scholarly journals The Significance of Bacillus spp. in Disease Suppression and Growth Promotion of Field and Vegetable Crops

2020 ◽  
Vol 8 (7) ◽  
pp. 1037 ◽  
Author(s):  
Dragana Miljaković ◽  
Jelena Marinković ◽  
Svetlana Balešević-Tubić
Keyword(s):  
Plant Growth ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Disease Suppression ◽  
Biocontrol Agents ◽  
Systemic Resistance ◽  
Steady Increase ◽  
Vegetable Crops ◽  
Wide Range ◽  
Bacillus Spp

Bacillus spp. produce a variety of compounds involved in the biocontrol of plant pathogens and promotion of plant growth, which makes them potential candidates for most agricultural and biotechnological applications. Bacilli exhibit antagonistic activity by excreting extracellular metabolites such as antibiotics, cell wall hydrolases, and siderophores. Additionally, Bacillus spp. improve plant response to pathogen attack by triggering induced systemic resistance (ISR). Besides being the most promising biocontrol agents, Bacillus spp. promote plant growth via nitrogen fixation, phosphate solubilization, and phytohormone production. Antagonistic and plant growth-promoting strains of Bacillus spp. might be useful in formulating new preparations. Numerous studies of a wide range of plant species revealed a steady increase in the number of Bacillus spp. identified as potential biocontrol agents and plant growth promoters. Among different mechanisms of action, it remains unclear which individual or combined traits could be used as predictors in the selection of the best strains for crop productivity improvement. Due to numerous factors that influence the successful application of Bacillus spp., it is necessary to understand how different strains function in biological control and plant growth promotion, and distinctly define the factors that contribute to their more efficient use in the field.

scholarly journals Genome Mining of Antimicrobial Gene Clusters from Phyllospheric Bacteria Isolated from Solanum Lycopersicum and Lactuca Sativa to Identify Biocontrol Properties

2021 ◽  
Author(s):  
Claudia Y. Muñoz ◽  
Lu Zhou ◽  
Yunhai Yi ◽  
Oscar P. Kuipers
Keyword(s):  
Antimicrobial Activity ◽  
Plant Growth ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Genome Mining ◽  
Gene Clusters ◽  
Biocontrol Agents ◽  
Biosynthetic Gene ◽  
Biosynthetic Gene Clusters ◽  
Microbe Interactions

Abstract BackgroundBiocontrol agents are sustainable eco-friendly alternatives for chemical pesticides that cause adverse effects in the environment and toxicity in animals including humans. An improved understanding of the phyllosphere microbiology is of vital importance for biocontrol development. Most studies have been directed towards beneficial plant-microbe interactions and ignore the pathogens that might affect humans when consuming vegetables. In this study we extended this perspective and investigated potential biocontrol strains isolated from the tomato and lettuce phyllosphere that can promote plant growth and antagonize mammalian pathogens as well as plant pathogens. Subsequently, we mined into their genomes for discovery of antimicrobial biosynthetic gene clusters (BGCs), several of which are good candidates to produce protectants against microbial plant and mammalian pathogens.Results The antimicrobial activity of 69 newly isolated strains from a healthy tomato and lettuce phyllosphere against several plant and mammalian pathogens was determined with plates assays. Three strains with the highest antimicrobial activity against the relevant pathogens were selected and characterized (Bacillus subtilis STRP31, Bacillus velezensis SPL51, and Paenibacillus sp. PL91). All three strains showed a plant growth promotion effect by the production of volatile compounds (VOCs) on tomato and lettuce. In addition, genome mining of these isolates showed the presence of a large variety of biosynthetic gene clusters. A total of 39 BGCs were identified, of which several are already known, such as bacilysin, bacillibactin, surfactin, subtilomycin, etc., but also several novel ones. Further analysis revealed that among the novel BGCs, one NRPS and two bacteriocins are encoded which were analyzed in more depth.Conclusions Several antimicrobial BGCs were found in the selected strains, including the rediscovery of known ones, but also the discovery of novel ones. Our study serves as support for subsequent examination and characterization of novel antimicrobial metabolites, and the possibility of developing biocontrol agents.

scholarly journals Genetic Potential of the Biocontrol Agent Pseudomonas brassicacearum (Formerly P. trivialis) 3Re2-7 Unraveled by Genome Sequencing and Mining, Comparative Genomics and Transcriptomics

Genes ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 601 ◽  
Author(s):  
Johanna Nelkner ◽  
Gonzalo Torres Tejerizo ◽  
Julia Hassa ◽  
Timo Wentong Lin ◽  
Julian Witte ◽  
...  
Keyword(s):  
Comparative Genomics ◽  
Plant Growth ◽  
Plant Growth Promotion ◽  
Growth Promotion ◽  
Genome Mining ◽  
Gene Clusters ◽  
Disease Suppression ◽  
Biocontrol Agents ◽  
Circular Chromosome ◽  
Pseudomonas Brassicacearum

