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Maitra P, Hrynkiewicz K, Szuba A, Jagodziński AM, Al-Rashid J, Mandal D, Mucha J. Metabolic niches in the rhizosphere microbiome: dependence on soil horizons, root traits and climate variables in forest ecosystems. Front Plant Sci 2024; 15:1344205. [PMID: 38645395 PMCID: PMC11026606 DOI: 10.3389/fpls.2024.1344205] [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] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 03/18/2024] [Indexed: 04/23/2024]
Abstract
Understanding belowground plant-microbial interactions is important for biodiversity maintenance, community assembly and ecosystem functioning of forest ecosystems. Consequently, a large number of studies were conducted on root and microbial interactions, especially in the context of precipitation and temperature gradients under global climate change scenarios. Forests ecosystems have high biodiversity of plants and associated microbes, and contribute to major primary productivity of terrestrial ecosystems. However, the impact of root metabolites/exudates and root traits on soil microbial functional groups along these climate gradients is poorly described in these forest ecosystems. The plant root system exhibits differentiated exudation profiles and considerable trait plasticity in terms of root morphological/phenotypic traits, which can cause shifts in microbial abundance and diversity. The root metabolites composed of primary and secondary metabolites and volatile organic compounds that have diverse roles in appealing to and preventing distinct microbial strains, thus benefit plant fitness and growth, and tolerance to abiotic stresses such as drought. Climatic factors significantly alter the quantity and quality of metabolites that forest trees secrete into the soil. Thus, the heterogeneities in the rhizosphere due to different climate drivers generate ecological niches for various microbial assemblages to foster beneficial rhizospheric interactions in the forest ecosystems. However, the root exudations and microbial diversity in forest trees vary across different soil layers due to alterations in root system architecture, soil moisture, temperature, and nutrient stoichiometry. Changes in root system architecture or traits, e.g. root tissue density (RTD), specific root length (SRL), and specific root area (SRA), impact the root exudation profile and amount released into the soil and thus influence the abundance and diversity of different functional guilds of microbes. Here, we review the current knowledge about root morphological and functional (root exudation) trait changes that affect microbial interactions along drought and temperature gradients. This review aims to clarify how forest trees adapt to challenging environments by leveraging their root traits to interact beneficially with microbes. Understanding these strategies is vital for comprehending plant adaptation under global climate change, with significant implications for future research in plant biodiversity conservation, particularly within forest ecosystems.
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Affiliation(s)
- Pulak Maitra
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
| | - Katarzyna Hrynkiewicz
- Department of Microbiology, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Toruń, Poland
| | - Agnieszka Szuba
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
| | - Andrzej M. Jagodziński
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
- Department of Game Management and Forest Protection, Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Poznań, Poland
| | - Jubair Al-Rashid
- Tianjin Institute of Industrial Biotechnology, University of Chinese Academy of Sciences, Tianjin, China
| | - Dipa Mandal
- Institute of Microbiology, University of Chinese Academy of Sciences, Beijing, China
| | - Joanna Mucha
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
- Department of Forest Entomology and Pathology, Faculty of Forestry and Wood Technology, Poznań University of Life Sciences, Poznań, Poland
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Khanna K, Thakur R, Bhardwaj R, Ahmad P. Editorial: Rhizospheric interactions: integrating plant-microbe signaling during stresses. Front Plant Sci 2024; 15:1357420. [PMID: 38606071 PMCID: PMC11008463 DOI: 10.3389/fpls.2024.1357420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/19/2024] [Indexed: 04/13/2024]
Affiliation(s)
- Kanika Khanna
- Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Raman Thakur
- Department of Microbiology, Lovely Professional University, Jalandhar, Punjab, India
| | - Renu Bhardwaj
- Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab, India
| | - Parvaiz Ahmad
- Department of Botany and Microbiology, King Saud University, Riyadh, Saudi Arabia
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3
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Chen L, Liu Y. The Function of Root Exudates in the Root Colonization by Beneficial Soil Rhizobacteria. Biology (Basel) 2024; 13:95. [PMID: 38392313 PMCID: PMC10886372 DOI: 10.3390/biology13020095] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/26/2024] [Accepted: 01/31/2024] [Indexed: 02/24/2024]
Abstract
Soil-beneficial microbes in the rhizosphere play important roles in improving plant growth and health. Root exudates play key roles in plant-microbe interactions and rhizobacterial colonization. This review describes the factors influencing the dynamic interactions between root exudates and the soil microbiome in the rhizosphere, including plant genotype, plant development, and environmental abiotic and biotic factors. We also discuss the roles of specific metabolic mechanisms, regulators, and signals of beneficial soil bacteria in terms of colonization ability. We highlight the latest research progress on the roles of root exudates in regulating beneficial rhizobacterial colonization. Organic acids, amino acids, sugars, sugar alcohols, flavonoids, phenolic compounds, volatiles, and other secondary metabolites are discussed in detail. Finally, we propose future research objectives that will help us better understand the role of root exudates in root colonization by rhizobacteria and promote the sustainable development of agriculture and forestry.
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Affiliation(s)
- Lin Chen
- National Permanent Scientific Research Base for Warm Temperate Zone Forestry of Jiulong Mountain, Experimental Center of Forestry in North China, Chinese Academy of Forestry, Beijing 102300, China
| | - Yunpeng Liu
- State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, The Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
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Qu S, Li H, Zhang X, Gao J, Ma R, Ma L, Ma J. Effects of Magnesium Imbalance on Root Growth and Nutrient Absorption in Different Genotypes of Vegetable Crops. Plants (Basel) 2023; 12:3518. [PMID: 37895981 PMCID: PMC10610338 DOI: 10.3390/plants12203518] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/04/2023] [Accepted: 10/06/2023] [Indexed: 10/29/2023]
Abstract
Magnesium (Mg) plays a crucial role in crop growth, but how Mg supply level affects root growth and nutrient absorption in vegetable crops with different genotypes has not been sufficiently investigated. In this study, the responses of tomato (Solanum lycopersicum L.) and cucumber (Cucumis sativus L.) crops to different levels of Mg supply were explored. Four levels of Mg treatment (i.e., 0.2, 1.0, 2.0, 3.0 mmol/L) were applied under hydroponic conditions, denoted as Mg0.2, Mg1, Mg2, and Mg3, respectively. The results showed that with increasing Mg levels, the plant biomass, root growth, and nutrient accumulation in both vegetable crops all increased until reaching their maximum values under the Mg2 treatment and then decreased. The total biomass per tomato plant of Mg2 treatment was 30.9%, 14.0%, and 14.0% higher than that of Mg0.2, Mg1, and Mg3 treatments, respectively, and greater increases were observed in cucumber plant biomass (by 54.3%, 17.4%, and 19.9%, respectively). Compared with the Mg0.2 treatment, the potassium (K) and calcium (Ca) contents in various plant parts of both crops remarkably decreased under the Mg3 treatment. This change was accompanied by prominently increased Mg contents in various plant parts and para-hydroxybenzoic acid and oxalic acid contents in root exudates. Irrespective of Mg level, plant biomass, root growth, nutrient accumulation, and root exudation of organic acids were all higher in tomato plants than in cucumber plants. Our findings indicate that excessive Mg supply promotes the roots to exude phenolic acids and hinders the plants from absorbing K and Ca in different genotypes of vegetable crops despite no effect on Mg absorption. A nutritional deficiency of Mg stimulates root exudation of organic acids and increases the types of exuded organic acids, which could facilitate plant adaption to Mg stress. In terms of root growth and nutrient absorption, tomato plants outperform cucumber plants under low and medium Mg levels, but the latter crop is more tolerant to Mg excess.
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Affiliation(s)
- Shuai Qu
- College of Agriculture, Ningxia University, Yinchuan 750021, China; (S.Q.); (R.M.); (L.M.); (J.M.)
| | - Huixia Li
- College of Agriculture, Ningxia University, Yinchuan 750021, China; (S.Q.); (R.M.); (L.M.); (J.M.)
| | - Xueke Zhang
- College of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China;
| | - Jingbo Gao
- College of Agronomy and Life Sciences, Shanxi Datong University, Datong 037009, China;
| | - Rui Ma
- College of Agriculture, Ningxia University, Yinchuan 750021, China; (S.Q.); (R.M.); (L.M.); (J.M.)
| | - Ling Ma
- College of Agriculture, Ningxia University, Yinchuan 750021, China; (S.Q.); (R.M.); (L.M.); (J.M.)
| | - Jing Ma
- College of Agriculture, Ningxia University, Yinchuan 750021, China; (S.Q.); (R.M.); (L.M.); (J.M.)
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Zhai X, Lu P, Zhang R, Bai W, Zhang WH, Chen J, Tian Q. Mowing accelerates phosphorus cycling without depleting soil phosphorus pool. Ecol Appl 2023; 33:e2861. [PMID: 37092906 DOI: 10.1002/eap.2861] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 04/01/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Mowing, as a common grassland utilization strategy, affects nutrient status in soil by plant biomass removal. Phosphorus (P) cycle plays an important role in determining grassland productivity. However, few studies have addressed the impacts of mowing on P cycling in grassland ecosystems. Here, we investigated the effects of various mowing regimes on soil P fractions and P accumulation in plants and litters. We specifically explored the mechanisms by which mowing regulates ecosystem P cycling by linking aboveground community with soil properties. Our results showed that mowing increased soil dissolvable P concentrations, which probably met the demand for P absorption and utilization by plants, thus contributing to an increased P accumulation by plants. Mowing promoted grassland P cycling by a reciprocal relationship between plants and microbes. Short-term mowing enhanced P cycling mainly through increased root exudation-evoked the extracellular enzyme activity of microbes rather than the alternations in microbial biomass and community composition. Long-term mowing increased P cycling mainly by promoting carbon allocation to roots, thereby leading to greater microbial metabolic activity. Although mowing-stimulation of organic P mineralization lasted for 15 consecutive years, mowing did not result in soil P depletion. These results demonstrate that P removal by mowing will not necessarily lead to soil P limitation. Our findings would advance the knowledge on soil P dynamic under mowing and contribute to resource-efficient grassland management.
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Affiliation(s)
- Xiufeng Zhai
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Peng Lu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Ruifang Zhang
- Mountain Area Research Institute, Agricultural University of Hebei, Baoding, China
| | - Wenming Bai
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Wen-Hao Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ji Chen
- Department of Agroecology, Aarhus University, Tjele, Denmark
- Aarhus University Centre for Circular Bioeconomy, Aarhus University, Tjele, Denmark
- iCLIMATE Interdisciplinary Centre for Climate Change, Aarhus University, Roskilde, Denmark
| | - Qiuying Tian
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
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Belimov AA, Shaposhnikov AI, Azarova TS, Yuzikhin OS, Sekste EA, Safronova VI, Tikhonovich IA. Aluminum-Immobilizing Rhizobacteria Modulate Root Exudation and Nutrient Uptake and Increase Aluminum Tolerance of Pea Mutant E107 ( brz). Plants (Basel) 2023; 12:2334. [PMID: 37375958 DOI: 10.3390/plants12122334] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/11/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
It is well known that plant-growth-promoting rhizobacteria (PGPRs) increase the tolerance of plants to abiotic stresses; however, the counteraction of Al toxicity has received little attention. The effects of specially selected Al-tolerant and Al-immobilizing microorganisms were investigated using pea cultivar Sparkle and its Al-sensitive mutant E107 (brz). The strain Cupriavidus sp. D39 was the most-efficient in the growth promotion of hydroponically grown peas treated with 80 µM AlCl3, increasing the plant biomass of Sparkle by 20% and of E107 (brz) by two-times. This strain immobilized Al in the nutrient solution and decreased its concentration in E107 (brz) roots. The mutant showed upregulated exudation of organic acids, amino acids, and sugars in the absence or presence of Al as compared with Sparkle, and in most cases, the Al treatment stimulated exudation. Bacteria utilized root exudates and more actively colonized the root surface of E107 (brz). The exudation of tryptophan and the production of IAA by Cupriavidus sp. D39 in the root zone of the Al-treated mutant were observed. Aluminum disturbed the concentrations of nutrients in plants, but inoculation with Cupriavidus sp. D39 partially restored such negative effects. Thus, the E107 (brz) mutant is a useful tool for studying the mechanisms of plant-microbe interactions, and PGPR plays an important role in protecting plants against Al toxicity.
