Variation in Fungal Community in Grapevine (Vitis vinifera) Nursery Stock Depends on Nursery, Variety and Rootstock.

Sarah B Lade,Dora Štraus,Jonàs Oliva

doi:10.3390/jof8010047

Sarah B Lade, Dora Štraus + Show 1 more

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https://doi.org/10.3390/jof8010047

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Abstract

Grapevine trunk diseases (GTDs) are caused by cryptic complexes of fungal pathogens and have become a growing problem for new grapevine (Vitis vinifera) plantations. We studied the role of the nursery, variety, and rootstock in the composition of the fungal communities in root collars and graft unions of planting material in Catalonia (NE Spain). We compared necrosis and fungal communities in graft unions and root collars at harvest, and then after three months of cold storage. We evaluated combinations of eleven red and five white varieties with four common rootstocks coming from six nurseries. Fungal communities were characterized by isolation and metabarcoding of the ITS2 region. Our data suggests that nursery followed by rootstock and variety had significant effects on necrosis and fungal community structure in graft and root tissues. Within the plant, we found large differences in terms fungal community distribution between graft and root tissues. Graft unions housed a significantly higher relative abundance of GTD-related Operational Taxonomic Units (OTUs) than root collars. More severe necrosis was correlated with a lower relative abundance of GTD-related OTUs based on isolation and metabarcoding analyses. Our results suggest that nurseries and therefore their plant production practices play a major role in determining the fungal and GTD-related fungal community in grapevine plants sold for planting. GTD variation across rootstocks and varieties could be explored as a venue for minimizing pathogen load in young plantations.

Highlights

Grapevine trunk diseases (GTDs) attack the wood of grapevines (Vitis vinifera) and devastate vineyards worldwide
When considerinAg. tThoetarloCloemomf iunnditiyvidual operational taxonomic units (OTUs), we found more negative than pFoacstiotrive associatioGnrasftbuentwionese(nr2)abundance anRdonoteccorlolasriss(rl2e)ngth (Figure 4TBot)a.lT(rh2)e only identified OTU to be positively associated with necrosis in graft unions was Cladosporium sp., Tissue type which was negatively associated with necrosis in root collars
Total and GTD-specific fungal communities were significantly different between graft and root tissues, in both tissues, nursery was the factor explaining the largest amount of variation in both in terms of fungal amplicons or isolates

Summary

Introduction

Grapevine trunk diseases (GTDs) attack the wood of grapevines (Vitis vinifera) and devastate vineyards worldwide. Methodologies used in the wine industry modernized, and operations were often transferred from family-sized businesses to large-scale productions that were held to a higher standard of regulation Such changes did not, take place at the nursery scale, leaving guidelines governing the quality of the planting material as they were [3]. The issues are most commonly attributed to the cutting quality, nursery practices and cold storage conditions [2,4,5] These defects are exacerbated in the field, especially as the increased demand for higher production puts additional stress on young vines by incorporating practices that favor fungal infection, such as training vines in high density spur-pruned trellises that are mechanically pruned, or leaving plants with more wounds [1]. In-depth study of the grapevine mycobiome and its interaction with the plant has been cited as necessary to fully understand the complexities of GTDs [9], and for technological development in the control of GTDs [10]

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