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Huang Y, Li J, Shan X, Wang H, Duan Y. Bioactivities evaluation of an endophytic bacterial strain Bacillus tequilensis QNF2 inhibiting apple ring rot caused by Botryosphaeria dothidea on postharvest apple fruits. Food Microbiol 2024; 123:104590. [PMID: 39038895 DOI: 10.1016/j.fm.2024.104590] [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: 05/04/2024] [Revised: 06/13/2024] [Accepted: 06/28/2024] [Indexed: 07/24/2024]
Abstract
Apple ring rot, one of the most common apple postharvest diseases during storage, is caused by Botryosphaeria dothidea. Presently, the disease management is primarily dependent on chemical fungicide application. Here we demonstrated an endophyte bacterium Bacillus tequilensis QNF2, isolated from Chinese leek (Allium tuberosum) roots considerably suppressed B. dothidea mycelial growth, with the highest suppression of 73.56 % and 99.5 % in the PDA and PDB medium, respectively in vitro confront experiments. In in vivo experiments, B. tequilensis QNF2 exhibited a control efficacy of 88.52 % and 100 % on ring rot disease on postharvest apple fruits inoculated with B. dothidea disc and dipped into B. dothidea culture, respectively. In addition, B. tequilensis QNF2 volatile organic compounds (VOCs) also manifested markedly inhibition against B. dothidea mycelial growth and the ring rot on postharvest apple fruits. Moreover, B. tequilensis QNF2 severely damaged the mycelial morphology of B. dothidea. Finally, B. tequilensis QNF2 significantly repressed the expression of six pathogenicity-related genes, such as adh, aldh, aldh3, galm, pdc1, pdc2, involved in glycolysis/gluconeogenesis of B. dothidea. The findings of the study proved that B. tequilensis QNF2 was a promising alternative for controlling apple ring rot of postharvest apple fruit.
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Affiliation(s)
- Yonghong Huang
- College of Horticulture, Qingdao Agricultural University, Qingdao, China; Laboratory of Quality & Safety Risk Assessment for Fruit (Qingdao), Ministry of Agriculture and Rural Affairs, Qingdao, China; National Technology Centre for Whole Process Quality Control of FSEN Horticultural Products (Qingdao), Qingdao, China; Qingdao Key Laboratory of Modern Agriculture Quality and Safety Engineering, Qingdao, China.
| | - Jinghui Li
- College of Horticulture, Qingdao Agricultural University, Qingdao, China; Laboratory of Quality & Safety Risk Assessment for Fruit (Qingdao), Ministry of Agriculture and Rural Affairs, Qingdao, China; National Technology Centre for Whole Process Quality Control of FSEN Horticultural Products (Qingdao), Qingdao, China; Qingdao Key Laboratory of Modern Agriculture Quality and Safety Engineering, Qingdao, China
| | - Xiaoying Shan
- College of Horticulture, Qingdao Agricultural University, Qingdao, China; Laboratory of Quality & Safety Risk Assessment for Fruit (Qingdao), Ministry of Agriculture and Rural Affairs, Qingdao, China; National Technology Centre for Whole Process Quality Control of FSEN Horticultural Products (Qingdao), Qingdao, China; Qingdao Key Laboratory of Modern Agriculture Quality and Safety Engineering, Qingdao, China
| | - Hanting Wang
- College of Horticulture, Qingdao Agricultural University, Qingdao, China; Laboratory of Quality & Safety Risk Assessment for Fruit (Qingdao), Ministry of Agriculture and Rural Affairs, Qingdao, China; National Technology Centre for Whole Process Quality Control of FSEN Horticultural Products (Qingdao), Qingdao, China; Qingdao Key Laboratory of Modern Agriculture Quality and Safety Engineering, Qingdao, China
| | - Yanxin Duan
- College of Horticulture, Qingdao Agricultural University, Qingdao, China; Laboratory of Quality & Safety Risk Assessment for Fruit (Qingdao), Ministry of Agriculture and Rural Affairs, Qingdao, China; National Technology Centre for Whole Process Quality Control of FSEN Horticultural Products (Qingdao), Qingdao, China; Qingdao Key Laboratory of Modern Agriculture Quality and Safety Engineering, Qingdao, China.
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Imran M, Sun Z, Abo-Elyousr KAM, Ali H, Aldayel MF, Li C. One stone two birds: Endophytes alleviating trace elements accumulation and suppressing soilborne pathogen by stimulating plant growth, photosynthetic potential and defense related gene expression. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:135084. [PMID: 38991649 DOI: 10.1016/j.jhazmat.2024.135084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 06/24/2024] [Accepted: 06/30/2024] [Indexed: 07/13/2024]
Abstract
In the present investigation, we utilized zinc nanoparticles (Zn-NPs) and bacterial endophytes to address the dual challenge of heavy metal (HM) toxicity in soil and Rhizoctonia solani causing root rot disease of tomato. The biocontrol potential of Bacillus subtilis and Bacillus amyloliquefaciens was harnessed, resulting in profound inhibition of R. solani mycelial growth and efficient detoxification of HM through strong production of various hydrolytic enzymes and metabolites. Surprisingly, Zn-NPs exhibited notable efficacy in suppressing mycelial growth and enhancing the seed germination (%) while Gas chromatography-mass spectrometry (GC-MS) analysis unveiled key volatile compounds (VOCs) crucial for the inhibition of pathogen. Greenhouse trials underscored significant reduction in the disease severity (%) and augmented biomass in biocontrol-mediated plants by improving photosynthesis-related attributes. Interestingly, Zn-NPs and biocontrol treatments enhanced the antioxidant enzymes and mitigate oxidative stress indicator by increasing H2O2 concentration. Field experiments corroborated these findings, with biocontrol-treated plants, particularly those receiving consortia-mediated treatments, displayed significant reduction in disease severity (%) and enhanced the fruit yield under field conditions. Root analysis confirmed the effective detoxification of HM, highlighting the eco-friendly potential of these endophytes and Zn-NPs as fungicide alternative for sustainable production that foster soil structure, biodiversity and promote plant health.
