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Gerlicz W, Sypka M, Jodłowska I, Białkowska AM. Isolation, Selection, and Identification of Keratinolytic Bacteria for Green Management of Keratin Waste. Molecules 2024; 29:3380. [PMID: 39064958 PMCID: PMC11280386 DOI: 10.3390/molecules29143380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/11/2024] [Accepted: 07/16/2024] [Indexed: 07/28/2024] Open
Abstract
The volume of difficult-to-process keratin waste is increasing as a result of rising global meat production. If not properly managed, this waste can contribute to environmental pollution and pose a threat to human and animal welfare. An interesting and more sustainable alternative is therefore the bioconversion of keratin using microorganisms and their enzymes. This work aimed to isolate bacteria from soil samples and zoonotic keratins and to evaluate their enzymatic capacity to degrade α- and β-keratin wastes. A total of 113 bacterial strains were isolated from environmental samples and subjected to taxonomic identification using the MALDI-TOF MS technique and to a two-step screening for proteolytic and keratinolytic activity. The ability to degrade a β-rich keratin substrate was observed in almost all of the strains isolated from soil and horsehairs. In contrast, when an α-rich keratin substrate was used, the highest levels of hydrolysis were observed only for Ker39, Ker66, Ker85, Ker100, and Ker101. Strains with the highest biodegradation potential were identified using molecular biology methods. Phylogenetic analysis of 16S rDNA gene sequences allowed the assignment of selected keratinolytic microorganisms to the genera Exiguobacterium, Priestia, Curtobacterium, Stenotrophomonas, Bacillus, Kocuria, or Pseudomonas. The results of this study are a promising precursor for the development of new, more sustainable methods of managing keratin waste to produce high-value hydrolysates.
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Affiliation(s)
| | | | | | - Aneta M. Białkowska
- Institute of Molecular and Industrial Biotechnology, Faculty of Biotechnology and Food Sciences, Lodz University of Technology, 90-537 Lodz, Poland; (W.G.); (M.S.); (I.J.)
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Liu Q, Zhao W, Li W, Zhang F, Wang Y, Wang J, Gao Y, Liu H, Zhang L. Lipopeptides from Bacillus velezensis ZLP-101 and their mode of action against bean aphids Acyrthosiphon pisum Harris. BMC Microbiol 2024; 24:231. [PMID: 38951812 PMCID: PMC11218388 DOI: 10.1186/s12866-024-03378-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 06/17/2024] [Indexed: 07/03/2024] Open
Abstract
BACKGROUND Natural products are important sources for the discovery of new biopesticides to control the worldwide destructive pests Acyrthosiphon pisum Harris. Here, insecticidal substances were discovered and characterized from the secondary metabolites of the bio-control microorganism Bacillus velezensis strain ZLP-101, as informed by whole-genome sequencing and analysis. RESULTS The genome was annotated, revealing the presence of four potentially novel gene clusters and eight known secondary metabolite synthetic gene clusters. Crude extracts, prepared through ammonium sulfate precipitation, were used to evaluate the effects of strain ZLP-101 on Acyrthosiphon pisum Harris aphid pests via exposure experiments. The half lethal concentration (LC50) of the crude extract from strain ZLP-101 against aphids was 411.535 mg/L. Preliminary exploration of the insecticidal mechanism revealed that the crude extract affected aphids to a greater extent through gastric poisoning than through contact. Further, the extracts affected enzymatic activities, causing holes to form in internal organs along with deformation, such that normal physiological activities could not be maintained, eventually leading to death. Isolation and purification of extracellular secondary metabolites were conducted in combination with mass spectrometry analysis to further identify the insecticidal components of the crude extracts. A total of 15 insecticidal active compounds were identified including iturins, fengycins, surfactins, and spergualins. Further insecticidal experimentation revealed that surfactin, iturin, and fengycin all exhibited certain aphidicidal activities, and the three exerted synergistic lethal effects. CONCLUSIONS This study improved the available genomic resources for B. velezensis and serves as a foundation for comprehensive studies of the insecticidal mechanism by Bacillus velezensis ZLP-101 in addition to the active components within biological control strains.
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Affiliation(s)
- Qiuyue Liu
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China
- Hebei Normal University, Shijiazhuang, 050024, PR China
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China
| | - Wenya Zhao
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China
| | - Wenya Li
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China
| | - Feiyan Zhang
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China
| | - Yana Wang
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China
| | - Jiangping Wang
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China
- Hebei Normal University, Shijiazhuang, 050024, PR China
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China
| | - Yumeng Gao
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China
- Hebei Normal University, Shijiazhuang, 050024, PR China
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China
| | - Hongwei Liu
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China.
