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 Investigating the Phylogenetic Range of Gibberellin Biosynthesis in Bacteria

2017 ◽  
Vol 30 (4) ◽  
pp. 343-349 ◽  
Author(s):  
Raimund Nagel ◽  
Reuben J. Peters
Keyword(s):  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Bacterial Pathogen ◽  
Xanthomonas Oryzae ◽  
Gibberella Fujikuroi ◽  
Gibberellin Biosynthesis ◽  
Erwinia Tracheiphila ◽  
Associated Bacteria ◽  
Exact Product ◽  
Ga Biosynthesis

Certain plant-associated microbes can produce gibberellin (GA) phytohormones, as first described for the rice fungal pathogen Gibberella fujikuroi and, more recently, for bacteria, including several rhizobia and the rice bacterial pathogen Xanthomonas oryzae pv. oryzicola. The relevant enzymes are encoded by a biosynthetic operon that exhibits both a greater phylogenetic range and scattered distribution among plant-associated bacteria. Here, the phylogenetic distribution of this operon was investigated. To demonstrate conserved functionality, the enzymes encoded by the disparate operon from X. translucens pv. translucens, along with those from the most divergent example, found in Erwinia tracheiphila, were biochemically characterized. In both of these phytopathogens, the operon leads to production of the bioactive GA4. Based on these results, it seems that this operon is widely dedicated to GA biosynthesis. However, there is intriguing variation in the exact product. In particular, although all plant pathogens seem to produce bioactive GA4, rhizobia generally only produce the penultimate hormonal precursor GA9. This is suggested to reflect their distinct interactions with plants, because production of GA4 counteracts the jasmonic-acid-mediated defense response, reflecting the importance of wounds as the entry point for these phytopathogens, whereas such suppression presumably is detrimental in the rhizobial symbiotic relationship.

scholarly journals In-Vitro Antagonistic Activity of Plant Extract on Fusarium Species

2019 ◽  
Vol 18 (4) ◽  
pp. 53-62
Author(s):  
P Asiya ◽  
PR Sreeraj ◽  
Joseph John ◽  
PB Ramya
Keyword(s):  
Fungal Pathogen ◽  
Biocontrol Agent ◽  
Plant Protection ◽  
Fusarium Species ◽  
Antagonistic Activity ◽  
Agricultural System ◽  
Maximum Inhibition ◽  
Fusarium Sp ◽  
Poison Food Technique

Plant protection is an important area which needs attention since most of the hazardous inputs added into the agricultural system are in the form of plant protection chemicals. Botanicals possess a variety of promising properties which make it a better biocontrol agent. The objectives of the present study were to isolate Fusarium sp. from soil and to check the effect of botanicals against this fungal pathogen in-vitro. The antagonistic activity of botanicals was studied by co-inoculation with the Fusarium sp. isolated from rhizosphere soil. In poison food technique, the botanicals in different concentration, showed decrease in the growth of the fungal pathogen. Maximum inhibition was observed in 10% Azadiracta sp. with 64% inhibition followed by 5% Azadiracta sp. with 57.8%

scholarly journals Stability of Dry and Liquid Metschnikowia pulcherrima Formulations for Biocontrol Applications against Apple Postharvest Diseases

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 459
Author(s):  
Andreas Bühlmann ◽  
Sandrine Kammerecker ◽  
Laurin Müller ◽  
Maja Hilber-Bodmer ◽  
Sarah Perren ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Plant Protection ◽  
Milk Powder ◽  
Skim Milk ◽  
Field Trials ◽  
Antagonistic Activity ◽  
Plant Protection Product ◽  
Postharvest Diseases ◽  
Metschnikowia Pulcherrima ◽  
Freeze Dried

The yeast Metschnikowia pulcherrima is frequently isolated from environmental samples and has often been reported to exhibit strong antagonistic activity against plant pathogens. In order to assess the potential of this species for its development into a plant protection product, the survival during formulation and storage were quantified and field efficacy was assessed over a period of five years. Freeze dried and liquid M. pulcherrima formulations (i.e., with skim milk powder (SMP), sucrose, glycerol, xanthan, without additives) were prepared and the number of viable cells was quantified during storage at different temperatures. Field trials against apple postharvest diseases (Neofabreae) were performed with different dry formulations. M. pulcherrima proved exceptionally stable for many months and even years. Five years of field trials with the yeast revealed variable effects, but reduced Neofabreae infections of stored apples were observed in some years. M. pulcherrima applications after prior fungicide treatments repeatedly showed an additive effect as compared to the fungicide treatments alone. In summary, M. pulcherrima exhibited highly advantageous storage properties and encouraging activity against apple postharvest rots. Further studies to identify the factors responsible for antagonistic activity in the field and survival during storage are expected to lay the foundation for the future development of a plant protection product.

scholarly journals Possible role of arbuscular mycorrhizal fungi and associated bacteria in the recruitment of endophytic bacterial communities by plant roots