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Affiliation(s)
- Muhammad Imran
- School of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China.
| | - Zhongke Sun
- School of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China.
| | - Kamal A M Abo-Elyousr
- Department of Plant Pathology, Faculty of Agriculture, University of Assiut, Assiut 71526, Egypt; Department of Agriculture, Faculty of Environmental Sciences, King Abdulaziz University, 80208 Jeddah, Saudi Arabia.
| | - Haider Ali
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.
| | - Munirah F Aldayel
- Department of Biological Sciences, College of Science, King Faisal University, 31982 Al-Ahsa, Saudi Arabia.
| | - Chengwei Li
- School of Biological Engineering, Henan University of Technology, Zhengzhou 450001, China; College of Life Science, Henan Agriculture University, Zhengzhou, 450046, China.
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Jannat M, Auyon ST, Tushar ASM, Tonny SH, Hasan MH, Shahi M, Singha UR, Sultana A, Akter S, Islam MR. Seed Priming with Rhizospheric Bacillus subtilis: A Smart Strategy for Reducing Fumonisin Contamination in Pre-Harvest Maize. Toxins (Basel) 2024; 16:337. [PMID: 39195747 PMCID: PMC11358949 DOI: 10.3390/toxins16080337] [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: 06/02/2024] [Revised: 07/03/2024] [Accepted: 07/05/2024] [Indexed: 08/29/2024] Open
Abstract
Maize, one of the most important cereal crops in Bangladesh, is severely contaminated by fumonisin, a carcinogenic secondary metabolite produced by Fusarium including Fusarium proliferatum. Biocontrol with Bacillus strains is an effective approach to controlling this F. proliferatum as Bacillus has proven antagonistic properties against this fungus. Therefore, the present study aimed to determine how native Bacillus strains can reduce fumonisin in maize cultivated in Bangladesh, where BDISO76MR (Bacillus subtilis) strains showed the highest efficacy both in vitro in detached cob and in planta under field conditions. The BDISO76MR strain could reduce the fumonisin concentration in detached cob at 98.52% over untreated control, by inhibiting the conidia germination and spore formation of F. proliferatum at 61.56% and 77.01%, respectively in vitro. On the other hand, seed treatment with formulated BDISO76MR showed higher efficacy with a reduction of 97.27% fumonisin contamination compared to the in planta cob inoculation (95.45%) over untreated control. This implies that Bacillus-based formulation might be a potential approach in mitigating fumonisin contamination in maize to ensure safe food and feed.
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Affiliation(s)
- Muhtarima Jannat
- Plant Bacteriology & Biotechnology Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.J.); (A.S.M.T.); (S.H.T.); (M.H.H.); (M.S.)
| | - Shah Tasdika Auyon
- Department of Environmental Science, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh;
| | - Abu Sina Md. Tushar
- Plant Bacteriology & Biotechnology Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.J.); (A.S.M.T.); (S.H.T.); (M.H.H.); (M.S.)
| | - Sadia Haque Tonny
- Plant Bacteriology & Biotechnology Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.J.); (A.S.M.T.); (S.H.T.); (M.H.H.); (M.S.)
| | - Md. Hasibul Hasan
- Plant Bacteriology & Biotechnology Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.J.); (A.S.M.T.); (S.H.T.); (M.H.H.); (M.S.)
| | - Mangal Shahi
- Plant Bacteriology & Biotechnology Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.J.); (A.S.M.T.); (S.H.T.); (M.H.H.); (M.S.)
| | - Uday Rana Singha
- Department of Agricultural Extension, Khamarbari, Dhaka 1215, Bangladesh; (U.R.S.); (A.S.); (S.A.)
| | - Ayesha Sultana
- Department of Agricultural Extension, Khamarbari, Dhaka 1215, Bangladesh; (U.R.S.); (A.S.); (S.A.)
| | - Sabera Akter
- Department of Agricultural Extension, Khamarbari, Dhaka 1215, Bangladesh; (U.R.S.); (A.S.); (S.A.)
| | - Md. Rashidul Islam
- Plant Bacteriology & Biotechnology Laboratory, Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.J.); (A.S.M.T.); (S.H.T.); (M.H.H.); (M.S.)
