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Research article2013Peer reviewed

The glyoxylate cycle is involved in pleotropic phenotypes, antagonism and induction of plant defence responses in the fungal biocontrol agent Trichoderma atroviride

Dubey, Mukesh; Broberg, Anders; Sooriyaarachchi, Sanjeewani; Ubhayasekera, Wimal; Jensen, Dan Funck; Karlsson, Magnus


Isocitrate lyase (ICL), a signature enzyme of the glyoxylate cycle, is required for metabolism of non-fermentable carbon compounds like acetate or ethanol, and virulence in bacteria and fungi. In the present study, we investigate the role of the glyoxylate cycle in the fungal biocontrol agent Trichoderma atroviride by generating id deletion and complementation mutants. Phenotypic analyses of the deletion mutant Delta icl suggest that ICL is required for normal growth, conidial pigmentation and germination, and abiotic stress tolerance. The Delta icl strain display reduced antagonism towards Botrytis cinerea in plate confrontation assays. Secretion and sandwich assays further show that secreted factors are partly responsible for the reduced antagonism. Furthermore, in vitro root colonization assays shows that the Delta icl strain retains the ability to internally colonize Arabidopsis thaliana roots. However, the Delta icl strain has a reduced ability to induce systemic defence in A. thaliana leaves that results in reduced protection against B. cinerea. These data shows that ICL and the glyoxylate cycle are important for biocontrol traits in T. atroviride, including direct antagonism and induction of defence responses in plants. (C) 2013 Elsevier Inc. All rights reserved.


Antagonism; Biocontrol; Glyoxylate cycle; Isocitrate lyase; Trichoderma atroviride

Published in

Fungal Genetics and Biology
2013, Volume: 58-59, pages: 33-41