Presentation description

Halophilic nematodes have been discovered in the Great Salt Lake (Jung et al., 2024). They were found to be associated with bacteria-built mounds called microbialite that line the shallow marginal areas of the lake (Lindsay et al., 2019); significantly higher numbers of nematodes were found living in microbialite sediment than in sediment adjacent to the microbialite (Jung et al. 2024).
The mechanism of survival in hypersalinity remains unknown, but we hypothesize that cross-kingdom interactions between bacteria and nematodes may provide part of the answer.
To test whether bacteria in GSL can increase saline tolerance of nematodes, we grew laboratory nematodes Caenorhabditis elegans and Pristionchus pacificus on either 1) standard laboratory bacteria E. coli OP-50 or 2) various bacterial isolates. Worm survival 5 minutes and 24 hours after exposure to saline water was then measured. Nematodes raised on microbialite were observed to have increased survival in salinity up to 10% over both time points. This suggests that bacteria from microbialites can provide salinity tolerance not only to Great Salt Lake nematodes but also to other species of nematodes. The reason for improved survivability is unknown and requires further investigation to understand how organisms can survive in extreme environments. We have isolated two distinct bacterial colonies that provide salinity tolerance to C. elegans. Ongoing work is being conducted to sequence their genomes and look for specific genes that can provide osmoregulation. Subsequently, the function of these candidate genes will be tested using knockouts or insertions into GSL bacteria and E. coli, respectively. Using a combination of laboratory, wild nematodes, and associated bacteria, this research aims to discover the mechanisms behind the Great Salt Lake nematodes' ability to survive in highly saline environments.