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Coban O, De Deyn GB, van der Ploeg M. Soil microbiota as game-changers in restoration of degraded lands. Science 2022; 375:abe0725. [PMID: 35239372 DOI: 10.1126/science.abe0725] [Citation(s) in RCA: 121] [Impact Index Per Article: 60.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Land degradation reduces soil functioning and, consequently, the services that soil provides. Soil hydrological functions are critical to combat soil degradation and promote soil restoration. Soil microorganisms affect soil hydrology, but the role of soil microbiota in forming and sustaining soil is not well explored. Case studies indicate the potential of soil microorganisms as game-changers in restoring soil functions. We review the state of the art of microorganism use in land restoration technology, the groups of microorganisms with the greatest potential for soil restoration, knowledge of the effect of microorganisms on soil physical properties, and proposed strategies for the long-term restoration of degraded lands. We also emphasize the need to advance the emerging research field of biophysical landscape interactions to support soil-plant ecosystem restoration practices.
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Affiliation(s)
- Oksana Coban
- Department of Environmental Sciences, Wageningen University & Research, Wageningen, Netherlands
| | - Gerlinde B De Deyn
- Department of Environmental Sciences, Wageningen University & Research, Wageningen, Netherlands
| | - Martine van der Ploeg
- Department of Environmental Sciences, Wageningen University & Research, Wageningen, Netherlands
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52
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Enhancing agronomic efficiency and maize grain yield with Azospirillum brasilense inoculation under Brazilian savannah conditions. EUROPEAN JOURNAL OF AGRONOMY 2022. [DOI: 10.1016/j.eja.2022.126471] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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53
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Tanunchai B, Kalkhof S, Guliyev V, Wahdan SFM, Krstic D, Schädler M, Geissler A, Glaser B, Buscot F, Blagodatskaya E, Noll M, Purahong W. Nitrogen fixing bacteria facilitate microbial biodegradation of a bio-based and biodegradable plastic in soils under ambient and future climatic conditions. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:233-241. [PMID: 35048922 DOI: 10.1039/d1em00426c] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We discovered a biological mechanism supporting microbial degradation of bio-based poly(butylene succinate-co-adipate) (PBSA) plastic in soils under ambient and future climates. Here, we show that nitrogen-fixing bacteria facilitate the microbial degradation of PBSA by enhancing fungal abundance, accelerating plastic-degrading enzyme activities, and shaping/interacting with plastic-degrading fungal communities.
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Affiliation(s)
- Benjawan Tanunchai
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany.
- Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
| | - Stefan Kalkhof
- Coburg University of Applied Sciences and Arts, Institute for Bioanalysis, Friedrich-Streib-Str. 2, D-96450 Coburg, Germany.
| | - Vusal Guliyev
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany.
- Institute of Soil Science and Agrochemistry of Azerbaijan National Academy of Sciences, M.Rahim, AZ1073, Baku, Azerbaijan
| | - Sara Fareed Mohamed Wahdan
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany.
- Department of Botany, Faculty of Science, Suez Canal University, Ismailia, 41522, Egypt
| | - Dennis Krstic
- Coburg University of Applied Sciences and Arts, Institute for Bioanalysis, Friedrich-Streib-Str. 2, D-96450 Coburg, Germany.
| | - Martin Schädler
- UFZ-Helmholtz Centre for Environmental Research, Department of Community Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany
| | - Andreas Geissler
- Department of Macromolecular Chemistry and Paper Chemistry, Technical University of Darmstadt, Darmstadt D-64287, Germany
| | - Bruno Glaser
- Soil Biogeochemistry, Martin Luther University Halle-Wittenberg, Von-Seckendorff-Platz 3, 06120 Halle, Germany
| | - François Buscot
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany.
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, D-04103 Leipzig, Germany
| | - Evgenia Blagodatskaya
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany.
- RUDN University, 6 Miklukho-Maklaya St, Moscow, 117198, Russia
| | - Matthias Noll
- Bayreuth Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, Bayreuth, Germany
- Coburg University of Applied Sciences and Arts, Institute for Bioanalysis, Friedrich-Streib-Str. 2, D-96450 Coburg, Germany.
| | - Witoon Purahong
- UFZ-Helmholtz Centre for Environmental Research, Department of Soil Ecology, Theodor-Lieser-Str. 4, D-06120 Halle (Saale), Germany.
