scholarly journals Sucrose triggers a novel signaling cascade promoting Bacillus subtilis rhizosphere colonization

2021 ◽  
Author(s):  
Tao Tian ◽  
Bingbing Sun ◽  
Haowen Shi ◽  
Tantan Gao ◽  
Yinghao He ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Plant Protection ◽  
Root Exudation ◽  
Plant Roots ◽  
Signaling Cascade ◽  
Rhizosphere Colonization ◽  
Promote Plant Growth ◽  
Surface Motility ◽  
And Storage ◽  
Carbon Transport

AbstractBeneficial rhizobacteria promote plant growth and protect plants against phytopathogens. Effective colonization on plant roots is critical for the rhizobacteria to exert beneficial activities. How bacteria migrate swiftly in the soil of semisolid or solid nature remains unclear. Here we report that sucrose, a disaccharide ubiquitously deployed by photosynthetic plants for fixed carbon transport and storage, and abundantly secreted from plant roots, promotes solid surface motility (SSM) and root colonization by Bacillus subtilis through a previously uncharacterized mechanism. Sucrose induces robust SSM by triggering a signaling cascade, first through extracellular synthesis of polymeric levan, which in turn stimulates strong production of surfactin and hyper-flagellation of the cells. B. subtilis poorly colonizes the roots of Arabidopsis thaliana mutants deficient in root-exudation of sucrose, while exogenously added sucrose selectively shapes the rhizomicrobiome associated with the tomato plant roots, promoting specifically bacilli and pseudomonad. We propose that sucrose activates a signaling cascade to trigger SSM and promote rhizosphere colonization by B. subtilis. Our findings also suggest a practicable approach to boost prevalence of beneficial Bacillus species in plant protection.

An Antagonism of Isolates of Root-Associated Bacteria Consortia Habituating in Banana Rhizosphere

2018 ◽  
Vol 879 ◽  
pp. 83-88 ◽  
Author(s):  
Duongruitai Nicomrat ◽  
Pattarika Soongsombat ◽  
Nednapa Suenonmueng ◽  
Ninlawan Marjang
Keyword(s):  
Bacterial Communities ◽  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Plant Protection ◽  
Root Exudation ◽  
Antagonistic Activity ◽  
Plant Roots ◽  
Associated Bacteria ◽  
Plant Microbe Interaction ◽  
Bioactive Agents

Microbial diversity based on plant-microbe interaction as well as most fungal diseases which are such multipathogen complexes have been long researched. Most beneficial microbes promote the growth of the plant but inhibit the growth of plant pathogen as biocontrol agents and are reported for their establishment being microbial communities associated to the plant roots. We were interested in understanding the antagonistic activity of root-associated bacterial communities in the rhizospheres. In this experiment, common bacteria associated with banana root exudation that were cultivated and isolated harbored specific antagonistic to common pathogen. In the experiments, the root (rhizosphere), and interior of the pseudostem (endosphere) samples were high CFU counts in the extracted endosphere than in rhizosphere of banana roots (6-8 and 4-5 CFU/ g, respectively). Antibacterial activity as bioactive agents were detected from these microbes as antagonis activity against plant pathogens that wereBacillus indicus, Pseudomonas palleroniana, Penicilliumspp andFusarium oxysporum. both mixed consortia could control Fusarium, fungal pathogen in banana. From this study, the isolates of indigenous bacteria obtained from banana rhizosphere can be potential for agricultural uses as further as disease-suppressive microorganisms provides promising perspectives for sustainable plant protection.

scholarly journals Stability Analysis of Ecological Slopes Based on a 3D Finite Element Model

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
ZiFan Sui ◽  
Weijia Yuan ◽  
Wen Yi ◽  
Weihuan Yang
Keyword(s):  
Finite Element ◽  
Root System ◽  
Safety Factor ◽  
Cynodon Dactylon ◽  
Plant Protection ◽  
Lateral Roots ◽  
Plant Distribution ◽  
Plant Roots ◽  
Research Subjects ◽  
Finite Element Software

