Seeding a salty agricultural future - DOE Joint Genome Institute

Fungal genome offers insights into growing crops in salty environments.

The Science:

Researchers sequenced and analyzed the genome of an extremophilic fungus that has adapted to thrive in the Dead Sea.

Dead Sea sampling site for E. rubrum study

Samples of the filamentous fungus E. rubrum were collected from the Dead Sea, the lowest and saltiest point on Earth. (Tami Kis-Papo, University of Haifa, Israel)

The Impact:

The genome provides information on how the fungus can tolerate extremely salty conditions. As climate change continues to affect agricultural lands and yields, these mechanisms could serve as targets in developing crops that can tolerate what are currently considered stressful growth conditions.

Summary

Despite being considered the lowest and saltiest point on Earth, the Dead Sea does harbor life, albeit primarily in the form of bacteria and fungi. The adaptations applied by these organisms vary: some lay dormant when salt concentrations are too high and others have become dependent on salt. A team including researchers from Israel’s University of Haifa and the U.S. Department of Energy Joint Genome Institute (DOE JGI) analyzed the genome of a fungus that thrives in this environment to learn which strategy it employs. They described their findings in the May 9, 2014 issue of Nature Communications.

The DOE JGI team sequenced, assembled and annotated the 26.2-million base genome of E. rubrum. They found that the E. rubrum proteins had higher aspartic and glutamic acid amino acid levels than expected. They also found that high acidic residues were a general trait all salt-tolerant microbes share after comparing E. rubrum’s gene families against those in two other halophilic species. Researchers from the University of Haifa then focused on the fungus’ tolerance for salt, growing samples in liquid and solid media at salinities from zero up to 90 percent of Dead Sea water. They found that E. rubrum had viable spores when grown in 70 percent diluted Dead Sea water, conditions equivalent to an algal bloom in the Dead Sea 20 years ago.

“Understanding the long-term adaptation of cells and organisms to high salinity is of great importance in a world with increasing desertification and salinity,” the team wrote. “The observed functional and structural adaptations provide new insight into the mechanisms that help organisms to survive under such extreme environmental conditions, but also point to new targets like the biotechnological improvement of salt tolerance in crops.”

Contact

Igor Grigoriev
DOE Joint Genome Institute
[email protected]

Funding

U.S. Department of Energy Office of Science
Ancell Teicher Research Foundation for Genetics and Molecular Evolution

Publication

Kis-Papo T et al. Genomic adaptations of the halophilic Dead Sea filamentous fungus Eurotium rubrum. Nat Commun. 2014 May 9;5:3745. doi: 10.1038/ncomms4745.