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Affiliation(s)
- Andrey A Belimov
- All-Russia Research Institute for Agricultural Microbiology, Podbelskogo sh. 3, Pushkin, 196608 Saint-Petersburg, Russia
| | - Alexander I Shaposhnikov
- All-Russia Research Institute for Agricultural Microbiology, Podbelskogo sh. 3, Pushkin, 196608 Saint-Petersburg, Russia
| | - Tatiana S Azarova
- All-Russia Research Institute for Agricultural Microbiology, Podbelskogo sh. 3, Pushkin, 196608 Saint-Petersburg, Russia
| | - Oleg S Yuzikhin
- All-Russia Research Institute for Agricultural Microbiology, Podbelskogo sh. 3, Pushkin, 196608 Saint-Petersburg, Russia
| | - Edgar A Sekste
- All-Russia Research Institute for Agricultural Microbiology, Podbelskogo sh. 3, Pushkin, 196608 Saint-Petersburg, Russia
| | - Vera I Safronova
- All-Russia Research Institute for Agricultural Microbiology, Podbelskogo sh. 3, Pushkin, 196608 Saint-Petersburg, Russia
| | - Igor A Tikhonovich
- All-Russia Research Institute for Agricultural Microbiology, Podbelskogo sh. 3, Pushkin, 196608 Saint-Petersburg, Russia
- Department of Biology, Saint-Petersburg State University, University Embankment, 199034 Saint-Petersburg, Russia
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Jiang Z, Fu Y, Zhou L, He Y, Zhou G, Dietrich P, Long J, Wang X, Jia S, Ji Y, Jia Z, Song B, Liu R, Zhou X. Plant growth strategy determines the magnitude and direction of drought-induced changes in root exudates in subtropical forests. Glob Chang Biol 2023; 29:3476-3488. [PMID: 36931867 DOI: 10.1111/gcb.16685] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 02/27/2023] [Accepted: 03/08/2023] [Indexed: 05/16/2023]
Abstract
Root exudates are an important pathway for plant-microbial interactions and are highly sensitive to climate change. However, how extreme drought affects root exudates and the main components, as well as species-specific differences in response magnitude and direction, are poorly understood. In this study, root exudation rates of total carbon (C) and its components (e.g., sugar, organic acid, and amino acid) were measured under the control and extreme drought treatments (i.e., 70% throughfall reduction) by in situ collection of four tree species with different growth rates in a subtropical forest. We also quantified soil properties, root morphological traits, and mycorrhizal infection rates to examine the driving factors underlying variations in root exudation. Our results showed that extreme drought significantly decreased root exudation rates of total C, sugar, and amino acid by 17.8%, 30.8%, and 35.0%, respectively, but increased root exudation rate of organic acid by 38.6%, which were largely associated with drought-induced changes in tree growth rates, root morphological traits, and mycorrhizal infection rates. Specifically, trees with relatively high growth rates were more responsive to drought for root exudation rates compared with those with relatively low growth rates, which were closely related to root morphological traits and mycorrhizal infection rates. These findings highlight the importance of plant growth strategy in mediating drought-induced changes in root exudation rates. The coordinations among root exudation rates, root morphological traits, and mycorrhizal symbioses in response to drought could be incorporated into land surface models to improve the prediction of climate change impacts on rhizosphere C dynamics in forest ecosystems.
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Affiliation(s)
- Zheng Jiang
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yuling Fu
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Lingyan Zhou
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yanghui He
- Northeast Asia Ecosystem Carbon Sink Research Center (NACC), Center for Ecological Research, Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin, China
| | - Guiyao Zhou
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Peter Dietrich
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Jilan Long
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Xinxin Wang
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Shuxian Jia
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Yuhuang Ji
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Zhen Jia
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Bingqian Song
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
| | - Ruiqiang Liu
- Northeast Asia Ecosystem Carbon Sink Research Center (NACC), Center for Ecological Research, Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin, China
| | - Xuhui Zhou
- Center for Global Change and Ecological Forecasting, Tiantong National Field Station for Forest Ecosystem, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China
- Northeast Asia Ecosystem Carbon Sink Research Center (NACC), Center for Ecological Research, Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin, China
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Hama JR, Hooshmand K, Laursen BB, Vestergård M, Fomsgaard IS. Clover Root Uptake of Cereal Benzoxazinoids (BXs) Caused Accumulation of BXs and BX Transformation Products Concurrently with Substantial Increments in Clover Flavonoids and Abscisic Acid. J Agric Food Chem 2022; 70:14633-14640. [PMID: 36350751 DOI: 10.1021/acs.jafc.2c04715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Metabolomic studies on root uptake and transformation of bioactive compounds, like cereal benzoxazinoids (BXs) in non-BX producing plants, are very limited. Therefore, a targeted mass-spectrometry-based metabolomics study was performed to elucidate the root uptake of BXs in white clover (Trifolium repens L.) and the impact of absorbed BXs on intrinsic clover secondary metabolites. Clover plants grew in a medium containing 100 μM of individual BXs (five aglycone and one glycoside BXs) for 3 weeks. Subsequently, plant tissues were analyzed by liquid chromatography-tandem mass spectrometry to quantify the BXs and clover secondary metabolite concentrations. All BXs were taken up by clover roots and translocated to the shoots. Upon uptake of 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA), 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), 2-hydroxy-1,4-benzoxazin-3-one (HBOA), and 2-β-d-glucopyranosyloxy-1,4-benzoxazin-3-one (HBOA-glc), the parent compounds and a range of transformation products were seen in the roots and shoots. The individual BX concentrations ranged from not detected (nd) to 469 μg/g of dry weight (dw) and from nd to 170 μg/g of dw in the roots and shoots, respectively. The root uptake of BXs altered the composition of intrinsic clover secondary metabolites. In particular, the concentration of flavonoids and the hormone abscisic acid increased substantially in comparison to control plants.
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Affiliation(s)
- Jawameer R Hama
- Department of Agroecology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
| | - Kourosh Hooshmand
- Department of Agroecology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
| | - Bente B Laursen
- Department of Agroecology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
| | - Mette Vestergård
- Department of Agroecology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
| | - Inge S Fomsgaard
- Department of Agroecology, Aarhus University, Forsøgsvej 1, 4200 Slagelse, Denmark
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Sun N, Yang C, Qin X, Liu Y, Sui M, Zhang Y, Cui X, Yin Y, Wang R, Hu Y, Chen X, Mao Z, Mao Y, Shen X. Effects of Organic Acid Root Exudates of Malus hupehensis Rehd. Derived from Soil and Root Leaching Liquor from Orchards with Apple Replant Disease. Plants (Basel) 2022; 11:2968. [PMID: 36365421 PMCID: PMC9654845 DOI: 10.3390/plants11212968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 10/31/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
Organic acids secreted by plants, such as p-hydroxybenzoic acid, ferulic acid, cinnamic acid, and benzoic acid, can inhibit seed germination and root growth. The effects of root and soil leaching liquor from orchards on the growth of M. hupehensis Rehd. seedlings under sand culture are studied; the seedlings are sampled at 15, 30, 45, and 60 d. Changes in the amount of root exudates are determined using HPLC. Low concentrations of root leaching liquor (A1) and soil leaching liquor (B1) significantly promoted plant growth and chlorophyll synthesis; high concentrations of root leaching liquor (A6) and soil leaching liquor (B4-6) inhibited growth. Low concentrations of soil leaching liquor had no significant effect on the POD, SOD, and CAT activities. A5-6 and B5-6 significantly decreased Fv/Fm and qP values, respectively, and increased NPQ values. All root and soil leaching liquor treatments inhibited the secretion of gallic acid, hydroxybenzoic acid, benzoic acid, and phloridzin, and promoted the secretion of caffeic acid. The root leaching liquor treatments inhibited the secretion of catechin and promoted the secretion of phloretin. The soil leaching liquor treatments promoted the secretion of cinnamic acid. The secretion of other phenolic acids is likely associated with the different concentrations of leaching liquor.
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Affiliation(s)
- Nan Sun
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Chen Yang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Xin Qin
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Yangbo Liu
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Mengyi Sui
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Yawen Zhang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Xueli Cui
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Yijun Yin
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Rong Wang
- College of Horticulture and Landscape, Tianjin Agricultural Univercity, Tianjin 301799, China
| | - Yanli Hu
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Xuesen Chen
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Zhiquan Mao
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Yunfei Mao
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
| | - Xiang Shen
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an 271002, China
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Manzoor A, Dippold MA, Loeppmann S, Blagodatskaya E. Two-Phase Conceptual Framework of Phosphatase Activity and Phosphorus Bioavailability. Front Plant Sci 2022; 13:935829. [PMID: 35928705 PMCID: PMC9343760 DOI: 10.3389/fpls.2022.935829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/15/2022] [Indexed: 06/02/2023]
Abstract
The activity of extracellular phosphatases is a dynamic process controlled by both plant roots and microorganisms, which is responsible for the mineralization of soil phosphorus (P). Plants regulate the availability of soil P through the release of root mucilage and the exudation of low-molecular weight organic acids (LMWOAs). Mucilage increases soil hydraulic conductivity as well as pore connectivity, both of which are associated with increased phosphatase activity. The LMWOAs, in turn, stimulate the mineralization of soil P through their synergistic effects of acidification, chelation, and exchange reactions. This article reviews the catalytic properties of extracellular phosphatases and their interactions with the rhizosphere interfaces. We observed a biphasic effect of root metabolic products on extracellular phosphatases, which notably altered their catalytic mechanism. In accordance with the proposed conceptual framework, soil P is acquired by both plants and microorganisms in a coupled manner that is characterized by the exudation of their metabolic products. Due to inactive or reduced root exudation, plants recycle P through adsorption on the soil matrix, thereby reducing the rhizosphere phosphatase activity. The two-phase conceptual framework might assist in understanding P-acquisition (substrate turnover) and P-restoration (phosphatase adsorption by soil) in various terrestrial ecosystems.
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Affiliation(s)
- Aamir Manzoor
- Biogeochemistry of Agroecosystems, University of Goettingen, Goettingen, Germany
| | - Michaela A. Dippold
- Geo-Biosphere Interactions, Department of Geosciences, University of Tuebingen, Tuebingen, Germany
| | - Sebastian Loeppmann
- Biogeochemistry of Agroecosystems, University of Goettingen, Goettingen, Germany
- Institute of Plant Nutrition and Soil Science, Christian–Albrechts University, Kiel, Germany
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11
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Barros RE, Mendes Reis M, Tuffi Santos LD, Fagundes Correia J, Fernandes de Souza R. Light availability in the cultivation environment and the action of glyphosate on Digitaria insularis: physiological aspects and herbicide root exudation. J Environ Sci Health B 2022; 57:597-607. [PMID: 35726612 DOI: 10.1080/03601234.2022.2088198] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The root exudation decreases the susceptibility of some species to herbicides, which is still little studied in Digitaria insularis, popularly known as sourgrass, one of the main weeds of annual crops in the world. Thus, we sought to identify whether there is an occurrence of root exudation of glyphosate in D. insularis and the influence of this herbicide on physiological and control parameters of this species when cultivated under different light conditions. The experimental design was 2 x 5, with the first factor represented by environments: full sun and artificial shading. The second factor was represented by doses 0, 370, 740, 1110, and 1480 g ha-1 of glyphosate. The plants grown in shading showed more significant injury in the initial phase. The increase in the glyphosate doses reduced the photochemical efficiency of the photosystem II (ФPSII), electron transport rate (ETR), photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency of D. insularis regardless of the cultivation environment. The light restriction increased the ФPSII in D. insularis at three days after applying the herbicide (DAH); at 6 DAH, the shaded plants showed a more pronounced reduction in ФPSII. D. insularis did not show root exudation of glyphosate, and shading did not influence this process.
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Affiliation(s)
- Rodrigo Eduardo Barros
- Instituto de Ciências Agrárias, Universidade Federal de Minas Gerais, Montes Claros, Minas Gerais, Brazil
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12
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Dror D, Klein T. The effect of elevated CO2 on aboveground and belowground carbon allocation and eco-physiology of four species of angiosperm and gymnosperm forest trees. Tree Physiol 2022; 42:831-847. [PMID: 34648020 DOI: 10.1093/treephys/tpab136] [Citation(s) in RCA: 2] [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: 04/13/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Although atmospheric CO2 concentration ([CO2]) continues to rise, the question of how tree carbon (C) allocation is affected by this change remains. Studies show that C assimilation increases under elevated CO2 (eCO2). Yet, no detailed study has determined the fate of the surplus C, i.e., its compartment and physiological process allocation, nor in multiple species together. In this project, we grew 2-year-old saplings of four key Mediterranean tree species (the conifers Cupressus sempervirens L. and Pinus halepensis Mill., and the broadleaf Quercus calliprinos Webb. and Ceratonia siliqua L.) to [CO2] levels of 400 or 700 p.p.m. for 6 months. We measured the allocation of C to below and aboveground growth, respiration, root exudation, storage and leaf litter. In addition, we monitored intrinsic water-use efficiency (WUE), soil moisture, soil chemistry and nutrient uptake. Net assimilation, WUE and soil nitrogen uptake significantly increased at eCO2 across the four species. Broadleaf species showed soil water savings, which were absent in conifers. All other effects were species-specific: Cupressus had higher leaf respiration, Pinus had lower starch in branches and transiently higher exudation rate and Quercus had higher root respiration. Elevated CO2 did not affect growth or litter production. Our results are pivotal to understanding the sensitivity of tree C allocation to the change in [CO2] when water is abundant. Species-specific responses should be regarded cautiously when predicting future changes in forest function in a higher CO2 world.
