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Zhang Y, Li Z, Wei S, Xu C, Chen M, Sang J, Han Y, Yan H, Li Z, Cui Z, Ye X. Antifungal Activity and Mechanisms of 2-Ethylhexanol, a Volatile Organic Compound Produced by Stenotrophomonas sp. NAU1697, against Fusarium oxysporum f. sp. cucumerinum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:15213-15227. [PMID: 38916250 DOI: 10.1021/acs.jafc.3c09851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Researchers often consider microorganisms from Stenotrophomonas sp. to be beneficial for plants. In this study, the biocidal effects and action mechanisms of volatile organic compounds (VOCs) produced by Stenotrophomonas sp. NAU1697 were investigated. The mycelial growth and spore germination of Fusarium oxysporum f. sp. cucumerinum (FOC), which is a pathogen responsible for cucumber wilt disease, were significantly inhibited by VOCs emitted from NAU1697. Among the VOCs, 33 were identified, 11 of which were investigated for their antifungal properties. Among the tested compounds, 2-ethylhexanol exhibited the highest antifungal activity toward FOC, with a minimum inhibitory volume (MIV) of 3.0 μL/plate (equal to 35.7 mg/L). Damage to the hyphal cell wall and cell membrane integrity caused a decrease in the ergosterol content and a burst of reactive oxygen species (ROS) after 2-ethylhexanol treatment. DNA damage, which is indicative of apoptosis-like cell death, was monitored in 2-ethylhexanol-treated FOC cells by using micro-FTIR analysis. Furthermore, the activities of mitochondrial dehydrogenases and mitochondrial respiratory chain complex III in 2-ethylhexanol-treated FOC cells were significantly decreased. The transcription levels of genes associated with redox reactions and the cell wall integrity (CWI) pathway were significantly upregulated, thus indicating that stress was caused by 2-ethylhexanol. The findings of this research provide a new avenue for the sustainable management of soil-borne plant fungal diseases.
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Affiliation(s)
- Yu Zhang
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Zeyuan Li
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Shuxin Wei
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Changsheng Xu
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Minhua Chen
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Jierong Sang
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Yiru Han
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Huang Yan
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhoukun Li
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhongli Cui
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
| | - Xianfeng Ye
- Key Laboratory of Agricultural Environmental Microbiology of Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China
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Lu X, Dai Z, Xue J, Li W, Ni P, Xu J, Zhou C, Zhang W. Discovery of novel RNA viruses through analysis of fungi-associated next-generation sequencing data. BMC Genomics 2024; 25:517. [PMID: 38797853 PMCID: PMC11129472 DOI: 10.1186/s12864-024-10432-w] [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: 03/19/2024] [Accepted: 05/20/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND Like all other species, fungi are susceptible to infection by viruses. The diversity of fungal viruses has been rapidly expanding in recent years due to the availability of advanced sequencing technologies. However, compared to other virome studies, the research on fungi-associated viruses remains limited. RESULTS In this study, we downloaded and analyzed over 200 public datasets from approximately 40 different Bioprojects to explore potential fungal-associated viral dark matter. A total of 12 novel viral sequences were identified, all of which are RNA viruses, with lengths ranging from 1,769 to 9,516 nucleotides. The amino acid sequence identity of all these viruses with any known virus is below 70%. Through phylogenetic analysis, these RNA viruses were classified into different orders or families, such as Mitoviridae, Benyviridae, Botourmiaviridae, Deltaflexiviridae, Mymonaviridae, Bunyavirales, and Partitiviridae. It is possible that these sequences represent new taxa at the level of family, genus, or species. Furthermore, a co-evolution analysis indicated that the evolutionary history of these viruses within their groups is largely driven by cross-species transmission events. CONCLUSIONS These findings are of significant importance for understanding the diversity, evolution, and relationships between genome structure and function of fungal viruses. However, further investigation is needed to study their interactions.