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Alarjani KM, Elshikh MS. Plant growth-promoting and biocontrol traits of endophytic Bacillus licheniformis against soft rot causing Pythium myriotylum in ginger plant. J Basic Microbiol 2024; 64:e2300643. [PMID: 38578065 DOI: 10.1002/jobm.202300643] [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: 10/29/2023] [Revised: 02/22/2024] [Accepted: 03/11/2024] [Indexed: 04/06/2024]
Abstract
Bacterial endophytes from plants harbor diverse metabolites that play major roles in biocontrol and improve plant growth. In this study, a total of 12 endophytic bacteria were isolated from the ginger rhizome. The strain K3 was highly effective in preventing mycelia growth of Pythium myriotylum (78.5 ± 1.5% inhibition) in dual culture. The cell-free extract (2.5%) of endophyte K3 inhibited 76.3 ± 4.8% mycelia growth, and 92.4 ± 4.2% inhibition was observed at a 5% sample concentration. The secondary metabolites produced by Bacillus licheniformis K3 showed maximum activity against Pseudomonas syringae (24 ± 1 mm zone of inhibition) and Xanthomonas campestris (28 ± 3 mm zone of inhibition). The strain K3 produced 28.3 ± 1.7 IU mL-1 protease, 28.3 ± 1.7 IU mL-1 cellulase, and 2.04 ± 0.13 IU mL-1 chitinase, respectively. The ginger rhizome treated with K3 in the greenhouse registered 53.8 ± 1.4% soft rot incidence, and the streptomycin-treated pot registered 78.3 ± 1.7% disease incidence. The selected endophyte K3 improved ascorbate peroxidase (1.37 ± 0.009 µmole ASC min-1 mg-1 protein), catalase (8.7 ± 0.28 µmole min-1 mg-1 protein), and phenylalanine ammonia-lyase (26.2 ± 0.99 Umg-1) in the greenhouse. In addition, K3 treatment in the field trial improved rhizome yield (730 ± 18.4 g) after 180 days (p < 0.01). The shoot length was 46 ± 8.3 cm in K3-treated plants, and it was about 31% higher than the control treatment (p < 0.01). The lytic enzyme-producing and growth-promoting endophyte is useful in sustainable crop production through the management of biotic stress.
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Affiliation(s)
- Khaloud Mohammed Alarjani
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Mohamed S Elshikh
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
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Yin C, Larson M, Lahr N, Paulitz T. Wheat Rhizosphere-Derived Bacteria Protect Soybean from Soilborne Diseases. PLANT DISEASE 2024; 108:1565-1576. [PMID: 38105448 DOI: 10.1094/pdis-08-23-1713-re] [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: 12/19/2023]
Abstract
Soybean (Glycine max [L.] Merr.) is an important oilseed crop with a high economic value. However, three damaging soybean diseases, soybean cyst nematode (SCN; Heterodera glycines Ichinohe), Sclerotinia stem rot caused by the fungus Sclerotinia sclerotiorum (Lid.) de Bary, and soybean root rot caused by Fusarium spp., are major constraints to soybean production in the Great Plains. Current disease management options, including resistant or tolerant varieties, fungicides, nematicides, and agricultural practices (crop rotation and tillage), have limited efficacy for these pathogens or have adverse effects on the ecosystem. Microbes with antagonistic activity are a promising option to control soybean diseases with the advantage of being environmentally friendly and sustainable. In this study, 61 bacterial strains isolated from wheat rhizospheres were used to examine their antagonistic abilities against three soybean pathogens. Six bacterial strains significantly inhibited the growth of Fusarium graminearum in the dual-culture assay. These bacterial strains were identified as Chryseobacterium ginsengisoli, C. indologenes, Pseudomonas poae, two Pseudomonas spp., and Delftia acidovorans by 16S rRNA gene sequencing. Moreover, C. ginsengisoli, C. indologenes, and P. poae significantly increased the mortality of SCN second-stage juveniles (J2), and two Pseudomonas spp. inhibited the growth of S. sclerotiorum in vitro. Further growth chamber tests found that C. ginsengisoli and C. indologenes reduced soybean Fusarium root rot disease. C. ginsengisoli and P. poae dramatically decreased SCN egg number on SCN-susceptible soybean 'Williams 82'. Two Pseudomonas spp. protected soybean plants from leaf damage and collapse after being infected by S. sclerotiorum. These bacteria exhibit versatile antagonistic potential. This work lays the foundation for further research on the field control of soybean pathogens.
