scholarly journals Soil microbiota manipulation and its role in suppressing soil-borne plant pathogens in organic farming systems under the light of microbiome-assisted strategies

Author(s):  
Ugo De Corato

Abstract Soil microbiota plays a key role in suppressing soil-borne plant pathogens improving the natural soil suppressiveness. Microbiome disturbance triggers specific perturbation to change and shape the soil microbial communities’ network for increasing suppression against phytopathogens and related diseases. Very important goals have been reached in manipulation of soil microbiota through agronomical practices based on soil pre-fumigation, organic amendment, crop rotation and intercropping. Nevertheless, to limit inconsistencies, drawbacks and failures related to soil microbiota disturbance, a detailed understanding of the microbiome shifts during its manipulation is needed under the light of the microbiome-assisted strategies. Next-generation sequencing often offers a better overview of the soil microbial communities during microbiomes manipulation, but sometime it does not provide information related to the highest taxonomic resolution of the soil microbial communities. This review work reports and discusses the most reliable findings in relation to a comprehensive understanding of soil microbiota and how its manipulation can improve suppression against soil-borne diseases in organic farming systems. Role and functionality of the soil microbiota in suppressing soil-borne pathogens affecting crops have been basically described in the first section of the paper. Characterization of the soil microbiomes network by high-throughput sequencing has been introduced in the second section. Some relevant findings by which soil microbiota manipulation can address the design of novel sustainable cropping systems to sustain crops’ health without use (or reduced use) of synthetic fungicides and fumigants have been extensively presented and discussed in the third and fourth sections, respectively, under the light of the new microbiome-assisted strategies. Critical comparisons on the next-generation sequencing have been provided in the fifth section. Concluding remarks have been drawn in the last section.

2018 ◽  
Author(s):  
Ryan M. Kepler ◽  
Dietrich J. Epp Schmidt ◽  
Stephanie A. Yarwood ◽  
Krishna N. Reddy ◽  
Stephen O. Duke ◽  
...  

AbstractIn spite of glyphosate’s wide use in agriculture, questions remain about effects of the herbicide on soil microbial communities. Conflicting scientific literature reports divergent results; from no observable effect of glyphosate to the enrichment of common agricultural pathogens such as Fusarium. We conducted a comprehensive field-based study to compare treatments that did and did not receive foliar application of glyphosate spray. The study included two field sites, Maryland and Mississippi; two crops, soybean and corn; four site years, 2013 and 2014; and a variety of organic and conventional farming systems. Using amplicon sequencing, the prokaryotic (16S rRNA) and fungal (ITS) communities were described along with chemical and physical properties of the soil. Sections of corn and soy roots were plated to screen for the presence of plant pathogens. Geography, farming system, and seasonal progression were significant factors determining composition of fungal and bacterial communities. Plots treated with or without glyphosate did not differ in overall microbial community composition after controlling for these factors. No differential effect of glyphosate treatment was found in the relative abundance of organisms such as Fusarium spp. or putative growth-promoting bacteria Pseudomonas spp.


2017 ◽  
Author(s):  
Taha Soliman ◽  
Sung-Yin Yang ◽  
Tomoko Yamazaki ◽  
Holger Jenke-Kodama

Structure and diversity of microbial communities are an important research topic in biology, since microbes play essential roles in the ecology of various environments. Different DNA isolation protocols can lead to data bias and can affect results of next-generation sequencing. To evaluate the impact of protocols for DNA isolation from soil samples and also the influence of individual handling of samples, we compared results obtained by two researchers (R and T) using two different DNA extraction kits: (1) MO BIO PowerSoil® DNA Isolation kit (MO_R and MO_T) and (2) NucleoSpin® Soil kit (MN_R and MN_T). Samples were collected from six different sites on Okinawa Island, Japan. For all sites, differences in the results of microbial composition analyses (bacteria, archaea, fungi, and other eukaryotes), obtained by the two researchers using the two kits, were analyzed. For both researchers, the MN kit gave significantly higher yields of genomic DNA at all sites compared to the MO kit (ANOVA; P <0.006). In addition, operational taxonomic units for some phyla and classes were missed in some cases: Micrarchaea were detected only in the MN_T and MO_R analyses; the bacterial phylum Armatimonadetes was detected only in MO_R and MO_T; and WIM5 of the phylum Amoebozoa of eukaryotes was found only in the MO_T analysis. Our results suggest the possibility of handling bias; therefore, it is crucial that replicated DNA extraction be performed by at least two technicians for thorough microbial analyses and to obtain accurate estimates of microbial diversity.


