Selection of high performance strains of edible mycorrhizal fungi for improved abiotic stress resistance

Ectomycorrhizal Fungi (EcM) may play an important role in improving tree vigor and enhancing ecosystem services delivered by trees. It is important to develop resilient EcM-inocula to improve tree health, including urban trees. The use of native strains with strong adaptive skills to different abiotic and biotic challenges could be determinant for the success of tree establishment. The present work focus on screening high performance strains of edible ectomycorrhizal specie Lactarius deliciosus and assess its performance and ability to grow and adapt to stresses scenarios to ensure a more sustainable choice of isolates. The ability of L. del to grow and acclimate to abiotic stresses was studied by analyzing the effects of exposure on growth and biochemical traits. Fungal plugs were placed in fresh medium, on top of a cellophane sheet and grown for four weeks at 3 levels of temperature, (15°C, 22°C, 29°C), water stress (0%, 15% and 30% of PEG 6000) and pH (5, 6, 7). They were also subjected to temperature shifts. Box-PCR technique was used as a molecular tool for fingerprinting to differentiate L. del strains. Among the different treatments the highest growth was obtained at 25°C, and 35°C was lethal to the mycelium after 15 days of exposure. Temperatures of 15°C and 30°C were clearly stress temperatures to be considered in subsequent studies. These points will represent innovative contributions to the understanding of what triggers mycelium development for sustaining healthy ecosystems.