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In the forest vine Smilax rotundifolia, fungal epiphytes show site-wide spatial correlation, while endophytes show evidence of niche partitioning
Abstract and Figures
Endophytic and epiphytic fungal assemblages from stems of S. rotundifolia, a shrubby vine, were studied in order to (1) quantify differences and the degree of overlap between fungal communities of both micro-habitats, and (2) examine whether fungal assemblages are spatially correlated at the local scale (tens to hundreds of meters), in order to understand if dispersal limitation may play a role in structuring these communities. Sampling was conducted over 160 m of growth along a forest edge. The communities showed low overlap
(Bray-Curtis Similarity=0.22), with most species that were common in one habitat appearing rarely if at all in the other, and only Aureobasidium pullulans showing high frequency in both. Epiphytic assemblages proved to be spatially correlated along the 160 mlength of the transect, and even more so when adjacent pairs of stems were considered as the unit of comparison rather than individual stems. Endophytic assemblages showed no significant spatial correlation along the transect. Unexpectedly, three species of endophytes showed a pattern in which abundance of colonies peaked at different heights on the stems. Colletotrichum boninense showed peak abundance at 3 cm from the stem base. Phomopsis sp. 1 peaked at 33 cm from the stem base. Endophytic isolates of A. pullulans peaked at 63 cm from the stem tip. It was also found that positive correlative relationships were detected between endophyte-endophyte, and epiphyte-epiphyte pairs. Cross-group interactions seemed to center around crossover species that were not entirely constrained within the surface or interior.
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Supplementary resource (1)
... This study showed that Ascomycota and Basidiomycota were relatively abundant in both epiphytic and endophytic fungal communities, which is in accordance with the findings of some previous studies using cultureindependent methods [21,47,48]. However, previous studies using culture-based methods revealed that Ascomycota but not Basidiomycota were dominant in epiphytic and endophytic fungal communities [3,23,49,50]. This difference may be ascribed to study methodology, as there are multiple challenges that limit the detection of Basidiomycota using traditional culture-based approaches [51]. ...
... This study showed that the community composition of epiphytic and endophytic fungi was significantly different, as reported in previous studies [13,[20][21][22][23]50]. This difference may be caused by the distinct leaf microenvironments where epiphytic and endophytic fungi live, as mentioned above [13,17,22,56]. ...
Background:
Revealing the relationship between plants and fungi is very important in understanding biodiversity maintenance, community stability, and ecosystem functioning. However, differences in the community and network structures of phyllosphere epiphytic and endophytic fungi are currently poorly documented. In this study, we examined epiphytic and endophytic fungal communities associated with the leaves of six mangrove species using Illumina MiSeq sequencing of internal transcribed spacer 2 (ITS2) sequences.
Results:
A total of 635 operational taxonomic units (OTUs) of endophytic and epiphytic fungi were obtained at a 97% sequence similarity level; they were dominated by Dothideomycetes and Tremellomycetes. Plant identity had a significant effect on the OTU richness of endophytic fungi, but not on epiphytic fungi. The community composition of epiphytic and endophytic fungi was significantly different, and plant identity had a greater effect on endophytic fungi than on epiphytic fungi. Network analysis showed that both epiphytic and endophytic network structures were characterized by significantly highly specialized and modular but lowly connected and anti-nested properties. Furthermore, the endophytic network had higher levels of specialization and modularity but lower connectance and stronger anti-nestedness than the epiphytic network.
Conclusions:
This study reveals that the phyllosphere epiphytic and endophytic fungal communities differ, and plant identity has a greater effect on the endophytic fungi than on epiphytic fungi. These findings demonstrate the role of host plant identity in driving phyllosphere epiphytic and endophytic community structure.
