1
|
Verstraete W. Nitrogen and me - How little did we, and do we know about "stikstof - azote - nitrogen"? WATER RESEARCH 2024; 258:121687. [PMID: 38754295 DOI: 10.1016/j.watres.2024.121687] [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: 02/20/2024] [Revised: 04/26/2024] [Accepted: 04/27/2024] [Indexed: 05/18/2024]
Abstract
This retrospective article reflects on the complex and evolving relationship between humans and nitrogen over several decades. Raised on a Flemish farm, the author's early experiences with nitrogen in agriculture - both its benefits and dangers - laid the foundation for a lifelong interest in this element. The article traverses a broad range of topics related to nitrogen, highlighting its critical role in various historical, agricultural, environmental, and industrial contexts. The narrative begins with a historical overview of nitrogen's role in agriculture and warfare. The development of industrial processes like the Haber and Ostwald methods transformed nitrogen into a key ingredient for both fertilizers and explosives. The dual nature of nitrogen - as a life-giver in agriculture and a destructive component in warfare and also in biodiversity - is an important theme. The article delves into the environmental impacts of nitrogen, particularly in the context of modern agriculture and industrialization. Issues like fertilization, water contamination, and the challenges of managing nitrogenous waste highlight the complex interplay between human activities and environmental health. Technological advancements are explored, including the development of bioaugmentation methods and the potential of genetic engineering in optimizing nitrogen fixation. Throughout the narrative, personal anecdotes are weaved with scientific information, offering a unique perspective on the historical and contemporary challenges of managing nitrogen. The discussion extends to the broader implications of nitrogen management in the context of sustainability, climate change, and global food security and its overall regulatory space. All these considerations call for a re-evaluation of our relationship with nitrogen, advocating for innovative solutions and systemic thinking to address the multifaceted challenges posed by this essential, yet often problematic element.
Collapse
Affiliation(s)
- W Verstraete
- Centre for Microbial Ecology and Technology, Ghent University, Belgium.
| |
Collapse
|
2
|
Lu Y, Wang F, Min J, Kronzucker HJ, Hua Y, Yu H, Zhou F, Shi W. Biological mitigation of soil nitrous oxide emissions by plant metabolites. GLOBAL CHANGE BIOLOGY 2024; 30:e17333. [PMID: 38798169 DOI: 10.1111/gcb.17333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 05/29/2024]
Abstract
Plant metabolites significantly affect soil nitrogen (N) cycling, but their influence on nitrous oxide (N2O) emissions has not been quantitatively analyzed on a global scale. We conduct a comprehensive meta-analysis of 173 observations from 42 articles to evaluate global patterns of and principal factors controlling N2O emissions in the presence of root exudates and extracts. Overall, plant metabolites promoted soil N2O emissions by about 10%. However, the effects of plant metabolites on N2O emissions from soils varied with experimental conditions and properties of both metabolites and soils. Primary metabolites, such as sugars, amino acids, and organic acids, strongly stimulated soil N2O emissions, by an average of 79%, while secondary metabolites, such as phenolics, terpenoids, and flavonoids, often characterized as both biological nitrification inhibitors (BNIs) and biological denitrification inhibitors (BDIs), reduced soil N2O emissions by an average of 41%. The emission mitigation effects of BNIs/BDIs were closely associated with soil texture and pH, increasing with increasing soil clay content and soil pH on acidic and neutral soils, and with decreasing soil pH on alkaline soils. We furthermore present soil incubation experiments that show that three secondary metabolite types act as BNIs to reduce N2O emissions by 32%-45%, while three primary metabolite classes possess a stimulatory effect of 56%-63%, confirming the results of the meta-analysis. Our results highlight the potential role and application range of specific secondary metabolites in biomitigation of global N2O emissions and provide new biological parameters for N2O emission models that should help improve the accuracy of model predictions.
