Abstract
Beauveria bassiana is an insect pathogenic fungus used as a biopesticide in crop pest management. It exists saprophytically in the soil. The pH of the soil and the insect cuticle and its haemocoel may influence fungal survival and infection potential. Therefore the tolerance and optimum pH ranges were studied in 29 isolates of B. bassiana. Germination and growth bioassays in liquid culture medium adjusted to pH values in the range 3–14 at unit intervals were studied. A pH of 3 was found to be toxic to all isolates – conidia germinated at this pH but growth was totally inhibited. All isolates tolerated a pH of 5–13. Some isolates showed tolerance to a pH of 4 and/or 14 as well. Sixteen isolates showed a wide range of pH optimum of 5–13 while others had a narrower optimal range. The relation of the pH tolerance and optimum range of an isolate to its phenotypic characters (colonial morphology and growth-rate) was studied. All isolates with a ‘chalky’ type colonial morphology had an intermediate growth rate and showed a wide optimum range of pH 5–13 or 5–14. All isolates with ‘dusty’ type colonial morphology were found to have a high growth rate and a wide pH tolerance range of 4–14. Both chalky and dusty colonial morphology are due to a growth pattern characterized by iterated conidiation with a very brief hyphal stage. The correlation observed between these traits based on external phenotype would facilitate prediction of the pH tolerance characters of an isolate of B. bassiana.
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Alfenes, A.C., Jeng, R. & Hubner, M. 1984 Isozyme and protein patterns of isolates of Cryphonectria eubensis differing in virulence. Canadian Journal of Botany 62, 1756-1762.
Bidochka, M.J., Kasperski, J.E. & Wild, G.A.M. 1998 Occurrence of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana in soils from temperate and near-northern habitats. Canadian Journal of Botany 76, 1198-1204.
Butt, M.T., Jackson, C. & Magan, N. 2001 Introduction-fungal biological control agents: progress, problems and potential. In Fungi as Biocontrol Agents, Progress, Problems and Potential, eds. Butt, T.M., Jackson, C. & Magan, N. pp. 1-8. Oxon, UK: CAB International. ISBN 085 199 356 7.
Caddick, M.X., Brownlee, A.G. & Arst, H.N. 1986 Regulation of gene expression by pH of the growth medium in Aspergillus nidulans. Molecular and General Genetics 203, 346-353.
Campbell, R.K., Barnes, G.L. & Eikennary, R.D. 1979 Nutritional and physiological studies of the pecan weevil pathogen Beauveria bassiana. Journal of the Kansas Entomological Society 52, 470.
Campbell, M.A., Medd, R.W. & Brown, J.F. 1996 Growth and sporulation of Pyrenophora semeniperda in vitro: effects of culture media, temperature and pH. Mycological Research 100, 311-317.
Fargues, J., Goettel, M.S., Smits, N., Ouedraogo, A. & Rougier, M. 1997 Effect of temperature on vegetative growth of Beauveria bassiana isolates from different origins. Mycologia 89, 383-392.
Ferron, P. 1978 Biological control of insect pests by entomogenous fungi. Annual Review of Entomology 23, 409-442.
Galani, G. 1988 Cultivation of some entomopathogenic fungi in liquid media with various initial pH values. Analel-Institutului-de-Cercetari-pentru-Protecta-Plantelor 21, 54.
Glare, T.R. & Milner, R.J. 1991 Ecology of entomopathogenic fungi. Handbook of Applied Mycology Vol. 2. Humans, Animal and Insects, vol. 2, eds. Arora, D.K., Ajello, L. & Mukerji, K.G. pp. 547-612. New York: Marcel Dekker. ISBN 0-82478435-9.
Goettel, M.S. & Inglis, G.D. 1997 Fungi: Hyphomycetes. In Manual of Techniques in Insect Pathology, ed. Lacey, L.A. pp. 213-249. London: Academic Press. ISBN 0-12-432555-6.
Goral, V.M. & Lappa, N.V. 1971 Toxins of the entomophagous fungus Beauveria bassiana II. Effect of nitrogen sources on formation of the toxic protease in submerged culture. Journal of Invertebrate Pathology 17, 211-215.
Groden, E. & Dunn, T. 1996 Germination, host infection and survival of Beauveria bassiana conidia in natural soils. In Microbial Control of Soil-Dwelling Pests, eds. Jackson, T.A. & Glare, T.R. pp. 137-145. Lincoln, New Zealand: The Microbial control group, Agriculture Research.
Groden, E. & Lockwood, J.L. 1991 Effects of soil fungistasis on Beauveria bassiana and its relationship to disease incidence in the Colorado potato beetle, Leptinotarsa decemlineata, in Michigan and Rhode island soils. Journal of Invertebrate Pathology 57, 7-16.
