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Ben Gaied R, Sbissi I, Tarhouni M, Brígido C. Bacterial Endophytes from Legumes Native to Arid Environments Are Promising Tools to Improve Mesorhizobium-Chickpea Symbiosis under Salinity. BIOLOGY 2024; 13:96. [PMID: 38392314 PMCID: PMC10886315 DOI: 10.3390/biology13020096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/26/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024]
Abstract
Symbiotic nitrogen fixation is a major contributor of N in agricultural ecosystems, but the establishment of legume-rhizobium symbiosis is highly affected by soil salinity. Our interest is focused on the use of non-rhizobial endophytes to assist the symbiosis between chickpea and its microsymbiont under salinity to avoid loss of production and fertility. Our aims were (1) to investigate the impact of salinity on both symbiotic partners; including on early events of the Mesorhizobium-chickpea symbiosis, and (2) to evaluate the potential of four non-rhizobial endophytes isolated from legumes native to arid regions (Phyllobacterium salinisoli, P. ifriqiyense, Xanthomonas translucens, and Cupriavidus respiraculi) to promote chickpea growth and nodulation under salinity. Our results show a significant reduction in chickpea seed germination rate and in the microsymbiont Mesorhizobium ciceri LMS-1 growth under different levels of salinity. The composition of phenolic compounds in chickpea root exudates significantly changed when the plants were subjected to salinity, which in turn affected the nod genes expression in LMS-1. Furthermore, the LMS-1 response to root exudate stimuli was suppressed by the presence of salinity (250 mM NaCl). On the contrary, a significant upregulation of exoY and otsA genes, which are involved in exopolysaccharide and trehalose biosynthesis, respectively, was registered in salt-stressed LMS-1 cells. In addition, chickpea co-inoculation with LMS-1 along with the consortium containing two non-rhizobial bacterial endophytes, P. salinisoli and X. translucens, resulted in significant improvement of the chickpea growth and the symbiotic performance of LMS-1 under salinity. These results indicate that this non-rhizobial endophytic consortium may be an appropriate ecological and safe tool to improve chickpea growth and its adaptation to salt-degraded soils.
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Affiliation(s)
- Roukaya Ben Gaied
- Laboratory of Pastoral Ecosystems and Promotion of Spontaneous Plants and Associated Micro-Organisms, Institute of Arid Lands, University of Gabes, Medenine 4119, Tunisia
- MED-Mediterranean Institute for Agriculture, Environment and Development, Universidade de Évora, Pólo da Mitra, Ap. 94, 7006-554 Évora, Portugal
| | - Imed Sbissi
- Laboratory of Pastoral Ecosystems and Promotion of Spontaneous Plants and Associated Micro-Organisms, Institute of Arid Lands, University of Gabes, Medenine 4119, Tunisia
| | - Mohamed Tarhouni
- Laboratory of Pastoral Ecosystems and Promotion of Spontaneous Plants and Associated Micro-Organisms, Institute of Arid Lands, University of Gabes, Medenine 4119, Tunisia
| | - Clarisse Brígido
- MED-Mediterranean Institute for Agriculture, Environment and Development & CHANGE-Global Change and Sustainability Institute, Institute for Advanced Studies and Research, Universidade de Évora, Pólo da Mitra, Ap. 94, 7006-554 Évora, Portugal
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del-Canto A, Sanz-Saez Á, Sillero-Martínez A, Mintegi E, Lacuesta M. Selected indigenous drought tolerant rhizobium strains as promising biostimulants for common bean in Northern Spain. FRONTIERS IN PLANT SCIENCE 2023; 14:1046397. [PMID: 37063203 PMCID: PMC10090513 DOI: 10.3389/fpls.2023.1046397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 03/14/2023] [Indexed: 06/19/2023]
Abstract
Drought is the most detrimental abiotic stress in agriculture, limiting crop growth and yield and, currently, its risk is increasing due to climate change. Thereby, ensuring food security will be one of the greatest challenges of the agriculture in the nearest future, accordingly it is essential to look for sustainable strategies to cope the negative impact of drought on crops. Inoculation of pulses with biostimulants such as rhizobium strains with high nitrogen fixation efficiency and drought-tolerance, has emerged as a promising and sustainable production strategy. However, some commercial inoculums are not effective under field conditions due to its lower effectiveness against indigenous rhizobium strains in the establishment of the symbiosis. Thus, in the present study, we evaluated the ability to improve drought tolerance in common bean plants of different indigenous rhizobia strains isolated from nearby crop fields in the Basque Country either affected by drought or salinity. The plants in this trial were grown in a climatic chamber under controlled conditions and exposed to values of 30% relative soil water content at the time of harvest, which is considered a severe drought. From the nine bacteria strains evaluated, three were found to be highly efficient under drought (namely 353, A12 and A13). These strains sustained high infectiveness (nodulation capacity) and effectiveness (shoot biomass production) under drought, even surpassing the plants inoculated with the CIAT899 reference strain, as well as the chemically N-fertilized plants. The tolerance mechanisms developed by plants inoculated with 353, A12 and A13 strains were a better adjustment of the cell wall elasticity that prevents mechanical damages in the plasma membrane, a higher WUE and an avoidance of the phenological delay caused by drought, developing a greater number of flowers. These results provide the basis for the development of efficient common bean inoculants able to increase the yield of this crop under drought conditions in the Northern Spain and, thus, to be used as biostimulants. In addition, the use of these efficient nitrogen fixation bacteria strains is a sustainable alternative to chemical fertilization, reducing cost and minimizing its negative impact on environment.
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Affiliation(s)
- Arantza del-Canto
- Department of Plant Biology and Ecology, Pharmacy Faculty, University of the Basque Country, Paseo de la Universidad n° 7, Vitoria-Gasteiz, Spain
| | - Álvaro Sanz-Saez
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL, United States
| | - Anna Sillero-Martínez
- Department of Plant Biology and Ecology, Pharmacy Faculty, University of the Basque Country, Paseo de la Universidad n° 7, Vitoria-Gasteiz, Spain
| | - Eider Mintegi
- Department of Plant Biology and Ecology, Pharmacy Faculty, University of the Basque Country, Paseo de la Universidad n° 7, Vitoria-Gasteiz, Spain
| | - Maite Lacuesta
- Department of Plant Biology and Ecology, Pharmacy Faculty, University of the Basque Country, Paseo de la Universidad n° 7, Vitoria-Gasteiz, Spain
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Dhali S, Acharya S, Pradhan M, Patra DK, Pradhan C. Synergistic effect of Bacillus and Rhizobium on cytological and photosynthetic performance of Macrotyloma uniflorum (Lam.) Verdc. Grown in Cr (VI) contaminated soil. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 190:62-69. [PMID: 36099809 DOI: 10.1016/j.plaphy.2022.08.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 08/24/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Macrotyloma uniflorum (horse gram) is considered an under-utilized legume crop despite its nutritional and medicinal values. In India, it has wide acceptance among farming communities. This investigation emphasized on the possible application of two endosymbionts (Bacillus sp. AS03 and Rhizobium sp. AS05) of horse gram cultivated on Cr (VI)-contaminated soil. The photosynthetic performance (PIφ) of Cr treated plants co-inoculated with AS03 and AS05 was significantly improved compared with non-inoculated Cr treated plants based on photosynthetic yield, which was evidenced from the rise in the fluorescence at I-P transient and rate of photosynthesis (pN), indicating synergistic action between plant and bacteria (AS03 and AS05). The smooth electron transport from PS II to PS I was achieved in the Cr stressed plants inoculated with both the bacterial strains. The detrimental effects of Cr toxicity on the root tips were also minimized with bioinoculation as revealed from mitotic index. Plants with dual inoculation of AS03 and AS05 had significantly lesser chromosomal aberration in the roots. Dual inoculation biochar or seed inoculation have beneficial impact on the plant photosynthetic performance along with improved growth of roots in plants treated with Cr (VI). The results of the current work suggest the possitive effect of dual inoculation of Cr tolerant endosymbionts, Bacillus sp. (AS03) and nodulating Rhizobium sp. (AS05), in reducing cytological as well as physiological stress of plants in Cr (VI) contaminated soil.
