Pleurotus citrinopileatus, popularly known as "golden oyster mushroom" have medicinal properties, which are attributed mainly to the presence of bioactive polysaccharides. In this work, two partially 3-O-methylated galactans were isolated from the fruiting bodies of this fungus, via successive aqueous extraction, followed by fractionation by freeze-thawing, and precipitation of soluble material with Fehling solution. The structural assignments were carried out using mono- and bidimensional NMR spectroscopy, monosaccharide composition, and methylation analyses. The polysaccharides were characterized as linear, partially 3-O-methylated (1 → 6)-linked α-galactopyranans, containing only Gal and 3-O-Me-Gal, in 2:1 and 1:1 molar ratios, with molar masses of 37.6 × 10³ g/mol and 28.5 × 10³ g/mol, respectively. Similar structures have been described for other Pleurotus spp., but showing a lower content of 3-O-Me-Gal.

Clonostachys rosea is a well-known mycoparasite that has recently been investigated as a bio-based alternative to chemical nematicides for the control of plant-parasitic nematodes. In the search for a promising biocontrol agent, the ability of the C. rosea strain PHP1701 to control the southern root-knot nematode Meloidogyne incognita was tested. Control of M. incognita in vitro and in soil by C. rosea strain PHP1701 was significant and concentration dependent. Small pot greenhouse trials confirmed a significant reduction in tomato root galling compared to the untreated control. In a large greenhouse trial, the control effect was confirmed in early and mid-season. Tomato yield was higher when the strain PHP1701 was applied compared to the untreated M. incognita-infected control. However, the yield of non-M. incognita-infected tomato plants was not reached. A similar reduction in root galling was also observed in a field trial. The results highlight the potential of this fungal strain as a promising biocontrol agent for root-knot nematode control in greenhouses, especially as part of an integrated pest management approach. We recommend the use of C. rosea strain PHP1701 for short-season crops and/or to reduce M. incognita populations on fallow land before planting the next crop.