Collapse
Affiliation(s)
- Yufang Lu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Fangjia Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ju Min
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Herbert J Kronzucker
- School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Yao Hua
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Haoming Yu
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, China
| | - Feng Zhou
- Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, China
- Jiangsu Province Engineering Research Center of Watershed Geospatial Intelligence, College of Geography and Remote Sensing, Hohai University, Nanjing, China
- Southwest United Graduate School, Kunming, China
| | - Weiming Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China
| |
Collapse
|
3
|
Lu Y, Kronzucker HJ, Yu M, Shabala S, Shi W. Nitrogen-loss and carbon-footprint reduction by plant-rhizosphere exudates. TRENDS IN PLANT SCIENCE 2024; 29:469-481. [PMID: 37802692 DOI: 10.1016/j.tplants.2023.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 09/02/2023] [Accepted: 09/08/2023] [Indexed: 10/08/2023]
Abstract
Low-carbon approaches to agriculture constitute a pivotal measure to address the challenge of global climate change. In agroecosystems, rhizosphere exudates are significantly involved in regulating the nitrogen (N) cycle and facilitating belowground chemical communication between plants and soil microbes to reduce direct and indirect emissions of greenhouse gases (GHGs) and control N runoff from cultivated sites into natural water bodies. Here, we discuss specific rhizosphere exudates from plants and microorganisms and the mechanisms by which they reduce N loss and subsequent N pollution in terrestrial and aquatic environments, including biological nitrification inhibitors (BNIs), biological denitrification inhibitors (BDIs), and biological denitrification promoters (BDPs). We also highlight promising application scenarios and challenges in relation to rhizosphere exudates in terrestrial and aquatic environments.
Collapse
Affiliation(s)
- Yufang Lu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Herbert J Kronzucker
- School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Min Yu
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000, China
| | - Sergey Shabala
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan 528000, China; School of Biological Sciences, University of Western Australia, Crawley, WA 6009, Australia
| | - Weiming Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| |
Collapse
|
4
|
Petroli CD, Subbarao GV, Burgueño JA, Yoshihashi T, Li H, Franco Duran J, Pixley KV. Genetic variation among elite inbred lines suggests potential to breed for BNI-capacity in maize. Sci Rep 2023; 13:13422. [PMID: 37591891 PMCID: PMC10435450 DOI: 10.1038/s41598-023-39720-3] [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: 10/06/2022] [Accepted: 07/29/2023] [Indexed: 08/19/2023] Open
Abstract
Biological nitrification inhibition (BNI) is a plant function where root systems release antibiotic compounds (BNIs) specifically aimed at suppressing nitrifiers to limit soil-nitrate formation in the root zone. Little is known about BNI-activity in maize (Zea mays L.), the most important food, feed, and energy crop. Two categories of BNIs are released from maize roots; hydrophobic and hydrophilic BNIs, that determine BNI-capacity in root systems. Zeanone is a recently discovered hydrophobic compound with BNI-activity, released from maize roots. The objectives of this study were to understand/quantify the relationship between zeanone activity and hydrophobic BNI-capacity. We assessed genetic variability among 250 CIMMYT maize lines (CMLs) characterized for hydrophobic BNI-capacity and zeanone activity, towards developing genetic markers linked to this trait in maize. CMLs with high BNI-capacity and ability to release zeanone from roots were identified. GWAS was performed using 27,085 SNPs (with unique positions on the B73v.4 reference genome, and false discovery rate = 10), and phenotypic information for BNI-capacity and zeanone production from root systems. Eighteen significant markers were identified; three associated with specific BNI-activity (SBNI), four with BNI-activity per plant (BNIPP), another ten were common between SBNI and BNIPP, and one with zeanone release. Further, 30 annotated genes were associated with the significant SNPs; most of these genes are involved in pathways of "biological process", and one (AMT5) in ammonium regulation in maize roots. Although the inbred lines in this study were not developed for BNI-traits, the identification of markers associated with BNI-capacity suggests the possibility of using these genomic tools in marker-assisted selection to improve hydrophobic BNI-capacity in maize.
Collapse
Affiliation(s)
- César D Petroli
- International Maize and Wheat Improvement Center (CIMMYT), Carretera México-Veracruz, Km. 45, El Batán, Texcoco, C.P. 56237, Mexico.
