The interaction between arbuscular mycorrhizal fungi and Piriformospora indica improves the growth and nutrient uptake in micropropagation-derived pineapple plantlets

Arbuscular mycorrhizal fungi (AMF) and Piriformospora indica are well known for promoting growth, development, and nutrient uptake and for improving plant photosynthesis. These fungi represent promising tools supporting micropropagated plants during the acclimatization stage, and their use can reduce the application of phosphate fertilizers, providing economic and environmental benefits. Therefore, this study aimed to evaluate the benefits of inoculation with AMF and P. indica for the growth of plantlets of the Imperial cultivar of pineapple inoculated during the acclimatization stage and grown with different levels of phosphorus (P). The experiment consisted of six P levels (0, 20, 40, 80, 160 and 320 mg kg −1 soil) with inoculation of Claroideoglomus etunicatum, Dentiscutata heterogama, Rhizophagus clarus, P. indica, a mixture of all fungi (Mix), or control (no inoculation). The parameters vegetative growth, the nutrient contents in the plants, photosynthetic efficiency, and the components of dependence and colonization by fungi were assessed. The fungal inoculation was effective for plantlet growth, especially up to a P dose of 40 mg kg^ −1 , increasing both plant biomass and the absorption of all evaluated nutrients. With P at 80 mg kg^ −1 , only the treatments with C. etunicatum and Mix produced plantlets of better quality than the non-inoculated control. The colonization by AMF and P. indica was not affected by the addition of P to the soil, although fungal dependence decreased under these conditions and could be considered moderate even at 40 mg kg^ −1 for plants inoculated with C. etunicatum, R. clarus, P. indica or Mix. The inoculation of pineapple plantlets is a promising method that can be employed to produce high-quality propagative material for the market