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Affiliation(s)
- Xiang Lu
- Institute of Critical Care Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, 212002, China
- Department of Microbiology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Ziyuan Dai
- Department of Clinical Laboratory, Affiliated Hospital 6 of Nantong University, Yancheng Third People's Hospital, Yancheng, Jiangsu, China
| | - Jiaxin Xue
- Department of Microbiology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Wang Li
- Clinical Laboratory Center, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou, 225300, China
| | - Ping Ni
- Clinical Laboratory Center, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou, 225300, China
| | - Juan Xu
- Clinical Laboratory Center, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou, 225300, China.
| | - Chenglin Zhou
- Clinical Laboratory Center, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou, 225300, China.
| | - Wen Zhang
- Institute of Critical Care Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, 212002, China.
- Department of Microbiology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China.
- Clinical Laboratory Center, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou, 225300, China.
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Saadaoui M, Faize M, Rifai A, Tayeb K, Omri Ben Youssef N, Kharrat M, Roeckel-Drevet P, Chaar H, Venisse JS. Evaluation of Tunisian wheat endophytes as plant growth promoting bacteria and biological control agents against Fusarium culmorum. PLoS One 2024; 19:e0300791. [PMID: 38758965 PMCID: PMC11101125 DOI: 10.1371/journal.pone.0300791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/05/2024] [Indexed: 05/19/2024] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) applications have emerged as an ideal substitute for synthetic chemicals by their ability to improve plant nutrition and resistance against pathogens. In this study, we isolated fourteen root endophytes from healthy wheat roots cultivated in Tunisia. The isolates were identified based from their 16S rRNA gene sequences. They belonged to Bacillota and Pseudomonadota taxa. Fourteen strains were tested for their growth-promoting and defense-eliciting potentials on durum wheat under greenhouse conditions, and for their in vitro biocontrol power against Fusarium culmorum, an ascomycete responsible for seedling blight, foot and root rot, and head blight diseases of wheat. We found that all the strains improved shoot and/or root biomass accumulation, with Bacillus mojavensis, Paenibacillus peoriae and Variovorax paradoxus showing the strongest promoting effects. These physiological effects were correlated with the plant growth-promoting traits of the bacterial endophytes, which produced indole-related compounds, ammonia, and hydrogen cyanide (HCN), and solubilized phosphate and zinc. Likewise, plant defense accumulations were modulated lastingly and systematically in roots and leaves by all the strains. Testing in vitro antagonism against F. culmorum revealed an inhibition activity exceeding 40% for five strains: Bacillus cereus, Paenibacillus peoriae, Paenibacillus polymyxa, Pantoae agglomerans, and Pseudomonas aeruginosa. These strains exhibited significant inhibitory effects on F. culmorum mycelia growth, sporulation, and/or macroconidia germination. P. peoriae performed best, with total inhibition of sporulation and macroconidia germination. These finding highlight the effectiveness of root bacterial endophytes in promoting plant growth and resistance, and in controlling phytopathogens such as F. culmorum. This is the first report identifying 14 bacterial candidates as potential agents for the control of F. culmorum, of which Paenibacillus peoriae and/or its intracellular metabolites have potential for development as biopesticides.
