scholarly journals Comparative Genomics Within the Bacillus Genus Reveal the Singularities of Two Robust Bacillus amyloliquefaciens Biocontrol Strains

2015 ◽  
Vol 28 (10) ◽  
pp. 1102-1116 ◽  
Author(s):  
M. C. Magno-Pérez-Bryan ◽  
P. M. Martínez-García ◽  
J. Hierrezuelo ◽  
P. Rodríguez-Palenzuela ◽  
E. Arrebola ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Biofilm Formation ◽  
Bacillus Amyloliquefaciens ◽  
Communication Systems ◽  
Defense Mechanisms ◽  
Ad Hoc ◽  
Cell Communication ◽  
Defense Responses ◽  
Microbial Pathogens ◽  
Stimulate Plant Growth

Bacillus amyloliquefaciens CECT 8237 and CECT 8238, formerly known as Bacillus subtilis UMAF6639 and UMAF6614, respectively, contribute to plant health by facing microbial pathogens or inducing the plant’s defense mechanisms. We sequenced their genomes and developed a set of ad hoc scripts that allowed us to search for the features implicated in their beneficial interaction with plants. We define a core set of genes that should ideally be found in any beneficial Bacillus strain, including the production of secondary metabolites, volatile compounds, metabolic plasticity, cell-to-cell communication systems, and biofilm formation. We experimentally prove that some of these genetic elements are active, such as i) the production of known secondary metabolites or ii) acetoin and 2-3-butanediol, compounds that stimulate plant growth and host defense responses. A comparison with other Bacillus genomes permits us to find differences in the cell-to-cell communication system and biofilm formation and to hypothesize variations in their persistence and resistance ability in diverse environmental conditions. In addition, the major protection provided by CECT 8237 and CECT 8238, which is different from other Bacillus strains against bacterial and fungal melon diseases, permits us to propose a correlation with their singular genetic background and determine the need to search for additional blind biocontrol-related features.

scholarly journals Plant Defense Responses to Biotic Stress and Its Interplay With Fluctuating Dark/Light Conditions

2021 ◽  
Vol 12 ◽  
Author(s):  
Zahra Iqbal ◽  
Mohammed Shariq Iqbal ◽  
Abeer Hashem ◽  
Elsayed Fathi Abd_Allah ◽  
Mohammad Israil Ansari
Keyword(s):  
Plant Defense ◽  
Biotic Stress ◽  
Defense Mechanisms ◽  
Defense Mechanism ◽  
Defense Responses ◽  
Light Environment ◽  
Microbial Pathogens ◽  
Signaling Cascade ◽  
Dark Light ◽  
The Impact

Plants are subjected to a plethora of environmental cues that cause extreme losses to crop productivity. Due to fluctuating environmental conditions, plants encounter difficulties in attaining full genetic potential for growth and reproduction. One such environmental condition is the recurrent attack on plants by herbivores and microbial pathogens. To surmount such attacks, plants have developed a complex array of defense mechanisms. The defense mechanism can be either preformed, where toxic secondary metabolites are stored; or can be inducible, where defense is activated upon detection of an attack. Plants sense biotic stress conditions, activate the regulatory or transcriptional machinery, and eventually generate an appropriate response. Plant defense against pathogen attack is well understood, but the interplay and impact of different signals to generate defense responses against biotic stress still remain elusive. The impact of light and dark signals on biotic stress response is one such area to comprehend. Light and dark alterations not only regulate defense mechanisms impacting plant development and biochemistry but also bestow resistance against invading pathogens. The interaction between plant defense and dark/light environment activates a signaling cascade. This signaling cascade acts as a connecting link between perception of biotic stress, dark/light environment, and generation of an appropriate physiological or biochemical response. The present review highlights molecular responses arising from dark/light fluctuations vis-à-vis elicitation of defense mechanisms in plants.

scholarly journals Transcriptional profiling reveals conserved and species-specific plant defense responses during the interaction of the early divergent plant Physcomitrium patens with Botrytis cinerea

2020 ◽  
Author(s):  
Guillermo Reboledo ◽  
Astrid Agorio ◽  
Lucía Vignale ◽  
Ramón Alberto Batista-García ◽  
Inés Ponce De León
Keyword(s):  
Immune Response ◽  
Botrytis Cinerea ◽  
Defense Mechanisms ◽  
Molecular Mechanisms ◽  
Defense Responses ◽  
Land Plants ◽  
Differentially Expressed ◽  
Microbial Pathogens ◽  
Limited Information ◽  
Pathogen Invasion

