Abstract

Studying new alternatives for promoting plant growth is crucial to face a changing climate. This study aimed to determine the beneficial effect of fungal strains isolated from the rhizospheric soil of two native plants from the Atacama Desert on physiological leaf traits of inoculated 'Chardonnay' grapevines. Rhizosphere fungi were isolated from Baccharis scandens and Solanum chilense and tested in vitro for plant growth-promoting traits, including indole acetic acid, phosphate solubilization, siderophore production, and polyamine production. Aspergillus niger, Microdochium bolleyi, and Westerdikeya centenaria were isolated, showing plant growth-promoting attributes and high salt tolerance in almost all tested isolates. Then, the fungi were stabilized and co-inoculated in pot-grown 'Chardonnay' plants (Vitis vinifera L.) growing in outdoor conditions to evaluate gas exchange variables, chlorophylls (as SPAD value), water potential, proline and sugar content, and lipid peroxidation in leaves. Inoculation of the fungal strains significantly increased the photosynthesis rate, which was associated with higher mesophyll conductance and SPAD values. The co-inoculation also induced an enhanced protective condition for oxidative damage. Increased carbon assimilation resulted in higher soluble sugars and intrinsic water use efficiency in leaves without altering the water status of treated plants. Our results demonstrated the beneficial effects of co-inoculating rhizosphere-inhabiting fungi isolated from native plants from the Atacama Desert on physiological traits of 'Chardonnay' grapevines.