Mycorrhizal symbiosis balances rootstock-mediated growth-defence tradeofs

It is well known that AM symbiosis provides several ecosystem services leading to plant adaptation in diferent environmental conditions and positively afects physiological and production features. Although benefcial efects from grapevine and AM fungi interactions have been reported, the impact on growth-defence tradeof features has still to be elucidated. In this study, the potential benefts of an inoculum formed by two AM fungal species, with or without a monosaccharide addition, were evaluated on young grapevine cuttings grafted onto 1103P and SO4 rootstocks. Inoculated and non-inoculated plants were maintained in potted vineyard substrate under greenhouse conditions for 3 months. Here, agronomic features were combined with biochemical and molecular techniques to assess the infuence of the diferent treatments. Despite the opposite behaviour of the two selected rootstocks, in AM samples, the evaluation of gene expression, agronomic traits and metabolites production revealed an involvement of the whole root microbiome in the growth-defence tradeof balancing. Noteworthy, we showed that rootstock genotypes and treatments shaped the root-associated microbes, stimulating plant growth and defence pathways. Progresses in this feld would open new perspectives, enabling the application of AMF or their inducers to achieve a more sustainable agriculture also in light of the ongoing climate change.