Field inoculation with arbuscular mycorrhizal fungi having contrasting life-history strategies differently affects tomato nutrient uptake and residue decomposition dynamics

Abstract Purpose: In the scenario of an increased atmospheric CO2 concentration, nutrients are reduced in all vegetables. In this context, arbuscular mycorrhizal fungi (AMF) could enhance nutrient concentration in edible portions of plants, including tomato. However, field studies on tomato AMF inoculation are scarse. AMF species belonging to Gigasporaceae and Glomeraceae families known to vary in life-history strategies may determine differential effects on plant nutrient benefits and residue decomposition. Despite this, the effect of different life-history strategies on nutrient acquisition of tomato fruits has not yet been investigated. Methods: We studied the effect of inoculation of two tomato varieties with AMF belonging to Glomeraceae and Gigasporaceae. Fungal establishment, yield, fruit nutrient concentration, litter decomposition, and bacterial and fungal abundances in soil were assessed in a two-year field trial under organic agriculture. Results: Overall Gigasporaceae promoted the concentration of nutrients in tomato fruits compared to Glomeraceae. A variability in AM fungal colonization and fruit nutrient concentration occurred within Glomeraceae. Scutellospora pellucida increased the yield (+27%) of var. Rio Grande respect to Gigaspora gigantea. In var. Rio Grande, Funneliformis mosseae determined a litter degradation similar to controls and lower than Sclerocystis sinuosa and Gigasporaceae species, which showed the highest decomposition rates. AMF inoculation promoted soil total bacterial and fungal abundance and fungal:bacterial (F:B) ratio compared to controls, and members of Gigasporaceae had the highest F:B ratio. Conclusion: These findings strongly support that AM fungal life-history strategy should be considered in biofertilizer development to enhance the nutritional value of vegetables under organic farming systems.