Convergent gene clusters underpin hyperforin biosynthesis in St John's wort

Area of Science:

• Plant biochemistry
• Metabolic engineering
• Evolutionary genomics

Background:

• Hyperforin, a meroterpenoid, is key to St. John's wort's antidepressant effects.
• The genetic basis for hyperforin biosynthesis remains largely unknown.

Purpose of the Study:

• To identify and characterize the biosynthetic gene clusters (BGCs) involved in hyperforin precursor synthesis.
• To understand the evolutionary assembly and functional divergence of these BGCs.

Main Methods:

• Genome mining
• Biochemical assays
• Phylogenetic and syntenic analyses

Main Results:

• Two distinct BGCs encoding the initial steps of hyperforin precursor biosynthesis were identified.
• Phylogenetic analysis suggests the first BGC predates the divergence of Hypericaceae and Calophyllaceae families.
• The second BGC arose from genomic fragment coalescence post-duplication, exhibiting distinct gene expression and enzymatic properties.

Conclusions:

• The parallel evolution of two similar BGCs provides insights into the formation and genomic organization of plant specialized metabolic pathways.
• Understanding hyperforin biosynthesis is crucial for advancing plant metabolism evolution studies and enabling future metabolic engineering efforts.