Analyses of the Temporal Dynamics of Fungal Communities Colonizing the Healthy Wood Tissues of Esca Leaf-Symptomatic and Asymptomatic Vines

Abstract

Esca, a Grapevine Trunk Disease (GTD), is of major concern for viticulture worldwide. Our study compares the fungal communities that inhabit the wood tissues of vines that expressed or not foliar esca-symptoms. The trunk and rootstock tissues were apparently healthy, whether the 10 year-old plants were symptomatic or not. The only difference was in the cordon, which contained white rot, a typical form of esca, in 79% of symptomatic plants. Observations over a period of one year using a fingerprint method, Single Strand Conformation Polymorphism (SSCP), and the ITS-DNA sequencing of cultivable fungi, showed that shifts occurred in the fungal communities colonizing the healthy wood tissues. However, whatever the sampling time, spring, summer, autumn or winter, the fungi colonizing the healthy tissues of asymptomatic or symptomatic plants were not significantly different. Forty-eight genera were isolated, with species of Hypocreaceae and Botryosphaeriaceae being the most abundant species. Diverse fungal assemblages, made up of potentially plant-pathogenic and -protective fungi, colonized these non-necrotic tissues. Some fungi, possibly involved in GTD, inhabited the non-necrotic wood of young plants, but no increase in necrosis areas was observed over the one-year period.

Qualitative and quantitative molecular analysis indicate the presence of Phaeomoniella chlamydospora in vineyard soils

“…The occurrence of Pch in soil regardless of external plant symptoms in the vineyards under study was consistent with the lack of association between Pch and plant decline symptoms already reported by several authors investigating on plant tissues (Bruez et al, ; Edwards & Pascoe, ; Halleen, Crous, & Petrini, ; Hofstetter et al, ). Indeed, the fungal agents of grapevine trunk diseases, including Pch, are commonly isolated from wood tissues, together with several potentially beneficial fungi in grapevines without foliar symptoms.…”

Isolation, molecular characterization and virome analysis of culturable wood fungal endophytes in esca symptomatic and asymptomatic grapevine plants

“…White rots observed in esca symptomatic vines are associated with the presence of basidiomycetes but the identity of the associated pathogens has been found to vary among world regions (Fischer, ). In line with data already observed, we isolated the white rot fungus F. mediterranea only from symptomatic vines (Bruez et al ., ; Elena et al ., ). Moreover, another white rot fungus, Coniothyrium diplodiella (phylum Ascomycota; Panigai, ), was recovered only from symptomatic plants.…”

Emergence Shapes the Structure of the Seed Microbiota

“…These bacterial taxa are frequently encountered in several plant compartments, including seeds, leaves, and roots (18,60,65,67). In addition, fungal aOTUs enriched during emergence, such as Trichoderma viride (68) and Chaetomium globosum (69), corresponded to biocontrol fungal species, which have the ability to colonize plant tissues both as epiphytes and as endophytes. All these microbial taxa enriched in seedlings are capable of rapid growth in response to increase in nutrient availability (52,54,55,56), which may indicate that r-strategists (70) are selected during emergence.…”