Preliminary observations on fungal endophytic community and mycorrhizal status in symptomless Quercus ilex seedlings

Abstract

Recently, a study on the Quercus ilex L. decay caused by biotic and abiotic agents has hypothesized alterations on endophytic and mycorrhizal fungal populations. Since holm oak is among the most representative Mediterranean species, that occurs widely in both urban and rural areas, in this work we preliminarly report these symbiotic fungal communities in asymptomatic seedlings, in order to compare these populations with those found in seedlings subjected to water and saline stress. Endophytic fungi were isolated from twigs and leaves and identified by morphological and molecular analysis. The ectomycorrhizal status was evaluated on root samples randomly selected to calculate the percentage of not vital and vital ectomycorrhizal root tips. Anatomical structure of the mantle was observed to assign each mycorrhiza to a morphotype. A total of 11 fungal species were isolated and isolation frequency (IF) ranged between 0,4% and 16,7%: Alternaria alternata, Biscogniauxia nummularia, Bjerkandera adusta, Diaporthe chamaeropis, Gnomoniopsis sp., Neosetophoma samarorum, Peziza varia, Phoma pinodella, Septoria sp., Stagonosporopsis cucurbitacearum and a Mycelia sterilia with the highest IF. Among these, A. alternata, B. adusta and the sterile mycelium were isolated from both organs, while the other were found only on twigs or on leaves, suggesting a possible organ specificity. A total of 393 colonized root tips were present in analyzed roots, of which only the 32% was vital. All examined tips were assigned to 2 different morphotypes. Further studies are also needed to understand the possible variability and role of these fungal communities on health status of host.