Native PGPR enhance propagation and specialized metabolites in the aromatic and medicinal plant Minthostachys verticillata.

In the native Argentine aromatic and medicinal plant Minthostachys verticillata, inoculation with native rhizobacterium Stutzerimonas stutzeri SM33 promoted rooting capacity, glandular trichome density, essential oil accumulation, and pulegone content.

• Why it matters: Sustainable cultivation of Minthostachys verticillata needs better propagation and phytochemical productivity to reduce pressure on wild populations, but PGPR effects on this species are poorly understood.
• What they did: The study inoculated plants with Stutzerimonas stutzeri SM33 or model PGPR Pseudomonas simiae WCS417r and assessed rooting, trichomes, phytohormones, phenolics, essential-oil biosynthesis gene expression, and essential oil production.
• The result: PGPR inoculation significantly modulated propagation and specialized metabolites with distinct strain-specific patterns, altered jasmonates and SA while leaving ABA unchanged, and regulated monoterpene-biosynthesis gene expression.