AbstractBryophytes were among the first plants that colonized earth and they evolved key defense mechanisms to counteract microbial pathogens present in the new environment. Although great advances have been made on pathogen perception and subsequent defense activation in angiosperms, limited information is available in early divergent land plants. In this study, a transcriptomic approach uncovered the molecular mechanisms underlying the defense response of the bryophyte Physcomitrium patens against the important plant pathogen Botrytis cinerea. A total of 3.072 differentially expressed genes were significantly affected during B. cinerea infection, including genes encoding proteins with known function in angiosperm immunity and involved in pathogen perception, signaling, transcription, hormonal signaling, metabolic pathways such as shikimate and phenylpropanoid, and proteins with diverse role in defense against biotic stress. Similarly as in other plants, B. cinerea infection leads to downregulation of genes involved in photosynthesis and cell cycle progression. These results highlight the existence of evolutionary conserved defense responses to pathogens throughout the green plant lineage, suggesting that they were probably present in the common ancestors of land plants. Moreover, several genes acquired by horizontal transfer from prokaryotes and fungi, and a high number of P. patens-specific orphan genes were differentially expressed during B. cinerea infection, indicating that they are part of the moss immune response and probably played an ancestral role related to effective adaptation mechanisms to cope with pathogen invasion during the conquest of land.Key MessageEvolutionary conserved defense mechanisms present in extant bryophytes and angiosperms, as well as moss-specific defenses are part of the immune response of the early divergent land plant Physcomitrium patens.

scholarly journals Biofilms Positively Contribute to Bacillus amyloliquefaciens 54-induced Drought Tolerance in Tomato Plants

2019 ◽  
Vol 20 (24) ◽  
pp. 6271 ◽  
Author(s):  
Da-Cheng Wang ◽  
Chun-Hao Jiang ◽  
Li-Na Zhang ◽  
Lin Chen ◽  
Xiao-Yun Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Biofilm Formation ◽  
Bacillus Amyloliquefaciens ◽  
Root Colonization ◽  
Stomatal Closure ◽  
Defense Responses ◽  
Antioxidant Enzyme Activities ◽  
Elevated Concentration ◽  
Tomato Plants

Drought stress is a major obstacle to agriculture. Although many studies have reported on plant drought tolerance achieved via genetic modification, application of plant growth-promoting rhizobacteria (PGPR) to achieve tolerance has rarely been studied. In this study, the ability of three isolates, including Bacillus amyloliquefaciens 54, from 30 potential PGPR to induce drought tolerance in tomato plants was examined via greenhouse screening. The results indicated that B. amyloliquefaciens 54 significantly enhanced drought tolerance by increasing survival rate, relative water content and root vigor. Coordinated changes were also observed in cellular defense responses, including decreased concentration of malondialdehyde and elevated concentration of antioxidant enzyme activities. Moreover, expression levels of stress-responsive genes, such as lea, tdi65, and ltpg2, increased in B. amyloliquefaciens 54-treated plants. In addition, B. amyloliquefaciens 54 induced stomatal closure through an abscisic acid-regulated pathway. Furthermore, we constructed biofilm formation mutants and determined the role of biofilm formation in B. amyloliquefaciens 54-induced drought tolerance. The results showed that biofilm-forming ability was positively correlated with plant root colonization. Moreover, plants inoculated with hyper-robust biofilm (ΔabrB and ΔywcC) mutants were better able to resist drought stress, while defective biofilm (ΔepsA-O and ΔtasA) mutants were more vulnerable to drought stress. Taken altogether, these results suggest that biofilm formation is crucial to B. amyloliquefaciens 54 root colonization and drought tolerance in tomato plants.

scholarly journals The MossPhyscomitrella patensas a Model System to Study Interactions between Plants and Phytopathogenic Fungi and Oomycetes

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Inés Ponce de León
Keyword(s):  
Cell Death ◽  
Defense Mechanisms ◽  
Physcomitrella Patens ◽  
Current Knowledge ◽  
Defense Responses ◽  
Phytopathogenic Fungi ◽  
Model System ◽  
High Rate ◽  
Microbial Pathogens ◽  
Functional Studies

The mossPhyscomitrella patenshas a great potential as a model system to perform functional studies of plant interacting with microbial pathogens.P. patensis susceptible to fungal and oomycete infection, which colonize and multiply in plant tissues generating disease symptoms. In response to infection,P. patensactivates defense mechanisms similar to those induced in flowering plants, including the accumulation of reactive oxygen species, cell death with hallmarks of programmed cell death, cell wall fortification, and induction of defense-related genes likePAL,LOX,CHS, andPR-1. Functional analysis of genes with possible roles in defense can be performed due to the high rate of homologous recombination present in this plant that enables targeted gene disruption. This paper reviews the current knowledge of defense responses activated inP. patensafter pathogen assault and analyzes the advantages of using this plant to gain further insight into plant defense strategies.

scholarly journals Cyclic Lipopeptides of Bacillus amyloliquefaciens subsp. plantarum Colonizing the Lettuce Rhizosphere Enhance Plant Defense Responses Toward the Bottom Rot Pathogen Rhizoctonia solani