Hallsworth, J.E. & Magan, N. 1996 Culture age, temperature, and pH after the polyol and trehalose contents of fungal propagules. Applied and Environmental. Microbiology 62, 2435-2442.
Humber, R.A. 1992 Collection of Entomopathogenic Fungal Cultures: Catalog of Strains. US Department of Agriculture, Agricultural Research Service ARS-110, 177pp.
Inglis, D.G., Goettel, S.M., Butt, M.T. & Strasser, H. 2001 Use of hyphomycetous fungi for managing insect pests. In Fungi as Biocontrol Agents, Progress, Problems and Potential. eds. Butt, T.M., Jackson, C. & Magan, N. pp. 23-69. Oxon, UK: CAB International. ISBN 0-82478435-9.
Leathers, T.D., Gupta, S.C. & Alexander, N.J. 1993 Mycopesticides: Status, challenges and potential. Journal of Industrial Microbiology 12, 69-75.
Lopez-Llorca, L.V. & Olivares-Bernabeu, C. 1997 Growth inhibition of nematophagous and entomopathogenic fungi by leaf litter and soil containing phenols. Mycological Research 101, 691-697.
MacLeod, D.M. 1954 Investigations on the genera Beauveria Vuill. and Tritirachium Limber. Canadian Journal of Botany 32, 818-890.
Mekalanos, J.J. 1992 Environmental signals controlling expression of virulence determinants in bacteria. Journal of Bacteriology 174, 1-7.
Milner, R.J. 1989 Ecological considerations on the use of Metarhizium for control of soil-dwelling pests. In Proceedings of a Soil-Invertebrate Workshop, eds. Robertson, L.N. & Allsopp, P.G. pp. 10-13. Queensland Department of Primary Industries Conference and Workshop series QC 89004, Indoorpilly, Queensland.
Mugani, L., Bridge, P.D. & Evans, H.C. 1989 A chemotaxonomic evaluation of the genus Beauveria. Mycological Research 92, 199-209.
Rath, A.C. 1992 Metarhizium anisopliae for control of the Tasmanian pasture scarab Adoryphorus couloni. In The Use of Pathogens in Scarab Pest Management, eds. Jackson, A.T. & Glare, R.T. pp. 217-227. Andover: Intercept Publications ISBN 0-94670735-9.
Rath, A.C., Worledge, D., Koen, T.B. & Rowe, B.A. 1995 Long-term field efficacy of the entomogenous fungus Metarhizium anisopliae against the subterranean scarab, Adoryphorus coulini. Biocontrol Science and Technology 5, 439-451.
Sanzhimitupova, R.D. 1980 Effect of the pH of the medium on the growth and development of the causal agent of mycosis of the seabuckthorn moth (Gelecjia hippophaellaSchrk. Izvestiya-Sibirskogo-Otdeleniya-Akademii-Nauk-SSSR-Biology 15, 39-41.
Sharma, S., Agarwal, G.P. & Rajak, R.C. 1992 Effect of temperature, pH and light on toxin production by Beauveria bassiana (Bal) Vuill. Indian Journal of Experimental Biology 30, 918-919.
Shimazu, M. & Sato, H. 1996 Media for selective isolation of an entomogenous fungus Beauveria bassiana Deuteromycotina, Hyphomycetes. Applied Entomology and Zoology 31, 291-298.
St. Leger, R.J., Joshi, L. & Roberts, D. 1998 Ambient pH is a major determinant in the expression of cuticle degrading enzymes and hydrophobin by Metarhizium anisopliae. Applied and Environmental Microbiology 64, 709-713.
St. Leger, R.J., Nelson, O.J. & Screen, E.S. 1999 The entomopathogenic fungus Metarhizium anisopliae alters ambient pH, allowing extracellular protease production and activity. Microbiology 145, 2691-2699.
Varela, A. & Morales, E. 1996 Characterization of some Beauveria bassiana isolates and their virulence toward the coffee berry borer Hypothenemus hampei. Journal of Invertebrate Pathology 67, 147-152.
Yip, H.Y., Rath, A.C. & Koen, T.B. 1992 Characterization of Metarhizium anisopliae isolates from Tasmanian pasture soils and their pathogenicity to redheaded cockchafer (Coleoptera: Scarabaeidae: Adoryphorus couloni). Mycological Research 96, 92-96.
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Padmavathi, J., Uma Devi, K. & Uma Maheswara Rao, C. The optimum and tolerance pH range is correlated to colonial morphology in isolates of the entomopathogenic fungus Beauveria bassiana – a potential biopesticide. World Journal of Microbiology and Biotechnology 19, 469–477 (2003). https://doi.org/10.1023/A:1025151000398
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DOI: https://doi.org/10.1023/A:1025151000398