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Wang X, Zhang Y, Lian Z, Lyu X, Yan C, Yan S, Gong Z, Li S, Ma C. Nitrate Inhibits Nodule Nitrogen Fixation by Accumulating Ureide in Soybean Plants. PLANTS (BASEL, SWITZERLAND) 2024; 13:2045. [PMID: 39124162 PMCID: PMC11313793 DOI: 10.3390/plants13152045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2024] [Revised: 07/10/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024]
Abstract
The mechanism by which nitrate inhibits nitrogen fixation in soybean (Glycine max L.) is not fully understood. Accumulation of ureide in soybean plant tissues may regulate the nitrogen fixation capacity through a feedback pathway. In this study, unilaterally nodulated dual-root soybeans prepared by grafting were grown in sand culture. They were subjected to the removal of the nodulated side roots, and were given either nitrate supply or no supply to the non-nodulated side roots for 3 days (experiment I). Additionally, they received nitrate supply to the non-nodulated side roots for 1-14 days (experiment II). The results showed that nitrate supply increased the levels of asparagine and ureide in soybean shoots (Experiment I). In Experiment II, nodule dry weight, nodule number, nodule nitrogenase activity, and nodule urate oxidase activity decreased significantly after 3, 7, and 14 days of nitrate supply. Ureide content in the shoots and nodules increased after 1, 3, and 7 days of nitrate supply, but decreased after 14 days of nitrate supply. There was a significant positive correlation between urate oxidase activity and nitrogenase activity. Hence, we deduced that nitrate supply increased the asparagine content in soybean shoots, likely inhibiting ureide degradation, which induced the accumulation of ureide in soybean shoots and nodules, and, in turn, feedback inhibited the nodule nitrogen fixation. In addition, urate oxidase activity can be used to assess the nitrogen fixation capacity of nodules.
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Affiliation(s)
- Xuelai Wang
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.W.); (Y.Z.); (Z.L.); (X.L.); (C.Y.); (S.Y.); (Z.G.)
| | - Yuchen Zhang
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.W.); (Y.Z.); (Z.L.); (X.L.); (C.Y.); (S.Y.); (Z.G.)
| | - Zhaohui Lian
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.W.); (Y.Z.); (Z.L.); (X.L.); (C.Y.); (S.Y.); (Z.G.)
| | - Xiaochen Lyu
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.W.); (Y.Z.); (Z.L.); (X.L.); (C.Y.); (S.Y.); (Z.G.)
| | - Chao Yan
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.W.); (Y.Z.); (Z.L.); (X.L.); (C.Y.); (S.Y.); (Z.G.)
| | - Shuangshuang Yan
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.W.); (Y.Z.); (Z.L.); (X.L.); (C.Y.); (S.Y.); (Z.G.)
| | - Zhenping Gong
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.W.); (Y.Z.); (Z.L.); (X.L.); (C.Y.); (S.Y.); (Z.G.)
| | - Sha Li
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Chunmei Ma
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.W.); (Y.Z.); (Z.L.); (X.L.); (C.Y.); (S.Y.); (Z.G.)