| | - Guntur V Subbarao
- Japan International Research Center for Agricultural Science, 1-1 Ohwashi, Tsukuba, Ibaraki, 305-8686, Japan
| | - Juan A Burgueño
- International Maize and Wheat Improvement Center (CIMMYT), Carretera México-Veracruz, Km. 45, El Batán, Texcoco, C.P. 56237, Mexico
| | - Tadashi Yoshihashi
- Japan International Research Center for Agricultural Science, 1-1 Ohwashi, Tsukuba, Ibaraki, 305-8686, Japan
| | - Huihui Li
- International Maize and Wheat Improvement Center (CIMMYT), Carretera México-Veracruz, Km. 45, El Batán, Texcoco, C.P. 56237, Mexico
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences (CAAS), No 12 Zhongguancun South Street, Beijing, 10081, China
| | - Jorge Franco Duran
- Departamento de Biometría y Estadística, Facultad de Agronomía, Universidad de la República, Ruta 3, Km 363, C.P. 60000, Paysandú, Uruguay
| | - Kevin V Pixley
- International Maize and Wheat Improvement Center (CIMMYT), Carretera México-Veracruz, Km. 45, El Batán, Texcoco, C.P. 56237, Mexico
| |
Collapse
|
5
|
Jáuregui I, Vega-Mas I, Delaplace P, Vanderschuren H, Thonar C. An optimized hydroponic pipeline for large-scale identification of wheat genotypes with resilient biological nitrification inhibition activity. THE NEW PHYTOLOGIST 2023; 238:1711-1721. [PMID: 36764923 DOI: 10.1111/nph.18807] [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: 09/05/2022] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Several plant species have been reported to inhibit nitrification via their root exudates, the so-called biological nitrification inhibition (BNI). Given the potential of BNI-producing plants to sustainably mitigate N losses in agrosystems, identification of BNI activity in existing germplasms is of paramount importance. A hydroponic system was combined with an optimized Nitrosomonas europaea-based bioassay to determine the BNI activity of root exudates. The pipeline allows collecting and processing hundreds of root exudates simultaneously. An additional assay was established to assess the potential bactericide effect of the root exudates. The pipeline was used to unravel the impact of developmental stage, temperature and osmotic stress on the BNI trait in selected wheat genotypes. Biological nitrification inhibition activity appeared consistently higher in wheat at the pretillering stage as compared to the tillering stage. While low-temperatures did not alter BNI activities in root exudates, osmotic stress appeared to change the BNI activity in a genotype-dependent manner. Further analysis of Nitrosomonas culture after pre-exposure to root exudates suggested that BNI activity has no or limited bactericide effects. The present pipeline will be instrumental to further investigating the dynamics of BNI activity and to uncover the diversity of the BNI trait in plant species.
Collapse
Affiliation(s)
- Iván Jáuregui
- Plant Genetics and Rhizosphere Processes laboratory, Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre, University of Liège, B-5030, Gembloux, Belgium
| | - Izargi Vega-Mas
- Plant Genetics and Rhizosphere Processes laboratory, Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre, University of Liège, B-5030, Gembloux, Belgium
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), 48940, Bilbao, Spain
| | - Pierre Delaplace
- Plant Genetics and Rhizosphere Processes laboratory, Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre, University of Liège, B-5030, Gembloux, Belgium
| | - Hervé Vanderschuren
- Plant Genetics and Rhizosphere Processes laboratory, Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre, University of Liège, B-5030, Gembloux, Belgium
- Tropical Crop Improvement Laboratory, Biosystems Department, KU Leuven, B-3001, Leuven, Belgium
| | - Cécile Thonar
- Plant Genetics and Rhizosphere Processes laboratory, Gembloux Agro-Bio Tech, TERRA Teaching and Research Centre, University of Liège, B-5030, Gembloux, Belgium
- Agroecology Lab, Université Libre de Bruxelles (ULB), B-1050, Brussels, Belgium
| |
Collapse
|
6
|
Lu Y, Hua Y, Lv N, Zu W, Kronzucker HJ, Dong G, Shi W. Syringic acid from rice roots inhibits soil nitrification and N 2O emission under red and paddy soils but not a calcareous soil. FRONTIERS IN PLANT SCIENCE 2022; 13:1099689. [PMID: 36605956 PMCID: PMC9808040 DOI: 10.3389/fpls.2022.1099689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Syringic acid (SA) is a novel biological nitrification inhibitor (BNIs) discovered in rice root exudates with significant inhibition of Nitrosomonas strains. However, the inhibitory effect of SA on nitrification and nitrous oxide (N2O) emissions in different soils and the environmental factors controlling the degree of inhibition have not been studied. Using 14-day microcosm incubation, we investigated the effects of different concentrations of SA on nitrification activity, abundance of ammonia-oxidizing microorganisms, and N2O emissions in three typical agricultural soils. The nitrification inhibitory efficacy of SA was strongest in acidic red soil, followed by weakly acidic paddy soil, with no significant effect in an alkaline calcareous soil. Potential nitrification activity (PNA) were also greatly reduced by SA additions in paddy and red soil. Pearson correlation analysis showed that the inhibitory efficacy of SA might be negatively correlated with soil pH and positively correlated with clay percentage. SA treatments significantly reduced N2O emissions by 69.1-79.3% from paddy soil and by 40.8%-46.4% from red soil, respectively, but no effect was recorded in the calcareous soil. SA addition possessed dual inhibition of both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) abundance in paddy and red soil. Structural equation modelling revealed that soil ammonium (NH4 +) and dissolved organic carbon content (DOC) were the key variables explaining AOA and AOB abundance and subsequent N2O emissions. Our results support the potential for the use of the BNI SA in mitigating N2O emissions and enhancing N utilization in red and paddy soils.