2017 ◽  
Author(s):  
Taha Soliman ◽  
Sung-Yin Yang ◽  
Tomoko Yamazaki ◽  
Holger Jenke-Kodama

Structure and diversity of microbial communities are an important research topic in biology, since microbes play essential roles in the ecology of various environments. Different DNA isolation protocols can lead to data bias and can affect results of next-generation sequencing. To evaluate the impact of protocols for DNA isolation from soil samples and also the influence of individual handling of samples, we compared results obtained by two researchers (R and T) using two different DNA extraction kits: (1) MO BIO PowerSoil® DNA Isolation kit (MO_R and MO_T) and (2) NucleoSpin® Soil kit (MN_R and MN_T). Samples were collected from six different sites on Okinawa Island, Japan. For all sites, differences in the results of microbial composition analyses (bacteria, archaea, fungi, and other eukaryotes), obtained by the two researchers using the two kits, were analyzed. For both researchers, the MN kit gave significantly higher yields of genomic DNA at all sites compared to the MO kit (ANOVA; P <0.006). In addition, operational taxonomic units for some phyla and classes were missed in some cases: Micrarchaea were detected only in the MN_T and MO_R analyses; the bacterial phylum Armatimonadetes was detected only in MO_R and MO_T; and WIM5 of the phylum Amoebozoa of eukaryotes was found only in the MO_T analysis. Our results suggest the possibility of handling bias; therefore, it is crucial that replicated DNA extraction be performed by at least two technicians for thorough microbial analyses and to obtain accurate estimates of microbial diversity.


Microbiome ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Chengyuan Tao ◽  
Rong Li ◽  
Wu Xiong ◽  
Zongzhuan Shen ◽  
Shanshan Liu ◽  
...  

Abstract Background Plant diseases caused by fungal pathogen result in a substantial economic impact on the global food and fruit industry. Application of organic fertilizers supplemented with biocontrol microorganisms (i.e. bioorganic fertilizers) has been shown to improve resistance against plant pathogens at least in part due to impacts on the structure and function of the resident soil microbiome. However, it remains unclear whether such improvements are driven by the specific action of microbial inoculants, microbial populations naturally resident to the organic fertilizer or the physical-chemical properties of the compost substrate. The aim of this study was to seek the ecological mechanisms involved in the disease suppressive activity of bio-organic fertilizers. Results To disentangle the mechanism of bio-organic fertilizer action, we conducted an experiment tracking Fusarium wilt disease of banana and changes in soil microbial communities over three growth seasons in response to the following four treatments: bio-organic fertilizer (containing Bacillus amyloliquefaciens W19), organic fertilizer, sterilized organic fertilizer and sterilized organic fertilizer supplemented with B. amyloliquefaciens W19. We found that sterilized bioorganic fertilizer to which Bacillus was re-inoculated provided a similar degree of disease suppression as the non-sterilized bioorganic fertilizer across cropping seasons. We further observed that disease suppression in these treatments is linked to impacts on the resident soil microbial communities, specifically by leading to increases in specific Pseudomonas spp.. Observed correlations between Bacillus amendment and indigenous Pseudomonas spp. that might underlie pathogen suppression were further studied in laboratory and pot experiments. These studies revealed that specific bacterial taxa synergistically increase biofilm formation and likely acted as a plant-beneficial consortium against the pathogen. Conclusion Together we demonstrate that the action of bioorganic fertilizer is a product of the biocontrol inoculum within the organic amendment and its impact on the resident soil microbiome. This knowledge should help in the design of more efficient biofertilizers designed to promote soil function.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4178 ◽  
Author(s):  
Taha Soliman ◽  
Sung-Yin Yang ◽  
Tomoko Yamazaki ◽  
Holger Jenke-Kodama

