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In vitro production of extracellular enzymes by fungi and their relationship with the symptoms described for the host plant

ABSTRACT

Soilborne phytopathogenic fungi cause economical losses to several crops and are difficult to control. These fungi can be grouped according to the common symptoms they cause in plants, as well as to the extracellular enzymes they can produce. The aim of this study was to verify the in vitroproduction of extracellular enzymes for soilborne fungi and to relate these enzymes to the symptoms that each fungus causes in the host plant. The assay was conducted in completely randomized design, including two factors, seven fungi (Cylindrocladium spathiphylli, Rhizoctonia solani, Sclerotium rolfsii, Ceratocystis fimbriata, Sclerotinia sclerotiorum, Fusarium oxysporum f. sp. dianthi and Verticillium dahliae) plus control and six enzymes (amylase, carboxymethyl cellulase, lipase, laccase, catalase and gelatinase) with 10 replicates. Catalase and gelatinase were measured based on a score scale, while the other enzymes were analyzed by calculating the circular crown area (mm2). The assay was repeated twice and statistical analysis was done by using data of both assays. The fungi that cause root and collar rot presented greater laccase production, while those that cause obstruction, fissure and even destruction of the vascular system demonstrated prevalence of lipase.

Additional key-words:
Soilborne fungi; enzymes-diseases interaction; symptomatology

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