ARS | Publication request: Liquid culture production of fungal microsclerotia for use in biological control

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: September 21, 2007
Publication Date: September 21, 2007
Citation: Jackson, M.A., Schisler, D.A., Shearer, J.F., Jaronski, S. 2007. Liquid culture production of fungal microsclerotia for use in biological control [abstract]. XV Congress of European Mycologists, St. Petersburg, Russia. p. 191.

Technical Abstract: A method has been developed for producing microsclerotia of various fungi in liquid culture. Colletotrichum truncatum, Mycoleptodiscus terrestris, Ascochyta caulina, and an entomopathogenic fungus have all been shown to produce microsclerotia in liquid culture under appropriate environmental and nutritional conditions. Highly aerated fermentations of 4-8 days were necessary to produce 0.5-50.0 x 10(6) microsclerotia l(-1). In general, media rich in carbon supported the production of the highest concentrations of microsclerotia. Depending on the fungus, 50-95% of the microsclerotia survived air-drying in diatomaceous earth with excellent storage stability at 4 degrees C. When hydrated and incubated at 28 degrees C, air-dried microsclerotia were capable of hyphal germination and/or sporogenic germination. For weed or insect control, the soil incorporation of microsclerotial propagules delivers stable fungal propagules which are capable of producing conidial inoculum in situ. The ability to produce high concentrations of sclerotia in liquid culture also should enable researchers to study sclerotial morphogenesis and physiology under gnotobiotic conditions. This liquid-culture production technique will also allow large quantities of sclerotial biomass to be obtained so that novel compounds, such as antibiotics and insecticidal compounds that contribute to the persistence of sclerotia in soil, may be identified and mass produced.