To explore the effect of grass and shrub plant roots on the stability of soil slopes in rainy areas in the south, this article relies on the Longlang Expressway construction project. Cynodon dactylon and Magnolia multiflora were selected as research subjects. The plant distribution characteristics and mechanical properties are analyzed. This paper uses ABAQUS finite element software to construct a 3D model of the planted slope in the test section. The stress and strain on the root system and the soil were observed, and the variation law of slope stability before and after plant protection under different rainfall events was compared and analyzed. The test and simulation results show that the root content of Cynodon dactylon gradually decreases with increasing depth. Cynodon dactylon was mainly distributed in the 0–30 cm soil body, and its effect on improving the cohesion of the soil body reached 75%. Magnolia multiflora belongs to vertical roots and has a strong and longer main root with relatively developed lateral roots. Its root system passes through the sliding surface of the slope bottom, which reduces the maximum equivalent plastic stress generated inside the slope by 61%. When the total rainfall duration is unchanged, under the three rainfall intensities of small, medium, and large, herbaceous plants increase the safety factor of the soil by 1.33%, 2.08%, and 6.1%, respectively, and the roots of shrubs increase the safety factor of the soil by 3.29%, 4.08%, and 4.32%, respectively. When the rainfall intensity does not change, as the rainfall time increases, the effect of plants on the slope safety factor first gradually increases and eventually stabilizes. The research results provide a reliable theoretical basis for analyzing the effect of plant roots on soil consolidation and slope protection, and they also lay a technical foundation for the promotion and application of ecological slope protection technology.

scholarly journals Bacterial Community Members Increase Bacillus subtilis Maintenance on the Roots of Arabidopsis thaliana

2020 ◽  
Vol 4 (4) ◽  
pp. 303-313
Author(s):  
Noam Eckshtain-Levi ◽  
Susanna Leigh Harris ◽  
Reizo Quilat Roscios ◽  
Elizabeth Anne Shank
Keyword(s):  
Arabidopsis Thaliana ◽  
Bacillus Subtilis ◽  
Crop Production ◽  
Crop Yields ◽  
Plant Root ◽  
Plant Roots ◽  
Plant Growth Promoting Bacteria ◽  
Bacterial Strains ◽  
Root Microbiome ◽  
Over Time

Plant-growth-promoting bacteria (PGPB) are used to improve plant health and promote crop production. However, because some PGPB (including Bacillus subtilis) do not maintain substantial colonization on plant roots over time, it is unclear how effective PGPB are throughout the plant growing cycle. A better understanding of the dynamics of plant root community assembly is needed to develop and harness the potential of PGPB. Although B. subtilis is often a member of the root microbiome, it does not efficiently monoassociate with plant roots. We hypothesized that B. subtilis may require other primary colonizers to efficiently associate with plant roots. We utilized a previously designed hydroponic system to add bacteria to Arabidopsis thaliana roots and monitor their attachment over time. We inoculated seedlings with B. subtilis and individual bacterial isolates from the native A. thaliana root microbiome either alone or together. We then measured how the coinoculum affected the ability of B. subtilis to colonize and maintain on A. thaliana roots. We screened 96 fully genome-sequenced strains and identified five bacterial strains that were able to significantly improve the maintenance of B. subtilis. Three of these rhizobacteria also increased the maintenance of two strains of B. amyloliquefaciens commonly used in commercially available bioadditives. These results not only illustrate the utility of this model system to address questions about plant–microbe interactions and how other bacteria affect the ability of PGPB to maintain their relationships with plant roots but also may help inform future agricultural interventions to increase crop yields. [Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

scholarly journals Effect of Nematodes on Rhizosphere Colonization by Seed-Applied Bacteria

2004 ◽  
Vol 70 (8) ◽  
pp. 4666-4671 ◽  
Author(s):  
Oliver G. G. Knox ◽  
Ken Killham ◽  
Rebekka R. E. Artz ◽  
Chris Mullins ◽  
Michael Wilson
Keyword(s):  
Pseudomonas Fluorescens ◽  
Water Flow ◽  
Soil Biota ◽  
Plant Roots ◽  
Soil Nematodes ◽  
Passive Transport ◽  
Commercial Products ◽  
Rhizosphere Colonization ◽  
Physical Conditions ◽  
Bacterial Movement