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Gao Y, Zhu J, Zhai H, Xu K, Zhu X, Wu H, Zhang W, Wu S, Chen X, Xia Z. Dysfunction of an Anaphase-Promoting Complex Subunit 8 Homolog Leads to Super-Short Petioles and Enlarged Petiole Angles in Soybean. Int J Mol Sci 2023; 24:11024. [PMID: 37446203 DOI: 10.3390/ijms241311024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/22/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
Plant height, petiole length, and the angle of the leaf petiole and branch angles are crucial traits determining plant architecture and yield in soybean (Glycine max L.). Here, we characterized a soybean mutant with super-short petioles (SSP) and enlarged petiole angles (named Gmssp) through phenotypic observation, anatomical structure analysis, and bulk sequencing analysis. To identify the gene responsible for the Gmssp mutant phenotype, we established a pipeline involving bulk sequencing, variant calling, functional annotation by SnpEFF (v4.0e) software, and Integrative Genomics Viewer analysis, and we initially identified Glyma.11G026400, encoding a homolog of Anaphase-promoting complex subunit 8 (APC8). Another mutant, t7, with a large deletion of many genes including Glyma.11G026400, has super-short petioles and an enlarged petiole angle, similar to the Gmssp phenotype. Characterization of the t7 mutant together with quantitative trait locus mapping and allelic variation analysis confirmed Glyma.11G026400 as the gene involved in the Gmssp phenotype. In Gmssp, a 4 bp deletion in Glyma.11G026400 leads to a 380 aa truncated protein due to a premature stop codon. The dysfunction or absence of Glyma.11G026400 caused severe defects in morphology, anatomical structure, and physiological traits. Transcriptome analysis and weighted gene co-expression network analysis revealed multiple pathways likely involved in these phenotypes, including ubiquitin-mediated proteolysis and gibberellin-mediated pathways. Our results demonstrate that dysfunction of Glyma.11G026400 leads to diverse functional consequences in different tissues, indicating that this APC8 homolog plays key roles in cell differentiation and elongation in a tissue-specific manner. Deciphering the molecular control of petiole length and angle enriches our knowledge of the molecular network regulating plant architecture in soybean and should facilitate the breeding of high-yielding soybean cultivars with compact plant architecture.
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Affiliation(s)
- Yi Gao
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Harbin 150081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinlong Zhu
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Harbin 150081, China
| | - Hong Zhai
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Harbin 150081, China
| | - Kun Xu
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Harbin 150081, China
| | - Xiaobin Zhu
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Harbin 150081, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongyan Wu
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Harbin 150081, China
| | - Wenjing Zhang
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Harbin 150081, China
| | - Shihao Wu
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Xin Chen
- Institute of Industrial Crops, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Zhengjun Xia
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Innovative Academy of Seed Design, Chinese Academy of Sciences, Harbin 150081, China
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Li S, Wu C, Liu H, Lyu X, Xiao F, Zhao S, Ma C, Yan C, Liu Z, Li H, Wang X, Gong Z. Systemic regulation of nodule structure and assimilated carbon distribution by nitrate in soybean. FRONTIERS IN PLANT SCIENCE 2023; 14:1101074. [PMID: 36814755 PMCID: PMC9939697 DOI: 10.3389/fpls.2023.1101074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 01/13/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND The nitrate regulates soybean nodulation and nitrogen fixation systemically, mainly in inhibiting nodule growth and reducing nodule nitrogenase activity, but the reason for its inhibition is still inconclusive. METHODS The systemic effect of nitrate on nodule structure, function, and carbon distribution in soybean (Glycine max (L.) Merr.) was studied in a dual-root growth system, with both sides inoculated with rhizobia and only one side subjected to nitrate treatment for four days. The non-nodulating side was genetically devoid of the ability to form nodules. Nutrient solutions with nitrogen concentrations of 0, 100, and 200 mg L-1 were applied as KNO3 to the non-nodulating side, while the nodulating side received a nitrogen-free nutrient solution. Carbon partitioning in roots and nodules was monitored using 13C-labelled CO2. Other nodule responses were measured via the estimation of the nitrogenase activity and the microscopic observation of nodule ultrastructure. RESULTS Elevated concentrations of nitrate applied on the non-nodulating side caused a decrease in the number of bacteroids, fusion of symbiosomes, enlargement of the peribacteroid spaces, and onset of degradation of poly-β-hydroxybutyrate granules, which is a form of carbon storage in bacteroids. These microscopic observations were associated with a strong decrease in the nitrogenase activity of nodules. Furthermore, our data demonstrate that the assimilated carbon is more likely to be allocated to the non-nodulating roots, as follows from the competition for carbon between the symbiotic and non-symbiotic sides of the dual-root system. CONCLUSION We propose that there is no carbon competition between roots and nodules when they are indirectly supplied with nitrate, and that the reduction of carbon fluxes to nodules and roots on the nodulating side is the mechanism by which the plant systemically suppresses nodulation under nitrogen-replete conditions.