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Affiliation(s)
- Shilpee Dhali
- Department of Botany, Utkal University, Vani Vihar, Bhubaneswar, 751004, Odisha, India
| | - Srinivas Acharya
- Department of Botany, Utkal University, Vani Vihar, Bhubaneswar, 751004, Odisha, India
| | - Madhusmita Pradhan
- MITS Institute of Professional Studies, Berhampur University, Rayagada, 765017, Odisha, India
| | - Deepak Kumar Patra
- Department of Botany, Nimapara Autonomous College, Nimapara, Puri, 752106, Odisha, India
| | - Chinmay Pradhan
- Department of Botany, Utkal University, Vani Vihar, Bhubaneswar, 751004, Odisha, India; Centre of Excellence in Integrated Omics and Computational Biology, Utkal University, India.
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WONGDEE JENJIRA, YUTTAVANICHAKUL WATCHARIN, LONGTHONGLANG APHAKORN, TEAMTISONG KAMONLUCK, BOONKERD NANTAKORN, TEAUMROONG NEUNG, TITTABUTR PANLADA. Enhancing the Efficiency of Soybean Inoculant for Nodulation under Multi-Environmental Stress Conditions. Pol J Microbiol 2021; 70:257-271. [PMID: 34349815 PMCID: PMC8326982 DOI: 10.33073/pjm-2021-024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 05/22/2021] [Accepted: 05/23/2021] [Indexed: 11/10/2022] Open
Abstract
The development of rhizobial inoculants with increased resistance to abiotic stress is critical to mitigating the challenges related to climate change. This study aims at developing a soybean stress-tolerant Bradyrhizobium inoculant to be used under the mixed stress conditions of acidity, high temperature, and drought. Six isolates of Bradyrhizobium with high symbiotic performance on soybean were tested to determine their growth or survival abilities under in vitro conditions. The representative stress-tolerant Bradyrhizobium isolates 184, 188, and 194 were selected to test their ability to promote soybean growth under stress conditions compared to the type strain Bradyrhizobium diazoefficiens USDA110. The plant experiment indicated that isolate 194 performed better in symbiosis with soybean than other Bradyrhizobium strains under stress conditions. Based on the stress tolerance index, soybeans inoculated with isolate 194 showed a high growth performance and significantly better nodulation competition ability than USDA110 under several stress conditions. Interestingly, supplementation of sucrose in the culture medium significantly enhances the survival of the isolate and leads to improved plant biomass under various stress conditions. Analysis of the intra-cellular sugars of isolate 194 supplemented with sucrose showed the accumulation of compatible solutes, such as trehalose and glycerol, that may act as osmoprotectants. This study indicates that inoculation of stress-tolerant Bradyrhizobium together with sucrose supplementation in a medium could enhance bacterial survival and symbiosis efficiency under stress conditions. Although it can be applied for inoculant production, this strategy requires validation of its performance in field conditions before adopting this technology.
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Affiliation(s)
- JENJIRA WONGDEE
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - WATCHARIN YUTTAVANICHAKUL
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - APHAKORN LONGTHONGLANG
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - KAMONLUCK TEAMTISONG
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - NANTAKORN BOONKERD
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - NEUNG TEAUMROONG
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - PANLADA TITTABUTR
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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Bhattacharyya A, Pablo CHD, Mavrodi OV, Weller DM, Thomashow LS, Mavrodi DV. Rhizosphere plant-microbe interactions under water stress. ADVANCES IN APPLIED MICROBIOLOGY 2021; 115:65-113. [PMID: 34140134 DOI: 10.1016/bs.aambs.2021.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Climate change, with its extreme temperature, weather and precipitation patterns, is a major global concern of dryland farmers, who currently meet the challenges of climate change agronomically and with growth of drought-tolerant crops. Plants themselves compensate for water stress by modifying aerial surfaces to control transpiration and altering root hydraulic conductance to increase water uptake. These responses are complemented by metabolic changes involving phytohormone network-mediated activation of stress response pathways, resulting in decreased photosynthetic activity and the accumulation of metabolites to maintain osmotic and redox homeostasis. Phylogenetically diverse microbial communities sustained by plants contribute to host drought tolerance by modulating phytohormone levels in the rhizosphere and producing water-sequestering biofilms. Drylands of the Inland Pacific Northwest, USA, illustrate the interdependence of dryland crops and their associated microbiota. Indigenous Pseudomonas spp. selected there by long-term wheat monoculture suppress root diseases via the production of antibiotics, with soil moisture a critical determinant of the bacterial distribution, dynamics and activity. Those pseudomonads producing phenazine antibiotics on wheat had more abundant rhizosphere biofilms and provided improved tolerance to drought, suggesting a role of the antibiotic in alleviation of drought stress. The transcriptome and metabolome studies suggest the importance of wheat root exudate-derived osmoprotectants for the adaptation of these pseudomonads to the rhizosphere lifestyle and support the idea that the exchange of metabolites between plant roots and microorganisms profoundly affects and shapes the belowground plant microbiome under water stress.
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Affiliation(s)
- Ankita Bhattacharyya
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Clint H D Pablo
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Olga V Mavrodi
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - David M Weller
- USDA Agricultural Research Service, Wheat Health, Genetics and Quality Research Unit, Pullman, WA, United States
| | - Linda S Thomashow
- USDA Agricultural Research Service, Wheat Health, Genetics and Quality Research Unit, Pullman, WA, United States
| | - Dmitri V Mavrodi
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States.