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54
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The Role of Plant Growth-Promoting Rhizobacteria (PGPR) in Mitigating Plant’s Environmental Stresses. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12031231] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Phytoremediation is a cost-effective and sustainable technology used to clean up pollutants from soils and waters through the use of plant species. Indeed, plants are naturally capable of absorbing metals and degrading organic molecules. However, in several cases, the presence of contaminants causes plant suffering and limited growth. In such situations, thanks to the production of specific root exudates, plants can engage the most suitable bacteria able to support their growth according to the particular environmental stress. These plant growth-promoting rhizobacteria (PGPR) may facilitate plant growth and development with several beneficial effects, even more evident when plants are grown in critical environmental conditions, such as the presence of toxic contaminants. For instance, PGPR may alleviate metal phytotoxicity by altering metal bioavailability in soil and increasing metal translocation within the plant. Since many of the PGPR are also hydrocarbon oxidizers, they are also able to support and enhance plant biodegradation activity. Besides, PGPR in agriculture can be an excellent support to counter the devastating effects of abiotic stress, such as excessive salinity and drought, replacing expensive inorganic fertilizers that hurt the environment. A better and in-depth understanding of the function and interactions of plants and associated microorganisms directly in the matrix of interest, especially in the presence of persistent contamination, could provide new opportunities for phytoremediation.
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55
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Malviya MK, Li CN, Lakshmanan P, Solanki MK, Wang Z, Solanki AC, Nong Q, Verma KK, Singh RK, Singh P, Sharma A, Guo DJ, Dessoky ES, Song XP, Li YR. High-Throughput Sequencing-Based Analysis of Rhizosphere and Diazotrophic Bacterial Diversity Among Wild Progenitor and Closely Related Species of Sugarcane ( Saccharum spp. Inter-Specific Hybrids). FRONTIERS IN PLANT SCIENCE 2022; 13:829337. [PMID: 35283913 PMCID: PMC8908384 DOI: 10.3389/fpls.2022.829337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 01/04/2022] [Indexed: 05/14/2023]
Abstract
Considering the significant role of genetic background in plant-microbe interactions and that most crop rhizospheric microbial research was focused on cultivars, understanding the diversity of root-associated microbiomes in wild progenitors and closely related crossable species may help to breed better cultivars. This study is aimed to fill a critical knowledge gap on rhizosphere and diazotroph bacterial diversity in the wild progenitors of sugarcane, the essential sugar and the second largest bioenergy crop globally. Using a high-throughput sequencing (HTS) platform, we studied the rhizosphere and diazotroph bacterial community of Saccharum officinarum L. cv. Badila (BRS), Saccharum barberi (S. barberi) Jesw. cv Pansahi (PRS), Saccharum robustum [S. robustum; (RRS), Saccharum spontaneum (S. spontaneum); SRS], and Saccharum sinense (S. sinense) Roxb. cv Uba (URS) by sequencing their 16S rRNA and nifH genes. HTS results revealed that a total of 6,202 bacteria-specific operational taxonomic units (OTUs) were identified, that were distributed as 107 bacterial groups. Out of that, 31 rhizobacterial families are commonly spread in all five species. With respect to nifH gene, S. barberi and S. spontaneum recorded the highest and lowest number of OTUs, respectively. These results were validated by quantitative PCR analysis of both genes. A total of 1,099 OTUs were identified for diazotrophs with a core microbiome of 9 families distributed among all the sugarcane species. The core microbiomes were spread across 20 genera. The increased microbial diversity in the rhizosphere was mainly due to soil physiochemical properties. Most of the genera of rhizobacteria and diazotrophs showed a positive correlation, and few genera negatively correlated with the soil properties. The results showed that sizeable rhizospheric diversity exists across progenitors and close relatives. Still, incidentally, the rhizosphere microbial abundance of progenitors of modern sugarcane was at the lower end of the spectrum, indicating the prospect of Saccharum species introgression breeding may further improve nutrient use and disease and stress tolerance of commercial sugarcane. The considerable variation for rhizosphere microbiome seen in Saccharum species also provides a knowledge base and an experimental system for studying the evolution of rhizobacteria-host plant association during crop domestication.