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Affiliation(s)
- Mouadh Saadaoui
- Université Clermont Auvergne, INRAE, PIAF, Clermont-Ferrand, France
- Université de Tunis El Manar, Campus Universitaire Farhat Hached, Tunis, Tunisia
- Field Crops Laboratory, National Institute for Agricultural Research of Tunisia, Tunisia, Tunisia
| | - Mohamed Faize
- Laboratory of Plant Biotechnology, Ecology and Ecosystem Valorization CNRST-URL10, Faculty of Sciences, University Chouaib Doukkali, El Jadida, Morocco
| | - Aicha Rifai
- Laboratory of Plant Biotechnology, Ecology and Ecosystem Valorization CNRST-URL10, Faculty of Sciences, University Chouaib Doukkali, El Jadida, Morocco
| | - Koussa Tayeb
- Laboratory of Plant Biotechnology, Ecology and Ecosystem Valorization CNRST-URL10, Faculty of Sciences, University Chouaib Doukkali, El Jadida, Morocco
| | - Noura Omri Ben Youssef
- Field Crops Laboratory, National Institute for Agricultural Research of Tunisia, Tunisia, Tunisia
- National Institute of Agronomy of Tunisia, Tunis, Tunisia
| | - Mohamed Kharrat
- Field Crops Laboratory, National Institute for Agricultural Research of Tunisia, Tunisia, Tunisia
| | | | - Hatem Chaar
- Field Crops Laboratory, National Institute for Agricultural Research of Tunisia, Tunisia, Tunisia
- National Institute of Agronomy of Tunisia, Tunis, Tunisia
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Rana A, Sudakov K, Carmeli S, Miyara SB, Bucki P, Minz D. Volatile organic compounds of the soil bacterium Bacillus halotolerans suppress pathogens and elicit defense-responsive genes in plants. Microbiol Res 2024; 281:127611. [PMID: 38228018 DOI: 10.1016/j.micres.2024.127611] [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: 10/22/2023] [Revised: 01/07/2024] [Accepted: 01/09/2024] [Indexed: 01/18/2024]
Abstract
Volatile organic compounds (VOCs) produced by bacteria play an important, yet relatively unexplored role in interactions between plants and phytopathogens. In this study, the soil bacterium Bacillus halotolerans NYG5 was identified as a potent biocontrol agent against several phytopathogenic fungi (Macrophomina phaseolina, Rhizoctonia solani, Pythium aphanidermatum, and Sclerotinia sclerotiorum) through the production of VOCs. NYG5-emitted VOCs also inhibited the growth of bacterial pathogens (Agrobacterium tumefaciens, Xanthomonas campestris, Clavibacter michiganensis, and Pseudomonas syringae). When cultured in various growth media, NYG5 produced a variety of VOCs. Five distinct VOCs (2-methylbutanoic acid, 5-methyl-2-hexanone, 2,3-hexanedione, 2-ethyl-1-hexanol, and 6-methyl-2-heptanone) were identified using headspace GC-MS. 2,3-Hexanedione exhibited potent lethal effects on the tested phytopathogens and nematicidal activity against Meloidogyne javanica at a concentration of 50 ppm. In addition, 0.05 ppm 2,3-hexanedione stimulated the expression of pathogenesis-related genes 1 and 2 in Arabidopsis thaliana. Interestingly, 2,3-hexanedione is used as a food additive at higher concentrations than those tested in this study. Hence, 2,3-hexanedione is a promising biologically active compound that might serve as a sustainable alternative to common chemical pesticides and an elicitor of plant defense.
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Affiliation(s)
- Anuj Rana
- Department of Soil Chemistry, Plant Nutrition and Microbiology, Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel; Department of Microbiology, College of Basic Science and Humanities, Chaudhary Charan Singh Haryana Agricultural University, Hisar, India
| | - Kobi Sudakov
- Department of Soil Chemistry, Plant Nutrition and Microbiology, Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel; Department of Agroecology and Plant Health, Robert H. Smith Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Israel
| | - Shmuel Carmeli
- School of Chemistry, Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Sigal Brown Miyara
- Institute of Plant Protection, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Patricia Bucki
- Institute of Plant Protection, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Dror Minz
- Department of Soil Chemistry, Plant Nutrition and Microbiology, Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel.