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OnfD, an AraC-Type Transcriptional Regulator Encoded by Rhizobium tropici CIAT 899 and Involved in Nod Factor Synthesis and Symbiosis. Appl Environ Microbiol 2020; 86:AEM.01297-20. [PMID: 32709725 PMCID: PMC7499043 DOI: 10.1128/aem.01297-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 07/16/2020] [Indexed: 02/06/2023] Open
Abstract
Rhizobium tropici CIAT 899 is a broad-host-range rhizobial strain that establishes symbiotic interactions with legumes and tolerates different environmental stresses such as heat, acidity, or salinity. This rhizobial strain produces a wide variety of symbiotically active nodulation factors (NF) induced not only by the presence of plant-released flavonoids but also under osmotic stress conditions through the LysR-type transcriptional regulators NodD1 (flavonoids) and NodD2 (osmotic stress). However, the activation of NodD2 under high-osmotic-stress conditions remains elusive. Here, we have studied the role of a new AraC-type regulator (named as OnfD) in the symbiotic interaction of R. tropici CIAT 899 with Phaseolus vulgaris and Lotus plants. We determined that OnfD is required under salt stress conditions for the transcriptional activation of the nodulation genes and therefore the synthesis and export of NF, which are required for a successful symbiosis with P. vulgaris Moreover, using bacterial two-hybrid analysis, we demonstrated that the OnfD and NodD2 proteins form homodimers and OnfD/NodD2 form heterodimers, which could be involved in the production of NF in the presence of osmotic stress conditions since both regulators are required for NF synthesis in the presence of salt. A structural model of OnfD is presented and discussed.IMPORTANCE The synthesis and export of rhizobial NF are mediated by a conserved group of LysR-type regulators, the NodD proteins. Here, we have demonstrated that a non-LysR-type regulator, an AraC-type protein, is required for the transcriptional activation of symbiotic genes and for the synthesis of symbiotically active NF under salt stress conditions.
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Sharma MP, Grover M, Chourasiya D, Bharti A, Agnihotri R, Maheshwari HS, Pareek A, Buyer JS, Sharma SK, Schütz L, Mathimaran N, Singla-Pareek SL, Grossman JM, Bagyaraj DJ. Deciphering the Role of Trehalose in Tripartite Symbiosis Among Rhizobia, Arbuscular Mycorrhizal Fungi, and Legumes for Enhancing Abiotic Stress Tolerance in Crop Plants. Front Microbiol 2020; 11:509919. [PMID: 33042042 PMCID: PMC7527417 DOI: 10.3389/fmicb.2020.509919] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 08/20/2020] [Indexed: 01/31/2023] Open
Abstract
Drought is a critical factor limiting the productivity of legumes worldwide. Legumes can enter into a unique tripartite symbiotic relationship with root-nodulating bacteria of genera Rhizobium, Bradyrhizobium, or Sinorhizobium and colonization by arbuscular mycorrhizal fungi (AMF). Rhizobial symbiosis provides nitrogen necessary for growth. AMF symbiosis enhances uptake of diffusion-limited nutrients such as P, Zn, Cu, etc., and also water from the soil via plant-associated fungal hyphae. Rhizobial and AMF symbioses can act synergistically in promoting plant growth and fitness, resulting in overall yield benefits under drought stress. One of the approaches that rhizobia use to survive under stress is the accumulation of compatible solutes, or osmolytes, such as trehalose. Trehalose is a non-reducing disaccharide and an osmolyte reported to accumulate in a range of organisms. High accumulation of trehalose in bacteroids during nodulation protects cells and proteins from osmotic shock, desiccation, and heat under drought stress. Manipulation of trehalose cell concentrations has been directly correlated with stress response in plants and other organisms, including AMF. However, the role of this compound in the tripartite symbiotic relationship is not fully explored. This review describes the biological importance and the role of trehalose in the tripartite symbiosis between plants, rhizobia, and AMF. In particular, we review the physiological functions and the molecular investigations of trehalose carried out using omics-based approaches. This review will pave the way for future studies investigating possible metabolic engineering of this biomolecule for enhancing abiotic stress tolerance in plants.
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Affiliation(s)
- Mahaveer P. Sharma
- Microbiology Section, ICAR-Indian Institute of Soybean Research, Indore, India
| | - Minakshi Grover
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Dipanti Chourasiya
- Microbiology Section, ICAR-Indian Institute of Soybean Research, Indore, India
| | - Abhishek Bharti
- Microbiology Section, ICAR-Indian Institute of Soybean Research, Indore, India
| | - Richa Agnihotri
- Microbiology Section, ICAR-Indian Institute of Soybean Research, Indore, India
| | | | - Ashwani Pareek
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Jeffrey S. Buyer
- Sustainable Agricultural Systems Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Beltsville, MD, United States
| | - Sushil K. Sharma
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | - Lukas Schütz
- Department of Environmental Sciences-Botany, University of Basel, Basel, Switzerland
| | - Natarajan Mathimaran
- Department of Environmental Sciences-Botany, University of Basel, Basel, Switzerland
- M S Swaminathan Research Foundation, Chennai, India
| | - Sneh L. Singla-Pareek
- Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Julie M. Grossman
- Department of Horticultural Science, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, St. Paul, MN, United States
| | - Davis J. Bagyaraj
- Center for Natural Biological Resources and Community Development, Bengaluru, India
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PGPR Modulation of Secondary Metabolites in Tomato Infested with Spodoptera litura. AGRONOMY-BASEL 2020. [DOI: 10.3390/agronomy10060778] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The preceding climate change demonstrates overwintering of pathogens that lead to increased incidence of insects and pest attack. Integration of ecological and physiological/molecular approaches are imperative to encounter pathogen attack in order to enhance crop yield. The present study aimed to evaluate the effects of two plant growth promoting rhizobacteria (Bacillus endophyticus and Pseudomonas aeruginosa) on the plant physiology and production of the secondary metabolites in tomato plants infested with Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). The surface sterilized seeds of tomato were inoculated with plant growth promoting rhizobacteria (PGPR) for 3–4 h prior to sowing. Tomato leaves at 6 to 7 branching stage were infested with S. litura at the larval stage of 2nd instar. Identification of secondary metabolites and phytohormones were made from tomato leaves using thin-layer chromatography (TLC) and high performance liquid chromatography (HPLC) and fourier-transform infrared spectroscopy (FTIR). Infestation with S. litura significantly decreased plant growth and yield. The PGPR inoculations alleviated the adverse effects of insect infestation on plant growth and fruit yield. An increased level of protein, proline and sugar contents and enhanced activity of superoxide dismutase (SOD) was noticed in infected tomato plants associated with PGPR. Moreover, p-kaempferol, rutin, caffeic acid, p-coumaric acid and flavonoid glycoside were also detected in PGPR inoculated infested plants. The FTIR spectra of the infected leaf samples pre-treated with PGPR revealed the presence of aldehyde. Additionally, significant amounts of indole-3-acetic acid (IAA), salicylic acid (SA) and abscisic acid (ABA) were detected in the leaf samples. From the present results, we conclude that PGPR can promote growth and yield of tomatoes under attack and help the host plant to combat infestation via modulation in IAA, SA, ABA and other secondary metabolites.