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Affiliation(s)
- Mukesh Kumar Malviya
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Chang-Ning Li
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Prakash Lakshmanan
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
- Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin, College of Resources and Environment, Southwest University, Chongqing, China
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, St. Lucia, QLD, Australia
| | - Manoj Kumar Solanki
- Plant Cytogenetics and Molecular Biology Group, Faculty of Natural Sciences, Institute of Biology, Biotechnology and Environmental Protection, University of Silesia in Katowice, Katowice, Poland
| | - Zhen Wang
- Guangxi Key Laboratory of Agricultural Resources Chemistry and Biotechnology, College of Biology and Pharmacy, Yulin Normal University, Yulin, China
| | | | - Qian Nong
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Krishan K. Verma
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Rajesh Kumar Singh
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Pratiksha Singh
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Anjney Sharma
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
| | - Dao-Jun Guo
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
- College of Agriculture, Guangxi University, Nanning, China
| | | | - Xiu-Peng Song
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
- *Correspondence: Xiu-Peng Song
| | - Yang-Rui Li
- Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs, Sugarcane Research Center, Chinese Academy of Agricultural Sciences, Guangxi Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences, Nanning, China
- College of Agriculture, Guangxi University, Nanning, China
- Yang-Rui Li ; orcid.org/0000-0002-7559-9244
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56
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Galindo FS, Brito VB, Teixeira Filho MCM. Assessing nutritional status and development of Pereskia aculeata Mill. affected by inoculation of Azospirillum brasilense combined with nitrogen rates. JOURNAL OF PLANT NUTRITION 2021. [DOI: 10.1080/01904167.2021.2014880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Fernando Shintate Galindo
- Department of Plant Health, Rural Engineering, and Soils, São Paulo State University, Ilha Solteira, São Paulo, Brazil
| | - Vanessa Biazotto Brito
- Department of Plant Health, Rural Engineering, and Soils, São Paulo State University, Ilha Solteira, São Paulo, Brazil
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57
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Schnabel T, Sattely E. Improved Stability of Engineered Ammonia Production in the Plant-Symbiont Azospirillum brasilense. ACS Synth Biol 2021; 10:2982-2996. [PMID: 34591447 PMCID: PMC8604774 DOI: 10.1021/acssynbio.1c00287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bioavailable nitrogen is the limiting nutrient for most agricultural food production. Associative diazotrophs can colonize crop roots and fix their own bioavailable nitrogen from the atmosphere. Wild-type (WT) associative diazotrophs, however, do not release fixed nitrogen in culture and are not known to directly transfer fixed nitrogen resources to plants. Efforts to engineer diazotrophs for plant nitrogen provision as an alternative to chemical fertilization have yielded several strains that transiently release ammonia. However, these strains suffer from selection pressure for nonproducers, which rapidly deplete ammonia accumulating in culture, likely limiting their potential for plant growth promotion (PGP). Here we report engineered Azospirillum brasilense strains with significantly extend ammonia production lifetimes of up to 32 days in culture. Our approach relies on multicopy genetic redundancy of a unidirectional adenylyltransferase (uAT) as a posttranslational mechanism to induce ammonia release via glutamine synthetase deactivation. Testing our multicopy stable strains with the model monocot Setaria viridis in hydroponic monoassociation reveals improvement in plant growth promotion compared to single copy strains. In contrast, inoculation of Zea mays in nitrogen-poor, nonsterile soil does not lead to increased PGP relative to WT, suggesting strain health, resource competition, or colonization capacity in soil may also be limiting factors. In this context, we show that while engineered strains fix more nitrogen per cell compared to WT strains, the expression strength of multiple uAT copies needs to be carefully balanced to maximize ammonia production rates and avoid excessive fitness defects caused by excessive glutamine synthetase shutdown.
