Trichoderma koningii (strain Tr5) grew in the epidermal mucilage of onion roots without entering healthy epidermal tissue. When placed on the epidermis of Sclerotium cepivorum-infected roots, T. koningii colonized epidermal passage cells, with little colonization of other epidermal tissues, then branched and spread throughout the root cortical tissues damaged by enzymes and toxins which diffused ahead of S. cepivorum hyphae, and impeded the path of the infection. When T. koningii colonized infected tissue, many S. cepivorum hyphae became detached at septa, cell walls dissolved and many hyphal apices burst. Contact between hyphae was not necessary for lysis to occur. T. koningii produced two endochitinases (Rf 0.15 and 0.24) and two exo-acting chitinolytic enzymes (Rf 0.46 and 0.62) during degradation of crabshell chitin and S. cepivorum cell walls. The Rf 0.24 and 0.46 proteins were detected when T. koningii colonized S. cepivorum-infected roots and are likely to be a component of the antagonism process.

Item Type:	Refereed Article
Research Division:	Agricultural and Veterinary Sciences
Research Group:	Horticultural Production
Research Field:	Horticultural Crop Protection (Pests, Diseases and Weeds)
Objective Division:	Plant Production and Plant Primary Products
Objective Group:	Horticultural Crops
Objective Field:	Vegetables
Author:	Metcalf, DA (Mr Dean Metcalf)
Author:	Wilson, CR (Associate Professor Calum Wilson)
ID Code:	21363
Year Published:	2001
Web of Science® Times Cited:	20
Deposited By:	Agricultural Science
Deposited On:	2001-08-01
Last Modified:	2011-08-02
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