2015 ◽  
Vol 28 (9) ◽  
pp. 984-995 ◽  
Author(s):  
Soumitra Paul Chowdhury ◽  
Jenny Uhl ◽  
Rita Grosch ◽  
Sylvia Alquéres ◽  
Sabrina Pittroff ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Plant Defense ◽  
Bacillus Amyloliquefaciens ◽  
Defense Responses ◽  
Disease Suppression ◽  
Plant Defense Responses ◽  
Defense Gene Expression ◽  
Defense Gene ◽  
Pathogen Challenge ◽  
Bottom Rot

The commercially available inoculant Bacillus amyloliquefaciens FZB42 is able to considerably reduce lettuce bottom rot caused by Rhizoctonia solani. To understand the interaction between FZB42 and R. solani in the rhizosphere of lettuce, we used an axenic system with lettuce bacterized with FZB42 and inoculated with R. solani. Confocal laser scanning microscopy showed that FZB42 could delay the initial establishment of R. solani on the plants. To show which secondary metabolites of FZB42 are produced under these in-situ conditions, we developed an ultra-high performance liquid chromatography coupled to time of flight mass spectrometry–based method and identified surfactin, fengycin, and bacillomycin D in the lettuce rhizosphere. We hypothesized that lipopeptides and polyketides play a role in enhancing the plant defense responses in addition to the direct antagonistic effect toward R. solani and used a quantitative real-time polymerase chain reaction–based assay for marker genes involved in defense signaling pathways in lettuce. A significant higher expression of PDF 1.2 observed in the bacterized plants in response to subsequent pathogen challenge showed that FZB42 could enhance the lettuce defense response toward the fungal pathogen. To identify if surfactin or other nonribosomally synthesized secondary metabolites could elicit the observed enhanced defense gene expression, we examined two mutants of FZB42 deficient in production of surfactin and the lipopetides and polyketides, by expression analysis and pot experiments. In the absence of surfactin and other nonribosomally synthesized secondary metabolites, there was no enhanced PDF 1.2–mediated response to the pathogen challenge. Pot experiment results showed that the mutants failed to reduce disease incidence in lettuce as compared with the FZB42 wild type, indicating, that surfactin as well as other nonribosomally synthesized secondary metabolites play a role in the actual disease suppression and on lettuce health. In conclusion, our study showed that nonribosomally synthesized secondary metabolites of FZB42 are actually produced in the lettuce rhizosphere and contribute to the disease suppression by mediating plant defense gene expression toward the pathogen R. solani.

Plant peptide hormone signalling

2015 ◽  
Vol 58 ◽  
pp. 115-131 ◽  
Author(s):  
Ayane Motomitsu ◽  
Shinichiro Sawa ◽  
Takashi Ishida
Keyword(s):  
Communication Systems ◽  
Cell Communication ◽  
Peptide Hormone ◽  
Peptide Hormones ◽  
Target Cells ◽  
Signalling Molecules ◽  
Receptor Complexes ◽  
Environmental Responses ◽  
Plant Life Cycle ◽  
Multicellular Organisms

The ligand–receptor-based cell-to-cell communication system is one of the most important molecular bases for the establishment of complex multicellular organisms. Plants have evolved highly complex intercellular communication systems. Historical studies have identified several molecules, designated phytohormones, that function in these processes. Recent advances in molecular biological analyses have identified phytohormone receptors and signalling mediators, and have led to the discovery of numerous peptide-based signalling molecules. Subsequent analyses have revealed the involvement in and contribution of these peptides to multiple aspects of the plant life cycle, including development and environmental responses, similar to the functions of canonical phytohormones. On the basis of this knowledge, the view that these peptide hormones are pivotal regulators in plants is becoming increasingly accepted. Peptide hormones are transcribed from the genome and translated into peptides. However, these peptides generally undergo further post-translational modifications to enable them to exert their function. Peptide hormones are expressed in and secreted from specific cells or tissues. Apoplastic peptides are perceived by specialized receptors that are located at the surface of target cells. Peptide hormone–receptor complexes activate intracellular signalling through downstream molecules, including kinases and transcription factors, which then trigger cellular events. In this chapter we provide a comprehensive summary of the biological functions of peptide hormones, focusing on how they mature and the ways in which they modulate plant functions.

