The effect of root pruning on the arbuscular mycorrhizal symbiosis in grapevine rootstocks

Background: Arbuscular mycorrhizal fungi provide benefits to plants, especially under stressful growing conditions. These symbiotic fungi can be applied as biofertilizers prior to transplant in order to increase establishment success in the field. Roots are often trimmed at the time of transplant to reduce the probability of J-rooting, the upward orientation of roots within a planting hole which can lead to root death and disease. The effect of root trimming on the mycorrhizal symbiosis is unknown. It is possible that trimming may remove the active mycelium, nullifying the effect of inoculation. We conducted a greenhouse study to test the effect of root trimming on the mycorrhizal symbiosis in grapevine. Results: The mycorrhizal symbiosis persisted after root trimming. Trimming reduced the abundance of AM fungi in older roots. The fungi were able to recolonize the new roots in trimmed vines, and these roots had more arbuscules compared to older roots, which had mostly vesicles. Trimmed vines had lower shoot, but not root, biomass. Conclusions: The mycorrhizal symbiosis persisted in the roots, despite trimming, likely due to fungal structures in older, untrimmed roots serving as propagules. We conclude that inoculation with AM fungi prior to field transplant is robust to root trimming, at least for the isolate examined in this study.Other UBCNon UBCReviewedFacult