scholarly journals The response of soil and phyllosphere microbial communities to repeated application of the fungicide iprodione: accelerated biodegradation or toxicity?

2020 ◽  
Vol 96 (6) ◽  
Author(s):  
A Katsoula ◽  
S Vasileiadis ◽  
M Sapountzi ◽  
Dimitrios G Karpouzas

ABSTRACT Pesticides interact with microorganisms in various ways with the outcome being negative or positive for the soil microbiota. Pesticides' effects on soil microorganisms have been studied extensively in soil but not in other pesticides-exposed microbial habitats like the phyllosphere. We tested the hypothesis that soil and phyllosphere support distinct microbial communities, but exhibit a similar response (accelerated biodegradation or toxicity) to repeated exposure to the fungicide iprodione. Pepper plants received four repeated foliage or soil applications of iprodione, which accelerated its degradation in soil (DT50_1st = 1.23 and DT50_4th = 0.48 days) and on plant leaves (DT50_1st > 365 and DT50_4th = 5.95 days). The composition of the epiphytic and soil bacterial and fungal communities, determined by amplicon sequencing, was significantly altered by iprodione. The archaeal epiphytic and soil communities responded differently; the former showed no response to iprodione. Three iprodione-degrading Paenarthrobacter strains were isolated from soil and phyllosphere. They hydrolyzed iprodione to 3,5-dichloraniline via the formation of 3,5-dichlorophenyl-carboxiamide and 3,5-dichlorophenylurea-acetate, a pathway shared by other soil-derived arthrobacters implying a phylogenetic specialization in iprodione biotransformation. Our results suggest that iprodione-repeated application could affect soil and epiphytic microbial communities with implications for the homeostasis of the plant–soil system and agricultural production.

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Pengfan Zhang ◽  
Stjin Spaepen ◽  
Yang Bai ◽  
Stephane Hacquard ◽  
Ruben Garrido-Oter

AbstractSynthetic microbial communities (SynComs) constitute an emerging and powerful tool in biological, biomedical, and biotechnological research. Despite recent advances in algorithms for the analysis of culture-independent amplicon sequencing data from microbial communities, there is a lack of tools specifically designed for analyzing SynCom data, where reference sequences for each strain are available. Here we present Rbec, a tool designed for the analysis of SynCom data that accurately corrects PCR and sequencing errors in amplicon sequences and identifies intra-strain polymorphic variation. Extensive evaluation using mock bacterial and fungal communities show that our tool outperforms current methods for samples of varying complexity, diversity, and sequencing depth. Furthermore, Rbec also allows accurate detection of contaminants in SynCom experiments.


2021 ◽  
Author(s):  
Pengfan Zhang ◽  
Stjin Spaepen ◽  
Yang Bai ◽  
Stephane Hacquard ◽  
Ruben Garrido-Oter

AbstractMotivationSynthetic microbial communities (SynComs) constitute an emergent and powerful tool in biological, biomedical, and biotechnological research. Despite recent advances in algorithms for analysis of culture-independent amplicon sequencing data from microbial communities, there is a lack of tools specifically designed for analysing SynCom data, where reference sequences for each strain are available.ResultsHere we present Rbec, a tool designed for analysing SynCom data that outperforms current methods by accurately correcting errors in amplicon sequences and identifying intra-strain polymorphic variation. Extensive evaluation using mock bacterial and fungal communities show that our tool performs robustly for samples of varying complexity, diversity, and sequencing depth. Further, Rbec also allows accurate detection of contaminations in SynCom experiments.AvailabilityRbec is freely available as an open-source R package and can be downloaded at: https://github.com/PengfanZhang/Microbiome.


