Search

During our ongoing survey of basidiomycetous yeasts associated with plant leaves in virgin forest, five Colacogloea strains were isolated in the Baotianman Nature Reserve, Henan Province, central China. Phenotypes from cultures and a phylogeny based on the internal transcribed spacer (ITS) regions and the D1/D2 domains of the large subunit (LSU) rRNA gene were employed to characterize and identify these isolates. As a result, two new species, namely Colacogloea celtidis sp. nov. and C. pararetinophila sp. nov., are introduced herein. In the phylogeny of combined ITS and LSU dataset, the new species C. celtidis sp. nov. formed a clade with the unpublished Colacogloea strain (KBP: Y-6832), and together these formed the sister group to C. armeniacae, while C. pararetinophila sp. nov. was retrieved as a sister to C. retinophila. A detailed description and illustration of both new species, as well as the differences between them and their closest relatives in the genus are provided. Results from the present study will add to our knowledge of the biodiversity of Colacogloea in China. [ABSTRACT FROM AUTHOR]

[Display omitted] • The critical mechanisms underlying the microbiome assembly in the tea plants are revealed. • There is a trade-off between stochastic and deterministic processes in microbiome assembly in the tea plants. • Assembly processes were dominated by deterministic processes in bulk and rhizosphere soils. • The stochastic processes in roots and leaves was critically driven by amino acids for environmental selection. • The core taxa assembled in phyllosphere could attenuate the virulence of a prevalent foliar pathogen. Assembly and co-occurrence of the host co-evolved microbiota are essential ecological and evolutionary processes, which is not only crucial for managing individual plant fitness but also ecological function. However, understanding of the microbiome assembly and co-occurrence in higher plants is not well understood. The tea plant was shown to contribute the forest fitness due to the microbiome assembled in the phyllosphere; the landscape of microbiome assembly in the tea plants and its potential implication on phyllosphere homestasis still remains untangled. This study aimed to deciphering of the microbiome networks of the tea plants at a continental scale. It would provide fundamental insights into the factors driving the microbiome assembly, with an extended focus on the resilience towards the potential pathogen in the phyllosphere. We collected 225 samples from 45 locations spanning approximately 2000-km tea growing regions across China. By integration of high-throughput sequencing data, physicochemical properties profiling and bioinformatics analyses, we investigated continental scale microbiome assembly and co-occurrence in the tea plants. Synthetic assemblages, interaction assay and RT-qPCR were further implemented to analyze the microbial interaction indexed in phyllosphere. A trade-off between stochastic and deterministic processes in microbiomes community assembly was highlighted. Assembly processes were dominated by deterministic processes in bulk and rhizosphere soils, and followed by stochastic processes in roots and leaves with amino acids as critical drivers for environmental selection. Sphingobacteria and Proteobacteria ascended from soils to leaves to sustain a core leaf taxa. The core taxa formed a close association with a prevalent foliar pathogen in the co-occurrence network and significantly attenuated the expression of a set of essential virulence genes in pathogen. Our study unveils the mechanism underpinning microbiome assembly in the tea plants, and a potential implication of the microbiome-mediated resilience framework on the phyllosphere homeostasis. [ABSTRACT FROM AUTHOR]

Sludge compost product (SCP) application may lead to an increase in antibiotic resistance genes (ARGs) in crops cultivated in soil with a low background of ARGs. Yet, the impact of SCP application on ARGs in crops cultivated in soils previously fertilized with manures remains unclear. Therefore, this study applied SCP to amend soil previously fertilized with manures and then cultivated lettuce to explore the variations of ARGs in soil and crops through pot experiments. After lettuce harvest, ARGs, and factors affecting ARGs, such as heavy metals, mobile genetic elements (MGEs), metal resistance genes (MRGs), and bacterial communities, were investigated. The results revealed that 2 %-15 % of SCP addition increased lettuce biomass by 1.92–2.27 times and strongly reduced the relative abundance of ARGs in both soils and lettuces. Furthermore, SCP addition resulted in significant alteration of bacterial communities in soil, lettuce phyllosphere and endophyte. The alteration of bacterial communities, particularly Proteobacteria and Firmicutes, explained the changes in ARGs in soil, lettuce phyllosphere and endophyte. Notably, MGEs did not contribute to the dissemination of ARGs in both soil and lettuce, while MRGs co-occurred with ARGs in soil and lettuce endophyte. Additionally, a SCP addition rate of 5 % is recommended in agricultural use because it not only increased lettuce biomass and reduced the relative abundance of ARGs by 53.59 % in lettuce, but also ensured that heavy metals in lettuce grown in 5 % SCP -amended soil met the requirement of China's national standards. This study provides valuable insights into the application of ARGs in agriculture soils fertilized with manures. • 2–15 % addition of sludge compost increased 1.92–2.27 times of lettuce biomass. • Sludge compost reduced antibiotic resistance genes (ARGs) in soil and lettuce. • Mobile genetic elements did not alter with the changes in ARGs in soil and lettuce. • Bacteria, especially Proteobacteria and Firmicutes, contributed to ARG spread. • Sludge compost ≤ 5 % did not cause heavy metal contamination in soil and lettuce. [ABSTRACT FROM AUTHOR]