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Affiliation(s)
- Chuntao Yin
- North Central Agricultural Research Laboratory, USDA-ARS, Brookings, SD
| | - Matt Larson
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD
| | - Nathan Lahr
- North Central Agricultural Research Laboratory, USDA-ARS, Brookings, SD
| | - Timothy Paulitz
- Wheat Health, Genetics, and Quality Research Unit, USDA-ARS, Pullman, WA
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Botlagunta N, Babu S. Growth enhancement and changes in bacterial microbiome of cucumber plants exhibited by biopriming with some native bacteria. Saudi J Biol Sci 2024; 31:103997. [PMID: 38646566 PMCID: PMC11031772 DOI: 10.1016/j.sjbs.2024.103997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 04/01/2024] [Accepted: 04/14/2024] [Indexed: 04/23/2024] Open
Abstract
This study investigated the impact of a mixture of six endophytic bacterial strains isolated from cucumber plants on the growth and microbiome diversity of six cucumber traditional varieties and hybrids. Six bacterial species were isolated and identified by 16 s rRNA sequencing. All the bacteria showed plant growth promoting traits. Bacillus tequilensis showed 80 % inhibition of the mycelia growth of Fusarium oxysporum f.sp. cucumarinum (Foc). Mixed culture of all the bacteria was prepared and applied back to the varieties and hybrids of cucumber plants through seed soaking. Plant growth characteristics indicated that the treated plants showed increased plant growth in terms of plant height, number of leaves, vine length, male:female flower ratio, number of fruits and fruit length. Bacteria treated plants of hybrid HiVeg Chitra recorded 19 cm increase in vine length compared to control plants. The matataxonomic analysis of leaf samples by Illumina sequencing highlighted a diverse bacterial community shift in treated plants, with significant increases in genera like Bacillus and Staphylococcus. The core microbiome analysis identified key genera such as Bacillus, Staphylococcus, Sphingomonas, Methylobacterium, etc that could be pivotal in plant growth promotion. Bacillus and Staphylococcus showed increased abundance in treated varieties, correlating with the observed in plant growth parameters thus indicating their role in growth promotion of cucumber plants. Endophytic bacterial species identified from cucumber plants when re-applied by seed soaking, they promote the plant growth by modulating the microbiome. The bacterial species identified in the study could be potential candidates as microbial bioinputs for cucumber cultivation.
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Affiliation(s)
- Navya Botlagunta
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore 632014, India
| | - Subramanian Babu
- VIT School of Agricultural Innovations and Advanced Learning (VAIAL), Vellore Institute of Technology, Vellore 632014, India
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Yadav A, Yadav R, Khare P. Impact of cultivating different Ocimum species on bioaerosol bacterial communities and functional genome at an agricultural site. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 356:124289. [PMID: 38825219 DOI: 10.1016/j.envpol.2024.124289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/10/2024] [Accepted: 05/30/2024] [Indexed: 06/04/2024]
Abstract
The effects of the surrounding environment on the bacterial composition of bioaerosol were well documented for polluted and contaminated sites. However, there is limited data on the impact of plant species, especially those that produce aromas, on bioaerosol composition at agricultural sites. Hence, the aim of this study is to evaluate the variability in bacterial communities present in bioaerosol samples collected from agricultural sites with aroma-producing crops. For this, PM2.5, PM10, and bioaerosol samples were collected from agricultural fields growing Ocimum [two varieties of O. sanctum (CIM-Aayu and CIM-Angana)] and O. kilimandscharicum (Kapoor), nearby traffic junctions and suburban areas. PM2.5 and PM10 concentrations at the agricultural site were in between the other two polluted sites. However, bioaerosol concentration was lower at agricultural sites than at other sites. The culturable bacteria Bacillus subtilis, Bacillus tequilensis, and Staphylococcus saprophyticus were more prevalent in agricultural sites than in other areas. However, the composition of non-culturable bacteria varied between sites and differed in three fields where Ocimum was cultivated. The CIM-Aayu cultivated area showed a high bacterial richness, lower Simpson and Shannon indices, and a distinctive metabolic profile. The sites CIM-Angana and CIM-Kapoor had a higher abundance of Aeromonas, while Pantoea and Pseudomonas were present at CIM-Aayu. Acinetobacter, Staphylococcus, and Bacillus were the dominant genera at the other two sites. Metabolic profiling showed that the CIM-Aayu site had a higher prevalence of pathways related to amino acid and carbohydrate metabolism and environmental information processing compared to other sites. The composition of bioaerosol among the three different Ocimum sites could be due to variations in the plant volatile and cross-feeding nature of bacterial isolates, which further needs to be explored.
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Affiliation(s)
- Anisha Yadav
- Crop Production and Protection Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow-226015, India
| | - Ranu Yadav
- Crop Production and Protection Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow-226015, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Puja Khare
- Crop Production and Protection Division, CSIR-Central Institute of Medicinal and Aromatic Plants, Lucknow-226015, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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Tang T, Wang F, Huang H, Guo J, Guo X, Duan Y, Wang X, Wang Q, You J. Bacillus velezensis LT1: a potential biocontrol agent for southern blight on Coptis chinensis. Front Microbiol 2024; 15:1337655. [PMID: 38500587 PMCID: PMC10946422 DOI: 10.3389/fmicb.2024.1337655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 02/12/2024] [Indexed: 03/20/2024] Open
Abstract
Introduction Southern blight, caused by Sclerotium rolfsii, poses a serious threat to the cultivation of Coptis chinensis, a plant with significant medicinal value. The overreliance on fungicides for controlling this pathogen has led to environmental concerns and resistance issues. There is an urgent need for alternative, sustainable disease management strategies. Methods In this study, Bacillus velezensis LT1 was isolated from the rhizosphere soil of diseased C. chinensis plants. Its biocontrol efficacy against S. rolfsii LC1 was evaluated through a confrontation assay. The antimicrobial lipopeptides in the fermentation liquid of B. velezensis LT1 were identified using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS). The effects of B. velezensis LT1 on the mycelial morphology of S. rolfsii LC1 were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results The confrontation assay indicated that B. velezensis LT1 significantly inhibited the growth of S. rolfsii LC1, with an inhibition efficiency of 78.41%. MALDI-TOF-MS analysis detected the presence of bacillomycin, surfactin, iturin, and fengycin in the fermentation liquid, all known for their antifungal properties. SEM and TEM observations revealed that the mycelial and cellular structures of S. rolfsii LC1 were markedly distorted when exposed to B. velezensis LT1. Discussion The findings demonstrate that B. velezensis LT1 has considerable potential as a biocontrol agent against S. rolfsii LC1. The identified lipopeptides likely contribute to the antifungal activity, and the morphological damage to S. rolfsii LC1 suggests a mechanism of action. This study underscores the importance of exploring microbial biocontrol agents as a sustainable alternative to chemical fungicides in the management of plant diseases. Further research into the genetic and functional aspects of B. velezensis LT1 could provide deeper insights into its biocontrol mechanisms and facilitate its application in agriculture.
