2009; Aveskamp et al. 2010; Chaverri et al. 2011; Schubert et al. 2007). Recovering more OTUs in the wood of nursery plants than in the wood of adult plants (Fig. 1b) was not expected because the diversity of endophytes has been shown to increase with plant age (McCutcheon et al. 1993; Zabalgogeazcoa 2008). However, this fact can be explained by the sampling bias mentioned in the Materials and methods section: compared to nursery plants, the isolation of fungi from the wood of adult plants was likely to be biased toward
the repeated recovery of the same species, since a single sample of wood was more likely to be completely occupied by the same fungal species. The diversity of fungi isolated MDV3100 mw from the wood of 180 grapevine plants was nevertheless unexpectedly high for each of the plant types analyzed (Simpson index ≥0.8, Fig. 1c), more than two times higher than the one found to be associated not only with wood, but also with shoots
and leaves of several cultivars of V. vinifera at different ages in the whole of the area surrounding Madrid, Spain (Gonzáles and Tello 2010). These divergent results may partially be explained by the different locations of the experiments, but are more likely related to the methodology used to isolate the fungi from the plants and to the sampling effort (Hyde and Soytong 2008). Species accumulation curves of each plant type (Fig. 2) Selleckchem INCB018424 also suggest that the cultivable part of the fungal community associated with the wood of grapevine in a single vineyard plot or with nursery plants is still far from completely sampled. Consequently, the diversity of fungal endophytes that can associate with V. vinifera remains probably largely CHIR98014 purchase unknown. When comparing asymptomatic and esca-symptomatic plants, the incidence and Gemcitabine mouse abundance of esca-related fungi were high independently of the plant type, and adult plants, diseased or not, carried the same fungal parasitic load (Figs. 3, 4). We observed no significant difference in
the systematic structure of the mycota associated with asymptomatic and esca-symptomatic plants, this at different systematic ranks (Fig. 5). Finding the same taxa in both diseased and healthy plants also suggests that they are part of the normal mycota associated with adult V. vinifera plants (Frias-Lopez et al. 2002; Toledo-Hernández et al. 2008). If the group of generally accepted, esca-associated fungi were indeed latent pathogens, the emergence of symptoms of the disease would be the consequence of a shift in species abundance in favor of pathogenic species, leading to the typical discoloration of the leaves associated with esca (Surico et al. 2006). Our results suggest that the esca-associated fungi are probably not pathogens, but more likely either true endophytes sensu Mostert et al. (2000) or latent saprobes sensu Promputtha et al.