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Affiliation(s)
- Tim Schnabel
- Department of Bioengineering, Stanford University, Stanford, California 94305, United States
| | - Elizabeth Sattely
- Department of Chemical Engineering, Stanford University and HHMI, Stanford, California 94305, United States
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58
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Diazotrophic Behaviour in a Non-Sterile Bioreactor: The Effect of O2-Availability. Processes (Basel) 2021. [DOI: 10.3390/pr9112039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The behaviour of a locally isolated diazotrophic consortium was investigated with the prospect of agricultural applications. A repeatable culture was obtained in a non-sterile bioreactor. Metagenomic analysis indicated Chryseobacterium ssp. and Flavobacterium ssp. were the dominant species, making up approximately 50% of the microbial community. The oxygen supply was varied and mass-transfer limited growth was attained under all experimental conditions. Negligible amounts of aqueous metabolites were formed, indicating a high selectivity towards biomass production. High oxygen availability resulted in decreased growth efficiencies i.e., the specific energy requirements for biomass synthesis. This was attributed to reduced electron transport chain efficiencies and nitrogenase protection mechanisms. Mass and energy balances indicated that sessile biomass with a high C:N served as a carbon sink. The most efficient growth was measured at an aeration feed composition of 21% oxygen and 79% nitrogen. The study presents one of the only known investigations of operational conditions on diazotrophic growth in a non-sterile bioreactor. In addition, it provides a strong foundation for the development of a Biological Nitrogen Fixation process with scaling potential.
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59
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Priyadarshini P, Choudhury S, Tilgam J, Bharati A, Sreeshma N. Nitrogen fixing cereal: A rising hero towards meeting food security. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 167:912-920. [PMID: 34547550 DOI: 10.1016/j.plaphy.2021.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 09/05/2021] [Accepted: 09/08/2021] [Indexed: 06/13/2023]
Abstract
Nitrogen serves as one of the primary components of major biomolecules and thus extends a significant contribution to crop growth and yield. But the inability of plants to utilize freely available atmospheric N2 makes the whole agricultural system dependent on chemical fertilizers, which incur significant input cost to supplement required quantities of nitrogen to crops. Only bacteria and archaea have been gifted with the power of drawing free N2 from air to convert them into NH3, which is one of the two utilizable forms of nitrogen taken up by plants. Legumes, the only family of crops, can engage themselves in symbiotic nitrogen fixation where they establish a mutualistic relationship with nitrogen-fixing bacteria and in turn, can waive off the necessity of adding nitrogen fertilizers. Sincere effort, therefore, has been undertaken to incorporate this capability of nitrogen-fixation into non-legume crops, especially cereals which make up a vital portion in the food basket. Biotechnological interventions have also played important role in providing nitrogen fixing trait to non-legumes. This review takes up an effort to look into and accumulate all the important updates to date regarding nitrogen-fixing non-legumes with a special focus on cereals, which is one of the most important future goals in the field of science in the present era.
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Affiliation(s)
- Parichita Priyadarshini
- ICAR-Crop Improvement Division, Indian Grassland and Fodder Research Institute, Jhansi, U.P., 284003, India
| | - Sharani Choudhury
- ICAR - National Institute for Plant Biotechnology, Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Jyotsana Tilgam
- ICAR- National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, U.P., 274103, India.
| | - Alka Bharati
- ICAR-Central Agroforestry Research Institute, Jhansi, U.P., 284003, India
| | - N Sreeshma
- ICAR - National Institute for Plant Biotechnology, Indian Agricultural Research Institute, New Delhi, 110012, India
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60
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Nadarajah K, Abdul Rahman NSN. Plant-Microbe Interaction: Aboveground to Belowground, from the Good to the Bad. Int J Mol Sci 2021; 22:ijms221910388. [PMID: 34638728 PMCID: PMC8508622 DOI: 10.3390/ijms221910388] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/14/2021] [Accepted: 09/17/2021] [Indexed: 02/06/2023] Open
Abstract
Soil health and fertility issues are constantly addressed in the agricultural industry. Through the continuous and prolonged use of chemical heavy agricultural systems, most agricultural lands have been impacted, resulting in plateaued or reduced productivity. As such, to invigorate the agricultural industry, we would have to resort to alternative practices that will restore soil health and fertility. Therefore, in recent decades, studies have been directed towards taking a Magellan voyage of the soil rhizosphere region, to identify the diversity, density, and microbial population structure of the soil, and predict possible ways to restore soil health. Microbes that inhabit this region possess niche functions, such as the stimulation or promotion of plant growth, disease suppression, management of toxicity, and the cycling and utilization of nutrients. Therefore, studies should be conducted to identify microbes or groups of organisms that have assigned niche functions. Based on the above, this article reviews the aboveground and below-ground microbiomes, their roles in plant immunity, physiological functions, and challenges and tools available in studying these organisms. The information collected over the years may contribute toward future applications, and in designing sustainable agriculture.