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China.
| | - Liping Zhang
- Institute of Biology, Hebei Academy of Science, Shijiazhuang, 050081, PR China.
- Main Crops Disease of Microbial Control Engineering Technology Research Center in Hebei Province, Shijiazhuang, 050081, PR China.
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González-León Y, De la Vega-Camarillo E, Ramírez-Vargas R, Anducho-Reyes MA, Mercado-Flores Y. Whole genome analysis of Bacillus velezensis 160, biological control agent of corn head smut. Microbiol Spectr 2024; 12:e0326423. [PMID: 38363138 PMCID: PMC10986511 DOI: 10.1128/spectrum.03264-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/18/2024] [Indexed: 02/17/2024] Open
Abstract
Corn head smut is a disease caused by the fungus Sporisorium reilianum. This phytosanitary problem has existed for several decades in the Mezquital Valley, an important corn-producing area in central Mexico. To combat the problem, a strain identified as Bacillus subtilis 160 was applied in the field, where it decreased disease incidence and increased crop productivity. In this study, the sequencing and analysis of the whole genome sequence of this strain were carried out to identify its genetic determinants for the production of antimicrobials. The B. subtilis 160 strain was found to be Bacillus velezensis. Its genome has a size of 4,297,348 bp, a GC content of 45.8%, and 4,174 coding sequences. Comparative analysis with the genomes of four other B. velezensis strains showed that they share 2,804 genes and clusters for the production of difficidin, bacillibactin, bacilysin, macrolantin, bacillaene, fengycin, butirosin A, locillomycin, and surfactin. For the latter metabolite, unlike the other strains that have only one cluster, B. velezensis 160 has three. A cluster for synthesizing laterocidine, an antimicrobial reported only in Brevibacillus laterosporus, was also identified. IMPORTANCE In this study, we performed sequencing and analysis of the complete genome of the strain initially identified as Bacillus subtilis 160 as part of its characterization. This bacterium has shown its ability to control corn head smut in the field, a disease caused by the basidiomycete fungus Sporisorium reilianum. Analyzing the complete genome sequence not only provides a more precise taxonomic identification but also sheds light on the genetic potential of this bacterium, especially regarding mechanisms that allow it to exert biological control. Employing molecular and bioinformatics tools in studying the genomes of agriculturally significant microorganisms offers insights into the development of biofungicides and bioinoculants. These innovations aim to enhance plant growth and pave the way for strategies that boost crop productivity.
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Ansari M, Devi BM, Sarkar A, Chattopadhyay A, Satnami L, Balu P, Choudhary M, Shahid MA, Jailani AAK. Microbial Exudates as Biostimulants: Role in Plant Growth Promotion and Stress Mitigation. J Xenobiot 2023; 13:572-603. [PMID: 37873814 PMCID: PMC10594471 DOI: 10.3390/jox13040037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/18/2023] [Accepted: 09/21/2023] [Indexed: 10/25/2023] Open
Abstract
Microbes hold immense potential, based on the fact that they are widely acknowledged for their role in mitigating the detrimental impacts of chemical fertilizers and pesticides, which were extensively employed during the Green Revolution era. The consequence of this extensive use has been the degradation of agricultural land, soil health and fertility deterioration, and a decline in crop quality. Despite the existence of environmentally friendly and sustainable alternatives, microbial bioinoculants encounter numerous challenges in real-world agricultural settings. These challenges include harsh environmental conditions like unfavorable soil pH, temperature extremes, and nutrient imbalances, as well as stiff competition with native microbial species and host plant specificity. Moreover, obstacles spanning from large-scale production to commercialization persist. Therefore, substantial efforts are underway to identify superior solutions that can foster a sustainable and eco-conscious agricultural system. In this context, attention has shifted towards the utilization of cell-free microbial exudates as opposed to traditional microbial inoculants. Microbial exudates refer to the diverse array of cellular metabolites secreted by microbial cells. These metabolites enclose a wide range of chemical compounds, including sugars, organic acids, amino acids, peptides, siderophores, volatiles, and more. The composition and function of these compounds in exudates can vary considerably, depending on the specific microbial strains and prevailing environmental conditions. Remarkably, they possess the capability to modulate and influence various plant physiological processes, thereby inducing tolerance to both biotic and abiotic stresses. Furthermore, these exudates facilitate plant growth and aid in the remediation of environmental pollutants such as chemicals and heavy metals in agroecosystems. Much like live microbes, when applied, these exudates actively participate in the phyllosphere and rhizosphere, engaging in continuous interactions with plants and plant-associated microbes. Consequently, they play a pivotal role in reshaping the microbiome. The biostimulant properties exhibited by these exudates position them as promising biological components for fostering cleaner and more sustainable agricultural systems.
