Hung-Che Lin and colleagues from Academia Sinica in Taipei, Taiwan, have conducted a detailed analysis shedding light on the molecular intricacies involved in the carnivorous behavior of Arthrobotrys oligospora, a fungus known for sensing, trapping, and consuming worms. Published in the open-access journal PLOS Biology, their research explores the genetic and molecular processes that occur at various stages of A. oligospora's predation on a nematode worm species called Caenorhabditis elegans.
While A. oligospora typically derives nutrients from decaying organic matter, instances of starvation and the presence of nearby worms prompt it to form traps for capturing and consuming these worms. Despite prior research unveiling some aspects of the biology behind this predator-prey relationship, the molecular details of the process have largely remained unclear.
To enhance understanding, Lin and his team conducted a series of lab experiments, relying significantly on RNAseq, a technique providing information on the activity levels of different genes in A. oligospora at different stages of predation. The findings revealed several key biological processes involved in A. oligospora predation.
Upon sensing a worm, the research suggests an increase in DNA replication and the production of ribosomes, essential structures for building proteins in a cell. Subsequently, the activity of numerous genes encoding proteins that aid in trap formation and function, including secreted worm-adhesive proteins and a newly identified family called “trap enriched proteins” (TEP), intensifies.
As A. oligospora extends filamentous structures known as hyphae into a worm for digestion, the researchers observed a boost in the activity of genes coding for various enzymes, particularly metalloproteases, a group of proteases. Proteases are enzymes that break down proteins, indicating that A. oligospora employs these enzymes to assist in worm digestion.
The researchers emphasize that these findings could serve as a foundational platform for future research into the molecular mechanisms governing A. oligospora predation and similar fungal predator-prey interactions. They highlight the significance of increased DNA replication, translation, and secretion in trap development and efficacy. Additionally, they identify a gene family, abundant in the genomes of nematode-trapping fungi, that is enriched in traps and crucial for trap adhesion to nematodes, further advancing our understanding of the essential processes in fungal carnivory.
Source: Public Library of Science