The genus Pseudomonas comprises many known plant-associated microbes with plant growth promotion and disease suppression properties. Genome-based studies allow the prediction of the underlying mechanisms using genome mining tools and the analysis of the genes unique for a strain by implementing comparative genomics. Here, we provide the genome sequence of the strain Pseudomonas brassicacearum 3Re2-7, formerly known as P. trivialis and P. reactans, elucidate its revised taxonomic classification, experimentally verify the gene predictions by transcriptome sequencing, describe its genetic biocontrol potential and contextualize it to other known Pseudomonas biocontrol agents. The P. brassicacearum 3Re2-7 genome comprises a circular chromosome with a size of 6,738,544 bp and a GC-content of 60.83%. 6267 genes were annotated, of which 6113 were shown to be transcribed in rich medium and/or in the presence of Rhizoctonia solani. Genome mining identified genes related to biocontrol traits such as secondary metabolite and siderophore biosynthesis, plant growth promotion, inorganic phosphate solubilization, biosynthesis of lipo- and exopolysaccharides, exoproteases, volatiles and detoxification. Core genome analysis revealed, that the 3Re2-7 genome exhibits a high collinearity with the representative genome for the species, P. brassicacearum subsp. brassicacearum NFM421. Comparative genomics allowed the identification of 105 specific genes and revealed gene clusters that might encode specialized biocontrol mechanisms of strain 3Re2-7. Moreover, we captured the transcriptome of P. brassicacearum 3Re2-7, confirming the transcription of the predicted biocontrol-related genes. The gene clusters coding for 2,4-diacetylphloroglucinol (phlABCDEFGH) and hydrogen cyanide (hcnABC) were shown to be highly transcribed. Further genes predicted to encode putative alginate production enzymes, a pyrroloquinoline quinone precursor peptide PqqA and a matrixin family metalloprotease were also found to be highly transcribed. With this study, we provide a basis to further characterize the mechanisms for biocontrol in Pseudomonas species, towards a sustainable and safe application of P. brassicacearum biocontrol agents.

The use of Bacillus spp. as bacterial biocontrol agents to control plant diseases

2021 ◽  
Author(s):  
Adrien Anckaert ◽  
◽  
Anthony Arguelles Arias ◽  
Grégory Hoff ◽  
Maryline Calonne-Salmon ◽  
...  
Keyword(s):  
Control Plant ◽  
Ecological Factors ◽  
Plant Growth Promoting Rhizobacteria ◽  
Plant Diseases ◽  
Biocontrol Agents ◽  
Systemic Resistance ◽  
Health Improvement ◽  
Wide Range ◽  
Bacillus Spp ◽  
Plant Growth Promoting

Biocontrol agents (BCAs) based on plant growth promoting rhizobacteria have recently been developed as alternatives to chemical pesticides. Among those beneficial bacteria, Bacillus spp. are one of the most promising BCAs. A wide range of bioactive secondary metabolites (BSMs) are involved in biocontrol via antibiosis to phytopathogens and/or via elicitation of systemic resistance in their host plants. This chapter illustrates the diversity of pathosystems in which BCA based on Bacillus spp. have proved effective. It describes the mechanisms underpinning this biocontrol activity via production of a wide range of enzymes, proteins and small-size BSMs. As these BSMs are clearly involved in pathogen control, we emphasise the importance of understanding the ecological factors influencing their production. In the last part of the chapter, we highlight the potential interactions between Bacillus spp. and other soil microorganisms in developing consortia of biocontrol agents combining species with synergistic activities for plant health improvement.

scholarly journals Mechanism of Plant Growth Promotion and Disease Suppression by Chitosan Biopolymer

Agriculture ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 624
Author(s):  
Moutoshi Chakraborty ◽  
Mirza Hasanuzzaman ◽  
Mahfuzur Rahman ◽  
Md. Arifur Rahman Khan ◽  
Pankaj Bhowmik ◽  
...  
Keyword(s):  
Plant Growth ◽  
Plant Pathogens ◽  
Growth Promotion ◽  
Defense Responses ◽  
Disease Suppression ◽  
Growth Promoter ◽  
Fungal Cell ◽  
Plant Growth Promoter ◽  
Chitosan Biopolymer ◽  
Division Cell