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Affiliation(s)
- Tao Tang
- Key Laboratory of Chinese Herbal Medicine Biology and Cultivation, Ministry of Agriculture and Rural Affairs, Institute of Chinese Herbal Medicine, Hubei Academy of Agricultural Science, Enshi, China
- Hubei Engineering Research Center of Good Agricultural Practices (GAP) Production for Chinese Herbal Medicines, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China
| | - Fanfan Wang
- Hubei Engineering Research Center of Good Agricultural Practices (GAP) Production for Chinese Herbal Medicines, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China
| | - Houyun Huang
- Key Laboratory of Chinese Herbal Medicine Biology and Cultivation, Ministry of Agriculture and Rural Affairs, Institute of Chinese Herbal Medicine, Hubei Academy of Agricultural Science, Enshi, China
| | - Jie Guo
- Key Laboratory of Chinese Herbal Medicine Biology and Cultivation, Ministry of Agriculture and Rural Affairs, Institute of Chinese Herbal Medicine, Hubei Academy of Agricultural Science, Enshi, China
- Hubei Engineering Research Center of Good Agricultural Practices (GAP) Production for Chinese Herbal Medicines, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China
| | - Xiaoliang Guo
- Hubei Engineering Research Center of Good Agricultural Practices (GAP) Production for Chinese Herbal Medicines, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China
| | - Yuanyuan Duan
- Hubei Engineering Research Center of Good Agricultural Practices (GAP) Production for Chinese Herbal Medicines, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China
| | - Xiaoyue Wang
- Hubei Engineering Research Center of Good Agricultural Practices (GAP) Production for Chinese Herbal Medicines, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China
| | - Qingfang Wang
- Key Laboratory of Chinese Herbal Medicine Biology and Cultivation, Ministry of Agriculture and Rural Affairs, Institute of Chinese Herbal Medicine, Hubei Academy of Agricultural Science, Enshi, China
- Hubei Engineering Research Center of Good Agricultural Practices (GAP) Production for Chinese Herbal Medicines, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China
| | - Jingmao You
- Key Laboratory of Chinese Herbal Medicine Biology and Cultivation, Ministry of Agriculture and Rural Affairs, Institute of Chinese Herbal Medicine, Hubei Academy of Agricultural Science, Enshi, China
- Hubei Engineering Research Center of Good Agricultural Practices (GAP) Production for Chinese Herbal Medicines, Institute of Chinese Herbal Medicines, Hubei Academy of Agricultural Sciences, Enshi, China
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Yadav U, Anand V, Kumar S, Verma I, Anshu A, Pandey IA, Kumar M, Behera SK, Srivastava S, Singh PC. Bacillus subtilis NBRI-W9 simultaneously activates SAR and ISR against Fusarium chlamydosporum NBRI-FOL7 to increase wilt resistance in tomato. J Appl Microbiol 2024; 135:lxae013. [PMID: 38268411 DOI: 10.1093/jambio/lxae013] [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: 08/02/2023] [Revised: 01/10/2024] [Accepted: 01/23/2024] [Indexed: 01/26/2024]
Abstract
AIMS The study aimed to determine the pathogenicity of Fusarium species currently prevalent in tomato fields having history of chemical fungicide applications and determine the bio-efficacy of Bacillus subtilis NBRI-W9 as a potent biological control agent. METHODS AND RESULTS Fusarium was isolated from surface-sterilized infected tomato plants collected from fields. Pathogenicity of 30 Fusarium isolates was determined by in vitro and in vivo assays. Following Koch's postulates, F. chlamydosporum (FOL7) was identified as a virulent pathogen. The biological control of FOL 7 by B. subtilis NBRI-W9 (W9) and the colonization potential of W9 were established using spontaneous rifampicin-resistant mutants. W9 showed 82% inhibition of FOL7 on a dual-culture plate and colonization levels in tomato plants of ∼5.5, ∼3.3, and ∼2.2 log10 CFU/g in root, stem, and leaf tissue, respectively. Antagonistic activity was shown by scanning electron microscopy (SEM) and cell-wall-degradative enzymes. W9 reduced FOL7 infection in net-house and field experiments by 60% and 41%, respectively. Biochemical investigation, defence enzymes, defence gene expression analysis, SEM, and field studies provide evidence of hyperparasitism and induced resistance as the mode of biological control. The study also demonstrates that the potent biocontrol agent W9, isolated from Piper, can colonize tomato plants, control fungal disease by inducing induced systemic resistance (ISR) and systemic acquired resistance (SAR) simultaneously, and increase crop yield by 21.58% under field conditions. CONCLUSIONS This study concludes that F. chlamydosporum (NBRI-FOL7) is a potent, fungicide-resistant pathogen causing wilt in tomatoes. NBRI-W9 controlled FOL7 through mycoparasitism and simultaneously activated ISR and SAR in plants, providing an attractive tool for disease control that acts at multiple levels.