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Rabiço F, Borelli TC, Alnoch RC, Polizeli MDLTDM, da Silva RR, Silva-Rocha R, Guazzaroni ME. Novel Pseudomonas Species Prevent the Growth of the Phytopathogenic Fungus Aspergillus flavus. BIOTECH 2024; 13:8. [PMID: 38651488 PMCID: PMC11036216 DOI: 10.3390/biotech13020008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 03/21/2024] [Accepted: 03/27/2024] [Indexed: 04/25/2024] Open
Abstract
In response to the escalating demand for sustainable agricultural methodologies, the utilization of microbial volatile organic compounds (VOCs) as antagonists against phytopathogens has emerged as a viable eco-friendly alternative. Microbial volatiles exhibit rapid diffusion rates, facilitating prompt chemical interactions. Moreover, microorganisms possess the capacity to emit volatiles constitutively, as well as in response to biological interactions and environmental stimuli. In addition to volatile compounds, these bacteria demonstrate the ability to produce soluble metabolites with antifungal properties, such as APE Vf, pyoverdin, and fragin. In this study, we identified two Pseudomonas strains (BJa3 and MCal1) capable of inhibiting the in vitro mycelial growth of the phytopathogenic fungus Aspergillus flavus, which serves as the causal agent of diseases in sugarcane and maize. Utilizing GC/MS analysis, we detected 47 distinct VOCs which were produced by these bacterial strains. Notably, certain volatile compounds, including 1-heptoxydecane and tridecan-2-one, emerged as primary candidates for inhibiting fungal growth. These compounds belong to essential chemical classes previously documented for their antifungal activity, while others represent novel molecules. Furthermore, examination via confocal microscopy unveiled significant morphological alterations, particularly in the cell wall, of mycelia exposed to VOCs emitted by both Pseudomonas species. These findings underscore the potential of the identified BJa3 and MCal1 Pseudomonas strains as promising agents for fungal biocontrol in agricultural crops.
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Affiliation(s)
- Franciene Rabiço
- Department of Cell and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3.900, Ribeirão Preto 14040-901, SP, Brazil; (F.R.); (T.C.B.)
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3.900, Ribeirão Preto 14040-901, SP, Brazil; (R.C.A.); (M.d.L.T.d.M.P.)
| | - Tiago Cabral Borelli
- Department of Cell and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3.900, Ribeirão Preto 14040-901, SP, Brazil; (F.R.); (T.C.B.)
- Department of Biomolecular Sciences, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3.900, Ribeirão Preto 14040-901, SP, Brazil;
| | - Robson Carlos Alnoch
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3.900, Ribeirão Preto 14040-901, SP, Brazil; (R.C.A.); (M.d.L.T.d.M.P.)
| | - Maria de Lourdes Teixeira de Moraes Polizeli
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3.900, Ribeirão Preto 14040-901, SP, Brazil; (R.C.A.); (M.d.L.T.d.M.P.)
| | - Ricardo R. da Silva
- Department of Biomolecular Sciences, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3.900, Ribeirão Preto 14040-901, SP, Brazil;
| | - Rafael Silva-Rocha
- ByMyCell Inova Simples, Av. Dra. Nadir Aguiar, 1805, Ribeirão Preto 14056-680, SP, Brazil;
| | - María-Eugenia Guazzaroni
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Av. Bandeirantes, 3.900, Ribeirão Preto 14040-901, SP, Brazil; (R.C.A.); (M.d.L.T.d.M.P.)
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Wei S, Zhang Y, Wu M, Lv Y, Zhang S, Zhai H, Hu Y. Mechanisms of methyl 2-methylbutyrate suppression on Aspergillus flavus growth and aflatoxin B1 biosynthesis. Int J Food Microbiol 2024; 409:110462. [PMID: 37918192 DOI: 10.1016/j.ijfoodmicro.2023.110462] [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: 08/02/2023] [Revised: 10/17/2023] [Accepted: 10/26/2023] [Indexed: 11/04/2023]
Abstract
Aspergillus flavus and subsequently produced carcinogenic aflatoxins frequently contaminate postharvest food crops, resulting in a threat to global food safety. Chemical preservatives are currently the main antifungal agents. However, fungal resistance effect, biological toxicity, and environmental contamination limit their practical applications. The application of natural volatile organic compounds has great potential for controlling fungal and mycotoxin contamination of postharvest food crops. This study therefore investigated the antifungal and anti-aflatoxigenic activities of the volatile compound, methyl 2-methylbutyrate (M2M), against Aspergillus flavus and its potential mechanisms. M2M effectively inhibited A. flavus mycelia growth, with a minimum inhibitory concentration of 2.0 μL/mL. Moreover, M2M also suppressed aflatoxin production, sclerotia production, and the pathogenicity on peanut and corn flour. RNA-Seq results showed that 2899 differentially expressed genes (DEGs), and DEGs involved in ergosterol synthesis, cell wall structure, glycolysis, citric acid cycle, mitogen activated protein kinase signaling pathway, DNA replication, and aflatoxin biosynthesis, were down-regulated in A. flavus. Further studies showed that M2M strongly damaged the cell membrane and cell wall integrity, reduced ATP levels, and induced reactive oxygen species (ROS) accumulation and DNA damage. Notably, a GATA type zinc finger transcription factor, AfSreA (AFLA_132440), which is essential for A. flavus growth and aflatoxin production, was identified. The growth and aflatoxin yield in the ΔAfSreA strain decreased by 94.94 % and 71.82 %, respectively. Additionally, deletion of AfSreA destroyed cell wall integrity and decreased expressions of genes involved in aflatoxin biosynthesis. Taken together, our results identified the antifungal and anti-aflatoxigenic mechanisms of M2M against A. flavus, and confirmed the potential of M2M in protecting peanut and corn from fungal contamination.