Mycorrhiza ◽  
2021 ◽  
Author(s):  
Gergely Ujvári ◽  
Alessandra Turrini ◽  
Luciano Avio ◽  
Monica Agnolucci
Keyword(s):  
Arbuscular Mycorrhizal Fungi ◽  
Root System ◽  
Bacterial Communities ◽  
Mycorrhizal Fungi ◽  
Plant Pathogens ◽  
Plant Hormone ◽  
Arbuscular Mycorrhizal ◽  
Plant Performance ◽  
Nutrient Mobilization ◽  
Associated Bacteria

AbstractArbuscular mycorrhizal fungi (AMF) represent an important group of root symbionts, given the key role they play in the enhancement of plant nutrition, health, and product quality. The services provided by AMF often are facilitated by large and diverse beneficial bacterial communities, closely associated with spores, sporocarps, and extraradical mycelium, showing different functional activities, such as N2 fixation, nutrient mobilization, and plant hormone, antibiotic, and siderophore production and also mycorrhizal establishment promotion, leading to the enhancement of host plant performance. The potential functional complementarity of AMF and associated microbiota poses a key question as to whether members of AMF-associated bacterial communities can colonize the root system after establishment of mycorrhizas, thereby becoming endophytic. Root endophytic bacterial communities are currently studied for the benefits provided to host plants in the form of growth promotion, stress reduction, inhibition of plant pathogens, and plant hormone release. Their quantitative and qualitative composition is influenced by many factors, such as geographical location, soil type, host genotype, and cultivation practices. Recent data suggest that an additional factor affecting bacterial endophyte recruitment could be AMF and their associated bacteria, even though the mechanisms allowing members of AMF-associated bacterial communities to actually establish in the root system, becoming endophytic, remain to be determined. Given the diverse plant growth–promoting properties shown by AMF-associated bacteria, further studies are needed to understand whether AMF may represent suitable tools to introduce beneficial root endophytes in sustainable and organic agriculture where the functioning of such multipartite association may be crucial for crop production.

scholarly journals Ecotype-Dependent Response of Bacterial Communities Associated with Arabidopsis to Cold Acclimation

2018 ◽  
Vol 2 (1) ◽  
pp. 3-13 ◽  
Author(s):  
Mohammad Etemadi ◽  
Ellen Zuther ◽  
Henry Müller ◽  
Dirk K. Hincha ◽  
Gabriele Berg
Keyword(s):  
Cold Acclimation ◽  
Freezing Tolerance ◽  
Bacterial Communities ◽  
Bacterial Community Composition ◽  
Additional Function ◽  
Associated Bacteria ◽  
Plant Microbe Interaction ◽  
Operational Taxonomic Units ◽  
Core Species ◽  
The Impact

Low temperature is a primary factor limiting geographical distribution of plants and crop yield in large areas of the world. Plant-associated microbial communities have rarely been acknowledged as possible determinants of cold acclimation, the process leading to freezing tolerance in plants. Here we studied the impact of cold acclimation on leaf-associated bacteria by analyzing 10 different Arabidopsis ecotypes differing widely in their freezing tolerance. In climate chamber experiments, we found that leaves of all Arabidopsis accessions were colonized by highly diverse bacterial taxa (852 operational taxonomic units) mainly from Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. During cold acclimation, in all ecotypes the bacterial community composition and diversity, and especially the core species composition changed drastically. However, the response of the bacterial communities was highly ecotype-dependent; sensitive and tolerant accessions shared only eight responders. Unique responders in tolerant accessions were identified as putative indicators of freezing tolerance. Thus, leaf bacteria appear to be genotype-dependent associated with cold acclimation, which suggests an additional function of plant−microbe interaction and may open new possibilities for biotechnological applications.

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.

scholarly journals The carbon source-dependent pattern of antimicrobial activity and gene expression in Pseudomonas donghuensis P482

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Matuszewska ◽  
Tomasz Maciąg ◽  
Magdalena Rajewska ◽  
Aldona Wierzbicka ◽  
Sylwia Jafra
Keyword(s):  
Gene Expression ◽  
Antimicrobial Activity ◽  
Carbon Source ◽  
Reference Genes ◽  
Plant Pathogens ◽  
Plant Protection ◽  
Carbon Sources ◽  
Unknown Compound ◽  
Fungal Plant Pathogens ◽  
The Impact

AbstractPseudomonas donghuensis P482 is a tomato rhizosphere isolate with the ability to inhibit growth of bacterial and fungal plant pathogens. Herein, we analysed the impact of the carbon source on the antibacterial activity of P482 and expression of the selected genes of three genomic regions in the P482 genome. These regions are involved in the synthesis of pyoverdine, 7-hydroxytropolone (7-HT) and an unknown compound (“cluster 17”) and are responsible for the antimicrobial activity of P482. We showed that the P482 mutants, defective in these regions, show variations and contrasting patterns of growth inhibition of the target pathogen under given nutritional conditions (with glucose or glycerol as a carbon source). We also selected and validated the reference genes for gene expression studies in P. donghuensis P482. Amongst ten candidate genes, we found gyrB, rpoD and mrdA the most stably expressed. Using selected reference genes in RT-qPCR, we assessed the expression of the genes of interest under minimal medium conditions with glucose or glycerol as carbon sources. Glycerol was shown to negatively affect the expression of genes necessary for 7-HT synthesis. The significance of this finding in the light of the role of nutrient (carbon) availability in biological plant protection is discussed.