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Affiliation(s)
- Udit Yadav
- Division of Microbial Technologies, CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Vandana Anand
- Division of Microbial Technologies, CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Sanjeev Kumar
- Division of Microbial Technologies, CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Isha Verma
- Division of Microbial Technologies, CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Anshu Anshu
- Division of Microbial Technologies, CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
- Department of Botany, University of Lucknow, Hasanganj, Lucknow 226007, India
| | - Ishan Alok Pandey
- Division of Microbial Technologies, CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
| | - Manoj Kumar
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
- Division of Molecular Biology and Biotechnology, CSIR-NBRI, Lucknow 226001, India
| | - Sandip Kumar Behera
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
- Division of Plant Systematics and Herbarium, CSIR-NBRI, Lucknow 226001, India
| | - Suchi Srivastava
- Division of Microbial Technologies, CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
- Division of Molecular Biology and Biotechnology, CSIR-NBRI, Lucknow 226001, India
| | - Poonam C Singh
- Division of Microbial Technologies, CSIR- National Botanical Research Institute, Rana Pratap Marg, Lucknow 226001, India
- Division of Molecular Biology and Biotechnology, CSIR-NBRI, Lucknow 226001, India
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10
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Wockenfuss A, Chan K, Cooper JG, Chaya T, Mauriello MA, Yannarell SM, Maresca JA, Donofrio NM. A Bacillus velezensis strain shows antimicrobial activity against soilborne and foliar fungi and oomycetes. FRONTIERS IN FUNGAL BIOLOGY 2024; 5:1332755. [PMID: 38465255 PMCID: PMC10920214 DOI: 10.3389/ffunb.2024.1332755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/05/2024] [Indexed: 03/12/2024]
Abstract
Biological control uses naturally occurring antagonists such as bacteria or fungi for environmentally friendly control of plant pathogens. Bacillus spp. have been used for biocontrol of numerous plant and insect pests and are well-known to synthesize a variety of bioactive secondary metabolites. We hypothesized that bacteria isolated from agricultural soil would be effective antagonists of soilborne fungal pathogens. Here, we show that the Delaware soil isolate Bacillus velezensis strain S4 has in vitro activity against soilborne and foliar plant pathogenic fungi, including two with a large host range, and one oomycete. Further, this strain shows putative protease and cellulase activity, consistent with our prior finding that the genome of this organism is highly enriched in antifungal and antimicrobial biosynthetic gene clusters. We demonstrate that this bacterium causes changes to the fungal and oomycete hyphae at the inhibition zone, with some of the hyphae forming bubble-like structures and irregular branching. We tested strain S4 against Magnaporthe oryzae spores, which typically form germ tubes and penetration structures called appressoria, on the surface of the leaf. Our results suggest that after 12 hours of incubation with the bacterium, fungal spores form germ tubes, but instead of producing appressoria, they appear to form rounded, bubble-like structures. Future work will investigate whether a single antifungal molecule induces all these effects, or if they are the result of a combination of bacterially produced antimicrobials.
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Affiliation(s)
- Anna Wockenfuss
- Microbiology Graduate Program, University of Delaware, Newark, DE, United States
| | - Kevin Chan
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, United States
| | - Jessica G. Cooper
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, United States
| | - Timothy Chaya
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, United States
| | - Megan A. Mauriello
- Microbiology Graduate Program, University of Delaware, Newark, DE, United States
| | - Sarah M. Yannarell
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, United States
| | - Julia A. Maresca
- Department of Civil and Environmental Engineering, University of Delaware, Newark, DE, United States
| | - Nicole M. Donofrio
- Department of Plant and Soil Sciences, University of Delaware, Newark, DE, United States
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11
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Valencia-Marin MF, Chávez-Avila S, Guzmán-Guzmán P, Orozco-Mosqueda MDC, de Los Santos-Villalobos S, Glick BR, Santoyo G. Survival strategies of Bacillus spp. in saline soils: Key factors to promote plant growth and health. Biotechnol Adv 2024; 70:108303. [PMID: 38128850 DOI: 10.1016/j.biotechadv.2023.108303] [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: 08/16/2023] [Revised: 11/16/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
Soil salinity is one of the most important abiotic factors that affects agricultural production worldwide. Because of saline stress, plants face physiological changes that have negative impacts on the various stages of their development, so the employment of plant growth-promoting bacteria (PGPB) is one effective means to reduce such toxic effects. Bacteria of the Bacillus genus are excellent PGPB and have been extensively studied, but what traits makes them so extraordinary to adapt and survive under harsh situations? In this work we review the Bacillus' innate abilities to survive in saline stressful soils, such as the production osmoprotectant compounds, antioxidant enzymes, exopolysaccharides, and the modification of their membrane lipids. Other survival abilities are also discussed, such as sporulation or a reduced growth state under the scope of a functional interaction in the rhizosphere. Thus, the most recent evidence shows that these saline adaptive activities are important in plant-associated bacteria to potentially protect, direct and indirect plant growth-stimulating activities. Additionally, recent advances on the mechanisms used by Bacillus spp. to improve the growth of plants under saline stress are addressed, including genomic and transcriptomic explorations. Finally, characterization and selection of Bacillus strains with efficient survival strategies are key factors in ameliorating saline problems in agricultural production.