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Kibido T, Kunert K, Makgopa M, Greve M, Vorster J. Improvement of rhizobium‐soybean symbiosis and nitrogen fixation under drought. Food Energy Secur 2020. [DOI: 10.1002/fes3.177] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Tsholofelo Kibido
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
- Forestry and Agricultural Biotechnology Institute University of Pretoria Pretoria South Africa
| | - Karl Kunert
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
- Forestry and Agricultural Biotechnology Institute University of Pretoria Pretoria South Africa
| | - Matome Makgopa
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
| | - Michelle Greve
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
| | - Juan Vorster
- Department of Plant and Soil Sciences University of Pretoria Pretoria South Africa
- Forestry and Agricultural Biotechnology Institute University of Pretoria Pretoria South Africa
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A bioinspired approach to engineer seed microenvironment to boost germination and mitigate soil salinity. Proc Natl Acad Sci U S A 2019; 116:25555-25561. [PMID: 31776251 PMCID: PMC6926070 DOI: 10.1073/pnas.1915902116] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In a world that strives to accommodate population growth and climate pattern changes, there is a compelling need to develop new technologies to enhance agricultural output while minimizing inputs and mitigating their effects on the environment. In this study, we describe a biomaterial-based approach to engineer the microenvironment of seeds through the preservation and delivery of plant growth promoting rhizobacteria (PGPRs) that are able to fix nitrogen and mitigate soil salinity. PGPRs are encapsulated in silk–trehalose (ST) coatings that achieve bacterial preservation and delivery upon sowing. The biomaterial choice is inspired by a recent finding that a combination of proteins and disaccharides is key for anhydrobiosis. This simple technology is effective to boost seed germination and mitigate soil salinity. Human population growth, soil degradation, and agrochemical misuse are significant challenges that agriculture must face in the upcoming decades as it pertains to global food production. Seed enhancement technologies will play a pivotal role in supporting food security by enabling germination of seeds in degraded environments, reducing seed germination time, and boosting crop yields. So far, a great effort has been pursued in designing plants that can adapt to different environments and germinate in the presence of abiotic stressors, such as soil salinity, heat, and drought. The technology proposed here seeks a different goal: To engineer the microenvironment of seeds by encapsulation, preservation, and precise delivery of biofertilizers that can boost seed germination and mitigate abiotic stressors. In particular, we developed a biomaterial based on silk fibroin (S) and trehalose that can be mixed with rhizobacteria and applied on the surface of seeds, retrofitting currently used techniques for seed coating, i.e., dip coating or spray drying. A micrometer thick transparent robust coating is formed by material assembly. The combination of a polymorphic protein as S and of a disaccharide used by living systems to tolerate abiotic stressors provides a beneficial environment for the survival of nonspore forming rhizobacteria outside the soil and in anhydrous conditions. Using Rhizobium tropici CIAT 899 and Phaseolus vulgaris as working models, we demonstrated that rhizobacteria delivered in the soil after coating dissolution infect seedlings’ roots, form root nodules, enhance yield, boost germination, and mitigate soil salinity.
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Osmotic stress activates nif and fix genes and induces the Rhizobium tropici CIAT 899 Nod factor production via NodD2 by up-regulation of the nodA2 operon and the nodA3 gene. PLoS One 2019; 14:e0213298. [PMID: 30917160 PMCID: PMC6436695 DOI: 10.1371/journal.pone.0213298] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 02/19/2019] [Indexed: 11/19/2022] Open
Abstract
The symbiosis between rhizobia and legumes is characterized by a complex molecular dialogue in which the bacterial NodD protein plays a major role due to its capacity to activate the expression of the nodulation genes in the presence of appropiate flavonoids. These genes are involved in the synthesis of molecules, the nodulation factors (NF), responsible for launching the nodulation process. Rhizobium tropici CIAT 899, a rhizobial strain that nodulates Phaseolus vulgaris, is characterized by its tolerance to multiple environmental stresses such as high temperatures, acidity or elevated osmolarity. This strain produces nodulation factors under saline stress and the same set of CIAT 899 nodulation genes activated by inducing flavonoids are also up-regulated in a process controlled by the NodD2 protein. In this paper, we have studied the effect of osmotic stress (high mannitol concentrations) on the R. tropici CIAT 899 transcriptomic response. In the same manner as with saline stress, the osmotic stress mediated NF production and export was controlled directly by NodD2. In contrast to previous reports, the nodA2FE operon and the nodA3 and nodD1 genes were up-regulated with mannitol, which correlated with an increase in the production of biologically active NF. Interestingly, in these conditions, this regulatory protein controlled not only the expression of nodulation genes but also the expression of other genes involved in protein folding and synthesis, motility, synthesis of polysaccharides and, surprinsingly, nitrogen fixation. Moreover, the non-metabolizable sugar dulcitol was also able to induce the NF production and the activation of nod genes in CIAT 899.
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Alaa FM. Effectiveness of exopolysaccharides and biofilm forming plant growth promoting rhizobacteria on salinity tolerance of faba bean (Vicia faba L.). ACTA ACUST UNITED AC 2018. [DOI: 10.5897/ajmr2018.8822] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Chromium(VI) Toxicity in Legume Plants: Modulation Effects of Rhizobial Symbiosis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8031213. [PMID: 29662899 PMCID: PMC5832134 DOI: 10.1155/2018/8031213] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 12/31/2017] [Indexed: 11/18/2022]
Abstract
Most legume species have the ability to establish a symbiotic relationship with soil nitrogen-fixing rhizobacteria that promote plant growth and productivity. There is an increasing evidence of reactive oxygen species (ROS) important role in formation of legume-rhizobium symbiosis and nodule functioning. Environmental pollutants such as chromium compounds can cause damage to rhizobia, legumes, and their symbiosis. In plants, toxic effects of chromium(VI) compounds are associated with the increased production of ROS and oxidative stress development as well as with inhibition of pigment synthesis and modification of virtually all cellular components. These metabolic changes result in inhibition of seed germination and seedling development as well as reduction of plant biomass and crop yield. However, if plants establish symbiosis with rhizobia, heavy metals are accumulated preferentially in nodules decreasing the toxicity of metals to the host plant. This review summarizes data on toxic effects of chromium on legume plants and legume-rhizobium symbiosis. In addition, we discussed the role of oxidative stress in both chromium toxicity and formation of rhizobial symbiosis and use of nodule bacteria for minimizing toxic effects of chromium on plants.
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Benidire L, Lahrouni M, Daoui K, Fatemi ZEA, Gomez Carmona R, Göttfert M, Oufdou K. Phenotypic and genetic diversity of Moroccan rhizobia isolated from Vicia faba and study of genes that are likely to be involved in their osmotolerance. Syst Appl Microbiol 2018; 41:51-61. [DOI: 10.1016/j.syapm.2017.09.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 01/28/2023]
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Dong R, Zhang J, Huan H, Bai C, Chen Z, Liu G. High Salt Tolerance of a Bradyrhizobium Strain and Its Promotion of the Growth of Stylosanthes guianensis. Int J Mol Sci 2017; 18:ijms18081625. [PMID: 28788047 PMCID: PMC5578016 DOI: 10.3390/ijms18081625] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/20/2017] [Accepted: 07/20/2017] [Indexed: 12/13/2022] Open
Abstract
Salinity is a serious limiting factor for the growth of rhizobia. Some rhizobia are tolerant to salt stress and promote plant growth, but the mechanisms underlying these effects are poorly characterized. The growth responses and osmoprotectants in four Bradyrhizobium strains were examined under salt stress in this study. Two-dimensional electrophoresis (2-DE) and mass spectrometry were conducted to investigate protein profiles in rhizobia exposed to salt stress. Subsequently, salt tolerance in stylo (Stylosanthesguianensis) inoculated with rhizobia was further detected in hydroponics. Results showed that the Bradyrhizobium strain RJS9-2 exhibited higher salt tolerance than the other three Bradyrhizobium strains. RJS9-2 was able to grow at 0.35 M NaCl treatment, while the other three Bradyrhizobium strains did not grow at 0.1 M NaCl treatment. Salt stress induced IAA production, and accumulation of proline, betaine, ectoine, and trehalose was observed in RJS9-2 but not in PN13-1. Proteomics analysis identified 14 proteins regulated by salt stress in RJS9-2 that were mainly related to the ABC transporter, stress response, and protein metabolism. Furthermore, under saline conditions, the nodule number, plant dry weight, and N concentration in stylo plants inoculated with RJS9-2 were higher than those in plants inoculated with PN13-1. These results suggest that the tolerance of RJS9-2 to salt stress may be achieved by the coordination of indole-3-acetic acid (IAA) production, osmoprotectant accumulation, and protein expression, thus promoting stylo growth.