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Affiliation(s)
- Mariya Ansari
- Department of Mycology and Plant Pathology, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India; (M.A.); (A.S.); (L.S.)
| | - B. Megala Devi
- Department of Environmental Biotechnology, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India;
| | - Ankita Sarkar
- Department of Mycology and Plant Pathology, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India; (M.A.); (A.S.); (L.S.)
| | - Anirudha Chattopadhyay
- Pulses Research Station, S.D. Agricultural University, Sardarkrushinagar 385506, Gujarat, India;
| | - Lovkush Satnami
- Department of Mycology and Plant Pathology, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India; (M.A.); (A.S.); (L.S.)
| | - Pooraniammal Balu
- Department of Biotechnology, Sastra Deemed University, Thanjavur 613401, Tamil Nadu, India;
| | - Manoj Choudhary
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA;
| | - Muhammad Adnan Shahid
- Horticultural Science Department, North Florida Research and Education Center, University of Florida/IFAS, Quincy, FL 32351, USA;
| | - A. Abdul Kader Jailani
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA;
- Plant Pathology Department, North Florida Research and Education Center, University of Florida, Quincy, FL 32351, USA
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Iqbal S, Qasim M, Rahman H, Khan N, Paracha RZ, Bhatti MF, Javed A, Janjua HA. Genome mining, antimicrobial and plant growth-promoting potentials of halotolerant Bacillus paralicheniformis ES-1 isolated from salt mine. Mol Genet Genomics 2023; 298:79-93. [PMID: 36301366 DOI: 10.1007/s00438-022-01964-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/11/2022] [Indexed: 01/10/2023]
Abstract
Salinity severely affects crop yield by hindering nitrogen uptake and reducing plant growth. Plant growth-promoting bacteria (PGPB) are capable of providing cross-protection against biotic/abiotic stresses and facilitating plant growth. Genome-level knowledge of PGPB is necessary to translate the knowledge into a product as efficient biofertilizers and biocontrol agents. The current study aimed to isolate and characterize indigenous plant growth-promoting strains with the potential to promote plant growth under various stress conditions. In this regard, 72 bacterial strains were isolated from various saline-sodic soil/lakes; 19 exhibited multiple in vitro plant growth-promoting traits, including indole 3 acetic acid production, phosphate solubilization, siderophore synthesis, lytic enzymes production, biofilm formation, and antibacterial activities. To get an in-depth insight into genome composition and diversity, whole-genome sequence and genome mining of one promising Bacillus paralicheniformis strain ES-1 were performed. The strain ES-1 genome carries 12 biosynthetic gene clusters, at least six genomic islands, and four prophage regions. Genome mining identified plant growth-promoting conferring genes such as phosphate solubilization, nitrogen fixation, tryptophan production, siderophore, acetoin, butanediol, chitinase, hydrogen sulfate synthesis, chemotaxis, and motility. Comparative genome analysis indicates the region of genome plasticity which shapes the structure and function of B. paralicheniformis and plays a crucial role in habitat adaptation. The strain ES-1 has a relatively large accessory genome of 649 genes (~ 19%) and 180 unique genes. Overall, these results provide valuable insight into the bioactivity and genomic insight into B. paralicheniformis strain ES-1 with its potential use in sustainable agriculture.
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Affiliation(s)
- Sajid Iqbal
- Department of Industrial Biotechnology, Atta-Ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Muhammad Qasim
- Department of Microbiology, Kohat University of Science and Technology (KUST), Kohat, Pakistan
| | - Hazir Rahman
- Department of Microbiology, Abdul Wali Khan University Mardan (AWKUM), Mardan, Pakistan
| | - Naeem Khan
- Department of Agronomy, University of Florida, Gainesville, FL, 32611, USA
| | - Rehan Zafar Paracha
- School of Interdisciplinary Engineering and Science (SINES, National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Muhammad Faraz Bhatti
- Department of Plant Biotechnology, Atta-Ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Aneela Javed
- Department of Healthcare Biotechnology, Atta-Ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan
| | - Hussnain Ahmed Janjua
- Department of Industrial Biotechnology, Atta-Ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12, Islamabad, Pakistan.
