Grapevines benefit from root system colonization by arbuscular mycorrhizal (AM) fungi (Glomeromycota) through enhanced nutrient uptake, increased resistance to soil pathogens, and improved tolerance to abiotic stresses like drought and salinity. However, the response of young grapevines to inoculation with AM fungi varies with rootstock variety, and the underlying mechanisms involved in this variation are unknown. We analyzed the root systems of young greenhouse-grown plants of six rootstocks (3309 Couderc, Riparia Gloire, Ramsey, 101-14 Millardet et de Grasset , Swarzmann, and Teleki 5C) with and without colonization with AM fungi (Rhizophagus irregularis) to characterize their morphological and architectural responses to AM infection. The response of vegetative growth, specific leaf area, and other physiological traits of the vines such as leaf P and N to AM infection was also evaluated. Over 20 weeks postinoculation, vine growth in two rootstocks was enhanced by AM infection. Root system growth and architecture were also altered by AM infection, and these effects also varied among rootstocks. The results of this study will help to elucidate how interactions between grapevine rootstocks and AM fungi may be beneficial to establishing new vineyards.

Funding Support: Agriculture & Agri-Food Canada BC Wine Grape Council