Soil Research ◽  
2019 ◽  
Vol 57 (2) ◽  
pp. 101 ◽  
Author(s):  
Gina M. Lucci

The incidence and extent of drought is predicted to increase and therefore understanding the effects on the plant–soil system is important. The objective of this review is to report on the fundamental processes involved in the effects of drought on pasture, soil, and soil microorganisms in grassland systems and evaluate the consequences of drought to determine whether management decisions could mitigate the impact of drought. There are associations within the plant–soil system affecting the flows and cycling of nutrients. Drought conditions often create a flush of nitrogen, carbon, and phosphorus upon rewetting that is at risk of loss to the environment. Prediction of the flush magnitude is difficult because it is influenced by drought characteristics such as duration, soil temperature, degree of drying, and rate at which the rewetting occurs post-drought. Response to drought is also affected by the microbial community population and structure of the soil-related flora and fauna. Increasing pasture diversity and soil organic matter may help to mitigate the effects of drought in grassland systems. More research is needed that incorporates all the components of the plant–soil system to examine the net effects of drought on grassland systems. Better measures are also needed to estimate the consequences for future climate change on nutrient stocks and flows.


2011 ◽  
Vol 57 (12) ◽  
pp. 1062-1066 ◽  
Author(s):  
Lihui Xu ◽  
Sabine Ravnskov ◽  
John Larsen ◽  
Mogens Nicolaisen

Most studies involving next-generation amplicon sequencing of microbial communities from environmental studies lack replicates. DNA extraction and PCR effects on the variation of read abundances of operational taxonomic units generated from deep amplicon 454 pyrosequencing was investigated using soil samples from an agricultural field with diseased pea. One sample was extracted four times, and one of these samples was PCR amplified four times to obtain eight replicates in total. Results showed that species richness was consistent among replicates. Variation among dominant taxa was low across replicates, whereas rare operational taxonomic units showed higher variation among replicates. The results indicate that pooling of several extractions and PCR amplicons will decrease variation among samples.


2021 ◽  
Author(s):  
Andreas Schneider ◽  
John Sundh ◽  
Görel Sundström ◽  
Kerstin Richau ◽  
Nicolas Delhomme ◽  
...  

<p>Microbial communities are major players in carbon and nitrogen cycling globally and are of particular importance for plant communities in the nutrient poor soils of boreal forests. Especially relevant are the fungal communities in the soil that interact with the plants in multiple ways, indirectly through their pivotal role in the breakdown of organic matter and, more directly, through mycorrhizal symbiosis with plant roots. Large-scale disturbances of these complex microbial communities can lead to shifts in soil carbon storage with unknown and global-scale long-term consequences. To understand the dynamics of these communities and their relationship to associated plants in response to climate change and anthropogenic influence, we need a better understanding of how modern “omics” methods can help us to understand compositional and functional shifts of these microbiomes. Microbial gene expression and functional activity can be assayed with RNA sequencing (RNA-Seq) data from environmental samples. In contrast, currently phylogenetic marker gene amplicon sequencing data is generally used to assess taxonomic composition and community structure of the microbiome. Few studies have considered how much of this structural and taxonomic information is included in RNA-Seq transcriptomic data from matched samples. Here we describe fungal communities using both RNA-Seq and fungal ITS1 DNA amplicon sequencing to compare the outcomes between the methods. We used a panel of root and needle samples from mature stands of the coniferous tree species Picea abies (Norway spruce) growing in untreated (nutrient deficient) and nutrient enriched plots at the Flakaliden forest research site in boreal northern Sweden. We created an assembly-based, reproducible and hardware agnostic workflow to taxonomically and functionally annotate fungal RNA-Seq data obtained from Norway spruce roots, which we compared to matching ITS amplicon sequencing data.<strong> </strong>We show that the community structure indicated by the fungal transcriptome is in agreement with that generated by the ITS data, while also identifying limitations imposed by current database coverage. Furthermore, we show examples to demonstrate how metatranscriptomics data additionally provides biologically informative functional insight at the community and individual species level. These findings highlight the potential of metatranscriptomics to advance our understanding of interaction, response and effect both between host plants and their associated microbial communities, and among the members of microbial communities in environmental samples in general.</p>


mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
S. Emilia Hannula ◽  
Anna M. Kielak ◽  
Katja Steinauer ◽  
Martine Huberty ◽  
Renske Jongen ◽  
...  