Effectors of biotrophic fungal plant pathogens

2010 ◽  
Vol 37 (10) ◽  
pp. 913 ◽  
Author(s):  
Pamela H. P. Gan ◽  
Maryam Rafiqi ◽  
Adrienne R. Hardham ◽  
Peter N. Dodds
Keyword(s):  
Plant Tissue ◽  
Fungal Pathogen ◽  
Plant Pathogens ◽  
Plant Cells ◽  
Host Cells ◽  
Plant Proteins ◽  
Living Plant ◽  
Host Cytoplasm ◽  
Fungal Plant Pathogens ◽  
Biotrophic Fungi

Plant pathogenic biotrophic fungi are able to grow within living plant tissue due to the action of secreted pathogen proteins known as effectors that alter the response of plant cells to pathogens. The discovery and identification of these proteins has greatly expanded with the sequencing and annotation of fungal pathogen genomes. Studies to characterise effector function have revealed that a subset of these secreted pathogen proteins interact with plant proteins within the host cytoplasm. This review focuses on the effectors of intracellular biotrophic and hemibiotrophic fungal plant pathogens and summarises advances in understanding the roles of these proteins in disease and in elucidating the mechanism of fungal effector uptake into host cells.

scholarly journals Sponge-Associated Bacteria Are Strictly Maintained in Two Closely Related but Geographically Distant Sponge Hosts

2011 ◽  
Vol 77 (20) ◽  
pp. 7207-7216 ◽  
Author(s):  
Naomi F. Montalvo ◽  
Russell T. Hill
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Bacterial Communities ◽  
Sponge Species ◽  
Rrna Gene ◽  
Gene Sequences ◽  
Associated Bacteria ◽  
Content Type ◽  
Key Species ◽  
Sponge Associated Bacteria

ABSTRACTThe giant barrel spongesXestospongiamutaandXestospongiatestudinariaare ubiquitous in tropical reefs of the Atlantic and Pacific Oceans, respectively. They are key species in their respective environments and are hosts to diverse assemblages of bacteria. These two closely related sponges from different oceans provide a unique opportunity to examine the evolution of sponge-associated bacterial communities. Mitochondrial cytochrome oxidase subunit I gene sequences fromX.mutaandX.testudinariashowed little divergence between the two species. A detailed analysis of the bacterial communities associated with these sponges, comprising over 900 full-length 16S rRNA gene sequences, revealed remarkable similarity in the bacterial communities of the two species. Both sponge-associated communities include sequences found only in the twoXestospongiaspecies, as well as sequences found also in other sponge species and are dominated by three bacterial groups,Chloroflexi,Acidobacteria, andActinobacteria. While these groups consistently dominate the bacterial communities revealed by 16S rRNA gene-based analysis of sponge-associated bacteria, the depth of sequencing undertaken in this study revealed clades of bacteria specifically associated with each of the twoXestospongiaspecies, and also with the genusXestospongia, that have not been found associated with other sponge species or other ecosystems. This study, comparing the bacterial communities associated with closely related but geographically distant sponge hosts, gives new insight into the intimate relationships between marine sponges and some of their bacterial symbionts.

Multifaceted Impacts of Bacteriophages in the Plant Microbiome

2018 ◽  
Vol 56 (1) ◽  
pp. 361-380 ◽  
Author(s):  
Britt Koskella ◽  
Tiffany B. Taylor
Keyword(s):  
Host Plant ◽  
Future Study ◽  
Plant Pathogens ◽  
Ecological Interactions ◽  
Selection Pressures ◽  
Bacterial Populations ◽  
Associated Bacteria ◽  
Open Questions ◽  
Microbe Interactions ◽  
Plant Microbiome

Plant-associated bacteria face multiple selection pressures within their environments and have evolved countless adaptations that both depend on and shape bacterial phenotype and their interaction with plant hosts. Explaining bacterial adaptation and evolution therefore requires considering each of these forces independently as well as their interactions. In this review, we examine how bacteriophage viruses (phages) can alter the ecology and evolution of plant-associated bacterial populations and communities. This includes influencing a bacterial population's response to both abiotic and biotic selection pressures and altering ecological interactions within the microbiome and between the bacteria and host plant. We outline specific ways in which phages can alter bacterial phenotype and discuss when and how this might impact plant-microbe interactions, including for plant pathogens. Finally, we highlight key open questions in phage-bacteria-plant research and offer suggestions for future study.

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