Quorum Sensing – A Stratagem for Conquering Multi-Drug Resistant Pathogens

2020 ◽  
Vol 26 ◽  
Author(s):  
Madison Tonkin ◽  
Shama Khan ◽  
Mohmmad Younus Wani ◽  
Aijaz Ahmad
Keyword(s):  
Drug Resistance ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Cell Communication ◽  
Natural Compounds ◽  
Quorum Sensing Inhibitors ◽  
Communication Technique ◽  
Multicellular Organisms ◽  
Chemical Strategies

: Quorum sensing is defined as cell to cell communication between microorganisms, which enables microorganisms to behave as multicellular organisms. Quorum sensing enables many collaborative benefits such as synchronisation of virulence factors and biofilm formation. Both quorum sensing as well as biofilm formation encourage the development of drug resistance in microorganisms. Biofilm formation and quorum sensing are causally linked to each other and play role in the pathogenesis of microorganisms. With the increasing drug resistance against the available antibiotics and antifungal medications, scientists are combining different options to develop new strategies. Such strategies rely on the inhibition of the communication and virulence factors rather than on killing or inhibiting the growth of the microorganisms. This review encompasses the communication technique used by microorganisms, how microorganism resistance is linked to quorum sensing and various chemical strategies to combat quorum sensing and thereby drug resistance. Several compounds have been identified as quorum sensing inhibitors and are known to be effective in reducing resistance as they do not kill the pathogens but rather disrupt their communication. Natural compounds have been identified as anti-quorum sensing agents. However, natural compounds present several related disadvantages. Therefore, the need for the development of synthetic or semi-synthetic compounds has arisen. This review argues that anti-quorum sensing compounds are effective in disrupting quorum sensing and could therefore be effective in reducing microorganism drug resistance.

scholarly journals Proteomics and Metabolomics Studies on the Biotic Stress Responses of Rice: an Update

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kieu Thi Xuan Vo ◽  
Md Mizanor Rahman ◽  
Md Mustafizur Rahman ◽  
Kieu Thi Thuy Trinh ◽  
Sun Tae Kim ◽  
...  
Keyword(s):  
Stress Responses ◽  
Biotic Stress ◽  
Defense Mechanisms ◽  
Defense Responses ◽  
Global Changes ◽  
Biotic Stresses ◽  
Novel Proteins ◽  
Stress Agent ◽  
Global Food ◽  
Shed Light

AbstractBiotic stresses represent a serious threat to rice production to meet global food demand and thus pose a major challenge for scientists, who need to understand the intricate defense mechanisms. Proteomics and metabolomics studies have found global changes in proteins and metabolites during defense responses of rice exposed to biotic stressors, and also reported the production of specific secondary metabolites (SMs) in some cultivars that may vary depending on the type of biotic stress and the time at which the stress is imposed. The most common changes were seen in photosynthesis which is modified differently by rice plants to conserve energy, disrupt food supply for biotic stress agent, and initiate defense mechanisms or by biotic stressors to facilitate invasion and acquire nutrients, depending on their feeding style. Studies also provide evidence for the correlation between reactive oxygen species (ROS) and photorespiration and photosynthesis which can broaden our understanding on the balance of ROS production and scavenging in rice-pathogen interaction. Variation in the generation of phytohormones is also a key response exploited by rice and pathogens for their own benefit. Proteomics and metabolomics studies in resistant and susceptible rice cultivars upon pathogen attack have helped to identify the proteins and metabolites related to specific defense mechanisms, where choosing of an appropriate method to identify characterized or novel proteins and metabolites is essential, considering the outcomes of host-pathogen interactions. Despites the limitation in identifying the whole repertoire of responsive metabolites, some studies have shed light on functions of resistant-specific SMs. Lastly, we illustrate the potent metabolites responsible for resistance to different biotic stressors to provide valuable targets for further investigation and application.

Biofilm Formation, Communication and Interactions of Mesophilic Leaching Bacteria during Pyrite Oxidation

2013 ◽  
Vol 825 ◽  
pp. 107-110
Author(s):  
Sören Bellenberg ◽  
Robert Barthen ◽  
Mario Vera ◽  
Nicolas Guiliani ◽  
Wolfgang Sand
Keyword(s):  
Quorum Sensing ◽  
Acidithiobacillus Ferrooxidans ◽  
Biofilm Formation ◽  
Pyrite Oxidation ◽  
Cell Communication ◽  
Homoserine Lactone ◽  
Mixed Cultures ◽  
Acyl Homoserine Lactone ◽  
Leaching Bacteria ◽  
Leaching Efficiency

A functional luxIR-type Quorum Sensing (QS) system is present in Acidithiobacillus ferrooxidans. However, cell-cell communication among various acidophilic chemolithoautotrophs growing on pyrite has not been studied in detail. These aspects are the scope of this study with emphasis on the effects exerted by the N-acyl-homoserine lactone (AHL) type signaling molecules which are produced by Acidithiobacillus ferrooxidans. Their effects on attachment and leaching efficiency by other leaching bacteria, such as Acidithiobacillus ferrivorans, Acidiferrobacter spp. SPIII/3 and Leptospirillum ferrooxidans in pure and mixed cultures growing on pyrite is shown.

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