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Affiliation(s)
- Rongshu Dong
- Institute of Tropical Crop Genetic Resources, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, China.
| | - Jie Zhang
- Institute of Tropical Crop Genetic Resources, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, China.
| | - Hengfu Huan
- Institute of Tropical Crop Genetic Resources, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, China.
| | - Changjun Bai
- Institute of Tropical Crop Genetic Resources, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, China.
| | - Zhijian Chen
- Institute of Tropical Crop Genetic Resources, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, China.
| | - Guodao Liu
- Institute of Tropical Crop Genetic Resources, Chinese Academy of Tropical Agriculture Sciences, Haikou 571101, China.
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Diel-scale temporal dynamics recorded for bacterial groups in Namib Desert soil. Sci Rep 2017; 7:40189. [PMID: 28071697 PMCID: PMC5223211 DOI: 10.1038/srep40189] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/01/2016] [Indexed: 11/23/2022] Open
Abstract
Microbes in hot desert soil partake in core ecosystem processes e.g., biogeochemical cycling of carbon. Nevertheless, there is still a fundamental lack of insights regarding short-term (i.e., over a 24-hour [diel] cycle) microbial responses to highly fluctuating microenvironmental parameters like temperature and humidity. To address this, we employed T-RFLP fingerprinting and 454 pyrosequencing of 16S rRNA-derived cDNA to characterize potentially active bacteria in Namib Desert soil over multiple diel cycles. Strikingly, we found that significant shifts in active bacterial groups could occur over a single 24-hour period. For instance, members of the predominant Actinobacteria phyla exhibited a significant reduction in relative activity from morning to night, whereas many Proteobacterial groups displayed an opposite trend. Contrary to our leading hypothesis, environmental parameters could only account for 10.5% of the recorded total variation. Potential biotic associations shown through co-occurrence networks indicated that non-random inter- and intra-phyla associations were ‘time-of-day-dependent’ which may constitute a key feature of this system. Notably, many cyanobacterial groups were positioned outside and/or between highly interconnected bacterial associations (modules); possibly acting as inter-module ‘hubs’ orchestrating interactions between important functional consortia. Overall, these results provide empirical evidence that bacterial communities in hot desert soils exhibit complex and diel-dependent inter-community associations.
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John R, Anjum NA, Sopory SK, Akram NA, Ashraf M. Some key physiological and molecular processes of cold acclimation. BIOLOGIA PLANTARUM 2016; 60:603-618. [PMID: 0 DOI: 10.1007/s10535-016-0648-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
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18
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Ormeño-Orrillo E, Gomes DF, Del Cerro P, Vasconcelos ATR, Canchaya C, Almeida LGP, Mercante FM, Ollero FJ, Megías M, Hungria M. Genome of Rhizobium leucaenae strains CFN 299(T) and CPAO 29.8: searching for genes related to a successful symbiotic performance under stressful conditions. BMC Genomics 2016; 17:534. [PMID: 27485828 PMCID: PMC4971678 DOI: 10.1186/s12864-016-2859-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 06/27/2016] [Indexed: 01/02/2023] Open
Abstract
Background Common bean (Phaseolus vulgaris L.) is the most important legume cropped worldwide for food production and its agronomic performance can be greatly improved if the benefits from symbiotic nitrogen fixation are maximized. The legume is known for its high promiscuity in nodulating with several Rhizobium species, but those belonging to the Rhizobium tropici “group” are the most successful and efficient in fixing nitrogen in tropical acid soils. Rhizobium leucaenae belongs to this group, which is abundant in the Brazilian “Cerrados” soils and frequently submitted to several environmental stresses. Here we present the first high-quality genome drafts of R. leucaenae, including the type strain CFN 299T and the very efficient strain CPAO 29.8. Our main objective was to identify features that explain the successful capacity of R. leucaenae in nodulating common bean under stressful environmental conditions. Results The genomes of R. leucaenae strains CFN 299T and CPAO 29.8 were estimated at 6.7–6.8 Mbp; 7015 and 6899 coding sequences (CDS) were predicted, respectively, 6264 of which are common to both strains. The genomes of both strains present a large number of CDS that may confer tolerance of high temperatures, acid soils, salinity and water deficiency. Types I, II, IV-pili, IV and V secretion systems were present in both strains and might help soil and host colonization as well as the symbiotic performance under stressful conditions. The symbiotic plasmid of CPAO 29.8 is highly similar to already described tropici pSyms, including five copies of nodD and three of nodA genes. R. leucaenae CFN 299T is capable of synthesizing Nod factors in the absence of flavonoids when submitted to osmotic stress, indicating that under abiotic stress the regulation of nod genes might be different. Conclusion A detailed study of the genes putatively related to stress tolerance in R. leucaenae highlighted an intricate pattern comprising a variety of mechanisms that are probably orchestrated to tolerate the stressful conditions to which the strains are submitted on a daily basis. The capacity to synthesize Nod factors under abiotic stress might follow the same regulatory pathways as in CIAT 899T and may help both to improve bacterial survival and to expand host range to guarantee the perpetuation of the symbiosis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2859-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Douglas Fabiano Gomes
- Embrapa Soja, C.P. 231, 86001-970, Londrina, Paraná, Brazil.,CAPES, SBN, Quadra 2, Bloco L, Lote 06, Edifício Capes, 70.040-020, Brasília, Federal District, Brazil
| | - Pablo Del Cerro
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avda. Reina Mercedes, 6 Apdo Postal, 41012, Sevilla, Spain
| | - Ana Tereza Ribeiro Vasconcelos
- Laboratório Nacional de Computação Científica (LNCC), Labinfo, Rua Getúlio Vargas 333, 25651-071, Petrópolis, Rio de Janeiro, Brazil
| | - Carlos Canchaya
- Department Biochemistry, Genetics and Immunology, Faculty of Biology, University of Vigo, 36310, Vigo, Spain
| | - Luiz Gonzaga Paula Almeida
- Laboratório Nacional de Computação Científica (LNCC), Labinfo, Rua Getúlio Vargas 333, 25651-071, Petrópolis, Rio de Janeiro, Brazil
| | | | - Francisco Javier Ollero
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avda. Reina Mercedes, 6 Apdo Postal, 41012, Sevilla, Spain
| | - Manuel Megías
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avda. Reina Mercedes, 6 Apdo Postal, 41012, Sevilla, Spain
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Mao YH, Li F, Ma JC, Hu Z, Wang HH. Sinorhizobium meliloti Functionally Replaces 3-Oxoacyl-Acyl Carrier Protein Reductase (FabG) by Overexpressing NodG During Fatty Acid Synthesis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:458-467. [PMID: 26975437 DOI: 10.1094/mpmi-07-15-0148-r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In Sinorhizobium meliloti, the nodG gene is located in the nodFEG operon of the symbiotic plasmid. Although strong sequence similarity (53% amino acid identities) between S. meliloti NodG and Escherichia coli FabG was reported in 1992, it has not been determined whether S. meliloti NodG plays a role in fatty acid synthesis. We report that expression of S. meliloti NodG restores the growth of the E. coli fabG temperature-sensitive mutant CL104 under nonpermissive conditions. Using in vitro assays, we demonstrated that NodG is able to catalyze the reduction of the 3-oxoacyl-ACP intermediates in E. coli fatty acid synthetic reaction. Moreover, although deletion of the S. meliloti nodG gene does not cause any growth defects, upon overexpression of nodG from a plasmid, the S. meliloti fabG gene encoding the canonical 3-oxoacyl-ACP reductase (OAR) can be disrupted without any effects on growth or fatty acid composition. This indicates that S. meliloti nodG encodes an OAR and can play a role in fatty acid synthesis when expressed at sufficiently high levels. Thus, a bacterium can simultaneously possess two or more OARs that can play a role in fatty acid synthesis. Our data also showed that, although SmnodG increases alfalfa nodulation efficiency, it is not essential for alfalfa nodulation.