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Affiliation(s)
- Dar Dror
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, 234 Herzl St., Rehovot 76100, Israel
| | - Tamir Klein
- Department of Plant & Environmental Sciences, Weizmann Institute of Science, 234 Herzl St., Rehovot 76100, Israel
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13
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Gui Y, Yu W, Ge X, Li H, Sun C, Mao X, Yuan K. Root exudation of prometryn and its metabolites from Chinese celery ( Apium graveolens). J Pestic Sci 2022; 47:1-7. [PMID: 35414755 PMCID: PMC8931558 DOI: 10.1584/jpestics.d21-035] [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: 07/13/2021] [Accepted: 10/12/2021] [Indexed: 06/14/2023]
Abstract
Root exudates from Chinese celery (Apium graveolens) and Chinese cabbage (pak choi, Brassica chinensis) plants treated by prometryn, an herbicide, were qualitatively and quantitatively investigated and compared under hydroponic cultivation. Prometryn and its metabolites released into the nutrient solution were analyzed by ultra-performance liquid chromatograph coupled with orbitrap mass spectrometer to investigate whether this xylem-mobile herbicide is exuded from the roots. The results showed that celery and pak choi had different root exudation profiles. Celery metabolized prometryn to prometryn sulfoxide and released both compounds from the roots. In contrast, pak choi barely metabolized or actively released prometryn from the roots. The concentration of prometryn sulfoxide released from celery after 96 hr was 21 µg/L, which was nearly one-third that of released prometryn. Our results indicate that the root exudation and translocation of xylem-mobile herbicides could be significant in plants and are highly species dependent compared with phloem-mobile herbicides.
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Affiliation(s)
- Yingai Gui
- Dalian Inspection, Examination and Certification Technical Service Center, Dalian 116021, China
| | - Wei Yu
- Dalian Inspection, Examination and Certification Technical Service Center, Dalian 116021, China
| | - Xiangwu Ge
- Dalian Inspection, Examination and Certification Technical Service Center, Dalian 116021, China
| | - Haiyan Li
- Dalian Inspection, Examination and Certification Technical Service Center, Dalian 116021, China
| | - Chengpeng Sun
- Dalian Inspection, Examination and Certification Technical Service Center, Dalian 116021, China
| | - Xiqin Mao
- Dalian Inspection, Examination and Certification Technical Service Center, Dalian 116021, China
| | - Kuijing Yuan
- Dalian Inspection, Examination and Certification Technical Service Center, Dalian 116021, China
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14
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Liu Y, Ma B, Chen W, Schlaeppi K, Erb M, Stirling E, Hu L, Wang E, Zhang Y, Zhao K, Lu Z, Ye S, Xu J. Rhizobium Symbiotic Capacity Shapes Root-Associated Microbiomes in Soybean. Front Microbiol 2021; 12:709012. [PMID: 34925249 PMCID: PMC8678110 DOI: 10.3389/fmicb.2021.709012] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 11/09/2021] [Indexed: 12/26/2022] Open
Abstract
Root-microbiome interactions are of central importance for plant performance and yield. A distinctive feature of legumes is that they engage in symbiosis with N2-fixing rhizobia. If and how the rhizobial symbiotic capacity modulates root-associated microbiomes are still not yet well understood. We determined root-associated microbiomes of soybean inoculated with wild type (WT) or a noeI mutant of Bradyrhizobium diazoefficiens USDA 110 by amplicon sequencing. UPLC-MS/MS was used to analyze root exudates. The noeI gene is responsible for fucose-methylation of Nod factor secreted by USDA 110 WT strain. Soybean roots inoculated with the noeI mutant showed a significant decrease in nodulation and root-flavonoid exudation compared to roots inoculated with WT strain. The noeI mutant-inoculated roots exhibited strong changes in microbiome assembly in the rhizosphere and rhizoplane, including reduced diversity, changed co-occurrence interactions and a substantial depletion of root microbes. Root exudates and soil physiochemical properties were significantly correlated with microbial community shift in the rhizosphere between different rhizobial treatments. These results illustrate that rhizobial symbiotic capacity dramatically alters root-associated microbiomes, in which root exudation and edaphic patterns play a vital role. This study has important implications for understanding the evolution of plant-microbiome interactions.
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Affiliation(s)
- Yuanhui Liu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China.,China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, China
| | - Bin Ma
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China.,Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, China
| | - Wenfeng Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences and Rhizobium Research Center, China Agricultural University, Ministry of Agriculture Key Laboratory of Soil Microbiology, Beijing, China
| | - Klaus Schlaeppi
- Department of Environmental Sciences, University of Basel, Basel, Switzerland.,Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Matthias Erb
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Erinne Stirling
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China.,Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, China.,Acid Sulfate Soils Centre, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Lingfei Hu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China
| | - Entao Wang
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, México
| | - Yunzeng Zhang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou, China
| | - Kankan Zhao
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China
| | - Zhijiang Lu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China
| | - Shudi Ye
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China
| | - Jianming Xu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China.,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou, China
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15
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Lohse M, Haag R, Lippold E, Vetterlein D, Reemtsma T, Lechtenfeld OJ. Direct Imaging of Plant Metabolites in the Rhizosphere Using Laser Desorption Ionization Ultra-High Resolution Mass Spectrometry. Front Plant Sci 2021; 12:753812. [PMID: 34925405 PMCID: PMC8678481 DOI: 10.3389/fpls.2021.753812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/03/2021] [Indexed: 06/14/2023]
Abstract
The interplay of rhizosphere components such as root exudates, microbes, and minerals results in small-scale gradients of organic molecules in the soil around roots. The current methods for the direct chemical imaging of plant metabolites in the rhizosphere often lack molecular information or require labeling with fluorescent tags or isotopes. Here, we present a novel workflow using laser desorption ionization (LDI) combined with mass spectrometric imaging (MSI) to directly analyze plant metabolites in a complex soil matrix. Undisturbed samples of the roots and the surrounding soil of Zea mays L. plants from either field- or laboratory-scale experiments were embedded and cryosectioned to 100 μm thin sections. The target metabolites were detected with a spatial resolution of 25 μm in the root and the surrounding soil based on accurate masses using ultra-high mass resolution laser desorption ionization Fourier-transform ion cyclotron resonance mass spectrometry (LDI-FT-ICR-MS). Using this workflow, we could determine the rhizosphere gradients of a dihexose (e.g., sucrose) and other plant metabolites (e.g., coumaric acid, vanillic acid). The molecular gradients for the dihexose showed a high abundance of this metabolite in the root and a strong depletion of the signal intensity within 150 μm from the root surface. Analyzing several sections from the same undisturbed soil sample allowed us to follow molecular gradients along the root axis. Benefiting from the ultra-high mass resolution, isotopologues of the dihexose could be readily resolved to enable the detection of stable isotope labels on the compound level. Overall, the direct molecular imaging via LDI-FT-ICR-MS allows for the first time a non-targeted or targeted analysis of plant metabolites in undisturbed soil samples, paving the way to study the turnover of root-derived organic carbon in the rhizosphere with high chemical and spatial resolution.
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Affiliation(s)
- Martin Lohse
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Rebecca Haag
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
- Ansbach University of Applied Sciences, Ansbach, Germany
| | - Eva Lippold
- Department of Soil System Science, Helmholtz Centre for Environmental Research – UFZ, Halle, Germany
| | - Doris Vetterlein
- Department of Soil System Science, Helmholtz Centre for Environmental Research – UFZ, Halle, Germany
- Soil Science, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Thorsten Reemtsma
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
- Institute of Analytical Chemistry, University of Leipzig, Leipzig, Germany
| | - Oliver J. Lechtenfeld
- Department of Analytical Chemistry, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
- ProVIS – Centre for Chemical Microscopy, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany
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16
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Fu R, Feng H, Dini-Andreote F, Wang Z, Bo C, Cao W, Yang K, Liu M, Yang T, Shen Q, Xu Y, Wei Z. Modulation of the Tomato Rhizosphere Microbiome via Changes in Root Exudation Mediated by the Ethylene Receptor NR. Microorganisms 2021; 9:2456. [PMID: 34946058 PMCID: PMC8705318 DOI: 10.3390/microorganisms9122456] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 11/17/2022] Open
Abstract
Plant hormones have been recently shown to exert an indirect influence on the recruitment of plant-associated microbiomes. However, it remains unclear the extent to which the disruption of the ethylene (ET) signaling pathway affects the assembly and functioning of plant-root microbiomes. In this study, the Never-ripe tomato mutant (Nr) was profiled for differences compared to the wild type (control). Tomato plants were subjected to root exudate profiling and the characterization of bacterial and fungal communities. Compared to the control, Nr revealed differences in the composition of root exudates, including lower amounts of esculetin, gallic acid, L-fucose, eicosapentaenoic acid, and higher amounts of β-aldehyde. Interestingly, Nr significantly differed in the composition and functioning of the rhizosphere bacterial community. We also identified the taxa that occurred at relatively higher abundances in Nr, including the genus Lysobacter, which displayed a significant negative correlation with changes in eicosapentaenoic acid and esculetin, and a significant positive correlation with changes in β-aldehyde. Taken together, our study provides evidence that a mutation in the ET receptor exerts predictable changes in the root-associated microbial taxa of tomato plants. These indirect effects can potentially be explored towards new strategies to engineer beneficial plant microbiomes via targeted changes in plant genetics and physiology.
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Affiliation(s)
- Ruixin Fu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Haichao Feng
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Francisco Dini-Andreote
- Department of Plant Science and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16801, USA;
| | - Zhen Wang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Chunbin Bo
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Wenhui Cao
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Keming Yang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Mingchun Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China;
| | - Tianjie Yang
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Qirong Shen
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Yangchun Xu
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
| | - Zhong Wei
- Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Jiangsu Collaborative Innovation Center of Solid Organic Waste Resource Utilization, National Engineering Research Center for Organic-Based Fertilizers, Nanjing Agricultural University, Nanjing 210095, China; (R.F.); (H.F.); (Z.W.); (C.B.); (W.C.); (K.Y.); (Q.S.); (Y.X.); (Z.W.)
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17
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Alzate Zuluaga MY, Martinez de Oliveira AL, Valentinuzzi F, Tiziani R, Pii Y, Mimmo T, Cesco S. Can Inoculation With the Bacterial Biostimulant Enterobacter sp. Strain 15S Be an Approach for the Smarter P Fertilization of Maize and Cucumber Plants? Front Plant Sci 2021; 12:719873. [PMID: 34504509 PMCID: PMC8421861 DOI: 10.3389/fpls.2021.719873] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
Phosphorus (P) is an essential nutrient for plants. The use of plant growth-promoting bacteria (PGPB) may also improve plant development and enhance nutrient availability, thus providing a promising alternative or supplement to chemical fertilizers. This study aimed to evaluate the effectiveness of Enterobacter sp. strain 15S in improving the growth and P acquisition of maize (monocot) and cucumber (dicot) plants under P-deficient hydroponic conditions, either by itself or by solubilizing an external source of inorganic phosphate (Pi) [Ca3(PO4)2]. The inoculation with Enterobacter 15S elicited different effects on the root architecture and biomass of cucumber and maize depending on the P supply. Under sufficient P, the bacterium induced a positive effect on the whole root system architecture of both plants. However, under P deficiency, the bacterium in combination with Ca3(PO4)2 induced a more remarkable effect on cucumber, while the bacterium alone was better in improving the root system of maize compared to non-inoculated plants. In P-deficient plants, bacterial inoculation also led to a chlorophyll content [soil-plant analysis development (SPAD) index] like that in P-sufficient plants (p < 0.05). Regarding P nutrition, the ionomic analysis indicated that inoculation with Enterobacter 15S increased the allocation of P in roots (+31%) and shoots (+53%) of cucumber plants grown in a P-free nutrient solution (NS) supplemented with the external insoluble phosphate, whereas maize plants inoculated with the bacterium alone showed a higher content of P only in roots (36%) but not in shoots. Furthermore, in P-deficient cucumber plants, all Pi transporter genes (CsPT1.3, CsPT1.4, CsPT1.9, and Cucsa383630.1) were upregulated by the bacterium inoculation, whereas, in P-deficient maize plants, the expression of ZmPT1 and ZmPT5 was downregulated by the bacterial inoculation. Taken together, these results suggest that, in its interaction with P-deficient cucumber plants, Enterobacter strain 15S might have solubilized the Ca3(PO4)2 to help the plants overcome P deficiency, while the association of maize plants with the bacterium might have triggered a different mechanism affecting plant metabolism. Thus, the mechanisms by which Enterobacter 15S improves plant growth and P nutrition are dependent on crop and nutrient status.
