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Shen S, Li Y, Chen M, Huang J, Liu F, Xie S, Kong L, Pan Y. Reduced cadmium toxicity in rapeseed via alteration of root properties and accelerated plant growth by a nitrogen-fixing bacterium. J Hazard Mater 2023; 449:131040. [PMID: 36821906 DOI: 10.1016/j.jhazmat.2023.131040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/09/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Cd accumulation in crops has become a global environmental problem because it endangers human health. Screening for microorganisms that can reduce Cd accumulation in crops is a possible measure to address this issue. However, success has been limited, and most previous work did not involve bacteria. In the present study, a strain of N-fixing bacteria (Burkholderia spp.) that exhibits high levels of Cd tolerance was screened. The ability of this bacterium to reduce Cd in rapeseed was then assessed in sterile hydroponic and open soil culture systems. In the hydroponic system, the Burkholderia inoculum promoted Cd fixation in rapeseed roots and thus reduced Cd enrichment in aboveground edible tissues (leaves). The mechanisms were related to increased activity of pectin methylesterase in root cell walls, and the transformation of the chemical form of root Cd from "active" (NaCl-extracted) to "inert" (HCl-extracted and residual Cd) states. Additionally, Burkholderia accelerated plant growth, thus shortening the period in which the plant is available for Cd absorption. In the soil culture system, Burkholderia also reduced Cd enrichment in rapeseed leaves in the presence of other microorganisms. Thus, the bacterial strain shows potential for broad application for reducing the accumulation of Cd in crops.
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Affiliation(s)
- Shili Shen
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Science, Yunnan University, Kunming 650091, Yunnan, China; Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China
| | - Yinghan Li
- School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China
| | - Mingbiao Chen
- School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming 650091, China
| | - Juan Huang
- Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming 650091, China
| | - Feng Liu
- Wuzhou Agricultural Products Quality and Safety Comprehensive Testing Center, Wuzhou 543000, Guangxi, China
| | - Shijie Xie
- Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming 650091, China
| | - Liping Kong
- Instititue of International Rivers and Eco-security, Yunnan Key Laboratory of International Rivers and Trans-Boundary Eco-security, Yunnan University, Kunming 650091, China
| | - Ying Pan
- Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China; School of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, Yunnan, China.
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Sithole N, Tsvuura Z, Kirkman K, Magadlela A. Altering Nitrogen Sources Affects Growth Carbon Costs in Vachellia nilotica Growing in Nutrient-Deficient Grassland Soils. Plants (Basel) 2021; 10:plants10091762. [PMID: 34579294 PMCID: PMC8470937 DOI: 10.3390/plants10091762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/12/2021] [Accepted: 08/18/2021] [Indexed: 11/16/2022]
Abstract
Vachellianilotica (L.) Willd. Ex Del. is a multipurpose leguminous tree that is common in grassland and savanna ecosystems in southern and eastern Africa. These ecosystem soils are reported to be acidic and nutrient-limited, specifically with regards to nitrogen (N) and phosphorus (P). The presence of this plant in these terrestrial ecosystems improves soil fertility benefiting the surrounding vegetation due to its ability to fix atmospheric N. This study seeks to understand the N-fixing bacteria symbiosis and physiological adaptations of V. nilotica in these acidic and nutrient-deficient KwaZulu-Natal soils. The soils used for this study were collected from the Ukulinga Grassland Nutrient Experiment located at the Ukulinga research farm of the University of KwaZulu-Natal, Pietermaritzburg, South Africa. Due to long-term soil nutrient addition treatments, these soils offered a diverse nutrient variation for better understanding the effects of acidity and nutrient variation on microbial symbiosis, plant nutrition, and biomass accumulation of V. nilotica. V. nilotica was able to maintain growth by relying on both atmospheric and soil-derived N across all treatments decreasing carbon (C) growth costs. There was an increased reliance on atmospheric-derived N of un-nodulated high N-treated plants. The plants grown in high N + P soils were able to nodulate with various species from the Mesorhizobium genus, which resulted in increased biomass compared to other plants. The results of this study show that V. nilotica can alter N sources to reduce C growth costs. In addition, both nodulating and free-living soil N2 fixing bacteria such as Caulobacter rhizosphaerae, Sphingomonas sp. and Burkholderia contaminans identified in the experimental soils may play an important role under P-deficient conditions.
