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ARS Home » Midwest Area » Madison, Wisconsin » Cereal Crops Research » Research » Publications at this Location » Publication #418985
Research Project: Harnessing Multi-omics for Augmenting Seed Quality and Stress Tolerance in Barley

Location: Cereal Crops Research

Title: Microbiome of fungal-like organisms in lake sturgeon eggs, and identification of chemical sensitivity thresholds for their control

Author
item Maccready, Kristi
item NOEL, ZACHARY - Auburn University
item SAVILLE, KEN - Albion College
item MARSH, TERENCE - Michigan State University
item SCRIBNER, KIM - Michigan State University
item TRAIL, FRANCES - Michigan State University

Submitted to: Microbial Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2025
Publication Date: 7/24/2025
Citation: Maccready, K.G., Noel, Z.A., Saville, K., Marsh, T., Scribner, K.T., Trail, F. 2025. Microbiome of fungal-like organisms in lake sturgeon eggs, and identification of chemical sensitivity thresholds for their control. Microbial Ecology. 88, 80, (2025). https://doi.org/10.1007/s00248-025-02566-5.
DOI: https://doi.org/10.1007/s00248-025-02566-5

Interpretive Summary: Lake sturgeon are members of hatchery programs to increase populations of these fish in North America. Sometimes survival rates of the sturgeon eggs in hatcheries are low. We classified microorganisms inhabiting healthy and diseased eggs to identify potential pathogens. Compounds used to control similar pathogens in agriculture were evaluated for effectiveness.

Technical Abstract: Eukaryotic microorganisms are an important, but understudied, component of freshwater aquatic ecosystems, and are significant sources of mortality in early life stages of fishes in natural and aquaculture systems. The eukaryotic microbiome colonizing egg surfaces of the lake sturgeon (Acipenser fulvescens) was characterized from eggs collected in natural stream habitats and a stream-side hatchery in the Cheboygan River watershed in Michigan, USA. The taxonomic diversity of members of the Kingdoms Fungi and Stramenopile associated with infections of lake sturgeon eggs during spawning are contributing to lake sturgeon mortality in the hatchery. Characterization of the microbial communities from deposited eggs demonstrated heavy influence of spawning location on the diversity of Pythium, an Oomycete predominating in the microbiome. The Ascomycota also had a strong and distinguishing presence, with members of the Dothidiales found only on eggs from the Research Facility. Aureobasidium pullulans, a ubiquitous pigmented yeast, was present in the greatest numbers of egg samples, and Helotiales were found only on samples from the Black River. Independent isolates were collected from egg surfaces and tested for chemical sensitivity to the oomicides ethaboxam and mefenoxam, which are used for control of Oomycete agricultural pathogens. Ethaboxam inhibited mycelial growth almost completely for all Saprolegnia strains tested, while mefenoxam, at 20 X the strength was largely ineffective. Water prevents the natural inactivation of mefenoxam by light, thus is not advisable in aquatic systems, where it can accumulate. Ethaboxam may be a nonpersistent, welcome control option for these fish pathogens.