scholarly journals Potassium Phosphite Modulated the Soil Microbiome and Enriched the Antagonistic Bacteria Streptomyces Coelicoflavus and Paenibacillus Favisporus to Inhibit the Tomato Pathogen Ralstonia Solanacearum Synergistically

Author(s):  
Lv Su ◽  
Xingxia Mo ◽  
Juan Sun ◽  
Pengfei Qiu ◽  
Ruifu Zhang ◽  
...  

Abstract Background: Application of certain agricultural chemicals could modulate the soil microbiome and induce potential antagonistic microbes. However, the specific selective effects of agricultural chemicals on soil bacterial functions and their co-occurrences are not well understood, and no studies have verified that the enriched potential antagonistic microbes could enhance the antagonistic functions of the soil microbiome.Results: Here, the effects of potassium phosphite (KP), an environment-friendly agricultural chemical, on the soil bacterial composition, co-occurrences and antagonistic functions were determined, and the potential antagonistic bacteria against the tomato bacterial wilt pathogen Ralstonia solanacearum were isolated to test their functions and associations among these strains. Our results showed that application of KP enriched Bacillus, Paenibacillus and Streptomyces. The positive links among the OTUs belonging to these genera were increased, and positive associations between these OTUs and predicted genes related to antagonistic substance production were revealed. Two strains, Streptomyces coelicoflavus F13 and Paenibacillus favisporus Y7, were isolated, and they inhibited the growth of R. solanacearum. Genomic sequencing showed that both strains harboured streptomycin synthetic genes, and P. favisporus Y7 also contained surfactin synthetic gene cluster. Synergistic inhibition of R. solanacearum growth by P. favisporus Y7 and S. coelicoflavus F13 was observed in soil. Genome-scale metabolic modelling showed that dextrin and lactic acid were potential cross-feeding metabolites. In addition, the KP-modulated soil microbiome could suppress R. solanacearum growth. Conclusions: Our results highlight that a KP-modulated soil microbiome has considerable potential for biocontrol and indicate a new mechanism for the inhibition of R. solanacearum by KP-enriched soil bacteria.

Plant Disease ◽  
2021 ◽  
Author(s):  
Lv Su ◽  
Pengfei Qiu ◽  
Zhiying Fang ◽  
Xingxia Mo ◽  
Juan Sun ◽  
...  

Bacterial wilt caused by Ralstonia solanacearum is a distributed and worldwide soil-borne disease. The application of biocontrol microbes or agricultural chemicals has been widely used to manage tomato bacterial wilt. However, whether and how agricultural chemicals affect the antagonistic ability of biocontrol microbes is still unknown. Here, we combined potassium phosphite (K-Phite), an environmentally friendly agricultural chemical, and the biocontrol agent Bacillus amyloliquefaciens QPF8 (strain F8) to manage tomato bacterial wilt disease. First, K-Phite at a concentration of 0.05% (w/v) could significantly inhibit the growth of Ralstonia solanacearum. Second, 0.05% K-Phite enhanced the antagonistic capability of B. amyloliquefaciens F8. Third, the greenhouse soil experiments showed that the control efficiency for tomato bacterial wilt in the combined treatment was significantly higher than that of the application of B. amyloliquefaciens F8 or K-Phite alone. Overall, our results highlighted a novel strategy for the control of tomato bacterial wilt disease via application and revealed a new integrated pattern depending on the enhancement of the antagonistic capability of biocontrol microbes by K-Phite.


2020 ◽  
Author(s):  
Capucine Baubin ◽  
Arielle M. Farrell ◽  
Adam Šťovíček ◽  
Lusine Ghazaryan ◽  
Itamar Giladi ◽  
...  

ABSTRACTEcosystem engineers (EEs) are present in every environment and are known to strongly influence ecological processes and thus shape the distribution of species and resources. In this study, we assessed the direct and indirect effect of two EEs (perennial shrubs and ant nests), individually and combined, on the composition and function of arid soil bacterial communities. To that end, top soil samples were collected in the Negev Desert Highlands during the dry season from four patch types: (1) barren soil; (2) under shrubs; (3) near ant nests; or (4) near ant nests situated under shrubs. The bacterial composition was evaluated in the soil samples (fourteen replicates per patch type) using 16S rRNA gene amplicon sequencing, together with physico-chemical measures of the soil, and the potential functions of the community. We have found that the EEs differently affected the community composition. Indeed, barren patches supported a soil microbiome, dominated by Rubrobacter and Proteobacteria, while in EE patches the Deinococcus-Thermus phylum was dominating. The presence of the EEs similarly enhanced the abundance of phototrophic, nitrogen cycle and stress- related genes. In addition, only when both EEs were combined, were the soil characteristics altered. Our results imply that arid landscapes foster unique communities selected by each EE(s), solo or in combination, yet these communities have similar potential biological traits to persist under the harsh arid conditions. Environments with multiple EEs are complicated to study due to the possibility of non-additive effects of EEs and thus further research should be done.IMPORTANCEEcosystem engineers are organisms that can create, modify, or maintain their habitat. They are present in various environments but are particularly conspicuous in desert ecosystems, where their presence is tightly linked to vital resources like water or nutrients. Despite their key role in structuring and controlling desert ecosystems, joint engineering, and their effect on soil function, are unknown. Our study explores the contributions of key ecosystem engineers to the diversity and function of their soil microbiome allowing better understanding of their role in shaping habitats and engineering their activity


