Nematode-trapping fungi have been found to be natural killers of nematodes and their mechanisms might facilitate the development of new drugs or biological control agents, an Academia Sinica researcher said yesterday.
Mostly measuring less than 1mm, nematodes are found in soil worldwide and most are not visible to the naked eye, Academia Sinica Institute of Molecular Biology assistant research fellow Hsueh Yen-ping told a news conference in Taipei.
Some nematodes can cause infections in humans or damage plants, but existing pesticides, such as ivermectin, aldicarb and levamisole, can only inhibit their activity and the poisons’ efficacy are declining due to their wide use over the past few decades, she said.
Hsueh’s team found that oyster mushrooms, when starving, prey on nematodes by producing potent toxins that can paralyze them within minutes.
Using Caenorhabditis elegans as their model nematode, the team found that the fungal hyphae of oyster mushrooms trigger a massive calcium influx and rapid cell necrosis in the neuromuscular system of the nematode, making them more effective than nematicides, she said.
However, further research is needed to uncover the mushrooms’ key toxic compounds and if they might affect other creatures, she said.
The team detailed their findings in a paper published in the journal Proceedings of the National Academy of Sciences of the US on March 17. The paper, authored by Academia Sinica researchers, was listed as one of the issue’s cover stories.
Another paper by Hsueh, published a week later in the same journal, investigated a different mechanism found in nematode-trapping fungi that she said are present in more than two-thirds of soil samples collected in Taiwan.
Such fungi prey on almost all nematodes by sensing their pheromones, producing fungal hyphae to capture and decompose them, she said.
Genetic and genomic tools were used in the study, which also involved researchers from Cornell University and the University of California, Riverside, she added.
Having studied nematodes since her postdoctoral research at the California Institute of Technology a decade ago, Hsueh said she has long been fascinated by the interactions between nematodes and other organisms.
While literature about nematodes is limited, studying nematodes is essential to understanding the biogeochemistry of soil, as some nematodes might be beneficial to the environment like earthworms are, she said.
The nematode-killing mechanisms in the two studies suggest new routes for targeting parasitic nematodes infection in humans, animals and agriculture, Hsueh said, expressing the hope that her team would develop new treatments and biocontrol methods from the mechanisms.
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Academia Sinica Institute of Molecular Biology assistant research fellow Hsueh Yen-ping, front row, center, and her research team pose for a group photograph at a news conference in Taipei yesterday./Photo courtesy of CNA