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Affiliation(s)
- Shan Wei
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Yige Zhang
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Menghan Wu
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Yangyong Lv
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Shuaibing Zhang
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Huanchen Zhai
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China
| | - Yuansen Hu
- College of Bioengineering, Henan University of Technology, Zhengzhou 450001, PR China; Food Laboratory of Zhongyuan, Henan University of Technology, Luohe 462300, PR China.
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Gil SS, Cappellari LDR, Giordano W, Banchio E. Antifungal Activity and Alleviation of Salt Stress by Volatile Organic Compounds of Native Pseudomonas Obtained from Mentha piperita. PLANTS (BASEL, SWITZERLAND) 2023; 12:1488. [PMID: 37050113 PMCID: PMC10097229 DOI: 10.3390/plants12071488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/07/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
As salt stress has a negative impact on plant growth and crop yield, it is very important to identify and develop any available biotechnology which can improve the salt tolerance of plants. Inoculation with plant-growth-promoting rhizobacteria (PGPR) is a proven environmentally friendly biotechnological resource for increasing the salt stress tolerance of plants and has a potential in-field application. In addition, bacterial volatile organic compounds (mVOCs) are signal molecules that may have beneficial roles in the soil-plant-microbiome ecosystem. We investigated the effects of mVOCs emitted by Pseudomona putida SJ46 and SJ04 on Mentha piperita grown under different levels of NaCl stress by evaluating their growth-promoting potential and capacity to increase salt tolerance effects. Furthermore, we evaluated under control and salt stress conditions the biocontrol ability of VOCs emitted by both these strains to inhibit the growth of Alternaria alternata and Sclerotium rolfsii. The VOCs emitted by both strains under control conditions did not lead to an significant improvement in peppermint growth. However, under salt stress conditions (75 or 100 mM NaCl), an amelioration of its physiological status was observed, with this effect being greater at 100 mM NaCl. This led to an enhancement of the number of leaves and nodes and, increased the shoot fresh and root dry weight by approximately twice in relation to control stressed plants. Moreover, the VOCs released by the two bacteria grown in control or saline media showed a significant reduction in the mycelial growth of A. alternata. In contrast, S. rolfsii growth was reduced 40% by the mVOCs released only under control conditions, with no effects being observed under salt stress. We also explored the composition of the bacterial volatile profiles by means of a solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) analysis. From the headspace of SJ46, three VOCs were identified: n-octanol, decane and tetradecane. The emission of SJ04 had the same chromatographic profile, with the addition of two more compounds: 1-(N-phenyl carbamyl)-2-morpholino cyclohexene and tridecane. Only compounds that were not present in the headspace of the control groups were recorded. The salt stress conditions where the bacteria were grown did not qualitatively modify the mVOC emissions. Taken together, our results suggest that plant-associated rhizobacterial VOCs play a potentially important role in modulating plant salt tolerance and reducing fungal growth. Thus, biological resources represent novel tools for counteracting the deleterious effects of salt stress and have the potential to be exploited in sustainable agriculture. Nevertheless, future studies are necessary to investigate technological improvements for bacterial VOC application under greenhouse and open field conditions.
