German scientists develop physalis-based agricultural biopesticides

Plants have developed an array of chemical substances as defenses against animals and pathogens, with many compounds notable for their medicinal properties. One such group, the withanolides, are steroids found in the nightshade family known for their health benefits. Despite their importance, the pathways of their biosynthesis and regulation have been less studied until recently.

A team led by Professor Claude Becker, a geneticist at the Faculty of Biology, Ludwig Maximilian University (LMU), has achieved a breakthrough. The team identified a specific gene cluster in the ground cherry (physalis grisea) responsible for the synthesis of withanolides. This discovery, published in the journal PNAS, was made in collaboration with the Max Planck Institute of Molecular Plant Physiology and the University of Hohenheim.

The gene cluster, closely packed with genes that encode enzymes for the biosynthetic pathway, ensures that these genes are regulated and inherited collectively. Intriguingly, the team found that this cluster had undergone duplication in the genome, leading to the formation of two functionally distinct units—one active in the plant root and the other in above-ground tissues.

Professor Becker explained that the separation and organizational pattern of these units are epigenetically regulated, which allows the plant to produce subtly different chemical defenses in its various tissues. The team’s comparative genomics research showed that while this withanolide gene cluster is specific to Physalis and its close relatives, it remains highly conserved within the broader nightshade family, excluding the genus that includes tomatoes and potatoes.

These findings have significant implications, suggesting potential applications in developing alternative pesticides and novel therapeutic agents. This study lays foundational knowledge for further exploration of withanolides, paving the way for innovative uses in agriculture and medicine.