... They can enter through its various structures and then move internally through the vascular system to establish in their tissues; in other words, they present a pattern of systemic colonization (Gómez-Vidal et al., 2006;Gurulingappa et al., 2010;Quesada-Moraga et al., 2006). Nevertheless, they can also enter and be located in certain plant parts (Wearn et al., 2012;Yan et al., 2015) or divided among plant parts (Behie et al., 2015;Zambell and White, 2015). Various studies have shown that M. anisopliae preferentially establishes in the roots (Barelli et al., 2016;Greenfield et al., 2016;Liao et al., 2014;Meyling et al., 2011), while B. bassiana has been reported as an endophyte of aboveground plant parts (Behie et al., 2015). ...
... (1912) has been found as an endophyte in maize [4,27], potato [2], tomato [17], Western white pineseeds and needles [6], and opium poppy [21]. Colonization by fungal endophytes can be systemic [21,8], localized in plant parts [29,31], or partitioned [5,32]. Different taxa of entomopathogenic fungi, on the other hand, have been found to be able to inoculate with plants and become endophytic. ...
Beauveria bassiana (Bals.-Criv.) Vuill. (1912) (EE Genbank No. MH374537) isolated from cucumber leaves as natural endophyte and B. bassiana (Bals.-Criv.) Vuill. (1912) (ES, Genbank No. MH374538),isolated from soil samples, were transplanted to pumpkin plants via foliar spray, soil drench, and seed treatments, among other ways. The results demonstrated that all three inoculation procedures were efficient in introducing B. bassiana (Bals.-Criv.) Vuill. (1912) isolates as endophytes into the pumpkin plant, but to varying degrees. B. bassiana (Bals.-Criv.) Vuill. (1912) was recovered from leaves and stems using foliar spray methods and from leaves, stems, and roots by seed treatment
inoculation method, and only the stem was separated in drench inoculation method.
... Commensal epiphytes are defined as nonpathogenic microbes (at least for the plant itself) that strictly colonize the plant surface without penetrating plant tissue throughout their life cycles (15). They strike up symbiotic relationships with the plants and other proand eukaryotes (16). ...
Field peas are important protein suppliers for human and animal nutrition. They can be grown in many areas of the world, which may reduce imports of protein plants and has beneficial economic and ecological effects.
... Epiphytes inhabiting the phyllosphere are under a set of selective pressures, which are distinct from those that endophytes are facing [67]. The epiphytic community was found to be significantly richer and more abundant than the endophytic community in some woody plant systems [40,68,69]. There was a great difference in the effects of seasons on the total abundance of phyllosphere epiphytic fungi and endophytic fungi. ...
Plant-leaf surface on Earth harbors complex microbial communities that influence plant productivity and health. To gain a detailed understanding of the assembly and key drivers of leaf microbial communities, especially for leaf-associated fungi, we investigated leaf-associated fungal communities in two seasons for three plant species at two sites by high-throughput sequencing. The results reveal a strong impact of growing season and plant species on fungal community composition, exhibiting clear temporal patterns in abundance and diversity. For the deciduous tree Gingko biloba, the number of enriched genera in May was much higher than that in October. The number of enriched genera in the two evergreen trees Pinus bungeana and Sabina chinensis was slightly higher in October than in May. Among the genus-level biomarkers, the abundances of Alternaria, Cladosporium and Filobasidium were significantly higher in October than in May in the three tree species. Additionally, network correlations between the leaf-associated fungi of G. biloba were more complex in May than those in October, containing extra negative associations, which was more obvious than the network correlation changes of leaf-associated fungi of the two evergreen plant species. Overall, the fungal diversity and community composition varied significantly between different growing seasons and host plant species.
... The forest type is consistent. The reason for the analysis may be that the soil moisture, pH, light intensity and other conditions in the forest environment are more conducive to the survival of white rot fungi than shrubs and forest edge grassland [9]. ...
The diversity of white rot fungi in Xian-weng Mountain National Forest Park was investigated by randomized method and key area sampling survey method. According to apparent characteristics, living habits and structural analysis, comparative literature and expert consultation were used. The collected white rot fungi specimens were classified and identified. The white rot fungi are abundant in the Xian-weng Mountain National Forest Park, mostly distributed in broad-leaved forests, followed by mixed forests and coniferous forests. The white rot fungi in Xian-weng Mountain National Forest Park has good development and application prospects.