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Rani A, Rana A, Dhaka RK, Singh AP, Chahar M, Singh S, Nain L, Singh KP, Minz D. Bacterial volatile organic compounds as biopesticides, growth promoters and plant-defense elicitors: Current understanding and future scope. Biotechnol Adv 2023; 63:108078. [PMID: 36513315 DOI: 10.1016/j.biotechadv.2022.108078] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 12/03/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Abstract
Bacteria emit a large number of volatile organic compounds (VOCs) into the environment. VOCs are species-specific and their emission depends on environmental conditions, such as growth medium, pH, temperature, incubation time and interaction with other microorganisms. These VOCs can enhance plant growth, suppress pathogens and act as signaling molecules during plant-microorganism interactions. Some bacterial VOCs have been reported to show strong antimicrobial, nematicidal, pesticidal, plant defense, induced tolerance and plant-growth-promoting activities under controlled conditions. Commonly produced antifungal VOCs include dimethyl trisulfide, dimethyl disulfide, benzothiazole, nonane, decanone and 1-butanol. Species of Bacillus, Pseudomonas, Arthrobacter, Enterobacter and Burkholderia produce plant growth promoting VOCs, such as acetoin and 2,3-butenediol. These VOCs affect expression of genes involved in defense and development in plant species (i.e., Arabidopsis, tobacco, tomato, potato, millet and maize). VOCs are also implicated in altering pathogenesis-related genes, inducing systemic resistance, modulating plant metabolic pathways and acquiring nutrients. However, detailed mechanisms of action of VOCs need to be further explored. This review summarizes the bioactive VOCs produced by diverse bacterial species as an alternative to agrochemicals, their mechanism of action and challenges for employment of bacterial VOCs for sustainable agricultural practices. Future studies on technological improvements for bacterial VOCs application under greenhouse and open field conditions are warranted.
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Affiliation(s)
- Annu Rani
- Department of Microbiology, College of Basic Science & Humanities, Chaudhary Charan Singh Haryana Agricultural University (CCS HAU), Hisar, India
| | - Anuj Rana
- Department of Microbiology, College of Basic Science & Humanities, Chaudhary Charan Singh Haryana Agricultural University (CCS HAU), Hisar, India; Centre for Bio-Nanotechnology, CCS HAU, Hisar, India.
| | - Rahul Kumar Dhaka
- Centre for Bio-Nanotechnology, CCS HAU, Hisar, India; Department of Chemistry, College of Basic Science & Humanities, CCS HAU, Hisar, India
| | - Arvind Pratap Singh
- Department of Microbiology, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Madhvi Chahar
- Department of Bio & Nano Technology, Guru Jambheshwar University of Science & Technology, Hisar, India
| | - Surender Singh
- Department of Microbiology, Central University of Haryana, Mahendargarh, India
| | - Lata Nain
- Division of Microbiology, ICAR - Indian Agricultural Research Institute, New Delhi, India
| | - Krishna Pal Singh
- Biophysics Unit, College of Basic Sciences and Humanities, G.B. Pant University of Agriculture & Technology, Pantnagar, India; Vice Chancellor's Secretariat, Mahatma Jyotiba Phule Rohilkhand University, Bareilly, UP, India
| | - Dror Minz
- Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Rishon LeZion, Israel.