Structure and diversity of microbial communities are an important research topic in biology, since microbes play essential roles in the ecology of various environments. Different DNA isolation protocols can lead to data bias and can affect results of next-generation sequencing. To evaluate the impact of protocols for DNA isolation from soil samples and also the influence of individual handling of samples, we compared results obtained by two researchers (R and T) using two different DNA extraction kits: (1) MO BIO PowerSoil®DNA Isolation kit (MO_R and MO_T) and (2) NucleoSpin®Soil kit (MN_R and MN_T). Samples were collected from six different sites on Okinawa Island, Japan. For all sites, differences in the results of microbial composition analyses (bacteria, archaea, fungi, and other eukaryotes), obtained by the two researchers using the two kits, were analyzed. For both researchers, the MN kit gave significantly higher yields of genomic DNA at all sites compared to the MO kit (ANOVA;P < 0.006). In addition, operational taxonomic units for some phyla and classes were missed in some cases: Micrarchaea were detected only in the MN_T and MO_R analyses; the bacterial phylum Armatimonadetes was detected only in MO_R and MO_T; and WIM5 of the phylum Amoebozoa of eukaryotes was found only in the MO_T analysis. Our results suggest the possibility of handling bias; therefore, it is crucial that replicated DNA extraction be performed by at least two technicians for thorough microbial analyses and to obtain accurate estimates of microbial diversity.


2019 ◽  
Author(s):  
Suzanne L. Ishaq ◽  
Tim Seipel ◽  
Carl J. Yeoman ◽  
Fabian D. Menalled

AbstractDespite knowledge that seasonality and plant phenology impact soil microbiota, farming system effects on soil microbiota are not often evaluated across the growing season. We assessed the bacterial diversity in wheat rhizosphere soil through the spring and summer of 2016 in winter wheat (Triticum aestivium L.) in Montana, USA, from three contrasting farming systems: a chemically-managed no-tillage system, and two USDA-certified organic systems in their fourth year, one including tillage and one where sheep grazing partially offsets tillage frequency. Bacterial richness (range 605 – 1174 OTUs) and evenness (range 0.80 – 0.92) peaked in early June and dropped by late July (range 92 – 1190, 0.62-0.92, respectively), but was not different by farming systems. Organic tilled plots contained more putative nitrogen-fixing bacterial genera than the other two systems. Bacterial community similarities were significantly altered by sampling date, minimum and maximum temperature at sampling, bacterial abundance at date of sampling, total weed richness, and coverage of Taraxacum officinale, Lamium ampleuxicaule, and Thlaspi arvense. This study highlights that weed diversity, season, and farming management system all influence rhizosphere soil microbial communities. Local environmental conditions will strongly affect any practical applications aimed at improving soil diversity and functionality, especially in semi-arid regions where abiotic stress and seasonal variability in temperature and water availability drive primary production.


2021 ◽  
Author(s):  
Alessandro Cestaro ◽  
emanuela coller ◽  
Davide Albanese ◽  
erika stefani ◽  
Massimo Pindo ◽  
...  

Agricultural soils harbor rich and diverse microbial communities that have a deep influence on soil properties and productivity. Large scale studies have shown the impact of environmental parameters like climate or chemical composition on the distribution of bacterial and fungal species. Comparatively, little data exists documenting how soil microbial communities change between different years. Quantifying the temporal stability of soil microbial communities will allow us to better understand the relevance of the differences between environments and their impact on ecological processes on the global and local scale. We characterized the bacterial and fungal components of the soil microbiota in ten vineyards in two consecutive years. Despite differences of species richness and diversity between the two years, we found a general stability of the taxonomic structure of the soil microbiota. Temporal differences were smaller than differences due to geographical location, vineyard land management or differences between sampling sites within the same vineyard. Using machine learning, we demonstrated that each site was characterized by a distinctive microbiota, and we identified a reduced set of indicator species that could classify samples according to their geographic origin across different years with high accuracy.


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