Depth structures the community of arbuscular mycorrhizal fungi amplified from grapevine (Vitis vinifera L.) roots

Authors: Schreiner, Roger

Submitted to: Mycorrhiza
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2020
Publication Date: 1/29/2020
Citation: Schreiner, R.P. 2020. Depth structures the community of arbuscular mycorrhizal fungi amplified from grapevine (Vitis vinifera L.) roots. Mycorrhiza. 30:149-160. https://doi.org/10.1007/s00572-020-00930-6.
DOI: https://doi.org/10.1007/s00572-020-00930-6

Interpretive Summary: The diversity of symbiotic, mycorrhizal fungi colonizing the roots of Pinot noir grapevines from different soil depths and locations in the vineyard at two different times during the growing season was determined based on fungal DNA sequences amplified from roots. Depth in the soil had a greater impact on the types of mycorrhizal fungi in grapevines than did location or time of the summer. However, the diversity of mycorrhizal fungi in grapevine roots was not altered by depth, and no fungal types were common in roots that were confined to either the topsoil or subsoil depths. The mycorrhizal fungi present in roots of the other plants growing in the vineyard alley was also compared to the fungi in the grapevine roots growing in the same location. The other plants in the vineyard were mostly colonized by different types of mycorrhizal fungi than those colonizing grapevines. These findings show that depth alters the community of fungi colonizing grapevine roots, but the community is comprised primarily of the same members. Making the extensive efforts to isolate mycorrhizal fungi that are located deep in the soil profile in vineyards may not be warranted. In addition, the low number mycorrhizal fungi shared among grapevines and the other plants in the vineyard indicate that how viticulturists manage the alley vegetation will have little impact on the diversity of mycorrhizal fungi in grapevines and the benefits they derive from their mycorrhizal partners.

Technical Abstract: Grapevines including the cultivar Pinot noir grown in Ultisols of western Oregon are intensely colonized by arbuscular mycorrhizal fungi (AMF) and depend on them to obtain ample phosphorus. While the diversity of AMF associating with grapevines has been determined previously, little is known of how the community in roots is shaped by depth in the soil or where roots occur in different management zones of the vineyard (vine row versus alley). The influence of depth, location, and time on the community of AMF in roots was examined. We also tested the potential influence of the alley vegetation on AMF in grapevines by comparing the taxa amplified from roots of the other plants in the alley topsoil to those from the grapevines growing in the same location. Sampling depth appeared to shape the AMF community in grapevine roots more so than sampling location or time of the growing season, although species richness and diversity indices did not differ due to depth. Seven virtual taxa were altered based on depth in the soil profile, and five taxa were each altered by time or location in grapevine roots. While the community in roots was shifted by depth, roots from the lowest depth of 50-75 cm did not reveal a substantial hidden diversity of fungi. The alley vegetation comprised primarily of grass and clover had little influence on AMF in grapevines. For example, 11 of the 19 taxa present in roots from the alley topsoil were found exclusively in roots of the alley vegetation or in the roots of grapevine. Fungi from the Acaulospora genus were only found in roots at bloom and were uncommon in grapevine roots.