How one plant makes more brain-healthy fat than its cousin — and what it means for farming

Nervonic acid (NA) — a rare fatty acid crucial for brain development and fighting neurodegenerative diseases — is notoriously difficult to source. Shark fishing bans and inefficient chemical synthesis have choked supply, while most NA-rich plants remain wild and undomesticated. Now, researchers have cracked the genomic code behind one tropical tree species that naturally packs over 30% NA in its seeds. By comparing two closely related Macaranga species with vastly different NA levels, the team uncovered how genomic simplification and specific environmental triggers drive high-yield NA accumulation. The findings offer a clear roadmap for domesticating these wild plants into reliable, industrial-scale NA crops.

The therapeutic promise of NA spans Alzheimer's disease, multiple sclerosis, and adrenoleukodystrophy, yet human bodies cannot produce it after birth. Traditional animal sources are dwindling, and plant alternatives face serious hurdles: long juvenile phases, difficult propagation, low yields, and unwanted byproducts. Among the few NA-producing plants introduced to horticulture, none have been truly domesticated for agriculture. Based on these challenges, there is an urgent need to dissect the molecular mechanisms that allow certain wild species to naturally concentrate NA, so that breeders can fast-track their domestication and unlock a sustainable, plant-based supply for the booming therapeutic market.

Now, a team from the Xishuangbanna Tropical Botanical Garden (XTBG) and the Kunming Institute of Botany, both part of the Chinese Academy of Sciences, along with collaborators, has assembled the first chromosome-level genomes of two Macaranga species. Published (DOI: 10.1093/hr/uhag114) on April 2, 2026, in Horticulture Research, the study reveals why M. indica accumulates over 30% nervonic acid in its seed oil — nearly five times more than its close relative M. denticulata (at just 6.5%) — despite having similar total oil content.

The team found that M. indica achieves high NA yields through a streamlined genomic strategy. While M. denticulata carries multiple redundant gene copies that spread metabolic flux across diverse lipids, M. indica uses fewer but far more highly expressed genes in two critical pathways: fatty acid elongation and triacylglycerol (TAG) synthesis. Specifically, the rate-limiting enzyme KCS (3-ketoacyl-CoA synthase) and the TAG-assembly genes PDAT (phospholipid:diacylglycerol acyltransferase) and DGAT (diacylglycerol O-acyltransferase) are tightly co-regulated in a single expression module directly linked to NA accumulation. By contrast, M. denticulata spreads its NA biosynthesis across five loosely connected modules, diluting output. The researchers also pinpointed cold temperatures, abscisic acid (ABA), and phosphate starvation as major environmental triggers that boost NA production specifically in M. indica. Population resequencing of 110 individuals further revealed two distinct genetic clusters — one in Yunnan and another across Guangxi-Guizhou — with evidence of northward gene flow. Interestingly, Guangxi accessions showed a shortened juvenile phase in common gardens, hinting at ongoing adaptation that could accelerate breeding cycles.

“We were surprised to find that more genes don't necessarily mean more oil,” said Bo Tian of XTBG, a corresponding author of the study. “M. indica essentially cut the clutter — it kept the core machinery and cranked up the volume on just the right genes, while its cousin spread the effort across too many pathways.” The authors added that this clear genetic blueprint, combined with defined environmental cues like mild cold and phosphate limitation, gives breeders direct handles to manipulate. “We're not just describing a natural curiosity — we're handing the field a practical toolkit for domestication,” they said.

Beyond basic science, the work has immediate practical value. As climate warming shifts Macaranga distributions northward, and Guangxi populations already show faster flowering in cultivation, the species may be undergoing a domestication process reminiscent of castor bean — evolving from woody perennials toward more crop-like, herbaceous forms. This study provides a genomic foundation for targeted breeding, offering a sustainable, plant-based alternative to dwindling animal-derived NA. Moreover, with a quarter of Macaranga species facing high extinction risk, turning these plants into valuable NA crops could directly incentivize their conservation. The authors believe their findings transform a wild tropical tree into a promising candidate for future oilseed agriculture.

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References

DOI

10.1093/hr/uhag114

Original Source URL

https://doi.org/10.1093/hr/uhag114

Funding information

This work was supported by the Applied and Basic Research Key Project of Yunnan, China (Grant No. 202101AS070011), Reserve Talents for Yunnan Young and Middle-aged Academic and Technical Leaders, China (Grant No. 202105 AC160083), and the 2022 Yunnan Postdoctoral Orientation Training Program (Grant No. E3YN011B).

About Horticulture Research

Horticulture Research is an open access journal of Nanjing Agricultural University and ranked number one in the Horticulture category of the Journal Citation Reports ™ from Clarivate, 2023. The journal is committed to publishing original research articles, reviews, perspectives, comments, correspondence articles and letters to the editor related to all major horticultural plants and disciplines, including biotechnology, breeding, cellular and molecular biology, evolution, genetics, inter-species interactions, physiology, and the origination and domestication of crops.