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Affiliation(s)
- Ya-Hui Mao
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Feng Li
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Jin-Cheng Ma
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Zhe Hu
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
| | - Hai-Hong Wang
- Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, College of Life Sciences, South China Agricultural University, Guangzhou, Guangdong 510642, China
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Diouf F, Diouf D, Klonowska A, Le Queré A, Bakhoum N, Fall D, Neyra M, Parrinello H, Diouf M, Ndoye I, Moulin L. Genetic and genomic diversity studies of Acacia symbionts in Senegal reveal new species of Mesorhizobium with a putative geographical pattern. PLoS One 2015; 10:e0117667. [PMID: 25658650 PMCID: PMC4319832 DOI: 10.1371/journal.pone.0117667] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/29/2014] [Indexed: 11/29/2022] Open
Abstract
Acacia senegal (L) Willd. and Acacia seyal Del. are highly nitrogen-fixing and moderately salt tolerant species. In this study we focused on the genetic and genomic diversity of Acacia mesorhizobia symbionts from diverse origins in Senegal and investigated possible correlations between the genetic diversity of the strains, their soil of origin, and their tolerance to salinity. We first performed a multi-locus sequence analysis on five markers gene fragments on a collection of 47 mesorhizobia strains of A. senegal and A. seyal from 8 localities. Most of the strains (60%) clustered with the M. plurifarium type strain ORS 1032T, while the others form four new clades (MSP1 to MSP4). We sequenced and assembled seven draft genomes: four in the M. plurifarium clade (ORS3356, ORS3365, STM8773 and ORS1032T), one in MSP1 (STM8789), MSP2 (ORS3359) and MSP3 (ORS3324). The average nucleotide identities between these genomes together with the MLSA analysis reveal three new species of Mesorhizobium. A great variability of salt tolerance was found among the strains with a lack of correlation between the genetic diversity of mesorhizobia, their salt tolerance and the soils samples characteristics. A putative geographical pattern of A. senegal symbionts between the dryland north part and the center of Senegal was found, reflecting adaptations to specific local conditions such as the water regime. However, the presence of salt does not seem to be an important structuring factor of Mesorhizobium species.
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Affiliation(s)
- Fatou Diouf
- Laboratoire Commun de Microbiologie IRD/ISRA/UCAD, Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Centre de Recherche de Bel Air, Dakar, Senegal
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux (LAPSE), Dakar, Senegal
- IRD-Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), Campus de Baillarguet, Montpellier, France
| | - Diegane Diouf
- Laboratoire Commun de Microbiologie IRD/ISRA/UCAD, Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Centre de Recherche de Bel Air, Dakar, Senegal
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux (LAPSE), Dakar, Senegal
| | - Agnieszka Klonowska
- IRD-Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), Campus de Baillarguet, Montpellier, France
| | - Antoine Le Queré
- Laboratoire Mixte International Biotechnologie Microbienne et Végétale (LBMV), Rabat, Morocco
| | - Niokhor Bakhoum
- Laboratoire Commun de Microbiologie IRD/ISRA/UCAD, Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Centre de Recherche de Bel Air, Dakar, Senegal
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux (LAPSE), Dakar, Senegal
| | - Dioumacor Fall
- Laboratoire Commun de Microbiologie IRD/ISRA/UCAD, Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Centre de Recherche de Bel Air, Dakar, Senegal
- Institut Sénégalais de Recherches Agricoles (ISRA), Dakar, Senegal
| | - Marc Neyra
- Irstea, UR MALY, centre de Lyon-Villeurbanne, Villeurbanne, France
| | - Hugues Parrinello
- MGX-Montpellier GenomiX, Institut de Génomique Fonctionnelle, Montpellier, France
| | - Mayecor Diouf
- Institut Sénégalais de Recherches Agricoles (ISRA), Dakar, Senegal
| | - Ibrahima Ndoye
- Laboratoire Commun de Microbiologie IRD/ISRA/UCAD, Département de Biologie Végétale, Faculté des Sciences et Techniques, Université Cheikh Anta DIOP de Dakar, Centre de Recherche de Bel Air, Dakar, Senegal
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux (LAPSE), Dakar, Senegal
| | - Lionel Moulin
- Laboratoire Mixte International Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux (LAPSE), Dakar, Senegal
- IRD-Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), Campus de Baillarguet, Montpellier, France
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Gulez G, Altıntaş A, Fazli M, Dechesne A, Workman CT, Tolker-Nielsen T, Smets BF. Colony morphology and transcriptome profiling of Pseudomonas putida KT2440 and its mutants deficient in alginate or all EPS synthesis under controlled matric potentials. Microbiologyopen 2014; 3:457-69. [PMID: 24912454 PMCID: PMC4287175 DOI: 10.1002/mbo3.180] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/23/2014] [Accepted: 05/05/2014] [Indexed: 12/04/2022] Open
Abstract
Pseudomonas putida is a versatile bacterial species adapted to soil and its fluctuations. Like many other species living in soil, P. putida often faces water limitation. Alginate, an exopolysaccharide (EPS) produced by P. putida, is known to create hydrated environments and alleviate the effect of water limitation. In addition to alginate, P. putida is capable of producing cellulose (bcs), putida exopolysaccharide a (pea), and putida exopolysaccharide b (peb). However, unlike alginate, not much is known about their roles under water limitation. Hence, in this study we examined the role of different EPS components under mild water limitation. To create environmentally realistic water limited conditions as observed in soil, we used the Pressurized Porous Surface Model. Our main hypothesis was that under water limitation and in the absence of alginate other exopolysaccharides would be more active to maintain homeostasis. To test our hypothesis, we investigated colony morphologies and whole genome transcriptomes of P. putida KT2440 wild type and its mutants deficient in synthesis of either alginate or all known EPS. Overall our results support that alginate is an important exopolysaccharide under water limitation and in the absence of alginate other tolerance mechanisms are activated.