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Affiliation(s)
- Sha Li
- College of Resources and Environment, Northeast Agricultural University, Harbin, China
| | - Chengbin Wu
- College of Resources and Environment, Northeast Agricultural University, Harbin, China
| | - Hao Liu
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Xiaochen Lyu
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Fengsheng Xiao
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Shuhong Zhao
- College of Engineering, Northeast Agricultural University, Harbin, China
| | - Chunmei Ma
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Chao Yan
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Zhilei Liu
- College of Resources and Environment, Northeast Agricultural University, Harbin, China
| | - Hongyu Li
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Xuelai Wang
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Zhenping Gong
- College of Agriculture, Northeast Agricultural University, Harbin, China
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Lyu X, Sun C, Lin T, Wang X, Li S, Zhao S, Gong Z, Wei Z, Yan C, Ma C. Systemic regulation of soybean nodulation and nitrogen fixation by nitrogen via isoflavones. FRONTIERS IN PLANT SCIENCE 2022; 13:968496. [PMID: 36035684 PMCID: PMC9403732 DOI: 10.3389/fpls.2022.968496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Nitrogen (N) inhibits soybean (Glycine max L.) nodulation and N2 fixation. Isoflavones secreted by soybean roots can stimulate signal transduction for symbiotic nodules, thus playing a key role in root nodule development and N2 fixation. The relationship between the inhibition of soybean nodulation, N2 fixation and isoflavones by N is still unclear. In this study, dual-root soybean plants were prepared by grafting, and N or isoflavones were supplied to unilateral roots. The number and dry weight of the soybean nodules, nitrogenase activity, isoflavone concentrations and relative changes in the level of expression of nodulation-related genes were measured to study the response relationship between the N systemic regulation the soybean nodule N2 fixation and changes in the concentrations of isoflavones in its roots. The results showed that N supply to one side of the dual-root soybeans systematically affected the N2 fixation of root nodules on both sides, and this effect began in the early stage of nodulation. Moreover, a unilateral supply of N systematically affected the concentrations of daidzein and genistein on both sides of the roots. The concentrations of isoflavones were consistent with the change trend of soybean root nodule and nodulation-related gene expression level. Treatment with unilateral N or isoflavones affected the soybean nodule N2 fixation and its nodulation-related genes, which had the same response to the changes in concentrations of root isoflavones. N regulates soybean nodulation and N2 fixation by systematically affecting the concentrations of isoflavones in the roots.
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Affiliation(s)
- Xiaochen Lyu
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Chunyan Sun
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Tao Lin
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Xuelai Wang
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Sha Li
- College of Agriculture, Northeast Agricultural University, Harbin, China
- College of Resources and Environment, Northeast Agricultural University, Harbin, China
| | - Shuhong Zhao
- College of Agriculture, Northeast Agricultural University, Harbin, China
- College of Engineering, Northeast Agricultural University, Harbin, China
| | - Zhenping Gong
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Ziwei Wei
- Harbin Agricultural Technology Extension Station, Harbin, China
| | - Chao Yan
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Chunmei Ma
- College of Agriculture, Northeast Agricultural University, Harbin, China
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Vincent B, Hannibal L, Galiana A, Ducousso M, Jourand P. Respective and combined roles of rhizobia and ectomycorrhizal fungi in the plant growth, symbiotic efficiency, nutrients and metals contents of a leguminous tree species growing on ultramafic soils. Symbiosis 2022. [DOI: 10.1007/s13199-022-00850-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kafle A, Frank HER, Rose BD, Garcia K. Split down the middle: studying arbuscular mycorrhizal and ectomycorrhizal symbioses using split-root assays. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1288-1300. [PMID: 34791191 DOI: 10.1093/jxb/erab489] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
Most land plants symbiotically interact with soil-borne fungi to ensure nutrient acquisition and tolerance to various environmental stressors. Among these symbioses, arbuscular mycorrhizal and ectomycorrhizal associations can be found in a large proportion of plants, including many crops. Split-root assays are widely used in plant research to study local and systemic signaling responses triggered by local treatments, including nutrient availability, interaction with soil microbes, or abiotic stresses. However, split-root approaches have only been occasionally used to tackle these questions with regard to mycorrhizal symbioses. This review compiles and discusses split-root assays developed to study arbuscular mycorrhizal and ectomycorrhizal symbioses, with a particular emphasis on colonization by multiple beneficial symbionts, systemic resistance induced by mycorrhizal fungi, water and nutrient transport from fungi to colonized plants, and host photosynthate allocation from the host to fungal symbionts. In addition, we highlight how the use of split-root assays could result in a better understanding of mycorrhizal symbioses, particularly for a broader range of essential nutrients, and for multipartite interactions.
