Metabarcoding Analysis of Fungal Diversity in the Phyllosphere and Carposphere of Olive (Olea europaea)

Abstract

The fungal diversity associated with leaves, flowers and fruits of olive (Olea europaea) was investigated in different phenological stages (May, June, October and December) using an implemented metabarcoding approach. It consisted of the 454 pyrosequencing of the fungal ITS2 region and the subsequent phylogenetic analysis of relevant genera along with validated reference sequences. Most sequences were identified up to the species level or were associated with a restricted number of related taxa enabling supported speculations regarding their biological role. Analyses revealed a rich fungal community with 195 different OTUs. Ascomycota was the dominating phyla representing 93.6% of the total number of detected sequences followed by unidentified fungi (3.6%) and Basidiomycota (2.8%). A higher level of diversity was revealed for leaves compared to flowers and fruits. Among plant pathogens the genus Colletotrichum represented by three species (C. godetiae syn. C. clavatum, C. acutatum s.s and C. karstii) was the most abundant on ripe fruits but it was also detected in other organs. Pseudocercospora cladosporioides was detected with a high frequency in all leaf samples and to a less extent in ripe fruits. A much lower relative frequency was revealed for Spilocaea oleagina and for other putative pathogens including Fusarium spp., Neofusicoccum spp., and Alternaria spp. Among non-pathogen taxa, Aureobasidium pullulans, the species complex of Cladosporium cladosporioides and Devriesia spp. were the most represented. This study highlights the existence of a complex fungal consortium including both phytopathogenic and potentially antagonistic microorganisms that can have a significant impact on olive productions.

Fungal community in olive fruits of cultivars with different susceptibilities to anthracnose and selection of isolates to be used as biocontrol agents

“…There is very limited information on isolation and characterization of epiphytes and endophytes from fresh olives. As far as we known, only Abdelfattah et al (2015) have recently evaluated the diversity of fungi associated to olive fruits of the Italian cultivar "Ottobratica" through metabarcoding. Although the difficult in comparing our results with this study, in which fungal diversity was assessed using culture-independent technique, both studies found that olive fruits were numerically dominated by Ascomycota and comprised a number of OTUs belonging to the genera Cladosporium, Alternaria and Colletotrichum.…”

“…However, knowledge about the diversity of those plant-associated microbes as well as of how phyllosphere microorganisms interact among themselves and with their plant hosts is still very incomplete, which could jeopardize that strategy. This is especially true for the olive tree, being only recently analyzed the fungal community associated to their fruits (Abdelfattah et al, 2015). These researchers identified a complex fungal consortium, comprising pathogenic (e.g.…”

Biodiversity of Fungi in Strawberry Fields in Anamur, TURKEY

“…Khairnar et al (2011) studied the soil-borne fungal biodiversity of some fruit crops in India and found 21 fungal species and suggested that all fungal species can be controlled with 500 ppm Moximate [19]. Abdelfattah et al (2015) researched fungal biodiversity of olive and found 195 different Operational Taxonomic Units (OTUs). They found Ascomycota was the most abundant phyla that can be found in olives [20].…”

“…Abdelfattah et al (2015) researched fungal biodiversity of olive and found 195 different Operational Taxonomic Units (OTUs). They found Ascomycota was the most abundant phyla that can be found in olives [20]. Mailafia et al (2017) researched fungi associated with fruit species and identified six different fungi and one yeast species [6].…”

Alternative management technologies for postharvest disease control: The journey from simplicity to complexity

“…The identification and quantification of endophytic and epiphytic microflora present in and on plants may provide information that can facilitate an understanding of the complex interactions that take place between plants and resident fungal microflora, including pathogenic and beneficial species (Schena et al, 2003;Ottesen et al, 2013;Pinto et al, 2014;Abdelfattah et al, 2015). Furthermore, these techniques enable an in-depth investigation of the effect of conventional and alternative control methods, including the application of biocontrol agents, on the composition and diversity of microbial communities (Sylla et al, 2013).…”