Genetic basis of phytoalexin-mediated chemical defense in plants
Summary
Phytoalexins are core components of plant chemical defense against pathogens. However, the genetic basis and regulatory mechanisms governing their biosynthesis remain preliminary. Debneyol is a well-defined, broad-spectrum fungicidal phytoalexin. Here, we elucidate its biosynthetic pathway, key regulators, and activity against multiple pathogens. We show that debneyol is synthesized from farnesyl pyrophosphate (FPP) through three steps catalyzed by 5-epi-aristolochene synthase (EAS), 5-epi
Content
# Genetic basis of phytoalexin-mediated chemical defense in plants
*Published: 2026 May 8*
Phytoalexins are core components of plant chemical defense against pathogens.
However, the genetic basis and regulatory mechanisms governing their
biosynthesis remain preliminary. Debneyol is a well-defined, broad-spectrum
fungicidal phytoalexin. Here, we elucidate its biosynthetic pathway, key
regulators, and activity against multiple pathogens. We show that debneyol is
synthesized from farnesyl pyrophosphate (FPP) through three steps catalyzed by
5-epi-aristolochene synthase (EAS), 5-epi-aristolochene epoxidase (EAE), and
epoxide hydrolase-1 (EH1). MCD1 (miR1919-targeted cell death-factor-1) interacts
with EAS and EAE, enhancing their association and EAE activity and promoting
debneyol biosynthesis. Increased MCD1 expression confers plant resistance not
only against fungal but also viral and bacterial pathogens. Our work reveals a
complete plant phytoalexin-based chemical defense machinery, opening avenues for
engineering broad-spectrum plant resistance and industrial-scale debneyol
production via synthetic biology.
DOI: 10.1016/j.cell.2026.04.021