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Volatile Organic Compounds from Pythium oligandrum Play a Role in Its Parasitism on Plant-Pathogenic Pythium myriotylum. Appl Environ Microbiol 2023; 89:e0203622. [PMID: 36744963 PMCID: PMC9973004 DOI: 10.1128/aem.02036-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The oomycete Pythium oligandrum is a soil-inhabiting parasite and predator of both fungi and oomycetes, and uses hydrolytic enzymes extensively to penetrate and hydrolyze its host or prey. Other mechanisms have been studied less, and we investigated the contribution of P. oligandrum-produced volatile organic compounds (VOCs) to parasitism. The growth-inhibiting activity of P. oligandrum VOCs was tested on Pythium myriotylum-a host or prey of P. oligandrum-coupled with electron microscopy, and biochemical and transcriptomic analyses. The P. oligandrum-produced VOCs reduced P. myriotylum growth by 80% and zoospore levels by 60%. Gas chromatography-mass spectrometry (GC-MS) identified 23 VOCs, and methyl heptenone, d-limonene, 2-undecanone, and 1-octanal were potent inhibitors of P. myriotylum growth and led to increased production of reactive oxygen species at a concentration that did not inhibit P. oligandrum growth. Exposure to the P. oligandrum VOCs led to shrinkage of P. myriotylum hyphae and lysis of the cellular membranes and organelles. Transcriptomics of P. myriotylum exposed to the P. oligandrum VOCs at increasing levels of growth inhibition initially showed a strong upregulation of putative detoxification-related genes that was not maintained later. The inhibition of P. myriotylum growth continued immediately after the exposure to the VOCs was discontinued and led to the reduced infection of its plant hosts. The VOCs produced by P. oligandrum could be another factor alongside hydrolytic enzymes contributing to its ecological role as a microbial parasite in particular ecological niches such as in soil, and may also contribute to the biocontrol of diseases using P. oligandrum commercial preparations. IMPORTANCE Microbe-microbe interactions in nature are multifaceted, with multiple mechanisms of action, and are crucial to how plants interact with microbes. Volatile organic compounds (VOCs) have diverse functions, including contributing to parasitism in ecological interactions and potential applications in biocontrol. The microbial parasite P. oligandrum is well known for using hydrolytic enzymes as part of its parasitism. We found that P. oligandrum VOCs reduced the growth of, and caused major damage to, the hyphae of P. myriotylum (a host or prey of P. oligandrum). Transcriptomic analyses of P. myriotylum exposed to the VOCs revealed the upregulation of genes potentially involved in an attempt to detoxify the VOCs. The inhibitory effects of the VOCs had a knock-on effect by reducing the virulence of P. myriotylum toward its plant hosts. The P. oligandrum VOCs could contribute to its ecological role as a microbial parasite. The VOCs analyzed here may also contribute to the biocontrol of diseases using P. oligandrum commercial preparations.
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Almeida OAC, de Araujo NO, Mulato ATN, Persinoti GF, Sforça ML, Calderan-Rodrigues MJ, Oliveira JVDC. Bacterial volatile organic compounds (VOCs) promote growth and induce metabolic changes in rice. FRONTIERS IN PLANT SCIENCE 2023; 13:1056082. [PMID: 36844905 PMCID: PMC9948655 DOI: 10.3389/fpls.2022.1056082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/13/2022] [Indexed: 06/18/2023]
Abstract
Plant growth-promoting bacteria (PGPB) represent an eco-friendly alternative to reduce the use of chemical products while increasing the productivity of economically important crops. The emission of small gaseous signaling molecules from PGPB named volatile organic compounds (VOCs) has emerged as a promising biotechnological tool to promote biomass accumulation in model plants (especially Arabidopsis thaliana) and a few crops, such as tomato, lettuce, and cucumber. Rice (Oryza sativa) is the most essential food crop for more than half of the world's population. However, the use of VOCs to improve this crop performance has not yet been investigated. Here, we evaluated the composition and effects of bacterial VOCs on the growth and metabolism of rice. First, we selected bacterial isolates (IAT P4F9 and E.1b) that increased rice dry shoot biomass by up to 83% in co-cultivation assays performed with different durations of time (7 and 12 days). Metabolic profiles of the plants co-cultivated with these isolates and controls (without bacteria and non-promoter bacteria-1003-S-C1) were investigated via 1H nuclear magnetic resonance. The analysis identified metabolites (e.g., amino acids, sugars, and others) with differential abundance between treatments that might play a role in metabolic pathways, such as protein synthesis, signaling, photosynthesis, energy metabolism, and nitrogen assimilation, involved in rice growth promotion. Interestingly, VOCs from IAT P4F9 displayed a more consistent promotion activity and were also able to increase rice dry shoot biomass in vivo. Molecular identification by sequencing the 16S rRNA gene of the isolates IAT P4F9 and E.1b showed a higher identity with Serratia and Achromobacter species, respectively. Lastly, volatilomes of these and two other non-promoter bacteria (1003-S-C1 and Escherichia coli DH5α) were evaluated through headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. Compounds belonging to different chemical classes, such as benzenoids, ketones, alcohols, sulfide, alkanes, and pyrazines, were identified. One of these VOCs, nonan-2-one, was validated in vitro as a bioactive compound capable of promoting rice growth. Although further analyses are necessary to properly elucidate the molecular mechanisms, our results suggest that these two bacterial isolates are potential candidates as sources for bioproducts, contributing to a more sustainable agriculture.