ABSTRACT There is much interest in the use of seed-applied bacteria for biocontrol and biofertilization, and several commercial products are available. However, many attempts to use this strategy fail because the seed-applied bacteria do not colonize the rhizosphere. Mechanisms of rhizosphere colonization may involve active bacterial movement or passive transport by percolating water or plant roots. Transport by other soil biota is likely to occur, but this area has not been well studied. We hypothesized that interactions with soil nematodes may enhance colonization. To test this hypothesis, a series of microcosm experiments was carried out using two contrasting soils maintained under well-defined physical conditions where transport by mass water flow could not occur. Seed-applied Pseudomonas fluorescens SBW25 was capable of rhizosphere colonization at matric potentials of −10 and −40 kPa in soil without nematodes, but colonization levels were substantially increased by the presence of nematodes. Our results suggest that nematodes can have an important role in rhizosphere colonization by bacteria in soil.

Plant protection potential and ultrastructure of Bacillus subtilis strain 3A25

2011 ◽  
Vol 30 (6) ◽  
pp. 739-744 ◽  
Author(s):  
A. Holzinger ◽  
D. Nagendra-Prasad ◽  
G. Huys
Keyword(s):  
Bacillus Subtilis ◽  
Plant Protection ◽  
Subtilis Strain ◽  
Protection Potential

scholarly journals Whole plant-environment microscopy reveals how Bacillus subtilis utilises the soil pore space to colonise plant roots

2021 ◽  
Author(s):  
Yangminghao Liu ◽  
Daniel Patko ◽  
Ilonka Engelhardt ◽  
Timothy S George ◽  
Nicola Stanley-Wall ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Pore Space ◽  
Light Sheet ◽  
Root Surface ◽  
Plant Roots ◽  
Soil Particles ◽  
Transparent Soil ◽  
Plant Environment ◽  
Small Pore ◽  
Soil Pore Space

AbstractPlant growth is supported by complex interactions with many biophysical elements of their environment including microorganisms, geochemicals, water and gas, all within the otherwise complex and heterogeneous soils’ physical environment. Our understanding of plant-environment interactions in soil are limited by the difficulty of observing such interactions at the microscopic scale which occur throughout the large volume of influence of the plant. Here, we present the development of 3D live microscopy approaches for resolving plant-microbe interactions across the environment of an entire seedling root growing in a transparent soil in tailor-made mesocosms, maintaining physical conditions for the culture of both plants and microorganisms. A dual-illumination light-sheet system was used to acquire scattering signals from the plant whilst fluorescence signals were captured from transparent soil particles and labelled microorganisms, allowing the generation of quantitative data on samples approximately 3600 mm3 in size with as good as 5 μm resolution at a rate of up to one scan every 30 minutes. The system can track the movement of Bacillus subtilis populations in the rhizosphere of lettuce plants in real time, revealing previously unseen patterns of activity. Motile bacteria favoured small pore spaces over the surface of soil particles, colonising the root in a pulsatile manner. Migrations appeared to be directed first towards the root cap as the point “first contact”, before subsequent colonisation of mature epidermis cells. Our findings show that microscopes dedicated to live environmental studies present an invaluable tool to understand life in soils.SignificanceBetter knowledge of microbial movement and interaction with plant roots is essential to understanding soil ecosystems. However, the lack of a suitable approach for observing biological activity in such environments severely impedes advances in this field of research. Here, we overcome this major limitation by combining the use of transparent soil with cutting edge live microscopy techniques. We performed a detailed analysis of the movements of Bacillus subtilis and revealed how the soil pore structure influences the behaviour of the bacteria, both before and during the formation of biofilms on the root surface. This work sheds light on previously unseen phenomenon, and accelerates our understanding of soil dwelling organisms which were, before now, unobserved in their native environment.

scholarly journals A Community Effort: Combining Functional Amplicon Sequencing and Metagenomics Reveals Potential Biosynthetic Gene Clusters Associated with Protective Phenotypes in Rhizosphere Microbiomes

mSystems ◽  
2021 ◽  
Author(s):  
Jaclyn M. Winter
Keyword(s):  
Plant Growth ◽  
Plant Pathogens ◽  
Gene Clusters ◽  
Amplicon Sequencing ◽  
Plant Roots ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
First Line ◽  
Community Effort ◽  
Promote Plant Growth

