Characterisation of growth and stain of different groups of sapstain fungi on lodgepole pine
C Fleet, C Breuil, A Uzunovic, A Byrne
Canada is the world's largest exporter of softwood lumber. These softwood shipments are susceptible to a variety of wood-inhabiting fungi that can lead to sapstain discolouration, which in turn decrease the product value. Furthermore, the presence of these microorganisms may be unacceptable to the importing countries. The objective of this work is to assess the sapstaining capability and basic nutrition of thirty-four fungi isolates representing nine species that were isolated from sawmills across western Canada. The isolates were infected onto fresh lodgepole pine billets and assessed for staining ability, longitudinal growth, host-nutrient consumption, and host viability. The results indicated that the most aggressive saptain species on fresh logs was Ceratocystis coerulescens, followed consecutively by Leptographium spp, Ophiostoma minus, O. piliferum, O. piceae, Ophiostoma spp (D and E) and Aureobasidium pullulans. Preliminary HPLC analysis of soluble sugars indicated that mannose was the free monomer carbohydrate of choice for most of the staining fungi, followed by glucose. Arabinose and galactose were not well utilised. Gas chromatography of infected wood extracts that Leptographium sp. and C. coerulescens significantly reduced the triglyceride fraction.