Olive Fungal Epiphytic Communities Are Affected by Their Maturation Stage

Abstract

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 1,565 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.

Leaf-Associated Epiphytic Fungi of Gingko biloba, Pinus bungeana and Sabina chinensis Exhibit Delicate Seasonal Variations

“…The leaf-associated fungal abundance of Ginkgo biloba was significantly higher in May than in October, which may be related to the different maturation of leaves. Studies have shown that significant differences in epiphytic fungal richness were observed among olives obtained in different production systems and maturation stages [ 55 ]; whereas, in the same production system, there was no statistical significance in richness regarding olive cultivars, and this result is consistent with the reports of epiphytic fungal communities in olives [ 56 ] and mango fruits [ 57 ] from different cultivars studied using culture-dependent methods. The screening role of host plant species on the epiphytic fungal communities [ 38 , 43 ] has been fully confirmed and attributed to different ecological strategies as well as the chemical and functional properties of host plants.…”

Distinguishing Allies from Enemies—A Way for a New Green Revolution

“…The plant genotype and physiology can also modulate associated microbial communities. When evaluating the phyllospheric epi- and endophytic communities from different olive cultivars, the importance of the plant genotype and phenological stage for the organization of microbiota becomes clear [ 44 , 45 , 46 ]. Furthermore, the resulting microbial structure seems to have repercussions on the establishment and progression of plant diseases.…”