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Affiliation(s)
- Mónica Yorlady Alzate Zuluaga
- Faculty of Science and Technology, Free University of Bolzano, Bolzano, Italy
- Department of Biochemistry and Biotechnology, State University of Londrina, Londrina, Brazil
| | | | - Fabio Valentinuzzi
- Faculty of Science and Technology, Free University of Bolzano, Bolzano, Italy
| | - Raphael Tiziani
- Faculty of Science and Technology, Free University of Bolzano, Bolzano, Italy
| | - Youry Pii
- Faculty of Science and Technology, Free University of Bolzano, Bolzano, Italy
| | - Tanja Mimmo
- Faculty of Science and Technology, Free University of Bolzano, Bolzano, Italy
| | - Stefano Cesco
- Faculty of Science and Technology, Free University of Bolzano, Bolzano, Italy
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18
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Zhang D, Peng Y, Li F, Yang G, Wang J, Yu J, Zhou G, Yang Y. Above- and below-ground resource acquisition strategies determine plant species responses to nitrogen enrichment. Ann Bot 2021; 128:31-44. [PMID: 33630994 PMCID: PMC8318111 DOI: 10.1093/aob/mcab032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND AIMS Knowledge of plant resource acquisition strategies is crucial for understanding the mechanisms mediating the responses of ecosystems to external nitrogen (N) input. However, few studies have considered the joint effects of above-ground (light) and below-ground (nutrient) resource acquisition strategies in regulating plant species responses to N enrichment. Here, we quantified the effects of light and non-N nutrient acquisition capacities on species relative abundance in the case of extra N input. METHODS Based on an N-manipulation experiment in a Tibetan alpine steppe, we determined the responses of species relative abundances and light and nutrient acquisition capacities to N enrichment for two species with different resource acquisition strategies (the taller Stipa purpurea, which is colonized by arbuscular mycorrhizal fungi, and the shorter Carex stenophylloides, which has cluster roots). Structural equation models were developed to explore the relative effects of light and nutrient acquisition on species relative abundance along the N addition gradient. KEY RESULTS We found that the relative abundance of taller S. purpurea increased with the improved light acquisition along the N addition gradient. In contrast, the shorter C. stenophylloides, with cluster roots, excelled in acquiring phosphorus (P) so as to elevate its leaf P concentration under N enrichment by producing large amounts of carboxylate exudates that mobilized moderately labile and recalcitrant soil P forms. The increased leaf P concentration of C. stenophylloides enhanced its light use efficiency and promoted its relative abundance even in the shade of taller competitors. CONCLUSIONS Our findings highlight that the combined effects of above-ground (light) and below-ground (nutrient) resources rather than light alone (the prevailing perspective) determine the responses of grassland community structure to N enrichment.
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Affiliation(s)
- Dianye Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yunfeng Peng
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Fei Li
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Guibiao Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jun Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jianchun Yu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Guoying Zhou
- Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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19
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Feng F, Zhan H, Wan Q, Wang Y, Li Y, Ge J, Sun X, Zhu H, Yu X. Rice recruits Sphingomonas strain HJY-rfp via root exudate regulation to increase chlorpyrifos tolerance and boost residual catabolism. J Exp Bot 2021; 72:5673-5686. [PMID: 33987653 DOI: 10.1093/jxb/erab210] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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: 12/16/2020] [Accepted: 05/12/2021] [Indexed: 06/12/2023]
Abstract
Inoculation with pollution-degrading endophytes boosts the catabolism of residual contaminants and promotes the pollution adaptation of host plants. We investigated the interaction pattern between Sphingomonas strain HJY-rfp, a chlorpyrifos-degrading endophytic bacterium, and rice (Oryza sativa) under pesticide stress using hydroponic cultivation. We observed a notable trend of endophytic root colonization in rice plants treated with 10 mg l-1 chlorpyrifos solution, and after 24 h the migration of HJY-rfp enhanced the chlorpyrifos degradation rate in leaves and stems by 53.36% and 40.81%, respectively. Critically, the rice root exudate profile (organic acids and amino acids) changed under chlorpyrifos stress, and variations in the contents of several components affected the chemotactic behaviour of HJY-rfp. HJY-rfp colonization dramatically activated defensive enzymes, which enabled efficient scavenging of reactive oxygen species, and led to 9.8%, 22.5%, and 41.9% increases in shoot length, fresh weight, and accumulation of total chlorophyll, respectively, in rice suffering from oxidative damage by chlorpyrifos. Endophytic colonization caused up-regulation of detoxification genes that have shown a significant positive correlation with chlorpyrifos degradation in vivo. Collectively, our results demonstrate that agrochemical stress causes plants to actively recruit specific symbiotic microbes to detoxify contaminants and survive better under pollution conditions.
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Affiliation(s)
- Fayun Feng
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Nanjing, China
| | - Honglin Zhan
- Department of Biotechnology, Qingdao University of Science &Technology, Qingdao, China
| | - Qun Wan
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Ya Wang
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Yong Li
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Jing Ge
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xing Sun
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Hong Zhu
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Xiangyang Yu
- Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology/Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Nanjing, China
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20
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Wegner LH, Li X, Zhang J, Yu M, Shabala S, Hao Z. Biochemical and biophysical pH clamp controlling Net H + efflux across the plasma membrane of plant cells. New Phytol 2021; 230:408-415. [PMID: 33423280 DOI: 10.1111/nph.17176] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [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: 10/26/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
P-type H+ ATPases mediate active H+ efflux from plant cells. They generate a proton motive force across the plasma membrane, providing the free energy to drive the transport of other solutes, partly by coupling to H+ influx. Wegner & Shabala (2020) recently suggested that passive H+ influx can exceed pump-driven efflux due to 'active buffering', that is, cytosolic H+ scavenging and apoplastic H+ generation by metabolism ('biochemical pH clamp'). Charge balance is provided by K+ efflux or anion influx. Here, this hypothesis is extended to net H+ efflux: even though H+ pumping is faster than backflow via symporters and antiporters, a progressive increase in the transmembrane pH gradient is avoided. Cytosolic H+ release is associated with bicarbonate formation from CO2 . Bicarbonate serves as substrate for the PEPCase, catalyzing the reaction from phosphoenolpyruvate to oxaloacetate, which is subsequently reduced to malate. Organic anions such as malate and citrate are released across the plasma membrane and are (partly) protonated in the apoplast, thus limiting pump-induced acidification. Moreover, a 'biophysical pH clamp' is introduced, that is, adjustment of apoplastic/cytosolic pH involving net H+ fluxes across the plasma membrane, while the gradient between compartments is maintained. The clamps are not mutually exclusive but are likely to coexist.
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Affiliation(s)
- Lars H Wegner
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
| | - Xuewen Li
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
| | - Jie Zhang
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
| | - Min Yu
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
| | - Sergey Shabala
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
- Tasmanian Institute of Agricultural Research, University of Tasmania, Hobart, 7001, Australia
| | - Zhifeng Hao
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China
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21
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Wang R, Bicharanloo B, Shirvan MB, Cavagnaro TR, Jiang Y, Keitel C, Dijkstra FA. A novel 13 C pulse-labelling method to quantify the contribution of rhizodeposits to soil respiration in a grassland exposed to drought and nitrogen addition. New Phytol 2021; 230:857-866. [PMID: 33253439 DOI: 10.1111/nph.17118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [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: 08/02/2020] [Accepted: 11/24/2020] [Indexed: 05/21/2023]
Abstract
Rhizodeposition plays an important role in below-ground carbon (C) cycling. However, quantification of rhizodeposition in intact plant-soil systems has remained elusive due to methodological issues. We used a 13 C-CO2 pulse-labelling method to quantify the contribution of rhizodeposition to below-ground respiration. Intact plant-soil cores were taken from a grassland field, and in half, shoots and roots were removed (unplanted cores). Both unplanted and planted cores were assigned to drought and nitrogen (N) treatments. Afterwards, shoots in planted cores were pulse labelled with 13 C-CO2 and then clipped to determine total below-ground respiration and its δ13 C. Simultaneously, δ13 C was measured for the respiration of live roots, soils with rhizodeposits, and unplanted treatments, and used as endmembers with which to determine root respiration and rhizodeposit C decomposition using two-source mixing models. Rhizodeposit decomposition accounted for 7-31% of total below-ground respiration. Drought reduced decomposition of both rhizodeposits and soil organic carbon (SOC), while N addition increased root respiration but not the contribution of rhizodeposit C decomposition to below-ground respiration. This study provides a new approach for the partitioning of below-ground respiration into different sources, and indicates that decomposition of rhizodeposit C is an important component of below-ground respiration that is sensitive to drought and N addition in grassland ecosystems.
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Affiliation(s)
- Ruzhen Wang
- Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
- School of Life and Environmental Sciences, Sydney Institute of Agriculture, The University of Sydney, Camden, NSW, 2570, Australia
| | - Bahareh Bicharanloo
- School of Life and Environmental Sciences, Sydney Institute of Agriculture, The University of Sydney, Camden, NSW, 2570, Australia
| | - Milad Bagheri Shirvan
- School of Life and Environmental Sciences, Sydney Institute of Agriculture, The University of Sydney, Camden, NSW, 2570, Australia
| | - Timothy R Cavagnaro
- School of Agriculture, Food and Wine, The University of Adelaide, PMB 1, Glen Osmond, SA, 5065, Australia
| | - Yong Jiang
- Erguna Forest-Steppe Ecotone Ecosystem Research Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Claudia Keitel
- School of Life and Environmental Sciences, Sydney Institute of Agriculture, The University of Sydney, Camden, NSW, 2570, Australia
| | - Feike A Dijkstra
- School of Life and Environmental Sciences, Sydney Institute of Agriculture, The University of Sydney, Camden, NSW, 2570, Australia
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22
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Proctor C, He Y. Modeling Root Exudate Accumulation Gradients to Estimate Net Exudation Rates by Peatland Soil Depth. Plants (Basel) 2021; 10:106. [PMID: 33419192 PMCID: PMC7825507 DOI: 10.3390/plants10010106] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/24/2020] [Accepted: 12/28/2020] [Indexed: 11/17/2022]
Abstract
Root exudates accumulate as a radial gradient around the root, yet little is known about variability at the individual root level. Vertical gradients in soil properties are hypothesized to cause greater accumulation of exudates in deeper soil through hindering diffusion, increasing sorption, and decreasing mineralization. To this end, a single root exudation model coupling concentration specific exudation and depth dependent soil properties was developed. The model was parameterized for a peatland ecosystem to explore deposition to the methanogen community. Numerical experiments indicate that exudates accumulated to a greater extent in deeper soil, albeit the effect was solute specific. Rhizosphere size for glucose doubled between the 10 and 80 cm depths, while the rhizoplane concentration was 1.23 times higher. Root influx of glucose increased from 1.431 to 1.758 nmol cm-1 hr-1, representing a recapture efficiency gain of 15.74% (i.e., 69.06% versus 84.8%). Driven by increased root influx, overall net exudation rates of select sugars and amino acids varied by a factor two. Model sensitivity analysis revealed that soil depth and root influx capability are key determinants of the rhizoplane concentration and subsequently net exudation, which determines whether effluxed compounds escape the root oxic shell and are available to the methanogen community.
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Affiliation(s)
- Cameron Proctor
- School of the Environment, University of Windsor, 401 Sunset Ave, Windsor, ON N9B 3P4, Canada
| | - Yuhong He
- Department of Geography, Geomatics and Environment, University of Toronto Mississauga, 3359 Mississauga Road, William G. Davis Bldg, Mississauga, ON L5L 1C6, Canada;
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23
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Sun L, Ataka M, Han M, Han Y, Gan D, Xu T, Guo Y, Zhu B. Root exudation as a major competitive fine-root functional trait of 18 coexisting species in a subtropical forest. New Phytol 2021; 229:259-271. [PMID: 32772392 DOI: 10.1111/nph.16865] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [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: 03/12/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
Root exudation stimulates microbial decomposition and enhances nutrient availability to plants. It remains difficult to measure and predict this carbon flux in natural conditions, especially for mature woody plants. Based on a known conceptual framework of root functional traits coordination, we proposed that root functional traits may predict root exudation. We measured root exudation and other seven root morphological/chemical/physiological traits for 18 coexisting woody species in a deciduous-evergreen mixed forest in subtropical China. Root exudation, respiration, diameter and nitrogen (N) concentration all exhibited significant phylogenetic signals. We found that root exudation positively correlated with competitive traits (root respiration, N concentration) and negatively with a conservative trait (root tissue density). Furthermore, these relationships were independent of phylogenetic signals. A principal component analysis showed that root exudation and morphological traits loaded on two perpendicular axes. Root exudation is a competitive trait in a multidimensional fine-root functional coordination. The metabolic dimension on which root exudation loaded was relatively independent of the morphological dimension, indicating that increasing nutrient availability by root exudation might be a complementary strategy for plant nutrient acquisition. The positive relationship between root exudation and root respiration and N concentration is a promising approach for the future prediction of root exudation.