The chitosan (CHT) biopolymer is a de-acetylated chitin derivative that exists in the outer shell of shrimp, shellfish, lobster or crabs, as well as fungal cell walls. Because of its biodegradability, environmental non-toxicity, and biocompatibility, it is an ideal resource for sustainable agriculture. The CHT emerged as a promising agent used as a plant growth promoter and also as an antimicrobial agent. It induces plant growth by influencing plant physiological processes like nutrient uptake, cell division, cell elongation, enzymatic activation and synthesis of protein that can eventually lead to increased yield. It also acts as a catalyst to inhibit the growth of plant pathogens, and alter plant defense responses by triggering multiple useful metabolic pathways. This review emphasizes the role and mechanisms of CHT as a plant growth promoter and disease suppressor, and its future implications in agriculture.

scholarly journals Greenhouse Screening of Commercial Products Marketed as Systemic Resistance and Plant Growth Promotion Inducers

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 433-437 ◽  
Author(s):  
Charles S. Vavrina ◽  
Pamela D. Roberts ◽  
Nancy Kokalis-Burelle ◽  
Esa O. Ontermaa
Keyword(s):  
Plant Growth ◽  
Plant Growth Promotion ◽  
Xanthomonas Campestris ◽  
Growth Promotion ◽  
Disease Suppression ◽  
Systemic Resistance ◽  
Bacterial Suspension ◽  
Growth Enhancement ◽  
Bacterial Spot ◽  
Commercial Products

Six greenhouse trials of five commercial products marketed as systemic resistance (SR) and plant growth promotion (PGP) inducers were evaluated on tomato (Lycopersicon esculentum Mill.) over a 21-month period. The effect of the inducers on treated plants was measured by monitoring plant growth and disease suppression after inoculation with either plant pathogenic bacteria or nematodes. The commercially available SR/PGP inducers included a bacterial suspension [Companion (Bacillus subtilis GB03)], two plant defense elicitors with nutrients (Keyplex 350DP plus Nutri-Phite, and Rezist with Cab'y), natural plant extracts (Liquid Seaweed Concentrate and Stimplex), and a synthetic growth regulator (Actigard 50W). Growth enhancement was noted in some trials, but the parameter of growth affected often varied with trial. Response to Actigard treatment included significant suppression of bacterial spot [Xanthomonas campestris pv. vesicatoria (Xcv)] in three of the six trials. Companion, Keyplex 350DP plus Nutri-Phite, Rezist and Cab'y, and seaweed products induced only partial disease suppression of bacterial spot in inoculated tomato plants. The alpha-keto acids plus nutrients (Keyplex 350DP plus Nutri-Phite) increased plant growth by 14.3% and improved root condition compared to the untreated control following exposure to nematodes. Results are encouraging, if not consistent, and with a greater understanding of the SR system and the conditions related to product efficacy, such materials may become effective tools for production agriculture.

scholarly journals Comparison of Two Commercial Recirculated Aquacultural Systems and Their Microbial Potential in Plant Disease Suppression

2021 ◽  
Author(s):  
Sammar Khalil ◽  
Preeti Panda ◽  
Farideh Ghadamgahi ◽  
AnnaKarin Rosberg ◽  
Ramesh R Vetukuri
Keyword(s):  
Plant Growth ◽  
Fish Species ◽  
Plant Pathogens ◽  
Extracellular Enzymes ◽  
Growth Promotion ◽  
Sampling Site ◽  
Plant Diseases ◽  
Disease Suppression ◽  
Plant Health ◽  
Microbial Potential

Background: Aquaponics are food production systems advocated for food security and health. Their sustainability from a nutritional and plant health perspective is, however, a significant challenge. Recirculated aquaculture systems (RAS) form a major part of aquaponic systems, but knowledge about their potential to benefit plant growth and plant health is limited. The current study tested if the diversity and function of microbial communities in two commercial RAS were specific to the fish species used (Tilapia or Clarias) and sampling site (fish tanks and wastewaters), and whether they confer benefits to plants and have invitro antagonistic potential towards plant pathogens. Results: Microbial diversity and composition was found to be dependent on fish species and sample site. The Tilapia RAS hosted higher bacterial diversity than the Clarias RAS; but the latter hosted higher fungal diversity. Both Tilapia and Clarias RAS hosted bacterial and fungal communities that promoted plant growth, inhibited plant pathogens and encouraged biodegradation. The production of extracellular enzymes, related to nutrient availability and pathogen control, by bacterial strains isolated from the Tilapia and Clarias systems, makes them a promising tool in aquaponics and in their system design. Conclusions: This study explored the microbial potential of the commercial RAS with either Tilapia or Clarias as a tool to benefit the aquaponic system with respect to plant growth promotion and control of plant diseases.

