The mycobiome of two threatened species in the Tatra Mountains: comparison of plants conserved ex situ and reintroduced ones

The low success of plant species reintroductions may be attributed to the environmental stress that the plants face, as the translocated seedlings are usually faced with different conditions in the target localities than those under which they were cultivated. This stress could be alleviated by the microbiome, including the endophytic fungi present in plant tissues. We checked for the occurrence of endophytic fungi in two species, Pulsatilla slavica and Senecio umbrossus, that underwent restoration programs in Tatra National Park, southern Poland. The fungal isolates were analyzed using the molecular markers ITS1 and ITS2. No fungal endophytes were found in the seeds of either species, deposited in a seedbank. Among freshly collected seeds, the occasional presence of two fungal species was confirmed: Phlebia radiata in P. slavica from horticulture and Fusarium oxysporum in P. slavica from the wild. The number of mycobiota species was greater in in situ populations than in garden populations, with the highest number of fungal taxa recorded in situ in S. umbrossus. The lists of fungal species for both plant species grown ex situ and in situ were distinctive, suggesting that the detected mycobiome is plant-specific and has not been transferred vertically. The identified fungal taxa were mostly satellite endophytes that inhabited plants during their growth. They were mainly plant parasites, with the exception of Aureobasidium pullulans. We recommend that mycobiome monitoring be performed during the course of plant restoration actions to increase their effectiveness.