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Affiliation(s)
- Lijuan Sun
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Mioko Ataka
- Graduate School of Agriculture, Kyoto University, Kyoto, 6068502, Japan
| | - Mengguang Han
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yunfeng Han
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Dayong Gan
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Tianle Xu
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yanpei Guo
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Biao Zhu
- Key Laboratory for Earth Surface Processes of the Ministry of Education, Institute of Ecology, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
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24
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Nazari M, Riebeling S, Banfield CC, Akale A, Crosta M, Mason-Jones K, Dippold MA, Ahmed MA. Mucilage Polysaccharide Composition and Exudation in Maize From Contrasting Climatic Regions. Front Plant Sci 2020; 11:587610. [PMID: 33363554 PMCID: PMC7752898 DOI: 10.3389/fpls.2020.587610] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 11/18/2020] [Indexed: 05/28/2023]
Abstract
Mucilage, a gelatinous substance comprising mostly polysaccharides, is exuded by maize nodal and underground root tips. Although mucilage provides several benefits for rhizosphere functions, studies on the variation in mucilage amounts and its polysaccharide composition between genotypes are still lacking. In this study, eight maize (Zea mays L.) genotypes from different globally distributed agroecological zones were grown under identical abiotic conditions in a randomized field experiment. Mucilage exudation amount, neutral sugars and uronic acids were quantified. Galactose (∼39-42%), fucose (∼22-30%), mannose (∼11-14%), and arabinose (∼8-11%) were the major neutral sugars in nodal root mucilage. Xylose (∼1-4%), and glucose (∼1-4%) occurred only in minor proportions. Glucuronic acid (∼3-5%) was the only uronic acid detected. The polysaccharide composition differed significantly between maize genotypes. Mucilage exudation was 135 and 125% higher in the Indian (900 M Gold) and Kenyan (DH 02) genotypes than in the central European genotypes, respectively. Mucilage exudation was positively associated with the vapor pressure deficit of the genotypes' agroecological zone. The results indicate that selection for environments with high vapor pressure deficit may favor higher mucilage exudation, possibly because mucilage can delay the onset of hydraulic failure during periods of high vapor pressure deficit. Genotypes from semi-arid climates might offer sources of genetic material for beneficial mucilage traits.
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Affiliation(s)
- Meisam Nazari
- Division of Biogeochemistry of Agroecosystems, Georg-August University of Göttingen, Göttingen, Germany
| | - Sophie Riebeling
- Division of Biogeochemistry of Agroecosystems, Georg-August University of Göttingen, Göttingen, Germany
| | - Callum C. Banfield
- Division of Biogeochemistry of Agroecosystems, Georg-August University of Göttingen, Göttingen, Germany
| | - Asegidew Akale
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Margherita Crosta
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Kyle Mason-Jones
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Michaela A. Dippold
- Division of Biogeochemistry of Agroecosystems, Georg-August University of Göttingen, Göttingen, Germany
| | - Mutez Ali Ahmed
- Division of Biogeochemistry of Agroecosystems, Georg-August University of Göttingen, Göttingen, Germany
- Chair of Soil Physics, Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
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25
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Zhou Y, Lambrides CJ, Li J, Xu Q, Toh R, Tian S, Yang P, Yang H, Ryder M, Denton MD. Nitrifying Microbes in the Rhizosphere of Perennial Grasses are Modified by Biological Nitrification Inhibition. Microorganisms 2020; 8:microorganisms8111687. [PMID: 33138329 PMCID: PMC7693952 DOI: 10.3390/microorganisms8111687] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/20/2020] [Accepted: 10/28/2020] [Indexed: 11/16/2022] Open
Abstract
Soil nitrification (microbial oxidation of ammonium to nitrate) can lead to nitrogen leaching and environmental pollution. A number of plant species are able to suppress soil nitrifiers by exuding inhibitors from roots, a process called biological nitrification inhibition (BNI). However, the BNI activity of perennial grasses in the nutrient-poor soils of Australia and the effects of BNI activity on nitrifying microbes in the rhizosphere microbiome have not been well studied. Here we evaluated the BNI capacity of bermudagrass (Cynodon dactylon L.), St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze), saltwater couch (Sporobolus virginicus), seashore paspalum (Paspalum vaginatum Swartz.), and kikuyu grass (Pennisetum clandestinum) compared with the known positive control, koronivia grass (Brachiaria humidicola). The microbial communities were analysed by sequencing 16S rRNA genes. St. Augustinegrass and bermudagrass showed high BNI activity, about 80 to 90% of koronivia grass. All the three grasses with stronger BNI capacities suppressed the populations of Nitrospira in the rhizosphere, a bacteria genus with a nitrite-oxidizing function, but not all of the potential ammonia-oxidizing archaea. The rhizosphere of saltwater couch and seashore paspalum exerted a weak recruitment effect on the soil microbiome. Our results demonstrate that BNI activity of perennial grasses played a vital role in modulating nitrification-associated microbial populations.
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Affiliation(s)
- Yi Zhou
- China-Australia Joint Laboratory for Soil Ecological Health and Remediation, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250103, China; (Y.Z.); (R.T.); (H.Y.); (M.R.); (M.D.D.)
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA 5064, Australia;
| | - Christopher J. Lambrides
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia;
| | - Jishun Li
- China-Australia Joint Laboratory for Soil Ecological Health and Remediation, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250103, China; (Y.Z.); (R.T.); (H.Y.); (M.R.); (M.D.D.)
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA 5064, Australia;
- Correspondence: ; Tel.: +86-531-8872-8276
| | - Qili Xu
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA 5064, Australia;
| | - Ruey Toh
- China-Australia Joint Laboratory for Soil Ecological Health and Remediation, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250103, China; (Y.Z.); (R.T.); (H.Y.); (M.R.); (M.D.D.)
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA 5064, Australia;
| | - Shenzhong Tian
- Institute of Agricultural Resources and Environment, Shandong Academy of Agricultural Sciences, Jinan 250013, China;
| | - Peizhi Yang
- College of Grassland Agriculture, Northwest A&F University, Yangling, Xianyang 712100, China;
| | - Hetong Yang
- China-Australia Joint Laboratory for Soil Ecological Health and Remediation, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250103, China; (Y.Z.); (R.T.); (H.Y.); (M.R.); (M.D.D.)
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA 5064, Australia;
| | - Maarten Ryder
- China-Australia Joint Laboratory for Soil Ecological Health and Remediation, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250103, China; (Y.Z.); (R.T.); (H.Y.); (M.R.); (M.D.D.)
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA 5064, Australia;
| | - Matthew D. Denton
- China-Australia Joint Laboratory for Soil Ecological Health and Remediation, Ecology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250103, China; (Y.Z.); (R.T.); (H.Y.); (M.R.); (M.D.D.)
- School of Agriculture, Food and Wine, The University of Adelaide, Urrbrae, SA 5064, Australia;
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26
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Sasse J, Kosina SM, de Raad M, Jordan JS, Whiting K, Zhalnina K, Northen TR. Root morphology and exudate availability are shaped by particle size and chemistry in Brachypodium distachyon. Plant Direct 2020; 4:e00207. [PMID: 32642632 PMCID: PMC7330624 DOI: 10.1002/pld3.207] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 02/04/2020] [Accepted: 02/11/2020] [Indexed: 05/26/2023]
Abstract
Root morphology and exudation define a plants' sphere of influence in soils. In turn, soil characteristics influence plant growth, morphology, root microbiome, and rhizosphere chemistry. Collectively, all these parameters have significant implications on the major biogeochemical cycles, crop yield, and ecosystem health. However, how plants are shaped by the physiochemistry of soil particles is still not well understood. We explored how particle size and chemistry of growth substrates affect root morphology and exudation of a model grass. We grew Brachypodium distachyon in glass beads with various sizes (0.5, 1, 2, 3 mm), as well as in sand (0.005, 0.25, 4 mm) and in clay (4 mm) particles and in particle-free hydroponic medium. Plant morphology, root weight, and shoot weight were measured. We found that particle size significantly influenced root fresh weight and root length, whereas root number and shoot weight remained constant. Next, plant exudation profiles were analyzed with mass spectrometry imaging and liquid chromatography-mass spectrometry. Mass spectrometry imaging suggested that both, root length and number shape root exudation. Exudate profiles were comparable for plants growing in glass beads or sand with various particles sizes, but distinct for plants growing in clay for in situ exudate collection. Clay particles were found to sorb 20% of compounds exuded by clay-grown plants, and 70% of compounds from a defined exudate medium. The sorbed compounds belonged to a range of chemical classes, among them nucleosides, organic acids, sugars, and amino acids. Some of the sorbed compounds could be desorbed by a rhizobacterium (Pseudomonas fluorescens WCS415), supporting its growth. This study demonstrates the effect of different characteristics of particles on root morphology, plant exudation and availability of nutrients to microorganisms. These findings further support the critical importance of the physiochemical properties of soils when investigating plant morphology, plant chemistry, and plant-microbe interactions.
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Affiliation(s)
- Joelle Sasse
- Environmental Genomics and Systems BiologyLawrence Berkeley National LaboratoryBerkeleyCAUSA
- Department of Plant and Microbial BiologyUniversity of ZurichZurichSwitzerland
| | - Suzanne M. Kosina
- Environmental Genomics and Systems BiologyLawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Markus de Raad
- Environmental Genomics and Systems BiologyLawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Jacob S. Jordan
- Environmental Genomics and Systems BiologyLawrence Berkeley National LaboratoryBerkeleyCAUSA
- Joint Genome InstituteLawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Katherine Whiting
- Environmental Genomics and Systems BiologyLawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Kateryna Zhalnina
- Environmental Genomics and Systems BiologyLawrence Berkeley National LaboratoryBerkeleyCAUSA
| | - Trent R. Northen
- Environmental Genomics and Systems BiologyLawrence Berkeley National LaboratoryBerkeleyCAUSA
- Joint Genome InstituteLawrence Berkeley National LaboratoryBerkeleyCAUSA
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27
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Korenblum E, Dong Y, Szymanski J, Panda S, Jozwiak A, Massalha H, Meir S, Rogachev I, Aharoni A. Rhizosphere microbiome mediates systemic root metabolite exudation by root-to-root signaling. Proc Natl Acad Sci U S A 2020; 117:3874-83. [PMID: 32015118 DOI: 10.1073/pnas.1912130117] [Citation(s) in RCA: 206] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Microbial communities associated with roots confer specific functions to their hosts, thereby modulating plant growth, health, and productivity. Yet, seminal questions remain largely unaddressed including whether and how the rhizosphere microbiome modulates root metabolism and exudation and, consequently, how plants fine tune this complex belowground web of interactions. Here we show that, through a process termed systemically induced root exudation of metabolites (SIREM), different microbial communities induce specific systemic changes in tomato root exudation. For instance, systemic exudation of acylsugars secondary metabolites is triggered by local colonization of bacteria affiliated with the genus Bacillus Moreover, both leaf and systemic root metabolomes and transcriptomes change according to the rhizosphere microbial community structure. Analysis of the systemic root metabolome points to glycosylated azelaic acid as a potential microbiome-induced signaling molecule that is subsequently exuded as free azelaic acid. Our results demonstrate that rhizosphere microbiome assembly drives the SIREM process at the molecular and chemical levels. It highlights a thus-far unexplored long-distance signaling phenomenon that may regulate soil conditioning.