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Affiliation(s)
- Gamze Gulez
- Department of Environmental Engineering, Technical University of DenmarkBuilding 113, Kongens Lyngby, Denmark
| | - Ali Altıntaş
- Center for Biological Sequencing, Department of Systems Biology, Technical University of DenmarkBuilding 208, Kongens Lyngby, Denmark
| | - Mustafa Fazli
- Faculty of Science, Department of Biology, University of CopenhagenOle Maaløes Vej 5, Copenhagen, Denmark
- Faculty of Health and Medical Sciences, Department of International Health, Immunology, and Microbiology, University of CopenhagenBlegdamsvej 3C, Copenhagen, Denmark
| | - Arnaud Dechesne
- Department of Environmental Engineering, Technical University of DenmarkBuilding 113, Kongens Lyngby, Denmark
| | - Christopher T Workman
- Center for Biological Sequencing, Department of Systems Biology, Technical University of DenmarkBuilding 208, Kongens Lyngby, Denmark
| | - Tim Tolker-Nielsen
- Faculty of Health and Medical Sciences, Department of International Health, Immunology, and Microbiology, University of CopenhagenBlegdamsvej 3C, Copenhagen, Denmark
| | - Barth F Smets
- Department of Environmental Engineering, Technical University of DenmarkBuilding 113, Kongens Lyngby, Denmark
- Correspondence Barth F. Smets, Department of Environmental Engineering, Technical University of Denmark, Building 113, Kongens Lyngby, Denmark. Tel: +45 45 25 22 30; Fax: +45 45 93 28 50;, E-mail:
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Barraza A, Estrada-Navarrete G, Rodriguez-Alegria ME, Lopez-Munguia A, Merino E, Quinto C, Sanchez F. Down-regulation of PvTRE1 enhances nodule biomass and bacteroid number in the common bean. THE NEW PHYTOLOGIST 2013; 197:194-206. [PMID: 23121215 DOI: 10.1111/nph.12002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 09/12/2012] [Indexed: 05/02/2023]
Abstract
Legume-rhizobium interactions have been widely studied and characterized, and the disaccharide trehalose has been commonly detected during this symbiotic interaction. It has been proposed that trehalose content in nodules during this symbiotic interaction might be regulated by trehalase. In the present study, we assessed the role of trehalose accumulation by down-regulating trehalase in the nodules of common bean plants. We performed gene expression analysis for trehalase (PvTRE1) during nodule development. PvTRE1 was knocked down by RNA interference (RNAi) in transgenic nodules of the common bean. PvTRE1 expression in nodulated roots is mainly restricted to nodules. Down-regulation of PvTRE1 led to increased trehalose content (78%) and bacteroid number (almost one order of magnitude). In addition, nodule biomass, nitrogenase activity, and GOGAT transcript accumulation were significantly enhanced too. The trehalose accumulation, triggered by PvTRE1 down-regulation, led to a positive impact on the legume-rhizobium symbiotic interaction. This could contribute to the agronomical enhancement of symbiotic nitrogen fixation.
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MESH Headings
- Agrobacterium/genetics
- Agrobacterium/metabolism
- Autophagy
- Bacterial Load
- Carbohydrate Metabolism
- Cloning, Molecular
- Escherichia coli/enzymology
- Escherichia coli/genetics
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Gene Knockdown Techniques
- Genes, Plant
- Microbial Viability
- Nitrogen Fixation
- Nitrogenase/genetics
- Nitrogenase/metabolism
- Phaseolus/enzymology
- Phaseolus/genetics
- Phaseolus/microbiology
- Phylogeny
- Plant Leaves/enzymology
- Plant Leaves/genetics
- Plant Root Nodulation
- Plants, Genetically Modified/enzymology
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/microbiology
- Promoter Regions, Genetic
- RNA Interference
- Rhizobium etli/growth & development
- Rhizobium etli/isolation & purification
- Rhizobium etli/metabolism
- Root Nodules, Plant/enzymology
- Root Nodules, Plant/microbiology
- Symbiosis
- Transformation, Genetic
- Trehalase/genetics
- Trehalase/metabolism
- Trehalose/metabolism
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Affiliation(s)
- Aarón Barraza
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología/Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, México
| | - Georgina Estrada-Navarrete
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología/Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, México
| | - Maria Elena Rodriguez-Alegria
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología/Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, México
| | - Agustin Lopez-Munguia
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología/Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, México
| | - Enrique Merino
- Departamento de Microbiología Molecular, Instituto de Biotecnología/Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, México
| | - Carmen Quinto
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología/Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, México
| | - Federico Sanchez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología/Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos, 62210, México
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Ormeño-Orrillo E, Menna P, Almeida LGP, Ollero FJ, Nicolás MF, Pains Rodrigues E, Shigueyoshi Nakatani A, Silva Batista JS, Oliveira Chueire LM, Souza RC, Ribeiro Vasconcelos AT, Megías M, Hungria M, Martínez-Romero E. Genomic basis of broad host range and environmental adaptability of Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 which are used in inoculants for common bean (Phaseolus vulgaris L.). BMC Genomics 2012; 13:735. [PMID: 23270491 PMCID: PMC3557214 DOI: 10.1186/1471-2164-13-735] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 12/15/2012] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 are α-Proteobacteria that establish nitrogen-fixing symbioses with a range of legume hosts. These strains are broadly used in commercial inoculants for application to common bean (Phaseolus vulgaris) in South America and Africa. Both strains display intrinsic resistance to several abiotic stressful conditions such as low soil pH and high temperatures, which are common in tropical environments, and to several antimicrobials, including pesticides. The genetic determinants of these interesting characteristics remain largely unknown. RESULTS Genome sequencing revealed that CIAT 899 and PRF 81 share a highly-conserved symbiotic plasmid (pSym) that is present also in Rhizobium leucaenae CFN 299, a rhizobium displaying a similar host range. This pSym seems to have arisen by a co-integration event between two replicons. Remarkably, three distinct nodA genes were found in the pSym, a characteristic that may contribute to the broad host range of these rhizobia. Genes for biosynthesis and modulation of plant-hormone levels were also identified in the pSym. Analysis of genes involved in stress response showed that CIAT 899 and PRF 81 are well equipped to cope with low pH, high temperatures and also with oxidative and osmotic stresses. Interestingly, the genomes of CIAT 899 and PRF 81 had large numbers of genes encoding drug-efflux systems, which may explain their high resistance to antimicrobials. Genome analysis also revealed a wide array of traits that may allow these strains to be successful rhizosphere colonizers, including surface polysaccharides, uptake transporters and catabolic enzymes for nutrients, diverse iron-acquisition systems, cell wall-degrading enzymes, type I and IV pili, and novel T1SS and T5SS secreted adhesins. CONCLUSIONS Availability of the complete genome sequences of CIAT 899 and PRF 81 may be exploited in further efforts to understand the interaction of tropical rhizobia with common bean and other legume hosts.
