A bizarre group of underground plants shows how life can thrive even after abandoning sunlight and sex.
Not all plants are green or rely on sexual reproduction, and these exceptions can reveal surprising insights into what it really means to be a plant. A new study involving researchers from Kobe University focused on the genus Balanophora to better understand how plants that lack photosynthesis and often reproduce asexually manage to evolve and survive.
“My long-standing aim is to rethink what it truly means to be a plant,” says Kobe University botanist Kenji Suetsugu. He continues, “For many years I have been fascinated by plants that have abandoned photosynthesis, and I want to uncover the changes that occur in the process.”
Balanophora plants represent an extreme example of this shift. They do not produce their own food through photosynthesis but instead draw nutrients directly from the roots of other plants. Most of their life is spent underground, and they surface only during the flowering season — and some species even reproduce exclusively asexually.
“However, while there have been individual studies on changes in the plants’ genomes, their ecology and their reproduction, we don’t know how they relate to each other,” explains Suetsugu.
Connecting Evolution, Plastids, and Reproduction
To address this gap, Suetsugu aimed to bring together three lines of evidence that had never been fully combined for Balanophora. His goal was to clarify how different species are related to one another, examine how their plastids have changed over time (a part of a plant’s cells which in green plants serves as the cell’s “solar panels”), and understand how their reproductive strategies align with their ecological conditions.
He notes that the research posed unique challenges: “These plants are rare, patchy and often restricted to steep, humid forests. But years of experience with studying Balanophora both in the lab and in field studies, as well as long-standing relationships with local naturalists made this project possible.”
To strengthen the genetic analysis, he also collaborated with scientists at the Okinawa Institute of Science and Technology who specialize in studying highly reduced genomes.
Plastid Genomes Shrunk Early but Remain Essential
The team has now published its findings in the journal New Phytologist. Their analysis revealed that every species examined shared an extremely reduced plastid genome (DNA not kept in the plant cell’s nucleus but directly in the plastid). This reduction appears to have occurred in a common ancestor before the group later diversified into separate species.
Suetsugu says, “It is exciting to see how far a plant can reduce its plastid genome, which at first glance looks as though the plastid is on the verge of disappearing. But looking more closely we found that many proteins are still transported to the plastid, showing that even though the plant has abandoned photosynthesis, the plastid is still a vital part of the plant’s metabolism.”
Asexual Reproduction Offers a Survival Advantage
Unlike the shared loss of photosynthesis, asexual reproduction appears to have emerged multiple times within the group. The researchers suggest that the ability to form seeds without fertilization may have arisen early and helped Balanophora spread across island chains stretching from mainland Japan through Okinawa to Taiwan.
“Over the past decade I have studied Balanophora pollination and seed dispersal where camel crickets and cockroaches play an unexpected role, but I also noticed that asexual seed production often ensured reproduction when mates or pollinators are scarce,” explains Suetsugu. Over time, this strategy may have become the dominant form of reproduction for some species.
Toward a Deeper Understanding of Parasitic Plants
For Suetsugu, the study represents meaningful progress in understanding how plants that no longer photosynthesize continue to function and persist in natural ecosystems.
Suetsugu says, “For someone who has spent many hours observing these plants in dark, humid forests, seeing their story unfold at the genomic level is deeply satisfying. My next goal is to connect these results with biochemical measurements to find out what Balanophora plastids actually produce and how these products help sustain the parasitic plants’ growth within the roots of their hosts.”
Reference: “Phylogenomics clarifies Balanophora evolution, metabolic retention in reduced plastids, and the origins of obligate agamospermy” by Petra Svetlikova, Huei-Jiun Su, Kenji Suetsugu and Filip Husnik, 26 November 2025, New Phytologist.
DOI: 10.1111/nph.70761
This research was funded by the Japan Society for the Promotion of Science (grant 23K14256), the Human Frontier Science Program (grant RGEC29/2024), the Japan Science and Technology Agency (grants JPMJPR21D6, JPMJFR2339) and the National Science and Technology Council, Taiwan (grant 109-2311-B-845-001). It was conducted in collaboration with researchers from the Okinawa Institute of Science and Technology and the University of Taipei.
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