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28
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Avellan A, Yun J, Zhang Y, Spielman-Sun E, Unrine JM, Thieme J, Li J, Lombi E, Bland G, Lowry GV. Nanoparticle Size and Coating Chemistry Control Foliar Uptake Pathways, Translocation, and Leaf-to-Rhizosphere Transport in Wheat. ACS Nano 2019; 13:5291-5305. [PMID: 31074967 DOI: 10.1021/acsnano.8b09781] [Citation(s) in RCA: 183] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Nanoenabled foliar-applied agrochemicals can potentially be safer and more efficient than conventional products. However, limited understanding about how nanoparticle properties influence their interactions with plant leaves, uptake, translocation through the mesophyll to the vasculature, and transport to the rest of the plant prevents rational design. This study used a combination of Au quantification and spatial analysis to investigate how size (3, 10, or 50 nm) and coating chemistry (PVP versus citrate) of gold nanoparticles (AuNPs) influence these processes. Following wheat foliar exposure to AuNPs suspensions (∼280 ng per plant), adhesion on the leaf surface was increased for smaller sizes, and PVP-AuNPs compared to citrate-AuNPs. After 2 weeks, there was incomplete uptake of citrate-AuNPs with some AuNPs remaining on the outside of the cuticle layer. However, the fraction of citrate-AuNPs that had entered the leaf was translocated efficiently to the plant vasculature. In contrast, for similar sizes, virtually all of the PVP-AuNPs crossed the cuticle layer after 2 weeks, but its transport through the mesophyll cells was lower. As a consequence of PVP-AuNP accumulation in the leaf mesophyll, wheat photosynthesis was impaired. Regardless of their coating and sizes, the majority of the transported AuNPs accumulated in younger shoots (10-30%) and in roots (10-25%), and 5-15% of the NPs <50 nm were exuded into the rhizosphere soil. A greater fraction of larger sizes AuNPs (presenting lower ζ potentials) was transported to the roots. The key hypotheses about the NPs physical-chemical and plant physiology parameters that may matter to predict leaf-to-rhizosphere transport are also discussed.
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Affiliation(s)
- Astrid Avellan
- Civil and Environmental Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Jie Yun
- Civil and Environmental Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Yilin Zhang
- Civil and Environmental Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Eleanor Spielman-Sun
- Civil and Environmental Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Jason M Unrine
- Department of Plant and Soil Sciences , University of Kentucky , Lexington , Kentucky 40546 , United States
| | - Juergen Thieme
- NSLS-II, Brookhaven National Laboratory , Brookhaven , New York 11973 , United States
| | - Jieran Li
- Department of Plant and Soil Sciences , University of Kentucky , Lexington , Kentucky 40546 , United States
| | - Enzo Lombi
- Future Industries Institute , University of South Australia , Mawson Lakes , South Australia 5095 , Australia
| | - Garret Bland
- Civil and Environmental Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
| | - Gregory V Lowry
- Civil and Environmental Engineering , Carnegie Mellon University , Pittsburgh , Pennsylvania 15213 , United States
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29
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Jacoby RP, Kopriva S. Metabolic niches in the rhizosphere microbiome: new tools and approaches to analyse metabolic mechanisms of plant-microbe nutrient exchange. J Exp Bot 2019; 70:1087-1094. [PMID: 30576534 DOI: 10.1093/jxb/ery438] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [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: 09/12/2018] [Accepted: 11/27/2018] [Indexed: 05/05/2023]
Abstract
Plants nourish rhizospheric microbes via provision of carbon substrates, and the composition of the microbiome is strongly influenced by metabolic phenomena such as niche differentiation, competitive exclusion, and cross-feeding. Despite intensive investigations of the taxonomic structure in root microbiomes, there is relatively little biochemical knowledge of the metabolic niches occupied by microbial strains in the rhizosphere. Here, we review new tools and approaches that are boosting our knowledge of the metabolic mechanisms that shape the composition of the root microbiome. New studies have elucidated biochemical pathways that mediate root colonisation and pathogen suppression, and synthetic communities are emerging as a powerful tool to understand microbe-microbe interactions. Knowledge of root exudate composition is being advanced by new metabolomics methodologies, which have highlighted that specific exudate components can inhibit pathogen growth, and that certain metabolites can recruit mutualistic strains according to substrate uptake preferences. Microbial genomics is rapidly advancing, with large collections of isolated rhizosphere strains and mutant libraries giving new insights into the metabolic mechanisms of root colonisation. Exometabolomics is emerging as a powerful methodology for directly observing microbial uptake of root metabolites, and also for profiling microbial cross-feeding. Integrative studies using these resources should enable rapid advances, particularly when applied to standardised experimental set-ups and model synthetic communities.
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Affiliation(s)
- Richard P Jacoby
- University of Cologne, Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Cologne, Germany
| | - Stanislav Kopriva
- University of Cologne, Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Cologne, Germany
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Pascale A, Proietti S, Pantelides IS, Stringlis IA. Modulation of the Root Microbiome by Plant Molecules: The Basis for Targeted Disease Suppression and Plant Growth Promotion. Front Plant Sci 2019; 10:1741. [PMID: 32038698 PMCID: PMC6992662 DOI: 10.3389/fpls.2019.01741] [Citation(s) in RCA: 203] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/11/2019] [Indexed: 05/18/2023]
Abstract
Plants host a mesmerizing diversity of microbes inside and around their roots, known as the microbiome. The microbiome is composed mostly of fungi, bacteria, oomycetes, and archaea that can be either pathogenic or beneficial for plant health and fitness. To grow healthy, plants need to surveil soil niches around the roots for the detection of pathogenic microbes, and in parallel maximize the services of beneficial microbes in nutrients uptake and growth promotion. Plants employ a palette of mechanisms to modulate their microbiome including structural modifications, the exudation of secondary metabolites and the coordinated action of different defence responses. Here, we review the current understanding on the composition and activity of the root microbiome and how different plant molecules can shape the structure of the root-associated microbial communities. Examples are given on interactions that occur in the rhizosphere between plants and soilborne fungi. We also present some well-established examples of microbiome harnessing to highlight how plants can maximize their fitness by selecting their microbiome. Understanding how plants manipulate their microbiome can aid in the design of next-generation microbial inoculants for targeted disease suppression and enhanced plant growth.
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Affiliation(s)
- Alberto Pascale
- Department of Agricultural Sciences, University of Naples Federico II, Naples, Italy
| | - Silvia Proietti
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy
| | - Iakovos S. Pantelides
- Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, Limassol, Cyprus
- *Correspondence: Iakovos S. Pantelides, ; Ioannis A. Stringlis,
| | - Ioannis A. Stringlis
- Plant-Microbe Interactions, Department of Biology, Science4Life, Utrecht University, Utrecht, Netherlands
- *Correspondence: Iakovos S. Pantelides, ; Ioannis A. Stringlis,
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31
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Guyonnet JP, Guillemet M, Dubost A, Simon L, Ortet P, Barakat M, Heulin T, Achouak W, Haichar FEZ. Plant Nutrient Resource Use Strategies Shape Active Rhizosphere Microbiota Through Root Exudation. Front Plant Sci 2018; 9:1662. [PMID: 30559748 PMCID: PMC6265440 DOI: 10.3389/fpls.2018.01662] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 10/26/2018] [Indexed: 05/20/2023]
Abstract
Plant strategies for soil nutrient uptake have the potential to strongly influence plant-microbiota interactions, due to the competition between plants and microorganisms for soil nutrient acquisition and/or conservation. In the present study, we investigate whether these plant strategies could influence rhizosphere microbial activities via root exudation, and contribute to the microbiota diversification of active bacterial communities colonizing the root-adhering soil (RAS) and inhabiting the root tissues. We applied a DNA-based stable isotope probing (DNA-SIP) approach to six grass species distributed along a gradient of plant nutrient resource strategies, from conservative species, characterized by low nitrogen (N) uptake, a long lifespans and low root exudation level, to exploitative species, characterized by high rates of photosynthesis, rapid rates of N uptake and high root exudation level. We analyzed their (i) associated microbiota composition involved in root exudate assimilation and soil organic matter (SOM) degradation by 16S-rRNA-based metabarcoding. (ii) We determine the impact of root exudation level on microbial activities (denitrification and respiration) by gas chromatography. Measurement of microbial activities revealed an increase in denitrification and respiration activities for microbial communities colonizing the RAS of exploitative species. This increase of microbial activities results probably from a higher exudation rate and more diverse metabolites by exploitative plant species. Furthermore, our results demonstrate that plant nutrient resource strategies have a role in shaping active microbiota. We present evidence demonstrating that plant nutrient use strategies shape active microbiota involved in root exudate assimilation and SOM degradation via root exudation.
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Affiliation(s)
- Julien P. Guyonnet
- Laboratoire d’Ecologie Microbienne, UMR CNRS 5557, Univ Lyon, Université Claude Bernard Lyon 1, UMR INRA 1418, Villeurbanne, France
| | - Martin Guillemet
- Laboratoire d’Ecologie Microbienne, UMR CNRS 5557, Univ Lyon, Université Claude Bernard Lyon 1, UMR INRA 1418, Villeurbanne, France
- Master de Biologie, École Normale Supérieure de Lyon, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Audrey Dubost
- Laboratoire d’Ecologie Microbienne, UMR CNRS 5557, Univ Lyon, Université Claude Bernard Lyon 1, UMR INRA 1418, Villeurbanne, France
| | - Laurent Simon
- CNRS, UMR 5023 LEHNA, Univ Lyon, Université Claude Bernard Lyon 1, Université Lyon 1, ENTPE, Villeurbanne, France
| | - Philippe Ortet
- CNRS, Laboratory for Microbial Ecology of the Rhizosphere and Extreme Environment, UMR 7265 BIAM, CEA, Aix Marseille Univ, Saint-Paul-lès-Durance, France
- CNRS, FR3098 ECCOREV, Aix Marseille Univ, Aix-en-Provence, France
| | - Mohamed Barakat
- CNRS, Laboratory for Microbial Ecology of the Rhizosphere and Extreme Environment, UMR 7265 BIAM, CEA, Aix Marseille Univ, Saint-Paul-lès-Durance, France
- CNRS, FR3098 ECCOREV, Aix Marseille Univ, Aix-en-Provence, France
| | - Thierry Heulin
- CNRS, Laboratory for Microbial Ecology of the Rhizosphere and Extreme Environment, UMR 7265 BIAM, CEA, Aix Marseille Univ, Saint-Paul-lès-Durance, France
- CNRS, FR3098 ECCOREV, Aix Marseille Univ, Aix-en-Provence, France
| | - Wafa Achouak
- CNRS, Laboratory for Microbial Ecology of the Rhizosphere and Extreme Environment, UMR 7265 BIAM, CEA, Aix Marseille Univ, Saint-Paul-lès-Durance, France
| | - Feth el Zahar Haichar
- Laboratoire d’Ecologie Microbienne, UMR CNRS 5557, Univ Lyon, Université Claude Bernard Lyon 1, UMR INRA 1418, Villeurbanne, France
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Wilson CH, Strickland MS, Hutchings JA, Bianchi TS, Flory SL. Grazing enhances belowground carbon allocation, microbial biomass, and soil carbon in a subtropical grassland. Glob Chang Biol 2018; 24:2997-3009. [PMID: 29377461 DOI: 10.1111/gcb.14070] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [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: 08/03/2017] [Accepted: 12/18/2017] [Indexed: 06/07/2023]
Abstract
Despite the large contribution of rangeland and pasture to global soil organic carbon (SOC) stocks, there is considerable uncertainty about the impact of large herbivore grazing on SOC, especially for understudied subtropical grazing lands. It is well known that root system inputs are the source of most grassland SOC, but the impact of grazing on partitioning of carbon allocation to root tissue production compared to fine root exudation is unclear. Given that different forms of root C have differing implications for SOC synthesis and decomposition, this represents a significant gap in knowledge. Root exudates should contribute to SOC primarily after microbial assimilation, and thus promote microbial contributions to SOC based on stabilization of microbial necromass, whereas root litter deposition contributes directly as plant-derived SOC following microbial decomposition. Here, we used in situ isotope pulse-chase methodology paired with plant and soil sampling to link plant carbon allocation patterns with SOC pools in replicated long-term grazing exclosures in subtropical pasture in Florida, USA. We quantified allocation of carbon to root tissue and measured root exudation across grazed and ungrazed plots and quantified lignin phenols to assess the relative contribution of microbial vs. plant products to total SOC. We found that grazing exclusion was associated with dramatically less overall belowground allocation, with lower root biomass, fine root exudates, and microbial biomass. Concurrently, grazed pasture contained greater total SOC, and a larger fraction of SOC that originated from plant tissue deposition, suggesting that higher root litter deposition under grazing promotes greater SOC. We conclude that grazing effects on SOC depend on root system biomass, a pattern that may generalize to other C4-dominated grasslands, especially in the subtropics. Improved understanding of ecological factors underlying root system biomass may be the key to forecasting SOC and optimizing grazing management to enhance SOC accumulation.