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Affiliation(s)
- Octávio Augusto Costa Almeida
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Natália Oliveira de Araujo
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Aline Tieppo Nogueira Mulato
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Gabriela Felix Persinoti
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Maurício Luís Sforça
- Brazilian Biosciences National Laboratory, Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | | | - Juliana Velasco de Castro Oliveira
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
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Almeida OAC, de Araujo NO, Dias BHS, de Sant’Anna Freitas C, Coerini LF, Ryu CM, de Castro Oliveira JV. The power of the smallest: The inhibitory activity of microbial volatile organic compounds against phytopathogens. Front Microbiol 2023; 13:951130. [PMID: 36687575 PMCID: PMC9845590 DOI: 10.3389/fmicb.2022.951130] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/20/2022] [Indexed: 01/06/2023] Open
Abstract
Plant diseases caused by phytopathogens result in huge economic losses in agriculture. In addition, the use of chemical products to control such diseases causes many problems to the environment and to human health. However, some bacteria and fungi have a mutualistic relationship with plants in nature, mainly exchanging nutrients and protection. Thus, exploring those beneficial microorganisms has been an interesting and promising alternative for mitigating the use of agrochemicals and, consequently, achieving a more sustainable agriculture. Microorganisms are able to produce and excrete several metabolites, but volatile organic compounds (VOCs) have huge biotechnology potential. Microbial VOCs are small molecules from different chemical classes, such as alkenes, alcohols, ketones, organic acids, terpenes, benzenoids and pyrazines. Interestingly, volatilomes are species-specific and also change according to microbial growth conditions. The interaction of VOCs with other organisms, such as plants, insects, and other bacteria and fungi, can cause a wide range of effects. In this review, we show that a large variety of plant pathogens are inhibited by microbial VOCs with a focus on the in vitro and in vivo inhibition of phytopathogens of greater scientific and economic importance in agriculture, such as Ralstonia solanacearum, Botrytis cinerea, Xanthomonas and Fusarium species. In this scenario, some genera of VOC-producing microorganisms stand out as antagonists, including Bacillus, Pseudomonas, Serratia and Streptomyces. We also highlight the known molecular and physiological mechanisms by which VOCs inhibit the growth of phytopathogens. Microbial VOCs can provoke many changes in these microorganisms, such as vacuolization, fungal hyphal rupture, loss of intracellular components, regulation of metabolism and pathogenicity genes, plus the expression of proteins important in the host response. Furthermore, we demonstrate that there are aspects to investigate by discussing questions that are still not very clear in this research area, especially those that are essential for the future use of such beneficial microorganisms as biocontrol products in field crops. Therefore, we bring to light the great biotechnological potential of VOCs to help make agriculture more sustainable.
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Affiliation(s)
- Octávio Augusto Costa Almeida
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil,Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Natália Oliveira de Araujo
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil,Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Bruno Henrique Silva Dias
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil,Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Carla de Sant’Anna Freitas
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil,Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Luciane Fender Coerini
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil,Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil
| | - Choong-Min Ryu
- Molecular Phytobacteriology Laboratory, Korea Research Institute of Bioscience & Biotechnology (KRIBB), Daejeon, South Korea,Biosystems and Bioengineering Program, University of Science and Technology, Daejeon, South Korea
| | - Juliana Velasco de Castro Oliveira
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil,Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, Brazil,*Correspondence: Juliana Velasco de Castro Oliveira,
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