Collapse
Affiliation(s)
- Yufang Lu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yao Hua
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Na Lv
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Weijun Zu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Herbert J. Kronzucker
- School of BioSciences, The University of Melbourne, Parkville, VIC, Australia
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, Canada
| | | | - Weiming Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
7
|
Higgins J, Tomaszewska P, Pellny TK, Castiblanco V, Arango J, Tohme J, Schwarzacher T, Mitchell RA, Heslop-Harrison JS, De Vega JJ. Diverged subpopulations in tropical Urochloa (Brachiaria) forage species indicate a role for facultative apomixis and varying ploidy in their population structure and evolution. ANNALS OF BOTANY 2022; 130:657-669. [PMID: 36112370 PMCID: PMC9670755 DOI: 10.1093/aob/mcac115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 09/13/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Urochloa (syn. Brachiaria) is a genus of tropical grasses sown as forage feedstock, particularly in marginal soils. Here we aimed to clarify the genetic diversity and population structure in Urochloa species to understand better how population evolution relates to ploidy level and occurrence of apomictic reproduction. METHODS We explored the genetic diversity of 111 accessions from the five Urochloa species used to develop commercial cultivars. These accessions were conserved from wild materials collected at their centre of origin in Africa, and they tentatively represent the complete Urochloa gene pool used in breeding programmes. We used RNA-sequencing to generate 1.1 million single nucleotide polymorphism loci. We employed genetic admixture, principal component and phylogenetic analyses to define subpopulations. RESULTS We observed three highly differentiated subpopulations in U. brizantha, which were unrelated to ploidy: one intermixed with U. decumbens, and two diverged from the former and the other species in the complex. We also observed two subpopulations in U. humidicola, unrelated to ploidy; one subpopulation had fewer accessions but included the only characterized sexual accession in the species. Our results also supported a division of U. decumbens between diploids and polyploids, and no subpopulations within U. ruziziensis and U. maxima. CONCLUSIONS Polyploid U. decumbens are more closely related to polyploid U. brizantha than to diploid U. decumbens, which supports the divergence of both polyploid groups from a common tetraploid ancestor and provides evidence for the hybridization barrier of ploidy. The three differentiated subpopulations of apomictic polyploid U. brizantha accessions constitute diverged ecotypes, which can probably be utilized in hybrid breeding. Subpopulations were not observed in non-apomictic U. ruziziensis. Sexual Urochloa polyploids were not found (U. brizantha, U. decumbens) or were limited to small subpopulations (U. humidicola). The subpopulation structure observed in the Urochloa sexual-apomictic multiploidy complexes supports geographical parthenogenesis, where the polyploid genotypes exploit the evolutionary advantage of apomixis, i.e. uniparental reproduction and clonality, to occupy extensive geographical areas.