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Affiliation(s)
- Arjun Kafle
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Hannah E R Frank
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Benjamin D Rose
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Kevin Garcia
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, NC 27695, USA
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Lyu X, Sun C, Zhang J, Wang C, Zhao S, Ma C, Li S, Li H, Gong Z, Yan C. Integrated Proteomics and Metabolomics Analysis of Nitrogen System Regulation on Soybean Plant Nodulation and Nitrogen Fixation. Int J Mol Sci 2022; 23:2545. [PMID: 35269687 PMCID: PMC8910638 DOI: 10.3390/ijms23052545] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 02/01/2023] Open
Abstract
The specific mechanisms by which nitrogen affects nodulation and nitrogen fixation in leguminous crops are still unclear. To study the relationship between nitrogen, nodulation and nitrogen fixation in soybeans, dual-root soybean plants with unilateral nodulation were prepared by grafting. At the third trifoliate leaf (V3) to fourth trifoliate leaf (V4) growth stages (for 5 days), nitrogen nutrient solution was added to the non-nodulated side, while nitrogen-free nutrient solution was added to the nodulated side. The experiment was designed to study the effects of exogenous nitrogen on proteins and metabolites in root nodules and provide a theoretical reference for analyzing the physiological mechanisms of the interaction between nitrogen application and nitrogen fixation in soybean root nodules. Compared with no nitrogen treatment, exogenous nitrogen regulated the metabolic pathways of starch and sucrose metabolism, organic acid metabolism, nitrogen metabolism, and amino acid metabolism, among others. Additionally, exogenous nitrogen promoted the synthesis of signaling molecules, including putrescine, nitric oxide, and asparagine in root nodules, and inhibited the transformation of sucrose to malic acid; consequently, the rhizobia lacked energy for nitrogen fixation. In addition, exogenous nitrogen reduced cell wall synthesis in the root nodules, thus inhibiting root nodule growth and nitrogen fixation.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Zhenping Gong
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.L.); (C.S.); (J.Z.); (C.W.); (S.Z.); (C.M.); (S.L.); (H.L.)
| | - Chao Yan
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (X.L.); (C.S.); (J.Z.); (C.W.); (S.Z.); (C.M.); (S.L.); (H.L.)
