Submitted to: Biocontrol Science and Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/18/2010
Publication Date: 10/29/2010
Publication URL: http://hdl.handle.net/10113/48768
Citation: Dunlap, C.A., Jackson, M.A., Saha, B.C. 2010. Compatible solutes of sclerotia of Mycoleptodiscus terrestris under different culture and drying conditions. Biocontrol Science and Technology. 21(1):113-123. Interpretive Summary: In this research, we identified compounds associated with stress tolerance of an important biocontrol organism. Our research addresses a technical challenge limiting the adoption of biocontrol technology in the commercial pest control industry, producing stable microorganisms in a cost-effective manner. Our study identified two compounds that are produced in this organism (Mycoleptodiscus terrestris) after exposure to drying stress. This work will support the development of more stress-tolerant organisms and processing methods for pest control applications through increased knowledge of the basic processes responsible for stress tolerance.
Technical Abstract: Mycoleptodiscus terrestris is plant pathogen which has been shown to be effective in controlling invasive aquatic weeds in inundative biocontrol applications. The preferred propagule for production and application is the sclerotia. In the current study, we evaluated the accumulation of carbohydrates and polyols in the sclerotia of M. terrestris under different culture and drying regimes. The carbohydrates and polyols screened for represent a class of compatible solutes found in fungi. The results show mannitol and trehalose are the major analytes identified in the sclerotia of M. terrestris. We identified higher levels of mannitol and trehalose in liquid-culture produced samples relative to solid-state produced samples. The impact of fermentation time was examined and shown to impact solute levels. In addition, the drying regime was varied to produce samples dried to different moisture contents. The experiments show greater drying led to higher mannitol levels, while trehalose levels remained constant. Rapid drying of the sclerotia in a fluidized-bed dryer also show rapid accumulation of mannitol and trehalose, which suggest the enzyme activities needed for production are readily available. The findings confirm mannitol and trehalose are important metabolytes in M. terrestris and their concentrations are responsive to osmotic stress conditions.