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Affiliation(s)
- Nonkululeko Sithole
- School of Life Sciences, College of Agriculture, Engineering and Science, Westville Campus, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa;
| | - Zivanai Tsvuura
- School of Life Sciences, College of Agriculture, Engineering and Science, Pietermaritzburg Campus, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, South Africa; (Z.T.); (K.K.)
| | - Kevin Kirkman
- School of Life Sciences, College of Agriculture, Engineering and Science, Pietermaritzburg Campus, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, South Africa; (Z.T.); (K.K.)
| | - Anathi Magadlela
- School of Life Sciences, College of Agriculture, Engineering and Science, Westville Campus, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa;
- Correspondence: ; Tel.: +27-31-260-2076
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Tang H, Li C, Cheng K, Shi L, Wen L, Li W, Xiao X. Effect of different short-term tillage management on nitroge n-fixing bacteria community in a double-cropping paddy field of southern China. J Basic Microbiol 2020; 61:241-252. [PMID: 33351219 DOI: 10.1002/jobm.202000608] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/20/2020] [Accepted: 12/11/2020] [Indexed: 11/07/2022]
Abstract
Soil nitrogen (N)-fixing bacteria community plays an important role in the N cycling process in soil, but there is still limited information about how the soil microbes that drive this process to respond to combined application of tillage and crop residue management under the double-cropping rice (Oryza sativa L.) paddy field in southern of China. Therefore, the effects of 6-years short-term tillage treatment on soil N-fixing bacteria community under the double-cropping rice paddy field in southern China were studied by using the polymerase chain reaction-denaturing gradient gel electrophoresis method. The field experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), rotary tillage with crop residue removed as control (RTO). The results showed that the diversity index and richness index of cbbLR and nifH genes with CT, RT, and NT treatments were increased, compared with RTO treatment. Compared with RTO treatment, the abundance of cbbLR gene with CT, RT, and NT treatments were increased by 6.54, 4.73, and 2.78 times, respectively. Meanwhile, the abundance of nifH gene with CT, RT, and NT treatments were 5.32, 3.71, and 2.45 times higher than that of RTO treatment. The results also indicated that soil autotrophic Azotobacter and nitrogenase activity with CT and RT treatments were significantly higher (p < .05) than that of RTO treatment. There was an obvious difference in characteristic of soil N-fixing bacteria community between the application of crop residue and without crop residue input treatments. In summary, the results indicated that the abundance of N-fixing bacteria community in the double-cropping rice paddy field increased with conventional tillage and rotary tillage practice.
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Affiliation(s)
- Haiming Tang
- Hunan Soil and Fertilizer Institute, Changsha, China
| | - Chao Li
- Hunan Soil and Fertilizer Institute, Changsha, China
| | - Kaikai Cheng
- Hunan Soil and Fertilizer Institute, Changsha, China
| | - Lihong Shi
- Hunan Soil and Fertilizer Institute, Changsha, China
| | - Li Wen
- Hunan Soil and Fertilizer Institute, Changsha, China
| | - Weiyan Li
- Hunan Soil and Fertilizer Institute, Changsha, China
| | - Xiaoping Xiao
- Hunan Soil and Fertilizer Institute, Changsha, China
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Barros-Carvalho GA, Hungria M, Lopes FM, Van Sluys MA. Brazilian-adapted soybean Bradyrhizobium strains uncover IS elements with potential impact on biological nitrogen fixation. FEMS Microbiol Lett 2019; 366:fnz046. [PMID: 30860585 DOI: 10.1093/femsle/fnz046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/15/2019] [Indexed: 11/14/2022] Open
Abstract
Bradyrhizobium diazoefficiens CPAC 7 and Bradyrhizobium japonicum CPAC 15 are broadly used in commercial inoculants in Brazil, contributing to most of the nitrogen required by the soybean crop. These strains differ in their symbiotic properties: CPAC 7 is more efficient in fixing nitrogen, whereas CPAC 15 is more competitive. Comparative genomics revealed many transposases close to genes associated with symbiosis in the symbiotic island of these strains. Given the importance that insertion sequences (IS) elements have to bacterial genomes, we focused on identifying the local impact of these elements in the genomes of these and other related Bradyrhizobium strains to further understand their phenotypic differences. Analyses were performed using bioinformatics approaches. We found IS elements disrupting and inserted at regulatory regions of genes involved in symbiosis. Further comparative analyses with 21 Bradyrhizobium genomes revealed insertional polymorphism with distinguishing patterns between B. diazoefficiens and B. japonicum lineages. Finally, 13 of these potentially impacted genes are differentially expressed under symbiotic conditions in B. diazoefficiens USDA 110. Thus, IS elements are associated with the diversity of Bradyrhizobium, possibly by providing mechanisms for natural variation of symbiotic effectiveness.
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Affiliation(s)
- Gesiele Almeida Barros-Carvalho
- GaTE Lab; Departamento de Botânica - Instituto de Biociências, Universidade de São Paulo, 277 Matão Street, 05508-090, São Paulo, SP, Brazil
- Instituto de Matemática e Estatística, Universidade de São Paulo, 1010 Matão Street, 05508-090, São Paulo, SP, Brazil
| | | | - Fabrício Martins Lopes
- Universidade Tecnológica Federal do Paraná, 1640 Alberto Carazzai Avenue, 86300-000, Cornélio Procópio, Pr, Brazil
| | - Marie-Anne Van Sluys
- GaTE Lab; Departamento de Botânica - Instituto de Biociências, Universidade de São Paulo, 277 Matão Street, 05508-090, São Paulo, SP, Brazil
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