Collapse
Affiliation(s)
- J Higgins
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK
| | - P Tomaszewska
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
- Department of Genetics and Cell Physiology, Faculty of Biological Sciences, University of Wroclaw, 50-328 Wroclaw, Poland
| | - T K Pellny
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - V Castiblanco
- International Center for Tropical Agriculture (CIAT), 6713 Cali, Colombia
| | - J Arango
- International Center for Tropical Agriculture (CIAT), 6713 Cali, Colombia
| | - J Tohme
- International Center for Tropical Agriculture (CIAT), 6713 Cali, Colombia
| | - T Schwarzacher
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - R A Mitchell
- Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
| | - J S Heslop-Harrison
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization/Guangdong Provincial, Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | | |
Collapse
|
8
|
Díaz-García L, Chaparro D, Jiménez H, Gómez-Ramírez LF, Bernal AJ, Burbano-Erazo E, Jiménez DJ. Top-Down Enrichment Strategy to Co-cultivate Lactic Acid and Lignocellulolytic Bacteria From the Megathyrsus maximus Phyllosphere. Front Microbiol 2022; 12:744075. [PMID: 35035382 PMCID: PMC8753987 DOI: 10.3389/fmicb.2021.744075] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 10/11/2021] [Indexed: 12/15/2022] Open
Abstract
Traditionally, starting inoculants have been applied to improve ensiling of forage used for livestock feed. Here, we aimed to build up a bioinoculant composed of lactic acid-producing and lignocellulolytic bacteria (LB) derived from the Megathyrsus maximus (guinea grass) phyllosphere. For this, the dilution-to-stimulation approach was used, including a sequential modification of the starting culture medium [Man, Rogosa, and Sharpe (MRS) broth] by addition of plant biomass (PB) and elimination of labile carbon sources. Along 10 growth-dilution steps (T1–T10), slight differences were observed in terms of bacterial diversity and composition. After the sixth subculture, the consortium started to degrade PB, decreasing its growth rate. The co-existence of Enterobacteriales (fast growers and highly abundance), Actinomycetales, Bacillales, and Lactobacillales species was observed at the end of the selection process. However, a significant structural change was noticed when the mixed consortium was cultivated in higher volume (500ml) for 8days, mainly increasing the proportion of Paenibacillaceae populations. Interestingly, Actinomycetales, Bacillales, and Lactobacillales respond positively to a pH decrease (4–5), suggesting a relevant role within a further silage process. Moreover, gene-centric metagenomic analysis showed an increase of (hemi)cellulose-degrading enzymes (HDEs) during the enrichment strategy. Reconstruction of metagenome-assembled genomes (MAGs) revealed that Paenibacillus, Cellulosimicrobium, and Sphingomonas appear as key (hemi)cellulolytic members (harboring endo-glucanases/xylanases, arabinofuranosidases, and esterases), whereas Enterococcus and Cellulosimicrobium have the potential to degrade oligosaccharides, metabolize xylose and might produce lactic acid through the phosphoketolase (PK) pathway. Based on this evidence, we conclude that our innovative top-down strategy enriched a unique bacterial consortium that could be useful in biotechnological applications, including the development/design of a synthetic bioinoculant to improve silage processes.
Collapse
Affiliation(s)
- Laura Díaz-García
- Microbiomes and Bioenergy Research Group, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Dayanne Chaparro
- Microbiomes and Bioenergy Research Group, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Hugo Jiménez
- Colombian Corporation for Agricultural Research (Agrosavia), Mosquera, Colombia
| | | | - Adriana J Bernal
- Laboratory of Molecular Interactions of Agricultural Microbes, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | | | - Diego Javier Jiménez
- Microbiomes and Bioenergy Research Group, Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| |
Collapse
|
9
|
Hanley SJ, Pellny TK, de Vega JJ, Castiblanco V, Arango J, Eastmond PJ, Heslop-Harrison JS(P, Mitchell RAC. Allele mining in diverse accessions of tropical grasses to improve forage quality and reduce environmental impact. ANNALS OF BOTANY 2021; 128:627-637. [PMID: 34320174 PMCID: PMC8422886 DOI: 10.1093/aob/mcab101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND AIMS The C4Urochloa species (syn. Brachiaria) and Megathyrsus maximus (syn. Panicum maximum) are used as pasture for cattle across vast areas in tropical agriculture systems in Africa and South America. A key target for variety improvement is forage quality: enhanced digestibility could decrease the amount of land required per unit production, and enhanced lipid content could decrease methane emissions from cattle. For these traits, loss-of-function (LOF) alleles in known gene targets are predicted to improve them, making a reverse genetics approach of allele mining feasible. We therefore set out to look for such alleles in diverse accessions of Urochloa species and Megathyrsus maximus from the genebank collection held at the CIAT. METHODS We studied allelic diversity of 20 target genes (11 for digestibility, nine for lipid content) in 104 accessions selected to represent genetic diversity and ploidy levels of U. brizantha, U. decumbens, U. humidicola, U. ruziziensis and M. maximum. We used RNA sequencing and then bait capture DNA sequencing to improve gene models in a U. ruziziensis reference genome to assign polymorphisms with high confidence. KEY RESULTS We found 953 non-synonymous polymorphisms across all genes and accessions; within these, we identified seven putative LOF alleles with high confidence, including those in the non-redundant SDP1 and BAHD01 genes present in diploid and tetraploid accessions. These LOF alleles could respectively confer increased lipid content and digestibility if incorporated into a breeding programme. CONCLUSIONS We demonstrated a novel, effective approach to allele discovery in diverse accessions using a draft reference genome from a single species. We used this to find gene variants in a collection of tropical grasses that could help reduce the environmental impact of cattle production.
