Detection of semi-quantitative and qualitative enzymatic activities of blue-stain fungi
M T De Troya, F Llinares, D Muñoz-Mingarro, M J Pozuelo, N Acero, C Rodríguez-Borrajo, A M Navarrete
Blue-stain, produced in forests, continues to be a problem in countries of moderate climate. In forestry, in certain geographical areas of Spain, it has been observed that anti-sapstain products have not always been efficient, as their fungicidal effectiveness varies on occasion, depending on the species of wood and microbiota that exist in the region. It is not always easy to identify the species causing this damage. Therefore, the object of this study was the grouping of diverse isolates according to the detection of simple enzymatic activities, following a simple and rapid method of application such as API-ZYM. 36 strains of Ceratocystis spp, isolated from divers species of Pinus spp., have been tested. The results were contrasted with the activities detected in the same conditions in Pullularia pullulans and Sclerophoma pityophila. To do this, these strains were inoculated in culture broths with a basic saline Eggins and Pugh medium, to which 1% sawdust of Pinus sylvestris was added in one trial. Another test was made with a mixture of the most frequent monosaccharides in woody cell-walls (glucose, mannose, galactose, arabinose, and xylose) at 1%. After 20 days of incubation, the extracts were centrifuged, and inoculated in microtubes series of API-ZYM. The analysis of the principal components, carried out with the results obtained, showed that the sawdust induces enzymatic activities implicated in the degradation of polysaccharides such as in a-mannosidase, a-galactosidase, b-glucuronidase, b-glucosidase and b-galactosidase, which appeared as the most weighty specific factors in the dispersion of data on the first two principal axes. Different strains of Ceratocystis also showed similar or greater activity than those of P. pullulans and S. pityophila, which suggests that the latter might be more virulent than the rest of the strains assayed.