2019 ◽  
Vol 9 ◽  
Author(s):  
Wenbing Li ◽  
Xiaofei Lv ◽  
Junchao Ruan ◽  
Miao Yu ◽  
Yao-Bin Song ◽  
...  

2019 ◽  
Vol 12 ◽  
pp. 194008291987607 ◽  
Author(s):  
Muhammad Tahir Jatoi ◽  
Guoyu Lan ◽  
Zhixiang Wu ◽  
Rui Sun ◽  
Chuan Yang ◽  
...  

This study aimed to compare monoculture and mixed rubber plantations in terms of their soil bacterial and fungal composition. An Illumina MiSeq sequencing analysis was performed to investigate the composition and diversity of the soil bacterial and fungal communities among three different rubber ( Hevea brasiliensis) plantations: monoculture, Mixed 1 ( Hevea brasiliensis and Mytilaria laosensis), and Mixed 2 ( Hevea brasiliensis and Michelia macclurei) in Hainan. The results showed that the bacterial composition of the three rubber plantations was basically similar. However, there was a significant difference in fungal communities among the three rubber plantations at both the phylum and operational taxonomic unit level. The species richness, Chao, and Shannon diversity of bacterial communities of monoculture rubber plantations were higher than the Mixed 1 and Mixed 2 rubber plantations, whereas all diversity indexes of fungal communities were relatively equal for the monoculture and mixed rubber plantations. Soil nutrition (such as total nitrogen and total potassium) and soil pH are the main drivers of the bacterial composition ( p <  .001). However, soil pH and water content are the main drivers of the fungal composition ( p <  .001), and to some extent, soil pH can increase soil bacteria diversity. We suggest that alkaline fertilizers should be applied in mixed rubber plantations to improve the soil pH and, consequently, to increase the total diversity of the rubber plantation.


2020 ◽  
Author(s):  
Regina B. Bledsoe ◽  
Carol Goodwillie ◽  
Ariane L. Peralta

ABSTRACTIn nutrient-limited conditions, plants rely on rhizosphere microbial members to facilitate nutrient acquisition, and in return plants provide carbon resources to these root-associated microorganisms. However, atmospheric nutrient deposition can affect plant-microbe relationships by changing soil bacterial composition and by reducing cooperation between microbial taxa and plants. To examine how long-term nutrient addition shapes rhizosphere community composition, we compared traits associated with bacterial (fast growing copiotrophs, slow growing oligotrophs) and plant (C3 forb, C4 grass) communities residing in a nutrient poor wetland ecosystem. Results revealed that oligotrophic taxa dominated soil bacterial communities and that fertilization increased the presence of oligotrophs in bulk and rhizosphere communities. Additionally, bacterial species diversity was greatest in fertilized soils, particularly in bulk soils. Nutrient enrichment (fertilized vs. unfertilized) and plant association (bulk vs. rhizosphere) determined bacterial community composition; bacterial community structure associated with plant functional group (grass vs. forb) was similar within treatments but differed between fertilization treatments. The core forb microbiome consisted of 602 unique taxa, and the core grass microbiome consisted of 372 unique taxa. Forb rhizospheres were enriched in potentially disease suppressive bacterial taxa and grass rhizospheres were enriched in bacterial taxa associated with complex carbon decomposition. Results from this study demonstrate that fertilization serves as a strong environmental filter on the soil microbiome, which leads to distinct rhizosphere communities and can shift plant effects on the rhizosphere microbiome. These taxonomic shifts within plant rhizospheres could have implications for plant health and ecosystem functions associated with carbon and nitrogen cycling.ImportanceOver the last century, humans have substantially altered nitrogen and phosphorus cycling. Use of synthetic fertilizer and burning of fossil fuels and biomass have increased nitrogen and phosphorous deposition, which results in unintended fertilization of historically low-nutrient ecosystems. With increased nutrient availability, plant biodiversity is expected to decline and bacterial communities are anticipated to increase in abundance of copiotrophic taxa. Here, we address how bacterial communities associated with different plant functional types (forb, grass) shift due to long-term nutrient enrichment. Unlike other studies, results revealed an increase in bacterial diversity, particularly, of oligotrophic bacteria in fertilized plots. We observed that nutrient addition strongly determines forb and grass rhizosphere composition, which could indicate different metabolic preferences in the bacterial communities. This study highlights how long-term fertilization of oligotroph-dominated wetlands could alter the metabolism of rhizosphere bacterial communities in unexpected ways.