The epiphytic and endophytic bacteria play an important role in the healthy growth of plants. Both plant species and growth environmental influence the bacterial population diversity, yet it is inconclusive whether it is the former or the latter that has a greater impact. To explore the communities of the epiphytic and endophytic microbes in Camellia oleifera, this study assessed three representative C. oleifera cultivars from three areas in Hunan, China by Illumina high-throughput sequencing. The results showed that the diversity and species richness of endophytic microbial community in leaves were significantly higher than those of microbial community in the epiphytic. The diversity and species richness of epiphytic and endophytic microbes are complex when the same cultivar was grown in different areas. The C. oleifera cultivars grown in Youxian had the highest diversity of epiphytic microbial community, but the lowest abundance, while the cultivars grown in Changsha had the highest diversity and species richness of endophytic microbes in leaves. It was concluded that the dominant phylum mainly included Proteobacteria, Actinobacteriota and Firmicutes through the analysis of the epiphytic and endophytic microbial communities of C. oleifera. The species and relative abundances of epiphytic and endophytic microbial community were extremely different at the genus level. The analysis of NMDS map and PERMANOVA shows that the species richness and diversity of microbial communities in epiphytes are greatly influenced by region. However, the community structure of endophytic microorganisms in leaves is influenced by region and cultivated varieties, but the influence of cultivars is more significant. Molecular ecological network analysis showed that the symbiotic interaction of epiphytic microbial community was more complex., (© 2024. The Author(s).)

The phyllosphere provides a habitat for a large sum of microorganisms which are modulated by numerous biotic and abiotic factors. While it is logical that host lineage must have some effect on the phyllosphere habitat, it is unclear if phyllospheres harbor similar microbial core communities across multiple ecosystems at the continental-scale. Here we collected 287 phyllosphere bacterial communities from seven ecosystems (including paddy field, dryland, urban area, protected agricultural land, forest, wetland, and grassland) in east-China to identify the regional core community and to characterize the importance of such communities in maintaining phyllosphere bacterial community structure and function. Despite significantly different bacterial richness and structure, the seven studied ecosystems contained a similar regional core community of 29 OTUs that comprised 44.9 % of the total bacterial abundance. The regional core community was less affected by environmental variables and less connected in the co-occurrence network compared with other non-core OTUs (the whole minus regional core community). Furthermore, the regional core community also had a large proportion (>50 %) of a constrained set of nutrient metabolism related functional potentials and less functional redundancy. This study suggests there is a robust regional core phyllosphere community regardless of ecosystem or spatial and environmental heterogeneity, and supports the argument that core communities are pivotal in maintaining microbial community structure and function., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In China, the common use of antibiotics in agriculture is recognized as a potential public health risk through the increasing use of livestock derived manure as a means of fertilization. By doing so this may increase the transfer of antibiotic resistance genes (ARGs) from animals, to soils and plants. In this study two staple crops (rice and wheat) were investigated for ARG enrichment under differing fertilization regimes. Here, we applied 4 treatments, no fertilizer, mineral fertilizer, clean (reduced antibiotic practice) and dirty (current antibiotic practice) pig manure, to soil microcosms planted with either rice or wheat, to investigate fertilization effects on the abundance of ARGs in the respective phyllospheres. For both rice and wheat, samples were collected after two separate fertilization periods. In total, 162 unique ARGs and 5 mobile genetic elements (MGEs) were detected from all rice and wheat samples. The addition of both clean and dirty manure, enhanced ARG abundance significantly when compared to no fertilizer treatments (P < 0.001), though clean manure enriched ARGs to a lesser extent than dirty manure, in all rice and wheat samples (P < 0.001). The classes of ARGs recorded were different between crops, with wheat samples having a higher ARG diversity than rice. These results revealed that staple crops in China such as rice and wheat may be a reservoir for ARGs when clean and dirty pig manure is used for fertilization. Image 1 • Antibiotic resistance genes in phyllosphere of staple crops. Antibiotic resistance genes are prevalent in the phyllosphere of rice and wheat. • The impact of ARGs in phyllosphere by clean and dirty pig manure. Manure from pigs with current levels (dirty) of antibiotic use has more impact on phyllosphere ARGs than manure from pigs with reduced levels (clean) of antibiotic use. • Clean pig manure application may reduce the risk of ARGs spreading Pig manure can enrich the antibiotic resistance genes in the phyllsophere of rice and wheat. [ABSTRACT FROM AUTHOR]