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Affiliation(s)
- María F Valencia-Marin
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Salvador Chávez-Avila
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Paulina Guzmán-Guzmán
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico
| | - Ma Del Carmen Orozco-Mosqueda
- Departamento de Ingeniería Bioquímica y Ambiental, Tecnológico Nacional de México en Celaya, 38010 Celaya, Gto, Mexico
| | | | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich. 58030, Mexico.
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12
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Al-Mutar DMK, Noman M, Alzawar NSA, Qasim HH, Li D, Song F. The Extracellular Lipopeptides and Volatile Organic Compounds of Bacillus subtilis DHA41 Display Broad-Spectrum Antifungal Activity against Soil-Borne Phytopathogenic Fungi. J Fungi (Basel) 2023; 9:797. [PMID: 37623568 PMCID: PMC10455929 DOI: 10.3390/jof9080797] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/26/2023] Open
Abstract
Fusarium oxysporum f. sp. niveum (Fon) is a devastating soil-borne fungus causing Fusarium wilt in watermelon. The present study investigated the biochemical mechanism underlying the antifungal activity exhibited by the antagonistic bacterial strain DHA41, particularly against Fon. Molecular characterization based on the 16S rRNA gene confirmed that DHA41 is a strain of Bacillus subtilis, capable of synthesizing antifungal lipopeptides, such as iturins and fengycins, which was further confirmed by detecting corresponding lipopeptide biosynthesis genes, namely ItuB, ItuD, and FenD. The cell-free culture filtrate and extracellular lipopeptide extract of B. subtilis DHA41 demonstrated significant inhibitory effects on the mycelial growth of Fon, Didymella bryoniae, Sclerotinia sclerotiorum, Fusarium graminearum, and Rhizoctonia solani. The lipopeptide extract showed emulsification activity and inhibited Fon mycelial growth by 86.4% at 100 µg/mL. Transmission electron microscope observations confirmed that the lipopeptide extract disrupted Fon cellular integrity. Furthermore, B. subtilis DHA41 emitted volatile organic compounds (VOCs) that exhibited antifungal activity against Fon, D. bryoniae, S. sclerotiorum, and F. graminearum. These findings provide evidence that B. subtilis DHA41 possesses broad-spectrum antifungal activity against different fungi pathogens, including Fon, through the production of extracellular lipopeptides and VOCs.
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Affiliation(s)
- Dhabyan Mutar Kareem Al-Mutar
- Key Laboratory of Crop Diseases and Insect Pests of Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (D.M.K.A.-M.); (M.N.); (D.L.)
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
- Basra Agriculture Directorate, Almudaina 61008, Iraq;
| | - Muhammad Noman
- Key Laboratory of Crop Diseases and Insect Pests of Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (D.M.K.A.-M.); (M.N.); (D.L.)
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | | | | | - Dayong Li
- Key Laboratory of Crop Diseases and Insect Pests of Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (D.M.K.A.-M.); (M.N.); (D.L.)
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Fengming Song
- Key Laboratory of Crop Diseases and Insect Pests of Ministry of Agriculture, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (D.M.K.A.-M.); (M.N.); (D.L.)
