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Medium components and culture conditions affect the thermotolerance of aerial conidia of fungal biocontrol agent Beauveria bassiana
Author(s) -
Ying S.H.,
Feng M.G.
Publication year - 2006
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.2006.01947.x
Subject(s) - beauveria bassiana , conidium , bassiana , sucrose , starch , biological pest control , food science , biology , sugar , botany , horticulture , fungi imperfecti , microbiology and biotechnology
Aims: To produce more thermotolerable conidia of Beauveria bassiana , a well‐known fungal biocontrol agent, by optimizing the medium components and culture conditions. Methods and Results: The conidia produced on media including 0·5–6% glucose, sucrose or starch as carbon source and 50–300‐ μ g ml −1 Cu 2+ , Zn 2+ , Mn 2+ or Fe 3+ as additive to Sabouraud dextrose medium at 15–30°C, pH 4–8 or KCl‐adjusted water availabilities were exposed to 30‐min wet heat stress at 48°C. The medium components for conidial production with greatly enhanced thermotolerance included 4% glucose as optimum or 1% starch as alternative for the carbon source and 50‐ μ g ml −1 Mn 2+ for the metal additive. The culture conditions were optimized as 25°C and pH 5–6. Conidial thermotolerance decreased remarkably when sucrose and Fe 3+ or Cu 2+ were used in the cultures, but altered slightly when 50–200‐ μ g ml −1 Zn 2+ were included. Conclusions: The tolerance of B. bassiana conidia to the thermal stress was significantly affected by the medium composition and culture conditions under which the conidia were produced. Significance and Impact of the Study: Proper treatment of small grains as mass production substrates for more glucose release and supplement of glucose or 50‐ μ g ml −1 Mn 2+ are possible means to enhancing conidial thermotolerance and field persistence for improved insect control.