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Diwan D, Rashid MM, Vaishnav A. Current understanding of plant-microbe interaction through the lenses of multi-omics approaches and their benefits in sustainable agriculture. Microbiol Res 2022; 265:127180. [PMID: 36126490 DOI: 10.1016/j.micres.2022.127180] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 08/26/2022] [Accepted: 08/27/2022] [Indexed: 11/28/2022]
Abstract
The success of sustainable agricultural practices has now become heavily dependent on the interactions between crop plants and their associated microbiome. Continuous advancement in high throughput sequencing platforms, omics-based approaches, and gene editing technologies has remarkably accelerated this area of research. It has enabled us to characterize the interactions of plants with associated microbial communities more comprehensively and accurately. Furthermore, the genomic and post-genomic era has significantly refined our perspective toward the complex mechanisms involved in those interactions, opening new avenues for efficiently deploying the knowledge in developing sustainable agricultural practices. This review focuses on our fundamental understanding of plant-microbe interactions and the contribution of existing multi-omics approaches, including those under active development and their tremendous success in unraveling different aspects of the complex network between plant hosts and microbes. In addition, we have also discussed the importance of sustainable and eco-friendly agriculture and the associated outstanding challenges ahead.
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Affiliation(s)
- Deepti Diwan
- Washington University School of Medicine, Saint Louis, MO 63110, USA.
| | - Md Mahtab Rashid
- Department of Plant Pathology, Bihar Agricultural University, Sabour, Bhagalpur, Bihar 813210, India; Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh 221005, India
| | - Anukool Vaishnav
- Department of Biotechnology, GLA University, Mathura, Uttar Pradesh 281121, India; Department of Plant and Microbial Biology, University of Zürich, Zollikerstrasse 107, Zürich CH-8008, Switzerland; Plant-Soil Interaction Group, Agroscope (Reckenholz), Reckenholzstrasse 191, Zürich 8046, Switzerland
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7
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Liang L, Fu Y, Deng S, Wu Y, Gao M. Genomic, Antimicrobial, and Aphicidal Traits of Bacillus velezensis ATR2, and Its Biocontrol Potential against Ginger Rhizome Rot Disease Caused by Bacillus pumilus. Microorganisms 2021; 10:63. [PMID: 35056513 PMCID: PMC8778260 DOI: 10.3390/microorganisms10010063] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/10/2021] [Accepted: 12/23/2021] [Indexed: 11/27/2022] Open
Abstract
Ginger rhizome rot disease, caused by the pathogen Bacilluspumilus GR8, could result in severe rot of ginger rhizomes and heavily threaten ginger production. In this study, we identified and characterized a new Bacillus velezensis strain, designated ATR2. Genome analysis revealed B. velezensis ATR2 harbored a series of genes closely related to promoting plant growth and triggering plant immunity. Meanwhile, ten gene clusters involved in the biosynthesis of various secondary metabolites (surfactin, bacillomycin, fengycin, bacillibactin, bacilysin, difficidin, macrolactin, bacillaene, plantazolicin, and amylocyclicin) and two clusters encoding a putative lipopeptide and a putative phosphonate which might be explored as novel bioactive compounds were also present in the ATR2 genome. Moreover, B. velezensis ATR2 showed excellent antagonistic activities against multiple plant pathogenic bacteria, plant pathogenic fungi, human pathogenic bacteria, and human pathogenic fungus. B. velezensis ATR2 was also efficacious in control of aphids. The antagonistic compound from B. velezensis ATR2 against B.pumilus GR8 was purified and identified as bacillomycin D. In addition, B. velezensis ATR2 exhibited excellent biocontrol efficacy against ginger rhizome rot disease on ginger slices. These findings showed the potential of further applications of B. velezensis ATR2 as a biocontrol agent in agricultural diseases and pests management.
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Affiliation(s)
- Leiqin Liang
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (L.L.); (Y.F.); (S.D.); (Y.W.)
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Yajuan Fu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (L.L.); (Y.F.); (S.D.); (Y.W.)
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Sangsang Deng
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (L.L.); (Y.F.); (S.D.); (Y.W.)
- University of Chinese Academy of Sciences, Beijing 100039, China
| | - Yan Wu
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (L.L.); (Y.F.); (S.D.); (Y.W.)
| | - Meiying Gao
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China; (L.L.); (Y.F.); (S.D.); (Y.W.)
