The king oyster mushroom Pleurotus eryngii behaves as a necrotrophic pathogen of Eryngium campestre

Abstract

Under natural conditions in Spain, the fruiting bodies of Pleurotus eryngii var. eryngii, a basidomycete of great economic and gastronomic importance, appears at the base of the stem of (mainly) Eryngium campestre, surrounded by the plant?s dried-out basal leaves. Traditionally collected in the wild of Mediterranean areas, this fungus is now cultivated all over the world for its culinary and even medicinal properties. However, controversy exists regarding its lifestyle. Some authors indicate it is a saprotroph, while others suggest it is a weak or even virulent parasite that causes male sterility in E. campestre. The present work aims to clarify whether P. eryngii behaves as a saprotroph, a weak or virulent parasite to E. campestre. The soil beside the roots of naturally growing E. campestre plants was inoculated with a commercial strain of P. eryngii, and the trophic mode of the fungus recorded. Soil and root samples were subjected to molecular analysis to confirm the absence/presence of the fungus. The death of the plants and the molecular analysis showed P. eryngii is a facultative necrotrophic parasite of E. campestre in natural conditions and a virulent parasite in greenhouse.