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Affiliation(s)
- Ernesto Ormeño-Orrillo
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Pâmela Menna
- Embrapa Soja, C. P. 231, Londrina, Paraná, 86001-970, Brazil
| | - Luiz Gonzaga P Almeida
- Laboratório Nacional de Computação Científica (LNCC), Avenida Getúlio Vargas 333, Petrópolis, Rio de Janeiro, Brazil
| | | | - Marisa Fabiana Nicolás
- Laboratório Nacional de Computação Científica (LNCC), Avenida Getúlio Vargas 333, Petrópolis, Rio de Janeiro, Brazil
| | | | | | | | | | - Rangel Celso Souza
- Laboratório Nacional de Computação Científica (LNCC), Avenida Getúlio Vargas 333, Petrópolis, Rio de Janeiro, Brazil
| | | | - Manuel Megías
- Universidad de Sevilla, Apdo Postal 874, Sevilla, 41080, Spain
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Reina-Bueno M, Argandoña M, Nieto JJ, Hidalgo-García A, Iglesias-Guerra F, Delgado MJ, Vargas C. Role of trehalose in heat and desiccation tolerance in the soil bacterium Rhizobium etli. BMC Microbiol 2012; 12:207. [PMID: 22985230 PMCID: PMC3518184 DOI: 10.1186/1471-2180-12-207] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 09/12/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The compatible solute trehalose is involved in the osmostress response of Rhizobium etli, the microsymbiont of Phaseolus vulgaris. In this work, we reconstructed trehalose metabolism in R. etli, and investigated its role in cellular adaptation and survival to heat and desiccation stress under free living conditions. RESULTS Besides trehalose as major compatible solute, R. etli CE3 also accumulated glutamate and, if present in the medium, mannitol. Putative genes for trehalose synthesis (otsAB/treS/treZY), uptake (aglEFGK/thuEFGK) and degradation (thuAB/treC) were scattered among the chromosome and plasmids p42a, p42c, p42e, and p42f, and in some instances found redundant. Two copies of the otsA gene, encoding trehalose-6-P-synthase, were located in the chromosome (otsAch) and plasmid p42a (otsAa), and the latter seemed to be acquired by horizontal transfer. High temperature alone did not influence growth of R. etli, but a combination of high temperature and osmotic stress was more deleterious for growth than osmotic stress alone. Although high temperature induced some trehalose synthesis by R. etli, trehalose biosynthesis was mainly triggered by osmotic stress. However, an otsAch mutant, unable to synthesize trehalose in minimal medium, showed impaired growth at high temperature, suggesting that trehalose plays a role in thermoprotection of R. etli. Desiccation tolerance by R. etli wild type cells was dependent of high trehalose production by osmotic pre-conditioned cells. Cells of the mutant strain otsAch showed ca. 3-fold lower survival levels than the wild type strain after drying, and a null viability after 4 days storage. CONCLUSIONS Our findings suggest a beneficial effect of osmotic stress in R. etli tolerance to desiccation, and an important role of trehalose on the response of R. etli to high temperature and desiccation stress.
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Affiliation(s)
- Mercedes Reina-Bueno
- Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, Profesor García González 2, Seville, 41012, Spain
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A specialized aspartokinase enhances the biosynthesis of the osmoprotectants ectoine and hydroxyectoine in Pseudomonas stutzeri A1501. J Bacteriol 2011; 193:4456-68. [PMID: 21725014 DOI: 10.1128/jb.00345-11] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The compatible solutes ectoine and hydroxyectoine are widely produced by bacteria as protectants against osmotic and temperature stress. l-Aspartate-beta-semialdehyde is used as the precursor molecule for ectoine/hydroxyectoine biosynthesis that is catalyzed by the EctABCD enzymes. l-Aspartate-beta-semialdehyde is a central intermediate in different biosynthetic pathways and is produced from l-aspartate by aspartokinase (Ask) and aspartate-semialdehyde-dehydrogenase (Asd). Ask activity is typically stringently regulated by allosteric control to avoid gratuitous synthesis of aspartylphosphate. Many organisms have evolved multiple forms of aspartokinase, and feedback regulation of these specialized Ask enzymes is often adapted to the cognate biochemical pathways. The ectoine/hydroxyectoine biosynthetic genes (ectABCD) are followed in a considerable number of microorganisms by an askgene (ask_ect), suggesting that Ask_Ect is a specialized enzyme for this osmoadaptive biosynthetic pathway. However, none of these Ask_Ect enzymes have been functionally characterized. Pseudomonas stutzeri A1501 synthesizes both ectoine and hydroxyectoine in response to increased salinity, and it possesses two Ask enzymes: Ask_Lys and Ask_Ect. We purified both Ask enzymes and found significant differences with regard to their allosteric control: Ask_LysC was inhibited by threonine and in a concerted fashion by threonine and lysine, whereas Ask_Ect showed inhibition only by threonine. The ectABCD_askgenes from P. stutzeri A1501 were cloned and functionally expressed in Escherichia coli, and this led to osmostress protection. An E. colistrain carrying the plasmid-based ectABCD_askgene cluster produced significantly more ectoine/hydroxyectoine than a strain expressing the ectABCDgene cluster alone. This finding suggests a specialized role for Ask_Ect in ectoine/hydroxyectoine biosynthesis.
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Fontenelle C, Blanco C, Arrieta M, Dufour V, Trautwetter A. Resistance to organic hydroperoxides requires ohr and ohrR genes in Sinorhizobium meliloti. BMC Microbiol 2011; 11:100. [PMID: 21569462 PMCID: PMC3107159 DOI: 10.1186/1471-2180-11-100] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 05/13/2011] [Indexed: 12/18/2022] Open
Abstract
Background Sinorhizobium meliloti is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants Medicago sativa. During nodule formation bacteria have to withstand oxygen radicals produced by the plant. Resistance to H2O2 and superoxides has been extensively studied in S. meliloti. In contrast resistance to organic peroxides has not been investigated while S. meliloti genome encodes putative organic peroxidases. Organic peroxides are produced by plants and are highly toxic. The resistance to these oxygen radicals has been studied in various bacteria but never in plant nodulating bacteria. Results In this study we report the characterisation of organic hydroperoxide resistance gene ohr and its regulator ohrR in S. meliloti. The inactivation of ohr affects resistance to cumene and ter-butyl hydroperoxides but not to hydrogen peroxide or menadione in vitro. The expression of ohr and ohrR genes is specifically induced by organic peroxides. OhrR binds to the intergenic region between the divergent genes ohr and ohrR. Two binding sites were characterised. Binding to the operator is prevented by OhrR oxidation that promotes OhrR dimerisation. The inactivation of ohr did not affect symbiosis and nitrogen fixation, suggesting that redundant enzymatic activity exists in this strain. Both ohr and ohrR are expressed in nodules suggesting that they play a role during nitrogen fixation. Conclusions This report demonstrates the significant role Ohr and OhrR proteins play in bacterial stress resistance against organic peroxides in S. meliloti. The ohr and ohrR genes are expressed in nodule-inhabiting bacteroids suggesting a role during nodulation.
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Affiliation(s)
- Catherine Fontenelle
- UMR CNRS 6026, DUALS, Université de Rennes I, Campus de Beaulieu, Av. du Général Leclerc, 35042 Rennes, France
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