Horizontal Gene Transfer Drives Metabolic Diversity in Grass Species, Study Shows
Researchers sequenced the genome of the grass Zuloagaea bulbosa and identified 56 candidate horizontally transferred genes, demonstrating that gene transfer between grasses like maize and Z. bulbosa occurs in both directions. The study found that horizontally transferred genes are disproportionately concentrated in biosynthetic gene clusters — groups of genes that encode entire metabolic pathways. This suggests that acquiring a complete functional pathway in a single transfer event provides an immediate adaptive advantage, helping explain the remarkable chemical diversity found across grass species.
A new preprint study published on bioRxiv reports that horizontal gene transfer (HGT) — the movement of DNA between organisms outside of normal reproduction — is bidirectional between the grass Zuloagaea bulbosa and maize, expanding understanding of how grasses exchange genetic material across evolutionary distances. The researchers first generated a high-quality phased reference genome for Z. bulbosa, then identified 56 candidate horizontally transferred genes, approximately 45% of which originated from the grass tribe Andropogoneae, including two genes likely derived specifically from maize. Because prior work had already documented transfers from Z. bulbosa into maize, the new findings confirm the exchange runs in both directions, though not necessarily in equal measure. A key finding is that horizontally transferred genes are significantly enriched within biosynthetic gene clusters (BGCs) — genomic regions where multiple enzymes of the same metabolic pathway are co-located — suggesting natural selection favors the transfer of entire functional pathways rather than isolated genes. Two of the transferred genes belong to the benzoxazinoid biosynthetic cluster, a defense-related pathway with a complex evolutionary history of prior transfers between grass subfamilies. The authors conclude that the dynamism of biosynthetic gene clusters, driven in part by recurrent horizontal gene transfers, is a major contributor to the extraordinary metabolic diversity observed in plants.
What's missing
As a preprint, this study has not yet undergone formal peer review, so findings should be treated as preliminary. It also remains unclear how many of the 56 candidate HTGs are definitively adaptive versus neutral or mildly deleterious.
What different sources said
- bioRxivCenter
Horizontal gene transfer fuels metabolic innovation in the grass Zuloagaea bulbosa
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