IMBIV   05474
INSTITUTO MULTIDISCIPLINARIO DE BIOLOGIA VEGETAL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Revisiting the secotioid and gasteroid Cortinarius species from Patagonia
Autor/es:
NOUHRA E; MUJIC, ALIJA; KUHAR, FRANCISCO; SMITH M.; TRUONG, CAMILLE
Reunión:
Congreso; International mycological congress; 2018
Resumen:
The diversity of secotioid taxa within Cortinarius in the Nothofagaceae forests of Patagoniahas drawn attention of mycologists during the last century. In the Patagonian region of Argentina andChile Cortinarius is among the most diverse and abundant genera of ectomycorrhizal fungi with at least240 species from the Andean mountains. Secotioid and gasteroid forms were until recently consideredprimarily within Thaxterogaster, resulting in a confusing intrageneric classification system. Moser andHorak suggested that Thaxterogaster was nested within Cortinarius. The modern molecular analysis ofPeintner et al. investigated the multiple origins of sequestrate taxa related to Cortinarius andconsequently synonymized Thaxterogaster to Cortinarius. Subsequent molecular phylogenies haveresolved the polyphyletic nature of Thaxterogaster and other ?cortinarioid? taxa within Cortinarius buthave also highlighted the fact that most sequestrate Patagonian taxa lack molecular data. Originaldescriptions of these fungi are available mostly in German and Spanish and the interpretations ofmorphological structures are outdated considering the current state of knowledge about sporemorphology and ontogeny. For example, verrucae on spores were illustrated as globose structureswhereas SEM shows that they are complex conical structures that are sometimes interconnected byreticula or sub-reticula. External walls or episporia were sometimes pictured in original descriptions butour analyses suggest that these may have been optical illusions due to non-DIC microscopy. Recently,the incorrect interpretation of this episporium in the ?cortinariod? fungi was found to be a misleadingcharacter. Despite recent advances in Cortinarius systematics, the current classification, diversity andecology of secotioid and hypogeous ?cortinarioid? fungi in the Nothofagaceae forests of southern SouthAmerica remains unclear. The objective of this study is to update descriptions with diagnostic characters,including color photos of basidiomata, SEM images of spores, and ITS sequence data to clarify the biodiversity of these fungi in Patagonia. Original descriptions of secotioid and gasteroid taxa were alsorevised and translated to English. Our analyses based on SEM and ITS rDNA resolves at least 15 specieswith names that need to be considered as synonyms. The use of these tools combined with an extensivedatabase of described species also facilitated the recognition of several new and undescribedPatagonian species. Analysis of spore ultrastructure across many specimens clearly shows thatsequestrate species of Cortinarius always lack a perisporium. It also indicates that there is a transitionprocess in shape and ornamentation that occurs in taxa as they switch from ballistosporic tostatimosporic spore dispersal.