• Soil salinity influenced the root endophytic microbiota of halophyte. • Halophyte leaf microbiome was affected by the dispersal effect. • Core halophyte microbiome mainly included Kushneria, Pelagibius and Rhodomicrobium. Although soil and rhizosphere microbiomes in highly saline environments have been well-studied, the role of soil salinity in the ecological processes affecting endophyte colonization and persistence remain largely unclear in halophytic plants. The present study sampled young and mature plants of the halophyte Suaeda salsa from 42 sites in the Yellow River Delta, China that varied in soil salinity. Soil physicochemical properties, root and leaf microbiomes, phylogenetic variation among plant ecotypes, and leaf metabolites were analysed. In the roots of both young and mature plants, soil salinity significantly influenced the composition of the endophytic microbiota (r = 0.29 ∼ 0.45, P < 0.001), and negatively correlated with endophyte alpha-diversity (r = -0.75 ∼ -0.78, P < 0.001). Leaf microbiome dissimilarity increased with geographic distance (r = 0.17 ∼ 0.26, P < 0.001), based on a distance-decay model, and was associated with plant phylogenetic variation (r = 0.15, P = 0.015 for young plants only). Additionally, leaf microbiome diversity and composition were correlated with soil age, pH, P content, and certain leaf metabolite compounds, but not with soil salinity. The dominant genera observed in young roots were Mesorhizobium spp. and Rhodomicrobium spp., while Pelagibius spp. was dominant in mature roots, and Pseudomonas spp. and Kushneria spp. were dominant in leaves. Soil salinity exerted a strong deterministic effect on the diversity and composition of the root endophyte community, while the acquisition and assembly of the leaf microbiome was affected by the dispersal effects, and the leaf metabolism of the host halophyte. [ABSTRACT FROM AUTHOR]

As an important nonwood bioresource, fishscale bamboo (Phyllostachys heteroclada Oliver) is widely distributed in the subtropical region of China. Rhombic-spot disease, caused by Neostagonosporella sichuanensis, is one of the most serious diseases that threatens fishscale bamboo health. However, there is limited knowledge about how rhombic-spot disease influences the diversity and structures of phyllosphere fungal communities. In this study, we investigated the phyllosphere fungal communities from stems, branches, and leaves of fishscale bamboo during a rhombic-spot disease outbreak using 18S rRNA sequencing. We found that only the phyllosphere fungal community from stems was significantly affected by pathogen invasion in terms of community richness, diversity, and structure. FUNGuild analysis revealed that the major classifications of phyllosphere fungi based on trophic modes in stems, branches, and leaves changed from symbiotroph-pathotroph, no obvious dominant trophic mode, and symbiotroph to saprotroph, saprotroph–pathotroph–symbiotroph, and saprotroph–symbiotroph, respectively, after pathogen invasion. The fungal community composition of the three tissues displayed significant differences at the genus level between healthy and diseased plants. The associations among fungal species in diseased samples showed more complex co-occurrence network structures than those of healthy samples. Taken together, our results highlight the importance of plant pathological conditions for the assembly of phyllosphere fungal communities in different tissues. [ABSTRACT FROM AUTHOR]