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Shan F, Zhang R, Zhang J, Wang C, Lyu X, Xin T, Yan C, Dong S, Ma C, Gong Z. Study on the Regulatory Effects of GA 3 on Soybean Internode Elongation. PLANTS 2021; 10:plants10081737. [PMID: 34451783 PMCID: PMC8398907 DOI: 10.3390/plants10081737] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 07/31/2021] [Accepted: 08/19/2021] [Indexed: 12/03/2022]
Abstract
Excessive plant height is an important factor that can lead to lodging, which is closely related to soybean yield. Gibberellins are widely used as plant growth regulators in agricultural production. Gibberellic acid (GA3), one of the most effective active gibberellins, has been used to regulate plant height and increase yields. The mechanism through which GA3 regulates internode elongation has been extensively investigated. In 2019 and 2020, we applied GA3 to the stems, leaves, and roots of two soybean cultivars, Heinong 48 (a high-stalk cultivar) and Henong 60 (a dwarf cultivar), and GA3 was also applied to plants whose apical meristem was removed or to girded plants to compare the internode length and stem GA3 content of soybean plants under different treatments. These results suggested that the application of GA3 to the stems, leaves, and roots of soybean increased the internode length and GA3 content in the stems. Application of GA3 decreased the proportion of the pith in the soybean stems and primary xylem while increasing the proportion of secondary xylem. The apical meristem is an important site of GA3 synthesis in soybean stems and is involved in the regulation of stem elongation. GA3 was shown to be transported acropetally through the xylem and laterally between the xylem and phloem in soybean stems. We conclude that the GA3 level in stems is an important factor affecting internode elongation.
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Affiliation(s)
- Fuxin Shan
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
| | - Rui Zhang
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
- College of Agronomy and Biotechnology, Yunnan Agricultural University, Kunming 650201, China
| | - Jin Zhang
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
| | - Chang Wang
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
| | - Xiaochen Lyu
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
| | - Tianyu Xin
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
| | - Chao Yan
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
| | - Shoukun Dong
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
| | - Chunmei Ma
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
| | - Zhenping Gong
- College of Agriculture, Northeast Agricultural University, Harbin 150030, China; (F.S.); (R.Z.); (J.Z.); (C.W.); (X.L.); (T.X.); (C.Y.); (S.D.); (C.M.)
- Correspondence:
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Thilakarathna MS, Cope KR. Split-root assays for studying legume-rhizobia symbioses, rhizodeposition, and belowground nitrogen transfer in legumes. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5285-5299. [PMID: 33954584 DOI: 10.1093/jxb/erab198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/03/2021] [Indexed: 06/12/2023]
Abstract
Split-root assays have been used widely in studies focused on understanding the complex regulatory mechanisms in legume-rhizobia symbioses, root nitrogen rhizodeposition, and belowground nitrogen transfer, and the effects of different biotic/abiotic factors on this symbiotic interaction. This assay allows a plant to have a root system that is physically divided into two distinct sections that are both still attached to a common shoot. Thus, each root section can be treated separately to monitor local and systemic plant responses. Different techniques are used to establish split-root assemblies, including double-pot systems, divided growth pouches, elbow root assembly, twin-tube systems, a single pot or chamber with a partition in the center, and divided agar plates. This review is focused on discussing the various types of split-root assays currently used in legume-based studies, and their associated advantages and limitations. Furthermore, this review also focuses on how split-root assays have been used for studies on nitrogen rhizodeposition, belowground nitrogen transfer, systemic regulation of nodulation, and biotic and abiotic factors affecting legume-rhizobia symbioses.