scholarly journals Molecular Aspects of Plant Growth Promotion and Protection by Bacillus subtilis

2020 ◽  
pp. MPMI-08-20-0225
Author(s):  
Christopher Blake ◽  
Mathilde Nordgaard Christensen ◽  
Ákos T. Kovács
Keyword(s):  
Bacillus Subtilis ◽  
Plant Growth ◽  
Crop Production ◽  
Plant Pathogens ◽  
Current Knowledge ◽  
Growth Promotion ◽  
Bacterial Colonization ◽  
Control Plant ◽  
Microbial Interactions ◽  
Systemic Resistance

Bacillus subtilis is one of the most widely studied plant growth–promoting rhizobacteria. It is able to promote plant growth as well as control plant pathogens through diverse mechanisms, including the improvement of nutrient availability and alteration of phytohormone homeostasis as well as the production of antimicrobials and triggering induced systemic resistance, respectively. Even though its benefits for crop production have been recognized and studied extensively under laboratory conditions, the success of its application in fields varies immensely. It is widely accepted that agricultural application of B. subtilis often fails because the bacteria are not able to persist in the rhizosphere. Bacterial colonization of plant roots is a crucial step in the interaction between microbe and plant and seems, therefore, to be of great importance for its growth promotion and biocontrol effects. A successful root colonization depends thereby on both bacterial traits, motility and biofilm formation, as well as on a signal interplay with the plant. This review addresses current knowledge about plant-microbial interactions of the B. subtilis species, including the various mechanisms for supporting plant growth as well as the necessity for the establishment of the relationship.

Induced Systemic Resistance and Promotion of Plant Growth by Bacillus spp.

2004 ◽  
Vol 94 (11) ◽  
pp. 1259-1266 ◽  
Author(s):  
Joseph W. Kloepper ◽  
Choong-Min Ryu ◽  
Shouan Zhang
Keyword(s):  
Salicylic Acid ◽  
Plant Growth ◽  
Jasmonic Acid ◽  
Plant Growth Promotion ◽  
Fungal Pathogen ◽  
Induced Systemic Resistance ◽  
Growth Promotion ◽  
Systemic Resistance ◽  
Pseudomonas Spp ◽  
Bacillus Spp

Elicitation of induced systemic resistance (ISR) by plant-associated bacteria was initially demonstrated using Pseudomonas spp. and other gram-negative bacteria. Several reviews have summarized various aspects of the large volume of literature on Pseudomonas spp. as elicitors of ISR. Fewer published accounts of ISR by Bacillus spp. are available, and we review this literature for the first time. Published results are summarized showing that specific strains of the species B. amyloliquefaciens, B. subtilis, B. pasteurii, B. cereus, B. pumilus, B. mycoides, and B. sphaericus elicit significant reductions in the incidence or severity of various diseases on a diversity of hosts. Elicitation of ISR by these strains has been demonstrated in greenhouse or field trials on tomato, bell pepper, muskmelon, watermelon, sugar beet, tobacco, Arabidopsis sp., cucumber, loblolly pine, and two tropical crops (long cayenne pepper and green kuang futsoi). Protection resulting from ISR elicited by Bacillus spp. has been reported against leaf-spotting fungal and bacterial pathogens, systemic viruses, a crown-rotting fungal pathogen, root-knot nematodes, and a stem-blight fungal pathogen as well as damping-off, blue mold, and late blight diseases. Reductions in populations of three insect vectors have also been noted in the field: striped and spotted cucumber beetles that transmit cucurbit wilt disease and the silver leaf whitefly that transmits Tomato mottle virus. In most cases, Bacillus spp. that elicit ISR also elicit plant growth promotion. Studies on mechanisms indicate that elicitation of ISR by Bacillus spp. is associated with ultrastructural changes in plants during pathogen attack and with cytochemical alterations. Investigations into the signal transduction pathways of elicited plants suggest that Bacillus spp. activate some of the same pathways as Pseudomonas spp. and some additional pathways. For example, ISR elicited by several strains of Bacillus spp. is independent of salicylic acid but dependent on jasmonic acid, ethylene, and the regulatory gene NPR1—results that are in agreement with the model for ISR elicited by Pseudomonas spp. However, in other cases, ISR elicited by Bacillus spp. is dependent on salicylic acid and independent of jasmonic acid and NPR1. In addition, while ISR by Pseudomonas spp. does not lead to accumulation of the defense gene PR1 in plants, in some cases, ISR by Bacillus spp. does. Based on the strains and results summarized in this review, two products for commercial agriculture have been developed, one aimed mainly at plant growth promotion for transplanted vegetables and one, which has received registration from the U.S. Environmental Protection Agency, for disease protection on soybean.

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