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
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13
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Zhou Q, Tu M, Fu X, Chen Y, Wang M, Fang Y, Yan Y, Cheng G, Zhang Y, Zhu Z, Yin K, Xiao Y, Zou L, Chen G. Antagonistic transcriptome profile reveals potential mechanisms of action on Xanthomonas oryzae pv. oryzicola by the cell-free supernatants of Bacillus velezensis 504, a versatile plant probiotic bacterium. Front Cell Infect Microbiol 2023; 13:1175446. [PMID: 37325518 PMCID: PMC10265122 DOI: 10.3389/fcimb.2023.1175446] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/27/2023] [Indexed: 06/17/2023] Open
Abstract
Bacterial leaf streak (BLS) of rice is a severe disease caused by the bacterial pathogen Xanthomonas oryzae pv. oryzicola (Xoc) that has gradually become the fourth major disease on rice in some rice-growing regions in southern China. Previously, we isolated a Bacillus velezensis strain 504 that exhibited apparent antagonistic activity against the Xoc wild-type strain RS105, and found that B. velezensis 504 was a potential biocontrol agent for BLS. However, the underlying mechanisms of antagonism and biocontrol are not completely understood. Here we mine the genomic data of B. velezensis 504, and the comparative transcriptomic data of Xoc RS105 treated by the cell-free supernatants (CFSs) of B. velezensis 504 to define differentially expressed genes (DEGs). We show that B. velezensis 504 shares over 89% conserved genes with FZB42 and SQR9, two representative model strains of B. velezensis, but 504 is more closely related to FZB42 than SQR9, as well as B. velezensis 504 possesses the secondary metabolite gene clusters encoding the essential anti-Xoc agents difficidin and bacilysin. We conclude that approximately 77% of Xoc RS105 coding sequences are differentially expressed by the CFSs of B. velezensis 504, which significantly downregulates genes involved in signal transduction, oxidative phosphorylation, transmembrane transport, cell motility, cell division, DNA translation, and five physiological metabolisms, as well as depresses an additional set of virulence-associated genes encoding the type III secretion, type II secretion system, type VI secretion system, type IV pilus, lipopolysaccharides and exopolysaccharides. We also show that B. velezensis 504 is a potential biocontrol agent for bacterial blight of rice exhibiting relative control efficiencies over 70% on two susceptible cultivars, and can efficiently antagonize against some important plant pathogenic fungi including Colletotrichum siamense and C. australisinense that are thought to be the two dominant pathogenic species causing leaf anthracnose of rubber tree in Hainan province of China. B. velezensis 504 also harbors some characteristics of plant growth-promoting rhizobacterium such as secreting protease and siderophore, and stimulating plant growth. This study reveals the potential biocontrol mechanisms of B. velezensis against BLS, and also suggests that B. velezensis 504 is a versatile plant probiotic bacterium.
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Affiliation(s)
- Qi Zhou
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Min Tu
- Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Xue Fu
- Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
- College of Plant Protection, Yunnan Agricultural University, Kunming, China
| | - Ying Chen
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Muyuan Wang
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Yuan Fang
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Yichao Yan
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Guanyun Cheng
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Yikun Zhang
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Zhongfeng Zhu
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Ke Yin
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Youlun Xiao
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha, China
| | - Lifang Zou
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Gongyou Chen
- Shanghai Collaborative Innovation Center of Agri-Seeds/School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
- Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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14
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Schommer VA, Vanin AP, Nazari MT, Ferrari V, Dettmer A, Colla LM, Piccin JS. Biochar-immobilized Bacillus spp. for heavy metals bioremediation: A review on immobilization techniques, bioremediation mechanisms and effects on soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163385. [PMID: 37054796 DOI: 10.1016/j.scitotenv.2023.163385] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 04/15/2023]
Abstract
Heavy metals contamination present risks to ecosystems and human health. Bioremediation is a technology that has been applied to minimize the levels of heavy metals contamination. However, the efficiency of this process varies according to several biotic and abiotic aspects, especially in environments with high concentrations of heavy metals. Therefore, microorganisms immobilization in different materials, such as biochar, emerges as an alternative to alleviate the stress that heavy metals have on microorganisms and thus improve the bioremediation efficiency. In this context, this review aimed to compile recent advances in the use of biochar as a carrier of bacteria, specifically Bacillus spp., with subsequent application for the bioremediation of soil contaminated with heavy metals. We present three different techniques to immobilize Bacillus spp. on biochar. Bacillus strains are capable of reducing the toxicity and bioavailability of metals, while biochar is a material that serves as a shelter for microorganisms and also contributes to bioremediation through the adsorption of contaminants. Thus, there is a synergistic effect between Bacillus spp. and biochar for the heavy metals bioremediation. Biomineralization, biosorption, bioreduction, bioaccumulation and adsorption are the mechanisms involved in this process. The application of biochar-immobilized Bacillus strains results in beneficial effects on the contaminated soil, such as the reduction of toxicity and accumulation of metals in plants, favoring their growth, in addition to increasing microbial and enzymatic activity in soil. However, competition and reduction of microbial diversity and the toxic characteristics of biochar are reported as negative impacts of this strategy. More studies using this emerging technology are essential to improve its efficiency, to elucidate the mechanisms and to balance positive and negative impacts, especially at the field scale.
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Affiliation(s)
- Vera Analise Schommer
- Graduate Program in Civil and Environmental Engineering (PPGEng), University of Passo Fundo (UPF), Passo Fundo, RS, Brazil
| | - Ana Paula Vanin
- Graduate Program in Civil and Environmental Engineering (PPGEng), University of Passo Fundo (UPF), Passo Fundo, RS, Brazil
| | - Mateus Torres Nazari
- Graduate Program in Civil and Environmental Engineering (PPGEng), University of Passo Fundo (UPF), Passo Fundo, RS, Brazil
| | - Valdecir Ferrari
- Graduate Program in Mining, Metallurgical and Materials Engineering (PPGE3M), Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Aline Dettmer
- Graduate Program in Food Science and Technology (PPGCTA), University of Passo Fundo (UPF), Passo Fundo, RS, Brazil
| | - Luciane Maria Colla
- Graduate Program in Civil and Environmental Engineering (PPGEng), University of Passo Fundo (UPF), Passo Fundo, RS, Brazil.
| | - Jeferson Steffanello Piccin
- Graduate Program in Civil and Environmental Engineering (PPGEng), University of Passo Fundo (UPF), Passo Fundo, RS, Brazil
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