... Since H. fraxineus also has specific affinity towards leaf veins, this raises the question of the nature of the interaction between the invader and other fungi competing for this niche. Aureobasidium pullulans is found on different hosts, e.g., Smilax rotundifolia L. [97] and has shown antagonistic activity towards a number of phytopathogenic fungi [98], while in our study there was no negative (or positive) association between read percentages of H. fraxineus and A. pullulans on ash leaflets. In the study of Schlegel et al. [99], exudates from A. pullulans did not have any impact on H. fraxineus ascospore germination. ...
European ash (Fraxinus excelsior) is threatened by the invasive ascomycete Hymenoscyphus fraxineus originating from Asia. Ash leaf tissues serve as a route for shoot infection but also as a sporulation substrate for this pathogen. Knowledge of the leaf niche partitioning by indigenous fungi and H. fraxineus is needed to understand the fungal community receptiveness to the invasion. We subjected DNA extracted from unwashed and washed leaflets of healthy and diseased European ash to PacBio sequencing of the fungal ITS1-5.8S-ITS2 rDNA region. Leaflets from co-inhabiting rowan trees (Sorbus aucuparia) served as a reference. The overlap in leaflet mycobiomes between ash and rowan was remarkably high, but unlike in rowan, in ash leaflets the sequence read proportion, and the qPCR-based DNA amount estimates of H. fraxineus increased vigorously towards autumn, concomitant with a significant decline in overall fungal richness. The niche of ash and rowan leaves was dominated by epiphytic propagules (Vishniacozyma yeasts, the dimorphic fungus Aureobasidion pullulans and the dematiaceous hyphomycete Cladosporium ramotenellum and H. fraxineus), and endophytic thalli of biotrophs (Phyllactinia and Taphrina species), the indigenous necrotroph Venturia fraxini and H. fraxineus. Mycobiome comparison between healthy and symptomatic European ash leaflets revealed no significant differences in relative abundance of H. fraxineus, but A. pullulans was more prevalent in symptomatic trees. The impacts of host specificity, spatiotemporal niche partitioning, species carbon utilization profiles and life cycle traits are discussed to understand the ecological success of H. fraxineus in Europe. Further, the inherent limitations of different experimental approaches in the profiling of foliicolous fungi are addressed.
... Endophytes are typically observed in intercellular spaces (Christensen et al. 2008); although bacterial endophytes, in particular, may become intracellular and enter into host cells via the cytoplasm or become confined within periplasmic spaces, i.e. between the cell wall and the cell plasma membrane (Thomas and Sekhar 2014). Epiphytes are organisms that may collectively play an important role in plant microbiomes, and are defined as non-pathogenic fungi, bacteria, or algae that remain restricted to plant surfaces (above or below-ground), without penetrating to internal tissues (Zambell and White 2015). Carroll (1988) defined two groups of endophytic fungi: constitutive mutualists (Class I endophytes) and inducible mutualists (Class II endophytes). ...