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Affiliation(s)
- Chris H Wilson
- School of Natural Resources and Environment, University of Florida, Gainesville, FL, USA
| | - Michael S Strickland
- Department of Biological Sciences, Virginia Tech University, Blacksburg, VA, USA
| | - Jack A Hutchings
- Department of Geological Sciences, University of Florida, Gainesville, FL, USA
| | - Thomas S Bianchi
- Department of Geological Sciences, University of Florida, Gainesville, FL, USA
| | - S Luke Flory
- Agronomy Department, University of Florida, Gainesville, FL, USA
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Hener C, Hummel S, Suarez J, Stahl M, Kolukisaoglu Ü. d-Amino Acids Are Exuded by Arabidopsis thaliana Roots to the Rhizosphere. Int J Mol Sci 2018; 19:ijms19041109. [PMID: 29642439 PMCID: PMC5979410 DOI: 10.3390/ijms19041109] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 12/27/2022] Open
Abstract
Proteinogenic l-amino acids (l-AAs) are essential in all kingdoms as building blocks of proteins. Their d-enantiomers are also known to fulfill important functions in microbes, fungi, and animals, but information about these molecules in plants is still sparse. Previously, it was shown that d-amino acids (d-AAs) are taken up and utilized by plants, but their ways to reduce excessive amounts of them still remained unclear. Analyses of plant d-AA content after d-Ala and d-Glu feeding opened the question if exudation of d-AAs into the rhizosphere takes place and plays a role in the reduction of d-AA content in plants. The exudation of d-Ala and d-Glu could be confirmed by amino acid analyses of growth media from plants treated with these d-AAs. Further tests revealed that other d-AAs were also secreted. Nevertheless, treatments with d-Ala and d-Glu showed that plants are still able to reduce their contents within the plant without exudation. Further exudation experiments with transport inhibitors revealed that d-AA root exudation is rather passive and comparable to the secretion of l-AAs. Altogether, these observations argued against a dominant role of exudation in the regulation of plant d-AA content, but may influence the composition of the rhizosphere.
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Affiliation(s)
- Claudia Hener
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
| | - Sabine Hummel
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
| | - Juan Suarez
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
| | - Mark Stahl
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
| | - Üner Kolukisaoglu
- Center for Plant Molecular Biology (ZMBP), University of Tübingen, Auf der Morgenstelle 32, 72076 Tübingen, Germany.
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Gfeller A, Glauser G, Etter C, Signarbieux C, Wirth J. Fagopyrum esculentum Alters Its Root Exudation after Amaranthus retroflexus Recognition and Suppresses Weed Growth. Front Plant Sci 2018; 9:50. [PMID: 29445385 PMCID: PMC5797785 DOI: 10.3389/fpls.2018.00050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/10/2018] [Indexed: 05/08/2023]
Abstract
Weed control by crops through growth suppressive root exudates is a promising alternative to herbicides. Buckwheat (Fagopyrum esculentum) is known for its weed suppression and redroot pigweed (Amaranthus retroflexus) control is probably partly due to allelopathic root exudates. This work studies whether other weeds are also suppressed by buckwheat and if the presence of weeds is necessary to induce growth repression. Buckwheat and different weeds were co-cultivated in soil, separating roots by a mesh allowing to study effects due to diffusion. Buckwheat suppressed growth of pigweed, goosefoot and barnyard grass by 53, 42, and 77% respectively without physical root interactions, probably through allelopathic compounds. Root exudates were obtained from sand cultures of buckwheat (BK), pigweed (P), and a buckwheat/pigweed mixed culture (BK-P). BK-P root exudates inhibited pigweed root growth by 49%. Characterization of root exudates by UHPLC-HRMS and principal component analysis revealed that BK and BK-P had a different metabolic profile suggesting that buckwheat changes its root exudation in the presence of pigweed indicating heterospecific recognition. Among the 15 different markers, which were more abundant in BK-P, tryptophan was identified and four others were tentatively identified. Our findings might contribute to the selection of crops with weed suppressive effects.
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Affiliation(s)
- Aurélie Gfeller
- Herbology in Field Crops and Viticulture, Plant Production Systems, Agroscope, Nyon, Switzerland
| | - Gaétan Glauser
- Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel, Switzerland
| | - Clément Etter
- Herbology in Field Crops and Viticulture, Plant Production Systems, Agroscope, Nyon, Switzerland
| | - Constant Signarbieux
- Laboratory of Ecological Systems ECOS, School of Architecture, Civil and Environmental Engineering ENAC, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Judith Wirth
- Herbology in Field Crops and Viticulture, Plant Production Systems, Agroscope, Nyon, Switzerland
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Pausch J, Kuzyakov Y. Carbon input by roots into the soil: Quantification of rhizodeposition from root to ecosystem scale. Glob Chang Biol 2018; 24:1-12. [PMID: 28752603 DOI: 10.1111/gcb.13850] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [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: 05/09/2017] [Accepted: 07/14/2017] [Indexed: 05/12/2023]
Abstract
Despite its fundamental role for carbon (C) and nutrient cycling, rhizodeposition remains 'the hidden half of the hidden half': it is highly dynamic and rhizodeposits are rapidly incorporated into microorganisms, soil organic matter, and decomposed to CO2 . Therefore, rhizodeposition is rarely quantified and remains the most uncertain part of the soil C cycle and of C fluxes in terrestrial ecosystems. This review synthesizes and generalizes the literature on C inputs by rhizodeposition under crops and grasslands (281 data sets). The allocation dynamics of assimilated C (after 13 C-CO2 or 14 C-CO2 labeling of plants) were quantified within shoots, shoot respiration, roots, net rhizodeposition (i.e., C remaining in soil for longer periods), root-derived CO2 , and microorganisms. Partitioning of C pools and fluxes were used to extrapolate belowground C inputs via rhizodeposition to ecosystem level. Allocation from shoots to roots reaches a maximum within the first day after C assimilation. Annual crops retained more C (45% of assimilated 13 C or 14 C) in shoots than grasses (34%), mainly perennials, and allocated 1.5 times less C belowground. For crops, belowground C allocation was maximal during the first 1-2 months of growth and decreased very fast thereafter. For grasses, it peaked after 2-4 months and remained very high within the second year causing much longer allocation periods. Despite higher belowground C allocation by grasses (33%) than crops (21%), its distribution between various belowground pools remains very similar. Hence, the total C allocated belowground depends on the plant species, but its further fate is species independent. This review demonstrates that C partitioning can be used in various approaches, e.g., root sampling, CO2 flux measurements, to assess rhizodeposits' pools and fluxes at pot, plot, field and ecosystem scale and so, to close the most uncertain gap of the terrestrial C cycle.
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Affiliation(s)
- Johanna Pausch
- Department of Agroecology, University of Bayreuth, Bayreuth, Germany
- Department of Soil Science of Temperate Ecosystems, Georg-August-University, Göttingen, Germany
| | - Yakov Kuzyakov
- Department of Soil Science of Temperate Ecosystems, Georg-August-University, Göttingen, Germany
- Department of Agricultural Soil Science, Georg-August-University, Göttingen, Germany
- Institute of Environmental Sciences, Kazan Federal University, Kazan, Russia
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Güsewell S, Schroth MH. How functional is a trait? Phosphorus mobilization through root exudates differs little between Carex species with and without specialized dauciform roots. New Phytol 2017; 215:1438-1450. [PMID: 28670743 DOI: 10.1111/nph.14674] [Citation(s) in RCA: 7] [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: 02/19/2017] [Accepted: 05/21/2017] [Indexed: 06/07/2023]
Abstract
Root structures secreting carboxylates and phosphatases are thought to enhance a plant's phosphorus (P) acquisition. But do closely related species with and without such structures really differ in root exudation, P mobilization, or ecological niche? We investigated this by comparing 23 European Carex species with and without 'dauciform roots' (DRs). Plants grown in pots with sand were screened for DR formation, phosphatase activities, carboxylate exudation, and utilization of various organic and inorganic P compounds. Ecological niches were compared using ecological indicator values and nutrient concentrations of plant shoots in natural habitats. Species of subgenus Carex formed DRs, while species of subgenus Vignea did not. Species with DRs had higher root diesterase activity than species without DRs, exuded more citrate but less oxalate and less total carboxylates, and allocated less biomass to roots. Species with and without DRs showed similar growth responses to different forms of P and different amounts of P supplied; their natural habitats do not differ in soil fertility or degree of P limitation. Despite some differences in physiological function, DRs did not influence the P acquisition and nutritional niche of European Carex species, suggesting that species with and without DRs do not exhibit distinct P-acquisition strategies.
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Affiliation(s)
- Sabine Güsewell
- Institute of Integrative Biology, ETH Zurich, Universitätstrasse 16, 8092, Zürich, Switzerland
| | - Martin H Schroth
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Universitätstrasse 16, 8092, Zürich, Switzerland
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Lyu Y, Tang H, Li H, Zhang F, Rengel Z, Whalley WR, Shen J. Major Crop Species Show Differential Balance between Root Morphological and Physiological Responses to Variable Phosphorus Supply. Front Plant Sci 2016; 7:1939. [PMID: 28066491 PMCID: PMC5174099 DOI: 10.3389/fpls.2016.01939] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 12/07/2016] [Indexed: 05/20/2023]
Abstract
The relationship between root morphological and physiological responses to variable P supply in different plant species is poorly understood. We compared root morphological and physiological responses to P supply in seven crop species (Zea mays, Triticum aestivum, Brassica napus, Lupinus albus, Glycine max, Vicia faba, Cicer arietinum) treated with or without 100 mg P kg-1 in two soils (acidic and calcareous). Phosphorus deficiency decreased root length more in fibrous root species (Zea mays, Triticum aestivum, Brassica napus) than legumes. Zea mays and Triticum aestivum had higher root/shoot biomass ratio and Brassica napus had higher specific root length compared to legumes, whereas legumes (except soybean) had higher carboxylate exudation than fibrous root species. Lupinus albus exhibited the highest P-acquisition efficiency due to high exudation of carboxylates and acid phosphatases. Lupinus albus and Cicer arietinum depended mostly on root exudation (i.e., physiological response) to enhance P acquisition, whereas Zea mays, Triticum aestivum and Brassica napus had higher root morphology dependence, with Glycine max and Vicia faba in between. Principal component analysis using six morphological and six physiological responses identified root size and diameter as the most important morphological traits, whereas important physiological responses included carboxylate exudation, and P-acquisition and P-utilization efficiency followed by rhizosphere soil pH and acid phosphatase activity. In conclusion, plant species can be grouped on the basis of their response to soil P being primarily via root architectural or exudation plasticity, suggesting a potential benefit of crop-specific root-trait-based management to cope with variable soil P supply in sustainable grain production.
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Affiliation(s)
- Yang Lyu
- Centre for Resources, Environment and Food Security, Department of Plant Nutrition, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural UniversityBeijing, China
| | - Hongliang Tang
- Centre for Resources, Environment and Food Security, Department of Plant Nutrition, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural UniversityBeijing, China
- College of Life Science, Hebei UniversityBaoding, China
| | - Haigang Li
- Centre for Resources, Environment and Food Security, Department of Plant Nutrition, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural UniversityBeijing, China
| | - Fusuo Zhang
- Centre for Resources, Environment and Food Security, Department of Plant Nutrition, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural UniversityBeijing, China
| | - Zed Rengel
- Soil Science and Plant Nutrition, School of Earth and Environment, The UWA Institute of Agriculture, The University of Western Australia, CrawleyWA, Australia
| | | | - Jianbo Shen
- Centre for Resources, Environment and Food Security, Department of Plant Nutrition, Key Laboratory of Plant-Soil Interactions, Ministry of Education, China Agricultural UniversityBeijing, China
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38
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Liu H, Tang C, Li C. The effects of nitrogen form on root morphological and physiological adaptations of maize, white lupin and faba bean under phosphorus deficiency. AoB Plants 2016; 8:plw058. [PMID: 27519912 PMCID: PMC5018397 DOI: 10.1093/aobpla/plw058] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 08/04/2016] [Indexed: 05/13/2023]
Abstract
Root morphological/physiological modifications are important for phosphorus (P) acquisition of plants under P deficiency, but strategies differ among plant species. Detailed studies on the response of maize roots to P deficiency are limited. Nitrogen (N) form influences root morphology/physiology, and thus may influence root responses to P deficiency. This work investigated adaptive mechanisms of maize roots to low P by comparison with white lupin and faba bean supplied with two N forms. Plants were grown for 7-16 days in hydroponics with sufficient (250 µmol L(-1)) and deficient P supply (1 µmol L(-1)) under supply of NH4NO3 or Ca(NO3)2 Plant growth and P uptake were measured, and release of protons and organic acid anions, and acid phosphatase activity in the root were monitored. The results showed that P deficiency significantly decreased shoot growth while increased root growth and total root length of maize and faba bean, but not white lupin. It enhanced the release of protons and organic acid anions, and acid phosphatase activity, from the roots of both legumes but not maize. Compared with Ca(NO3)2, NH4NO3 dramatically increased proton release by roots but did not alter root morphology or physiology of the three species in response to low P. It is concluded that the N form did not fundamentally change root morphological/physiological responses of the three species to P deficiency. Morphological variation in maize and morpho-physiological modifications in white lupin and faba bean were the main adaptive strategies to P deficiency.