Phyllosphere and rhizosphere are unique and wide-ranging habitats that harbor various microbial communities, which influence plant growth and health, and the productivity of the ecosystems. In this study, we characterized the shared microbiome of the phyllosphere and rhizosphere among three plants (Ipomoea pes-caprae, Wedelia chinensis, and Cocos nucifera), to obtain an insight into the relationships between bacteria (including diazotrophic bacteria) and fungi, present on these host plants. Quantitative PCR showed that the abundances of the microbiome in the soil samples were significantly higher than those in the phyllosphere samples, though there was an extremely low abundance of fungi in bulk soil. High-throughput sequencing showed that the alpha-diversity of bacteria and fungi was higher in the rhizosphere than the phyllosphere samples associated with the same plant, while there was no obvious shift in the alpha-diversity of diazotrophic communities between all the tested phyllosphere and soil samples. Results of the microbial composition showed that sample-specific bacteria and fungi were found among the phyllosphere and rhizosphere of the different host plants. About 10%-27% of bacteria, including diazotrophs, and fungi overlapped between the phyllosphere and the rhizosphere of these host plants. No significant difference in microbial community structure was found among the tested rhizosphere samples, and soil properties had a higher influence on the soil microbial community structures than the host plant species., (© 2020 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

Euonymus japonicus Thunb. is a woody and ornamental plant popular in China, Europe and North America. Powdery mildew is one of the most serious diseases that affect E. japonicus growth. In this study, the diseased and apparently healthy leaves were collected from E. japonicus planted in a greenbelt in Beijing, and the effect of powdery mildew on the epiphytic microbial community was investigated by using Illumina sequencing. The results showed that the healthy leaves (HL) harbored greater bacterial and fungal diversity than diseased leaves (DL). Furthermore, both bacterial and fungal communities in DL exhibited significantly different structures from those in HL. The relative abundance of several bacterial phyla (Proteobacteria and Firmicutes) and fungal phyla (Ascomycota and Basidiomycota) were altered by powdery mildew. At the genus level, most genera decreased as powdery mildew pathogen Erysiphe increased, while the genera Kocuria and Exiguobacterium markedly increased. Leaf properties, especially protein content was found to significantly affect beta-diversity of the bacterial and fungal community. Network analysis revealed that positive bacterial interactions in DL were stronger than those in HL samples. Insights into the underlying the indigenous microbial phyllosphere populations of E. japonicus response to powdery mildew will help in the development of methods for controlling plant diseases.

Backgroud: Foliicolous algae are a common occurrence in tropical forests. They are referable to a few simple morphotypes (unicellular, sarcinoid-like or filamentous), which makes their morphology of limited usefulness for taxonomic studies and species diversity assessments. The relationship between algal community and their host phyllosphere was not clear. In order to obtain a more accurate assessment, we used single molecule real-time sequencing of the 18S rDNA gene to characterize the eukaryotic algal community in an area of South-western China., Result: We annotated 2922 OTUs belonging to five classes, Ulvophyceae, Trebouxiophyceae, Chlorophyceae, Dinophyceae and Eustigmatophyceae. Novel clades formed by large numbers sequences of green algae were detected in the order Trentepohliales (Ulvophyceae) and the Watanabea clade (Trebouxiophyceae), suggesting that these foliicolous communities may be substantially more diverse than so far appreciated and require further research. Species in Trentepohliales, Watanabea clade and Apatococcus clade were detected as the core members in the phyllosphere community studied. Communities from different host trees and sampling sites were not significantly different in terms of OTUs composition. However, the communities of Musa and Ravenala differed from other host plants significantly at the genus level, since they were dominated by Trebouxiophycean epiphytes., Conclusion: The cryptic diversity of eukaryotic algae especially Chlorophytes in tropical phyllosphere is very high. The community structure at species-level has no significant relationship either with host phyllosphere or locations. The core algal community in tropical phyllopshere is consisted of members from Trentepohliales, Watanabea clade and Apatococcus clade. Our study provided a large amount of novel 18S rDNA sequences that will be useful to unravel the cryptic diversity of phyllosphere eukaryotic algae and for comparisons with similar future studies on this type of communities.