Entomopathogenic fungi from the genus Beauveria play an important role in controlling insect populations and have been utilised widely for the biological control of insect pests. Only relatively recently has research focused more on the ecology of these fungi. Various studies have reported that Beauveria bassiana have the ability to become endophytic and may colonise a broad range of plant hosts, while still maintaining pathogenicity to insects. However, the nature of these interactions within plant tissues and the mechanism for colonisation still require elucidation. The aim of this project was to address some of the fundamental questions relating to endophytic colonisation and host interaction in planta. Three putative endophytic isolates of Beauveria were subsequently investigated for interactions with a single Zea mays (maize) cultivar Pioneer 34H31. The overall hypothesis was that isolates of B. bassiana differ in their ability to colonise a single maize cultivar, as evidenced by differential effects to the plant microbiome (in the rhizosphere roots/soil), as well as plant growth and immune response following inoculation. In order to test this hypothesis, endophytic isolates had to be first obtained. Consequently, a nested PCR protocol was developed based on the translation elongation factor 1-alpha (ef1α) gene that was designed to find and amplify isolates in planta from the genus Beauveria. The nested protocol was also designed to enable species differentiation by sequence analysis and quantification of fungal biomass in planta. A prior review of the literature pertaining to Beauveria endophyte detection methodology for PCR indicated the need to optimise plant surface sterilisation for reliable detection of Beauveria in plant tissues. However, elimination of Beauveria inocula and/or DNA from the plant surfaces proved difficult. The focus of the project therefore shifted more to the plant host response to all plant-associated Beauveria. This was achieved by (1) testing the plant growth response to three different B. bassiana putative endophytic isolates (BG11, FRh2 and J18) versus the growth-promoting Trichoderma atroviride isolate LU132, all of which were introduced artificially through a wound made to the emerging maize seedlings to avoid the confounding effects of surface inoculation, (2) by assessing the impact of the three B. bassiana isolates applied topically to roots of maize on the rhizosphere soil community structure and function and (3) by investigating differences in gene expression in maize roots in the response to the topical application of two different B. bassiana isolates (BG11 and J18), relative to a no-inoculum control using an RNA microarray transcriptome analysis. Results of the growth experiment showed predominantly neutral or negative effects to plant growth in terms of biomass, although plants exhibited root architecture changes as a result of one B. bassiana isolate (FRh2), and a higher chlorophyll content for another isolate (J18) when measured with a SPAD-502 chlorophyll meter, providing initial evidence for phenotypic differences between the selected study isolates. However, variation between the three B. bassiana isolates was less evident in the ecological study of the rhizosphere of maize. Neither the microbial community structure nor function was significantly affected by the presence of the isolates. However, retention of the inocula in the rhizosphere over 30 days after inoculation (DAI) was positively affected by a simulated herbivory treatment made to the maize foliage at 23 DAI, as was the general microbial community composition. The transcriptome analysis indicated putative differential gene expression in maize roots as a result of colonisation by the two B. bassiana isolates, suggesting that they may differ in their ability to colonise and/or effect the plant host immune response. Isolate J18-treated plants upregulated genes encoding for antioxidant glutathione S-transferases (GSTs) relative to BG11-treated plants, presumably to counteract excesses of reactive oxygen species (ROS). In contrast, BG11-treated plants upregulated a larger suite of genes involved in plant defence including ethylene responsive transcription factors, auxin responsive and dehydration responsive genes. Overall, this research suggests that the relationship between Beauveria and the plant host is modulated by the plant host, but may sometimes also be isolate-dependent.
Keywords: Biological control, insect pathogen, biopesticide, microbiome, microbial diversity, rhizosphere, endophyte, transcriptomics, DGGE, MicroRespTM.
Over the past decades, rapid industrialization along with the overutilization of organic pollutants/pesticides has altered the environmental circumstances. Moreover, various anthropogenic, xenobiotics and natural activities also affected plants, soil, and human health, in both direct and indirect ways. To counter this, several conventional methods are currently practiced, but are uneconomical, noxious, and is yet inefficient for large-scale application. Plant-microbe interactions are mediated naturally in an ecosystem and are practiced in several areas. Plant growth promoting rhizobacteria (PGPR) possess certain attributes affecting plant and soil consequently performing decontamination activity via a direct and indirect mechanism. PGPR also harbors indispensable genes stimulating the mineralization of several organic and inorganic compounds. This makes microbes potential candidates for contributing to sustainably remediating the harmful pesticide contaminants. There is a limited piece of information about the plant-microbe interaction pertaining predict and understand the overall interaction concerning a sustainable environment. Therefore, this review focuses on the plant-microbe interaction in the rhizosphere and inside the plant's tissues, along with the utilization augmenting the crop productivity, reduction in plant stress along with decontamination of pesticides/organic pollutants in soil for sustainable environmental management.
FIRST REPORT OF SOOTY MOLD OF LONGAN (DIMOCARPUS LONGAN L.) CAUSED BY TRIPOSPERMUM POROSPORIFERUM MATSUSHIMA AND T. VARIABILE MATSUSHIMA IN PUERTO RICO
