Abstract
Apparently, wild types of Trichoderma spp. do not possess the attribute of rhizosphere competence (RC), i.e. they cannot colonize the rhizosphere adjacent to developing roots from a seed treatment. To enhance RC, strains of T. harzianum were exposed to N-methyl-N-nitro-N-nitrosoguanidine and mutants selected for benomyl resistance. When benomyl was added to soil, these mutants applied to seeds colonized the rhizosphere 8 cm below the seed at densities approaching 106 cfu/g rhizosphere soil. Unexpectedly, RC was induced when benomyl was not added to the soil. There is no evidence that benomyl resistance is related to RC; however, a perfect correlation was observed between increased cellulase production by mutants and RC. This suggested that mutants may utilize the mucigel on roots as a substrate. Mutation to RC and faster growth rate, comparable to root elongation, was induced in a slow growing species such as T. polysporum. Mutants with RC also were more efficient biocontrol agents and induced greater increased growth responses from a seed treatment than wild-type parents.
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Baker, R. (1991). Induction of rhizosphere competence in the biocontrol fungus Trichoderma. In: Keister, D.L., Cregan, P.B. (eds) The Rhizosphere and Plant Growth. Beltsville Symposia in Agricultural Research, vol 14. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-3336-4_48
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DOI: https://doi.org/10.1007/978-94-011-3336-4_48
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