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Affiliation(s)
- Malinda S Thilakarathna
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Kevin R Cope
- Biology and Microbiology Department, South Dakota State University, Brookings, SD, USA
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Li S, Xiao F, Yang D, Lyu X, Ma C, Dong S, Yan C, Gong Z. Nitrate Transport and Distribution in Soybean Plants With Dual-Root Systems. FRONTIERS IN PLANT SCIENCE 2021; 12:661054. [PMID: 34093618 PMCID: PMC8174562 DOI: 10.3389/fpls.2021.661054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/21/2021] [Indexed: 06/12/2023]
Abstract
Nitrate absorbed by soybean (Glycine max L. Merr.) roots from the soil can promote plant growth, while nitrate transported to nodules inhibits nodulation and nodule nitrogen fixation activity. The aim of this study was to provide new insights into the inhibition of nodule nitrogen (N) fixation by characterizing the transport and distribution of nitrate in soybean plants. In this research, pot culture experiments were conducted using a dual root system of soybeans. In the first experiment, the distribution of 15N derived from nitrate was observed. In the second experiment, nitrate was supplied-withdrawal-resupplied to one side of dual-root system for nine consecutive days, and the other side was supplied with N-free solution. Nitrate contents in leaves, stems, petioles, the basal root of pealed skin and woody part at the grafting site were measured. Nitrate transport and distribution in soybean were analyzed combining the results of two experiments. The results showed that nitrate supplied to the N-supply side of the dual-root system was transported to the shoots immediately through the basal root pealed skin (the main transport route was via the phloem) and woody part (transport was chiefly related to the xylem). There was a transient storage of nitrate in the stems. After the distribution of nitrate, a proportion of the nitrate absorbed by the roots on the N-supply side was translocated to the roots and nodules on the N-free side with a combination of the basal root pealed skin and woody part. In conclusion, the basal root pealed skin and woody part are the main transport routes for nitrate up and down in soybean plants. Nitrate absorbed by roots can be transported to the shoots and then retranslocated to the roots again. The transport flux of nitrate to the N-free side was regulated by transient storage of nitrate in the stems.
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Affiliation(s)
- Sha Li
- College of Agriculture, Northeast Agricultural University, Harbin, China
- College of Resources and Environment, Northeast Agricultural University, Harbin, China
| | - Fengsheng Xiao
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Daocheng Yang
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Xiaochen Lyu
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Chunmei Ma
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Shoukun Dong
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Chao Yan
- College of Agriculture, Northeast Agricultural University, Harbin, China
| | - Zhenping Gong
- College of Agriculture, Northeast Agricultural University, Harbin, China
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Langholtz M, Davison BH, Jager HI, Eaton L, Baskaran LM, Davis M, Brandt CC. Increased nitrogen use efficiency in crop production can provide economic and environmental benefits. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 758:143602. [PMID: 33234272 DOI: 10.1016/j.scitotenv.2020.143602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 10/26/2020] [Accepted: 10/30/2020] [Indexed: 05/22/2023]
Abstract
Potential economic and environmental benefits of increasing nitrogen-use efficiency (NUE) are widely recognized but scarcely quantified. This study quantifies the effects of increased NUE on 1) the national agricultural economy using a simulation model of US agriculture and 2) regional water quality effects using a biogeochemical model for the Arkansas-White-Red river basin. National economic effects are reported for NUE improvement scenarios of 10%, 20%, 50%, and 100%, whereas regional water quality effects are estimated for a 20% NUE improvement scenario in the Arkansas-White-Red river basin. Simulating a 20% increase in NUE in row crops is shown to reduce N requirements by 1.4 million tonnes y-1 and increase farmer net profits by 1.6% ($743 million) per year by 2026 over the baseline simulation for the same period. For each 10% increase in NUE, annual farm revenues for commodity crops increased over the baseline by approximately $350 million per year by 2026. Changes in crop prices and land-use relative to the baseline were less than 2%. This suggests a net benefit even though fertilizer cost savings can result in increased cultivation of land, i.e., 'Jevon's paradox'. Results from the biogeochemical model of the Arkansas-White-Red river basin suggest that a 20% increase in NUE corresponds to a 5.72% reduction in nitrate loadings to freshwaters, with higher reductions in agricultural watersheds. The value of these reductions was estimated as $43 ha-1, for a total of $15.3 to 136.7 million yr-1 in avoided water treatment costs. After estimating the social value of increased NUE, we conclude with a discussion of potential strategies to increase efficiency and the research needed to achieve this goal. These include perennialization of the agricultural landscape, genetic crop improvement, targeted fertilizer application, and manipulation of the plant-root microbiome.
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Affiliation(s)
- Matthew Langholtz
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
| | - Brian H Davison
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Henriette I Jager
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Laurence Eaton
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Latha M Baskaran
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Maggie Davis
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Craig C Brandt
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
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