Published 9th October, 2025

https://doi.org/10.1371/journal.pone.0333313

Related Studies

2) Ornamental exterior versus therapeutic interior of Madagascar periwinkle (Catharanthus roseus): the two faces of a versatile herb.

https://doi.org/10.1155/2015/982412

3) Examining the transcriptional response of overexpressing anthranilate synthase in the hairy roots of an important medicinal plant Catharanthus roseus by RNA-seq.

https://doi.org/10.1186/s12870-016-0794-4

4) Fungal endophytes of Catharanthus roseus enhance vindoline content by modulating structural and regulatory genes related to terpenoid indole alkaloid biosynthesis.

https://doi.org/10.1038/srep26583


Related Articles

An unhandled error has occurred. Reload 🗙