Biology subjects

Egidi, E.

Publications and source records attributed to Egidi, E..

5 recordsLinked to original sources

bioRxiv2025

Leaf microbiome assembly is linked to plant phylogeny

Background and AimsThe plant microbiome is considered as an extended part of the plant genome, and it provides key functions in regulating plant fitness, and stress tolerance. Plants and associated microbiomes have co-evolved over millennia, yet evidence for a strong influence of plant phylogeny in influencing their microbiomes is largely lacking. Our main aims was to identify key drivers of plant microbiome assembly. MethodsHere, we conducted a full factorial experiment that included three levels of soil microbial diversity, five plant species from three functional groups (C3, C4, and C3 nitrogen-fixing), and two moisture availability levels. ResultsOur results showed that host identity and plant functional group exerted the strongest effect on leaf microbial assembly, while root and soil microbiomes showed less sensitivity to host selection. The initial soil microbial diversity and community structure significantly impacted soil and root microbial composition, but not leaf microbiomes. Importantly, we observed significant positive linkage between host phylogeny distance and Bray-Curtis dissimilarity index in leaf microbiomes. This finding was further validated through analysis of microbiome data from seven plant species grown across different field and environmental conditions. Interestingly, there was no significant impact of short-term water stress on plant microbial communities. ConclusionsBy providing empirical evidence for important role of host selection in shaping plant microbiomes, this study advances our fundamental knowledge of plant-microbe interactions and their co-evolutionary relationships, and enhances our ability to develop future tools harnessing plant microbiome to improve plant health and productivity.

microbiology↗

bioRxiv2024

AusAMF: database of arbuscular mycorrhizal fungal communities in Australia

MotivationArbuscular mycorrhizal (AM) fungi are integral to plant nutrient acquisition, carbon cycling, and ecosystem resilience, yet our knowledge of their biogeography is severely limited, especially in the Southern Hemisphere. Australia, despite its landmass and unique geoecological characteristics, has been vastly undersampled, leaving a significant gap in our understanding of AM fungal diversity and distribution. The AusAMF database was created to address this deficiency, the first release comprises AM fungal community data from 610 sampling locations across mainland Australia and Tasmania, collected between 2011 and 2023. Using standardised sampling, DNA extraction, sequencing methods and platforms, this database provides a robust resource for exploring spatial patterns in AM fungal diversity, community composition, and the ecological drivers shaping AM fungal biogeography. The AusAMF database will continue to be updated and maintain standardised approaches to facilitate future research into plant-mycorrhizal interactions, nutrient cycling, and to understand the broader role of AM fungi in ecosystem processes. The data here will provide the foundation for more informed management and conservation efforts in Australia while providing valuable data for global-scale analyses. Main types of variables containedGeoreferenced occurrence and abundance of high-throughput amplicon sequences of arbuscular mycorrhizal (AM) fungi. Spatial location and grainAustralia. Decimal degrees between 0.000001 - 0.1 resolution. Time period and grain2011-2023. Month and year of sampling. Major taxa and level of measurementArbuscular mycorrhizal fungi identified to family, genus, and virtual taxon (VT). Geographic occurrence and amplicon sequence abundance. Software formatInteract with data via online application. Dataset available as .csv files and raw sequencing data as .fastq files.

ecology↗

bioRxiv2023

Host selection has stronger impact on leaf microbiome assembly compared to land-management practices

Plant microbiome contribute directly to plant health and productivity but mechanisms that underpin plant microbiome assembly in different compartments (e.g. root, leaf) are not fully understood. Identifying environmental and management factors that affect plant microbiome assembly is important to advance understanding of fundamental ecological processes and harnessing microbiome for improved primary productivity and environmental sustainability. Irrigation and fertilization are two common management practices in Australian tree plantations, but little is known about the effects of these treatments on soil, plant host, and their microbiome. Here, we investigated the impact of a decade long irrigation, fertilization, and their combined application, on soil, plant traits and microbiome of a Eucalyptus saligna plantation at the Hawkesbury Forest Experiment, Western Sydney University, Richmond, NSW. Microbial profiling of bulk soil, rhizosphere, root, and leaves was performed using amplicon sequencing 16S rDNA and ITS markers for bacteria and fungi, respectively, along with measurements of soil properties and plant traits. The results indicated that both management practices affected soil properties and soil and root microbiome significantly. Irrigation increased but fertilizer treatment reduced microbial alpha diversity. However, neither irrigation nor fertilizer treatment significantly impacted the leaf microbiome. Our findings imply that management practices impact soil edaphic factors, which in turn influence the below ground microbiome (soil and root). In addition, the leaf microbiome was distinct from soil and root microbiome, and a source tracker analysis suggested root and bulk soils only contributed to 53% and 10% OTUs of the leaf bacterial community, suggesting strong and sequential host selection of the leaf microbiome. In addition, management practices had limited impact on leaf traits and, consequently, the leaf microbiome maintained its distinct composition. These findings provide mechanistic evidence for ecological processes that drive plant microbiome assembly and indicate that host selection plays a more important role than management practices on leaf microbiome assembly.

microbiology↗

bioRxiv2022

Environmental thresholds in the functional mycobiome of global drylands

Fungi are major drivers of ecosystem functions. Increases in aridity are known to negatively impact fungal communities in dryland ecosystems globally, however, much less is known on the potential influence of other environmental drivers. To fill this knowledge gap, we reanalyzed fungal data from 912 soil samples, providing the largest and most complete fungal community dataset from global drylands. We used machine learning tools to examine geographical patterns in community composition and spatial, edaphic, and climatic factors driving them. Further, we determined critical thresholds of community turnover along those gradients. Our analysis identifies UV index, climate seasonality, and sand content as the most important environmental predictors of community shifts, harbouring greatest association with the richness of putative plant pathogens and saprobes. Important nonlinear relationships existed with each of these fungal guilds, with increases in UV and temperature seasonality above 7.5 and 900 SD, respectively, being associated with an increased probability of plant pathogens and unspecified saprotrophs occurrence. Conversely, these environmental parameters had a negative relationship with litter and soil saprotrophs richness. Consequently, these functional groups might be differentially sensitive to environmental changes, which might result in an inevitable disturbance of current plant-soil dynamics in drylands.

ecology↗

bioRxiv2019

Bacterial and fungal communities are differentially modified by melatonin in agricultural soils under abiotic stress

An extensive body of evidence from this last decade indicates that melatonin enhances plant resistance to several biotic and abiotic stressors. This has led to an interest in the use of melatonin in agriculture to reduce negative physiological effects from environmental stresses that affect yield and crop quality. However, there are no reports regarding the effects of melatonin on soil microbial communities under abiotic stress, despite the importance of microbes for plant root health and function. Three agricultural soils associated with different land usage histories (pasture, canola or wheat) were placed under abiotic stress by cadmium (100 or 280 mg/kg) or salt (4 or 7 g/kg) and treated with melatonin (0.2 and 4 mg/kg). Automated Ribosomal Intergenic Spacer Analysis (ARISA) was used to generate Operational Taxonomic Units (OTU) for microbial community analysis in each soil. Significant differences in richness ( diversity) and community structures ({beta} diversity) were observed between bacterial and fungal assemblages across all three soils, demonstrating the effect of melatonin on soil microbial communities under abiotic stress. The analysis also indicated that the microbial response to melatonin is governed by the type of soil and history. The effects of melatonin on soil microbes needs to be regarded in potential future agricultural applications.

microbiology↗