2017 ◽  
Vol 9 (1) ◽  
pp. 40-47
Author(s):  
Heru Adi Djatmiko ◽  
Triwidodo Arwiyanto ◽  
Bambang Hadisutrisno ◽  
Bambang Hendro Sunarminto

Objectives of this research were to characterize three genera of bacteria isolated from three of crop rhizosphere, and to measure the ability of the antagonistic bacteria in suppressing lincat disease caused by Ralstonia solanacearum and Meloidogyne incognita. The research showed that the sixth bacteria were able to utilize some carbon and nitrogen compounds, degrade macromolecules, grew at different temperatures and salt contents, and grew at medium with chitin and pectin.  The bacteria isolated from pepper rhizosphere (Pf51, Ba4, Ba22), groundnut (Pf83), and eggplant (S4 dan S7) was included to fluorescent pseudomonads (Pf51 and Pf 83), Bacillus spp. (Ba4 and Ba22), and Streptomyces spp. (S4 and S7).  The sixth bacteria having the ability in antagonist.  The bacteria isolate having the best ability in suppressing Ralstonia solanacearum and Meloidogyne incognita was Streptomyces spp. (S4). The bacteria isolate having the best ability in suppresssing R. solanacearum by antibiosis and the inhibition mechanism by bacteriostatic was S4


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6147 ◽  
Author(s):  
Shu-Hong Wu ◽  
Bing-Hong Huang ◽  
Jian Gao ◽  
Siqi Wang ◽  
Pei-Chun Liao

Grassland afforestation dramatically affects the abiotic, biotic, and ecological function properties of the original ecosystems. Interference from afforestation might disrupt the stasis of soil physicochemical properties and the dynamic balance of microbiota. Some studies have suggested low sensitivity of soil properties and bacterial community to afforestation, but the apparent lack of a significant relationship is probably due to the confounding effects of the generalist habitat and rare bacterial communities. In this study, soil chemical and prokaryotic properties in a 30-year-old Mongolia pine (Pinus sylvestris var. mongolica Litv.) afforested region and adjacent grassland in Inner Mongolia were classified and quantified. Our results indicate that the high richness of rare microbes accounts for the alpha-diversity of the soil microbiome. Few OTUs of generalist (core bacteria) and habitat-specialist bacteria are present. However, the high abundance of this small number of OTUs governs the beta-diversity of the grassland and afforested land bacterial communities. Afforestation has changed the soil chemical properties, thus indirectly affecting the soil bacterial composition rather than richness. The contents of soil P, Ca2+, and Fe3+ account for differentially abundant OTUs such as Planctomycetes and subsequent changes in the ecologically functional potential of soil bacterial communities due to grassland afforestation. We conclude that grassland afforestation has changed the chemical properties and composition of the soil and ecological functions of the soil bacterial community and that these effects of afforestation on the microbiome have been modulated by changes in soil chemical properties.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana Novoa ◽  
Llewellyn C. Foxcroft ◽  
Jan-Hendrik Keet ◽  
Petr Pyšek ◽  
Johannes J. Le Roux

AbstractThe patchy distribution of trees typical of savannas often results in a discontinuous distribution of water, nutrient resources, and microbial communities in soil, commonly referred to as “islands of fertility”. We assessed how this phenomenon may affect the establishment and impact of invasive plants, using the invasion of Opuntia stricta in South Africa’s Kruger National Park as case study. We established uninvaded and O. stricta-invaded plots under the most common woody tree species in the study area (Vachellia nilotica subsp. kraussiana and Spirostachys africana) and in open patches with no tree cover. We then compared soil characteristics, diversity and composition of the soil bacterial communities, and germination performance of O. stricta and native trees between soils collected in each of the established plots. We found that the presence of native trees and invasive O. stricta increases soil water content and nutrients, and the abundance and diversity of bacterial communities, and alters soil bacterial composition. Moreover, the percentage and speed of germination of O. stricta were higher in soils conditioned by native trees compared to soils collected from open patches. Finally, while S. africana and V. nilotica trees appear to germinate equally well in invaded and uninvaded soils, O. stricta had lower and slower germination in invaded soils, suggesting the potential release of phytochemicals by O. stricta to avoid intraspecific competition. These results suggest that the presence of any tree or shrub in savanna ecosystems, regardless of origin (i.e. native or alien), can create favourable conditions for the establishment and growth of other plants.


2020 ◽  
Vol 709 ◽  
pp. 134654 ◽  
Author(s):  
I. Miralles ◽  
R. Lázaro ◽  
M. Sánchez-Marañón ◽  
M. Soriano ◽  
R. Ortega

Sign in / Sign up

Export Citation Format

Share Document