Fungal Epiphytes and Endophytes of Coffee Leaves (Coffea arabica)

Abstract

Plants harbor diverse communities of fungi and other microorganisms. Fungi are known to occur both on plant surfaces (epiphytes) and inside plant tissues (endophytes), but the two communities have rarely been compared. We compared epiphytic and endophytic fungal communities associated with leaves of coffee (Coffea arabica) in Puerto Rico. We asked whether the dominant fungi are the same in both communities, whether endophyte and epiphyte communities are equally diverse, and whether epiphytes and endophytes exhibit similar patterns of spatial heterogeneity among sites. Leaves of naturalized coffee plants were collected from six sites in Puerto Rico. Epiphytic and endophytic fungi were isolated by placing leaf pieces on potato dextrose agar without and with surface sterilization, respectively. A total of 821 colonies were isolated and grouped into 131 morphospecies. The taxonomic affinities of the four most common nonsporulating fungi were determined by sequencing the nuclear ribosomal internal transcribed spacer (ITS) region: two grouped with Xylaria and one each with Botryosphaeria and Guignardia. Of the most common genera, Pestalotia and Botryosphaeria were significantly more common as epiphytes; Colletotrichum, Xylaria, and Guignardia were significantly more common as endophytes. Suprisingly, more morphospecies occurred as endophytes than as epiphytes. Differences among sites in number of fungi per plant were significant. Thus epiphytic and endophytic communities differed greatly on a single leaf, despite living only millimeters apart, and both communities differed from site to site. Significant correlations between occurrence of fungal morphospecies suggested that fungi may have positive or negative effects on their neighbors. This is the first quantitative comparison of epiphytic and endophytic fungal floras in any plant, and the first to examine endophytic fungi or epiphytic fungi in leaves of coffee, one of the world's most valuable crops.

Novel Endophytic Trichoderma spp. Isolated from Healthy Coffea arabica Roots are Capable of Controlling Coffee Tracheomycosis

“…The surveys on endophytic fungi in coffee performed in Colombia, Hawaii, and Puerto Rico showed the presence of Colletotrichum, Fusarium, Penicillium, Xylaria as the most common genera but also included several entomopathogenic fungi, such as Acremonium spp., Beauveria spp., Cladosporium spp., Clonostachys spp., and Paecilomyces spp. [8]. However, in this study 63% of fungi isolated from healthy coffee roots represented Trichoderma and Fusarium species.…”

“…However, in this study 63% of fungi isolated from healthy coffee roots represented Trichoderma and Fusarium species. Thus, our results show that there are different endopytic fungal communities colonizing leaves (see [8]) and roots of C. arabica. The fact that Trichoderma was isolated from C. arabica roots but not from leaves support the suggestion that Trichoderma dominates in the rhizosphere community of coffee plants [19], where it plays important role for the plant protection founding special external and also endophytic association with the plant.…”

“…Despite the potential benefit for C. arabica, the community of its endophytic microorganisms has not received much attention. In fact, the only studies so far have been focusing on endophytic bacteria [41], fungal foliar endosymbionts [8] and the presence of ochratoxin producing Penicillium spp. [42] in C. arabica.…”

“…arabica and other plants rich in xanthine alkaloids such as caffeine represent a special ecological and evolutionary challenge for microorganisms that colonize them. However, the recent studies report on a diversity of fungal endophytes in Theobroma cacao (cacao tree, [18]) and C. arabica (coffee plant, [8]). The surveys on endophytic fungi in coffee performed in Colombia, Hawaii, and Puerto Rico showed the presence of Colletotrichum, Fusarium, Penicillium, Xylaria as the most common genera but also included several entomopathogenic fungi, such as Acremonium spp., Beauveria spp., Cladosporium spp., Clonostachys spp., and Paecilomyces spp.…”

“…Although being biotrophic and consume plants nutrients, endophytic fungi may exhibit a beneficial role for plant health antagonizing pests via mycoparasitism, competition, and/or antibiosis. In addition they may directly stimulate plant growth and immune response inducing resistance to diseases [6][7][8].…”