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Affiliation(s)
- Haitao Liu
- Department of Plant Nutrition, China Agricultural University, Beijing 100193, China
| | - Caixian Tang
- Department of Animal, Plant and Soil Sciences, La Trobe University, Melbourne Campus, Bundoora, VIC 3086, Australia
| | - Chunjian Li
- Department of Plant Nutrition, China Agricultural University, Beijing 100193, China
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39
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Abstract
Plant productivity is limited by the scarcity of the essential micronutrient iron particularly in alkaline soils. The root secretion of phenolics has long been recognized as a component of the acidification-reduction strategy to acquire iron (strategy I). However, very little molecular insight into this process was available until recently several research groups independently discovered the important role of coumarins for the growth of Arabidopsis thaliana under Fe-limited conditions. Genome-wide analyses of iron deficiency responses, mutant screening and metabolomics experiments all converged on the finding that the synthesis and root exudation of scopoletin, esculetin and other coumarins is essential for iron uptake from substrates with low iron availability. Here we describe the evidence supporting this conclusion and discuss important questions that now have to be addressed in order to better understand the mechanistic basis of coumarin-dependent iron uptake and its significance within the plant kingdom.
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Affiliation(s)
- Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Germany
| | - Michael Weber
- Department of Plant Physiology, University of Bayreuth, Germany
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40
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Abstract
In the last decade cheaper and faster sequencing methods have resulted in an enormous increase in genomic data. High throughput genotyping, genotyping by sequencing and genomic breeding are becoming a standard in plant breeding. As a result, the collection of phenotypic data is increasingly becoming a limiting factor in plant breeding. Genetic studies on root traits are being hampered by the complexity of these traits and the inaccessibility of the rhizosphere. With an increasing interest in phenotyping, breeders and scientists try to overcome these limitations, resulting in impressive developments in automated phenotyping platforms. Recently, many such platforms have been thoroughly described, yet their efficiency to increase genetic gain often remains undiscussed. This efficiency depends on the heritability of the phenotyped traits as well as the correlation of these traits with agronomically relevant breeding targets. This review provides an overview of the latest developments in root phenotyping and describes the environmental and genetic factors influencing root phenotype and heritability. It also intends to give direction to future phenotyping and breeding strategies for optimizing root system functioning. A quantitative framework to determine the efficiency of phenotyping platforms for genetic gain is described. By increasing heritability, managing effects caused by interactions between genotype and environment and by quantifying the genetic relation between traits phenotyped in platforms and ultimate breeding targets, phenotyping platforms can be utilized to their maximum potential.
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Affiliation(s)
- René C P Kuijken
- Wageningen UR, Greenhouse Horticulture, Wageningen, 6708 PB, The Netherlands Wageningen UR, Laboratory of Plant Physiology, Wageningen, 6708 PB, The Netherlands
| | | | - Leo F M Marcelis
- Wageningen UR, Horticulture and Product Physiology, Wageningen, 6708 PB, The Netherlands
| | - Harro J Bouwmeester
- Wageningen UR, Laboratory of Plant Physiology, Wageningen, 6708 PB, The Netherlands
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41
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Chaparro JM, Badri DV, Vivanco JM. Rhizosphere microbiome assemblage is affected by plant development. ISME J 2014; 8:790-803. [PMID: 24196324 PMCID: PMC3960538 DOI: 10.1038/ismej.2013.196] [Citation(s) in RCA: 585] [Impact Index Per Article: 58.5] [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: 03/06/2013] [Revised: 08/22/2013] [Accepted: 09/29/2013] [Indexed: 01/11/2023]
Abstract
There is a concerted understanding of the ability of root exudates to influence the structure of rhizosphere microbial communities. However, our knowledge of the connection between plant development, root exudation and microbiome assemblage is limited. Here, we analyzed the structure of the rhizospheric bacterial community associated with Arabidopsis at four time points corresponding to distinct stages of plant development: seedling, vegetative, bolting and flowering. Overall, there were no significant differences in bacterial community structure, but we observed that the microbial community at the seedling stage was distinct from the other developmental time points. At a closer level, phylum such as Acidobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria and specific genera within those phyla followed distinct patterns associated with plant development and root exudation. These results suggested that the plant can select a subset of microbes at different stages of development, presumably for specific functions. Accordingly, metatranscriptomics analysis of the rhizosphere microbiome revealed that 81 unique transcripts were significantly (P<0.05) expressed at different stages of plant development. For instance, genes involved in streptomycin synthesis were significantly induced at bolting and flowering stages, presumably for disease suppression. We surmise that plants secrete blends of compounds and specific phytochemicals in the root exudates that are differentially produced at distinct stages of development to help orchestrate rhizosphere microbiome assemblage.
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Affiliation(s)
- Jacqueline M Chaparro
- Center for Rhizosphere Biology, Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO, USA
| | - Dayakar V Badri
- Center for Rhizosphere Biology, Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO, USA
| | - Jorge M Vivanco
- Center for Rhizosphere Biology, Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO, USA
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42
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Florez-Sarasa I, Lambers H, Wang X, Finnegan PM, Ribas-Carbo M. The alternative respiratory pathway mediates carboxylate synthesis in white lupin cluster roots under phosphorus deprivation. Plant Cell Environ 2014; 37:922-928. [PMID: 24118034 DOI: 10.1111/pce.12208] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [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: 07/22/2013] [Revised: 09/04/2013] [Accepted: 09/09/2013] [Indexed: 06/02/2023]
Abstract
Plant adaptations associated with a high efficiency of phosphorus (P) acquisition can be used to increase productivity and sustainability in a world with a growing population and decreasing rock phosphate reserves. White lupin (Lupinus albus) produces cluster roots that release carboxylates to efficiently mobilize P from P-sorbing soils. It has been hypothesized that an increase in the activity of the alternative oxidase (AOX) would allow for the mitochondrial oxidation of NAD(P)H produced during citrate synthesis in cluster roots at a developmental stage when there is a low demand for ATP. We used the oxygen-isotope fractionation technique to study the in vivo respiratory activities of the cytochrome oxidase pathway (COP) and the alternative oxidase pathway (AOP) in different root sections of white lupins grown hydroponically with and without P. In parallel, AOX protein levels and internal carboxylate concentrations were determined in cluster and non-cluster roots. Higher in vivo AOP activity was measured in cluster roots when malate and citrate concentrations were also high, thus confirming our hypothesis. AOX protein levels were not always correlated with in vivo AOP activity, suggesting post-translational regulation of AOX.
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Affiliation(s)
- Igor Florez-Sarasa
- Grup de Recerca en Biologia de les Plantes en Condicions Mediterranies, Departament de Biologia, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Spain
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Neal AL, Ton J. Systemic defense priming by Pseudomonas putida KT2440 in maize depends on benzoxazinoid exudation from the roots. Plant Signal Behav 2013; 8:e22655. [PMID: 23221758 PMCID: PMC3745568 DOI: 10.4161/psb.22655] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 10/24/2012] [Indexed: 05/18/2023]
Abstract
Exudation of benzoxazinoid metabolites from roots of young maize seedlings recruits the rhizobacterial strain Pseudomonas putida KT2440 from the soil to the rhizosphere. In this study, we have investigated whether these rhizobacteria are beneficial for maize by eliciting systemic defense priming. Root colonization of the maize hybrid cultivar Delprim by P. putida primed wound- and jasmonic acid (JA)-inducible emission of aromatic and terpenoid volatiles, but not the emission of the green leaf volatile (Z)-3-hexenyl acetate. Furthermore, root colonization by P. putida primed stress-inducible transcription of the JA-dependent gene SerPIN, whereas JA-dependent induction of the MPI gene was unaffected. Systemic priming of SerPIN by P. putida only occurred in benzoxazinoid-producing plants, and was absent in benzoxazinoid-deficient plants. The results from this study suggest that root colonization by P. putida primes a selection of JA-dependent defenses in Maize, which is reliant on benzoxazinoid exudation from the roots.
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Affiliation(s)
- Andrew L. Neal
- Centre for Sustainable Soils and Grassland Systems; Rothamsted Research; Harpenden, UK
| | - Jurriaan Ton
- Department of Animal and Plant Sciences; University of Sheffield; Sheffield, UK
- Correspondence to: Jurriaan Ton,
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Subbarao GV, Nakahara K, Hurtado MP, Ono H, Moreta DE, Salcedo AF, Yoshihashi AT, Ishikawa T, Ishitani M, Ohnishi-Kameyama M, Yoshida M, Rondon M, Rao IM, Lascano CE, Berry WL, Ito O. Evidence for biological nitrification inhibition in Brachiaria pastures. Proc Natl Acad Sci U S A 2009; 106:17302-7. [PMID: 19805171 PMCID: PMC2752401 DOI: 10.1073/pnas.0903694106] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [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: 04/06/2009] [Indexed: 11/18/2022] Open
Abstract
Nitrification, a key process in the global nitrogen cycle that generates nitrate through microbial activity, may enhance losses of fertilizer nitrogen by leaching and denitrification. Certain plants can suppress soil-nitrification by releasing inhibitors from roots, a phenomenon termed biological nitrification inhibition (BNI). Here, we report the discovery of an effective nitrification inhibitor in the root-exudates of the tropical forage grass Brachiaria humidicola (Rendle) Schweick. Named "brachialactone," this inhibitor is a recently discovered cyclic diterpene with a unique 5-8-5-membered ring system and a gamma-lactone ring. It contributed 60-90% of the inhibitory activity released from the roots of this tropical grass. Unlike nitrapyrin (a synthetic nitrification inhibitor), which affects only the ammonia monooxygenase (AMO) pathway, brachialactone appears to block both AMO and hydroxylamine oxidoreductase enzymatic pathways in Nitrosomonas. Release of this inhibitor is a regulated plant function, triggered and sustained by the availability of ammonium (NH(4)(+)) in the root environment. Brachialactone release is restricted to those roots that are directly exposed to NH(4)(+). Within 3 years of establishment, Brachiaria pastures have suppressed soil nitrifier populations (determined as amoA genes; ammonia-oxidizing bacteria and ammonia-oxidizing archaea), along with nitrification and nitrous oxide emissions. These findings provide direct evidence for the existence and active regulation of a nitrification inhibitor (or inhibitors) release from tropical pasture root systems. Exploiting the BNI function could become a powerful strategy toward the development of low-nitrifying agronomic systems, benefiting both agriculture and the environment.
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Affiliation(s)
- G V Subbarao
- Japan International Research Center for Agricultural Sciences, Ibaraki 305-8686, Japan.
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Abstract
The loss of carbon from roots (rhizodeposition) and the consequent proliferation of microorganisms in the surrounding soil, coupled with the physical presence of a root and processes associated with nutrient uptake, gives rise to a unique zone of soil called the rhizosphere. In this review, we bring together evidence to show that roots can directly regulate most aspects of rhizosphere C flow either by regulating the exudation process itself or by directly regulating the recapture of exudates from soil. Root exudates have been hypothesized to be involved in the enhanced mobilization and acquisition of many nutrients from soil or the external detoxification of metals. With few exceptions, there is little mechanistic evidence from soil-based systems to support these propositions. We conclude that much more integrated work in realistic systems is required to quantify the functional significance of these processes in the field. We need to further unravel the complexities of the rhizosphere in order to fully engage with key scientific ideas such as the development of sustainable agricultural systems and the response of ecosystems to climate change. Contents I. Introduction 460 II. What is rhizodeposition? 460 III. Regulation of rhizodeposition 460 IV. How large is the root exudation C flux? 463 V. How responsive is the root exudation C flux? 463 VI. How responsive is the microbial community to root exudation? 464 VII. The role of root exudates in nutrient acquisition 464 VIII. Mycorrhizal fungi and rhizodeposition 471 IX. Future thoughts 474 Acknowledgements 474 References 474.
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Affiliation(s)
- David L Jones
- School of Agricultural and Forest Sciences, University of Wales, Bangor, Gwynedd, LL57 2UW, Wales, UK
| | - Angela Hodge
- Department of Biology, University of York, PO Box 373, York YO10 5YW, England, UK
| | - Yakov Kuzyakov
- Department of Soil Science and Land Evaluation, Institute of Soil Science and Land Evaluation, Hohenheim University, Emil-Wolff-Strasse 27, D-70599 Stuttgart
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