The phyllosphere comprises the aerial parts of plants and is colonized by a great diversity of
microorganisms, either growing inside (as endophytes) or on the surface (as epiphytes) of plant tissues.
The factors that structure the diversity of epiphytes and the importance of these microorganisms for
host plant protection have been less studied when compared to the case of endophytes. In this work,
the epiphytic fungal communities from fruits of the olive tree (olives) in different maturation stages
(green and semi-ripened), obtained from different olive orchard managements (integrated and organic
production) and from distinct cultivars displaying different susceptibilities to olive anthracnose
(Cobrançosa and Madural), are compared by using a metabarcoding approach. We discuss whether
such differences in host resistance against anthracnose depend on both the fungal taxa or fungal
community composition. A total of 1565 amplicon sequence variants (ASVs) were obtained, mainly
belonging to the Ascomycota phylum and Saccharomycetes class. Although significant differences
on epiphytic fungal richness were observed among olives obtained in different production systems
and maturation stages, these factors in addition to host cultivar did not influence the composition
of the epiphytes. Despite these results, a co-inertia analysis showed that Aureobasidium spp. and
Sporocadaceae spp. were positively associated with the green olives of the cv. Madural produced
under integrated production, while Saccharomycetales spp. (Kluyveromyces, Candida, Kazachstania
and Saccharomyces) were positively associated with the semi-ripened olives of the cv. Cobrançosa
obtained from organic production. The discriminant power of these fungi, some of them recognized
as biocontrol agents, suggest that they might be important in conferring differences on host plant
susceptibility to anthracnose.
This research was funded by FEDER funds through COMPETE (Programa Operacional
Factores de Competitividade) and by national funds by FCT (Fundação para a Ciência e a Tecnologia)
in the framework of the projects PTDC/ASP-PLA/31133/2017, as well as BioISI (UIDB/04046/2020),
CBMA (UIDB/04050/2020) and Mountain Research Center—CIMO (UIDB/00690/2020).