Collapse
Affiliation(s)
| | | | | | | | - Jacobo Arango
- International Center for Tropical Agriculture (CIAT), Cali, Colombia
| | | | | | | |
Collapse
|
10
|
Wang X, Bai J, Xie T, Wang W, Zhang G, Yin S, Wang D. Effects of biological nitrification inhibitors on nitrogen use efficiency and greenhouse gas emissions in agricultural soils: A review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 220:112338. [PMID: 34015632 DOI: 10.1016/j.ecoenv.2021.112338] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/26/2021] [Accepted: 05/10/2021] [Indexed: 05/27/2023]
Abstract
To maintain and increase crop yields, large amounts of nitrogen fertilizers have been applied to farmland. However, the nitrogen use efficiency (NUE) of chemical fertilizer remains very low, which may lead to serious environmental problems, including nitrate pollution, air quality degradation and greenhouse gas (GHG) emissions. Nitrification inhibitors can alleviate nitrogen loss by inhibiting nitrification; thus, biological nitrification inhibition by plants has gradually attracted increasing attention due to its low cost and environmental friendliness. Research progress on BNI is reviewed in this article, including the source, mechanisms, influencing factors and application of BNIs. In addition, the impact of BNI on agriculture and GHG emissions is summarized from the perspective of agricultural production and environmental protection, and the key future research prospects of BNIs are also noted.
Collapse
Affiliation(s)
- Xin Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Junhong Bai
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
| | - Tian Xie
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Wei Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Guangliang Zhang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Shuo Yin
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| | - Dawei Wang
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China
| |
Collapse
|
11
|
Durango Morales SG, Barahona R, Bolívar DM, Arango J, Verchot L, Chirinda N. Apparent Nitrogen Recovery in Milk and Early Dry Season Nitrous Oxide Emission Factors for Urine Deposited by Dual-Purpose Cattle on Different Soil Types. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021. [DOI: 10.3389/fsufs.2020.602657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pasture conditions influence the nutrients use efficiency and nitrogen (N) losses from deposited excreta. Part of the N is lost as nitrous oxide (N2O), a potent greenhouse gas. The objective of this study was to characterize apparent N recovery in milk of dual-purpose cattle and to quantify N2O emissions from the urine they deposit following grazing on Megathyrsus maximus cv. Mombasa. The N content in the grass and the milk produced by the cattle and the milk urea N (MUN) content were quantified in two contrasting regions of Colombia (Casanare and Atlántico). Dry matter intake (DMI) by the cattle was estimated using the Cornell Net Carbohydrate and Protein System. We used a closed static chamber technique to measure N2O emissions from soils in areas with and without urine patches (21 days in Atlántico and 35 Days in Casanare). Estimated DMI values were 11.5 and 11.6 kg DM day−1, milk production was 6.5 and 5.9 L day−1, apparent N recovery in milk was 24 and 23%, and the MUN content was 4.4 and 17.2 mg N dl−1 in Casanare and Atlántico, respectively. N applied to soil in the form of urine corresponded at rates of 20 and 64 g N m−2 and net cumulative N2O emissions were 350 and 20 mg N2O-N m−2 in Casanare and Atlántico, respectively. Despite low digestibility of offered diet, N recovery in milk was above the values reported at dairy cattle in tropical conditions. High urine-N inputs at Atlántico site did not result in high N2O emissions suggesting that the default Tier 1 emission factor (EF) which is based on N inputs would have overestimated urine-based N2O emissions in Atlántico. Comparing previous studies conducted in Colombia, we observed inter-regional differences by urine-based N2O emissions. This observation suggests that to increase certainty in estimating urine-based N2O emissions, Colombia needs to move toward more region-specific Tier 2 EF and reduce its dependence on the default IPCC Tier 1 EF. In addition, the adoption of Tier 2 EF in the cattle sector will facilitate accounting for the effect of animal diets on N2O inventories.
Collapse
|
12
|
Baptistella JLC, de Andrade SAL, Favarin JL, Mazzafera P. Urochloa in Tropical Agroecosystems. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2020. [DOI: 10.3389/fsufs.2020.00119] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|