Soil-dwelling microorganisms associated with plant roots carry out essential processes that promote plant growth and productivity. In addition to these beneficial functions, the rhizosphere microbiome also serves as the first line of defense against many plant pathogens.

scholarly journals MISIRoot: A Robotic Minimum Invasion in Situ Imaging System for Plant Root Phenotyping

2020 ◽  
Author(s):  
Zhihang Song ◽  
Wei Qiu ◽  
Jian Jin
Keyword(s):  
Plant Protection ◽  
Plant Root ◽  
Low Cost ◽  
3D Structure ◽  
Color Images ◽  
Plant Roots ◽  
Natural Soil ◽  
Wide Range ◽  
Root Phenotyping

Abstract Background: Plant root phenotyping technologies play an important role in breeding, plant protection, and other plant science research projects. The root phenotyping customers urgently need technologies that are low-cost, in situ, non-destructive to the roots, and suitable for the natural soil environment. Many recently developed root phenotyping methods such as minirhizotron, X-CT, and MRI scanners have their unique advantages in observing plant roots, but they also have disadvantages and cannot meet all the critical requirements simultaneously. Results: The study in this paper focuses on the development of a new plant root phenotyping robot that is minimally invasive to plants and working in situ inside natural soil, called “MISIRoot”. The MISIRoot system mainly consists of an industrial-level robotic arm, a mini-size camera with lighting set, a plant pot holding platform, and the image processing software for root recognition and feature extraction. MISIRoot can take high-resolution color images of the roots in soil with minimal disturbance to the root and reconstruct the plant roots’ three-dimensional (3D) structure at an accuracy of 0.1 mm. In a test assay, well-watered and drought-stressed groups of corn plants were measured by MISIRoot at V3, V4, and V5 stages. The system successfully acquired the RGB color images of the roots and extracted the 3D points cloud data containing the locations of the detected roots. The plants measured by MISIRoot and plants not measured (control) were carefully compared with the results from the Hyperspectral Imaging Facility (reference). No significant differences were found between the two groups of plants at different growth stages. Conclusion: The MISIRoot system recently developed at Purdue University has been proved effective in root phenotyping with multiple advantages: With a comparatively low cost and minimal invasion to the plant, this system can automatically measure the root’s 3D structure and take color images of the roots in ordinary soil media, and in situ. This system provides a new option for root phenotyping researchers and has a potential to be applied in a wide range of research topics such as breeding, plant protection and so on.

Beef Jerky: Viability of Food-Poisoning Microorganisms on Jerky during its Manufacture and Storage

1985 ◽  
Vol 48 (2) ◽  
pp. 100-106 ◽  
Author(s):  
RICHARD A. HOLLEY
Keyword(s):  
Staphylococcus Aureus ◽  
Bacillus Subtilis ◽  
Relative Humidity ◽  
Clostridium Perfringens ◽  
Food Poisoning ◽  
High Relative Humidity ◽  
Protein Ratio ◽  
Beef Jerky ◽  
Shelf Stable ◽  
And Storage

Beef jerky was made from slices of flank steak inoculated with Staphylococcus aureus, vegetative cells of Clostridium perfringens as well as Bacillus subtilis and a two species-composite of Salmonella. Slices were placed in a domestic food dehydrator for 4 h at 52.9±0.8°C (127.2°F) followed by 4 h at 48.2±0.4°C (118.8°F). Meat slices dried rapidly, reaching an aw of 0.86 and a shelf-stable moisture-protein ratio of ≤1.6 within the first 2.5–3 h of drying. Samples originally contained about 68% moisture, but this dropped to about 30% by 4 h and 20% by 8 h. Some growth of inoculated S. aureus occurred initially but total numbers of all other added microorganisms decreased rapidly from the start of drying and although significantly reduced in numbers at the end of 8 h treatment, they survived processing. C. perfringens cells were not detected at the end of the heated-drying regimen but were recovered later in an inoculated sample stored at 2.5°C for a month. Contaminated jerky stored at 20°C and high relative humidity (RH) for 26–28 d did not contain detectable added bacteria, whereas identical samples stored at 2.5°C and low RH contained viable S. aureus and B. subtilis as well as C. perfringens. Domestic preparation of jerky from beef of normal retail quality would involve little risk provided initial drying is done rapidly at temperatures equal to or greater than those used in the present study.

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