ABSTRACT Microorganisms are found everywhere and have critical roles in most ecosystems, but compared to plants and animals, little is known about their temporal dynamics. Here, we investigated the temporal stability of bacterial and fungal communities in the soil and how their temporal variation varies between grasses and forb species. We established 30 outdoor mesocosms consisting of six plant monocultures and followed microbial communities for an entire year in these soils. We demonstrate that bacterial communities vary greatly over time and that turnover plays an important role in shaping microbial communities. We further show that bacterial communities rapidly shift from one state to another and that this is related to changes in the relative contribution of certain taxa rather than to extinction. Fungal soil communities are more stable over time, and a large part of the variation can be explained by plant species and by whether they are grasses or forbs. Our findings show that the soil bacterial community is shaped by time, while plant group and plant species-specific effects drive soil fungal communities. This has important implications for plant-soil research and highlights that temporal dynamics of soil communities cannot be ignored in studies on plant-soil feedback and microbial community composition and function. IMPORTANCE Our findings highlight how soil fungal and bacterial communities respond to time, season, and plant species identity. We found that succession shapes the soil bacterial community, while plant species and the type of plant species that grows in the soil drive the assembly of soil fungal communities. Future research on the effects of plants on soil microbes should take into consideration the relative roles of both time and plant growth on creating soil legacies that impact future plants growing in the soil. Understanding the temporal (in)stability of microbial communities in soils will be crucial for predicting soil microbial composition and functioning, especially as plant species compositions will shift with global climatic changes and land-use alterations. As fungal and bacterial communities respond to different environmental cues, our study also highlights that the selection of study organisms to answer specific ecological questions is not trivial and that the timing of sampling can greatly affect the conclusions made from these studies.


2019 ◽  
Vol 366 (17) ◽  
Author(s):  
Reid Longley ◽  
Gian Maria Niccoló Benucci ◽  
Gary Mills ◽  
Gregory Bonito

ABSTRACT Morel mushrooms (Morchella, Pezizales) are highly prized edible fungi. Approaches to cultivate morels indoors in pasteurized composted substrates have been successful for Morchella rufobrunnea. We used DNA amplicon sequencing of the Internal Transcribed Spacer (ITS) ribosomal DNA and 16S rRNA gene to follow bacterial and fungal communities in substrates during indoor morel cultivation. Our goal was to determine changes in microbial communities at key stages of morel cultivation, which included primordia development, fundament initiation, differentiation and maturation. Additionally, we compared microbial communities between trays that successfully fruited to those that produced conidia and primordia but aborted before ascocarp formation (non-fruiting). The prokaryotic community was dominated by Firmicutes belonging to Bacillus and Paenibacillus with a lower abundance of Flavobacteria. At earlier stages, the fungal community was dominated by Pezizomycetes including Morchella and other species, whereas, later in the cropping cycle Sordariomycetes dominated. Additionally, differences were observed between trays with successful fruiting, which were dominated by Gilmaniella; compared to trays that did not fruit, which were dominated by Cephalotrichum. Our findings inform understanding of microbial community dynamics during morel cultivation, and show that fungal genera, such as Gilmaniella, and prokaryotic genera, such as Bacillus, are abundant in substrates that support M. rufobrunnea fruiting.


2020 ◽  
Author(s):  
Zhijie Zhang ◽  
Yanjie Liu ◽  
Caroline Brunel ◽  
Mark van Kleunen

AbstractSixty year ago, Elton proposed that diverse communities are more resistant to biological invasion. However, still little is known about which processes could drive this diversity-invasibility relationship. Here we examined whether plant-soil feedback on alien invaders is more negative when the soil originates from multiple native species. We trained soils with five individually grown native species, and used amplicon sequencing to analyze the resulting bacterial and fungal soil communities. We mixed the soils to create trained soils from one, two or four native species. We then grew four alien species separately on these differently trained soils. In the soil-conditioning phase, the five native species built species-specific bacterial and fungal communities in their rhizospheres. In the test phase, it did not matter whether the soil had been trained by one or two native species. However, the alien species achieved 11.7% less aboveground biomass when grown on soils trained by four native species than on soils trained by two native species. Our results showed for the first time, that plant-soil feedback could be a process that contributes to the negative relationship between diversity and invasibility.


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