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Diale MO, Kayitesi E, Serepa-Dlamini MH. Genome In Silico and In Vitro Analysis of the Probiotic Properties of a Bacterial Endophyte, Bacillus Paranthracis Strain MHSD3. Front Genet 2021; 12:672149. [PMID: 34858466 PMCID: PMC8631869 DOI: 10.3389/fgene.2021.672149] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 10/11/2021] [Indexed: 01/25/2023] Open
Abstract
Spore-forming Bacillus species are gaining interest in human health recently, due to their ability to withstand the harsh environment of the gastrointestinal tract. The present study explores probiotic features of Bacillus paranthracis strain MHSD3 through genomic analysis and in vitro probiotic assays. The draft genome of strain MHSD3 contained genes associated with tolerance to gastrointestinal stress and adhesion. Cluster genes responsible for the synthesis of antimicrobial non-ribosomal peptide synthetases, bacteriocins, and linear azole-containing peptides were identified. Additionally, strain MHSD3 was able to survive in an acidic environment, had the tolerance to bile salt, and exhibited the capability to tolerate gastric juices. Moreover, the isolate was found to possess strong cell surface traits such as high auto-aggregation and hydrophobicity indices of 79 and 54%, respectively. Gas chromatography-mass spectrometry analysis showed that the strain produced secondary metabolites such as amino acids, phenolic compounds, and organic acid, known to exert health-promoting properties, including the improvement of gastrointestinal tract health.
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Affiliation(s)
- Mamonokane Olga Diale
- Department of Biotechnology and Food Technology, University of Johannesburg, Johannesburg, South Africa
| | - Eugenie Kayitesi
- Department of Consumer and Food Science, University of Pretoria, Pretoria, South Africa
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Horak I, Jansen van Rensburg PJ, Claassens S. Effect of cultivation media and temperature on metabolite profiles of three nematicidal Bacillus species. NEMATOLOGY 2021. [DOI: 10.1163/15685411-bja10137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Summary
Globally, root-knot nematode (RKN) infestations cause great financial losses. Although agrochemicals are used to manage these pests, there is increased interest in using biocontrol agents based on natural antagonistic microorganisms, such as Bacillus. These nematicidal bacteria demonstrate antagonism towards RKN through different modes of action, including specialised metabolite production. The aim of this study was to compare metabolite profiles of nematicidal Bacillus species and assess the influence of cultivation conditions on these profiles. Two hyphenated metabolomics platforms, gas chromatography-mass spectrometry (GC-MS) and liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), were employed to profile and compare metabolite features produced during the cultivation of three nematicidal Bacillus species (Bacillus firmus, B. cereus and B. soli) in complex Luria-Bertani broth (LB) and a simpler minimal broth (MB), at three different temperatures (25, 30 and 37°C). Cultivation in complex LB as opposed to simpler MB resulted in the production of more statistically significant metabolite features. Selected temperatures in this study did not have a significant influence on metabolite profiles. Moreover, media-specific influences outweighed temperature-specific influences on metabolite profiles. Results from this study are a valuable first step in establishing suitable cultivation conditions for the production of Bacillus metabolites of interest.
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Affiliation(s)
- Ilzé Horak
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2520, South Africa
| | | | - Sarina Claassens
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2520, South Africa
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From Genome to Field-Observation of the Multimodal Nematicidal and Plant Growth-Promoting Effects of Bacillus firmus I-1582 on Tomatoes Using Hyperspectral Remote Sensing. PLANTS 2020; 9:plants9050592. [PMID: 32384661 PMCID: PMC7285481 DOI: 10.3390/plants9050592] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/20/2020] [Accepted: 04/29/2020] [Indexed: 12/26/2022]
Abstract
Root-knot nematodes are considered the most important group of plant-parasitic nematodes due to their wide range of plant hosts and subsequent role in yield losses in agricultural production systems. Chemical nematicides are the primary control method, but ecotoxicity issues with some compounds has led to their phasing-out and consequential development of new control strategies, including biological control. We evaluated the nematicidal activity of Bacillus firmus I-1582 in pot and microplot experiments against Meloidogyne luci. I-1582 reduced nematode counts by 51% and 53% compared to the untreated control in pot and microplot experiments, respectively. I-1582 presence in the rhizosphere had concurrent nematicidal and plant growth-promoting effects, measured using plant morphology, relative chlorophyll content, elemental composition and hyperspectral imaging. Hyperspectral imaging in the 400–2500 nm spectral range and supervised classification using partial least squares support vector machines successfully differentiated B. firmus-treated and untreated plants, with 97.4% and 96.3% accuracy in pot and microplot experiments, respectively. Visible and shortwave infrared spectral regions associated with chlorophyll, N–H and C–N stretches in proteins were most relevant for treatment discrimination. This study shows the ability of hyperspectral imaging to rapidly assess the success of biological measures for pest control.
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