Summary
A bioRxiv preprint describes BRIDGE, a platform that transferred a 16-kilobase, five-gene violacein pathway into ten phylogenetically diverse yeast genera. Expression was strongest across six tested Saccharomyces species and varied in other yeasts.
Researchers have described BRIDGE, a synthetic-biology platform for moving DNA from bacteria into a broad range of yeasts. In a bioRxiv preprint posted on September 21, 2026, the team reports transferring a complete 16-kilobase pathway containing five genes into ten phylogenetically diverse yeast genera.
The platform is intended to make non-conventional yeasts easier to engineer and evaluate as microbial cell factories. These organisms can have useful biological properties, but DNA delivery is a basic prerequisite for testing engineered traits. The authors describe BRIDGE as a way to combine DNA construction, recovery and delivery in one workflow.
How BRIDGE delivers DNA across yeast groups
BRIDGE—short for Bacteria-to-yeast Rapid Interkingdom DNA Gene Exchange—centres on a compact 6-kilobase Pan/ARS-oriT broad-host vector and a superconjugative helper plasmid called pSC5. The system expands interkingdom DNA transfer from representatives of four genera previously accessible using pSC5 alone to ten genera: Saccharomyces, Maudiozyma, Starmerella, Kazachstania, Yarrowia, Zygosaccharomyces, Lachancea, Kluyveromyces, Pichia and Komagataella.
The workflow separates several engineering steps. Individual transcriptional units—DNA segments designed to control the expression of particular genes—were first constructed with the YeastFab modular cloning system. The researchers then assembled the full multigene pathway in Saccharomyces cerevisiae through single-step in vivo homologous recombination. The completed plasmid was recovered using the EASY-C platform before being delivered to the different yeasts.
This design allows a pathway to be assembled in one yeast host and then tested across multiple genera, rather than requiring a separate construction process for every organism.
A visible test of multigene pathway transfer
To test whether BRIDGE could move more than a simple marker gene, the researchers built a 16-kilobase visual reporter containing a synthetic five-gene violacein biosynthetic pathway from Chromobacterium violaceum. Violacein is a purple pigment, allowing pathway activity to be assessed visually in suitable hosts.
The reporter was delivered to all ten yeast genera. Robust violacein production was observed in all six Saccharomyces species tested, providing a rapid visual marker for identifying transformants. The pathway also showed modest functional expression in Kazachstania and Kluyveromyces.
In the remaining genera, the researchers achieved pathway transfer without visible pigmentation. This distinction is important: DNA reaching a cell is a delivery result, while producing the intended compound also requires the recipient organism to read and regulate the introduced genes effectively.
The authors identify regulatory compatibility as the principal factor determining whether a transferred pathway is expressed in more distantly related yeasts. Regulatory sequences that work in one organism may not function in another because gene-control systems differ between species and lineages.
Why the platform matters
The study presents BRIDGE as an integrated Design-Build-Recover-Deliver workflow for rapidly modifying yeasts that have been difficult to engineer. Broadening access to these organisms could allow researchers to investigate their metabolism and test them for the production of chemicals, materials or other biological products.
The immediate result is a DNA-delivery capability spanning ten yeast genera, together with a demonstration that complete multigene pathways can be transferred between them. The variation in violacein expression also gives the platform a practical use beyond delivery: it can help reveal which hosts are compatible with a particular engineered pathway and which require redesigned regulatory elements.
The findings are reported in a bioRxiv preprint rather than a peer-reviewed journal article. The supplied abstract reports pathway transfer and expression outcomes, but not industrial-scale production performance, quantitative product yields or the detailed experimental replication needed to compare the hosts as manufacturing platforms.