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61
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Galindo FS, Pagliari PH, Buzetti S, Rodrigues WL, Fernandes GC, Biagini ALC, Tavanti RFR, Teixeira Filho MCM. Nutrient availability affected by silicate and
Azospirillum brasilense
application in corn–wheat rotation. AGRONOMY JOURNAL 2021. [DOI: 10.1002/agj2.20802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
| | - Paulo Humberto Pagliari
- Dep. of Soil, Water, and Climate Univ. of Minnesota, Southwest Research and Outreach Center Lamberton MN USA
| | - Salatiér Buzetti
- Dep. of Plant Health, Rural Engineering, and Soils São Paulo State Univ. Ilha Solteira São Paulo Brazil
| | - Willian Lima Rodrigues
- Dep. of Plant Health, Rural Engineering, and Soils São Paulo State Univ. Ilha Solteira São Paulo Brazil
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62
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Buzdin AV, Patrushev MV, Sverdlov ED. Will Plant Genome Editing Play a Decisive Role in "Quantum-Leap" Improvements in Crop Yield to Feed an Increasing Global Human Population? PLANTS (BASEL, SWITZERLAND) 2021; 10:1667. [PMID: 34451712 PMCID: PMC8398637 DOI: 10.3390/plants10081667] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/04/2021] [Accepted: 08/07/2021] [Indexed: 02/08/2023]
Abstract
Growing scientific evidence demonstrates unprecedented planetary-scale human impacts on the Earth's system with a predicted threat to the existence of the terrestrial biosphere due to population increase, resource depletion, and pollution. Food systems account for 21-34% of global carbon dioxide (CO2) emissions. Over the past half-century, water and land-use changes have significantly impacted ecosystems, biogeochemical cycles, biodiversity, and climate. At the same time, food production is falling behind consumption, and global grain reserves are shrinking. Some predictions suggest that crop yields must approximately double by 2050 to adequately feed an increasing global population without a large expansion of crop area. To achieve this, "quantum-leap" improvements in crop cultivar productivity are needed within very narrow planetary boundaries of permissible environmental perturbations. Strategies for such a "quantum-leap" include mutation breeding and genetic engineering of known crop genome sequences. Synthetic biology makes it possible to synthesize DNA fragments of any desired sequence, and modern bioinformatics tools may hopefully provide an efficient way to identify targets for directed modification of selected genes responsible for known important agronomic traits. CRISPR/Cas9 is a new technology for incorporating seamless directed modifications into genomes; it is being widely investigated for its potential to enhance the efficiency of crop production. We consider the optimism associated with the new genetic technologies in terms of the complexity of most agronomic traits, especially crop yield potential (Yp) limits. We also discuss the possible directions of overcoming these limits and alternative ways of providing humanity with food without transgressing planetary boundaries. In conclusion, we support the long-debated idea that new technologies are unlikely to provide a rapidly growing population with significantly increased crop yield. Instead, we suggest that delicately balanced humane measures to limit its growth and the amount of food consumed per capita are highly desirable for the foreseeable future.
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Affiliation(s)
- Anton V Buzdin
- The Laboratory of Clinical and Genomic Bioinformatics, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region, 141701 Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Maxim V Patrushev
- Kurchatov Center for Genome Research, National Research Center Kurchatov Institute, 123182 Moscow, Russia
| | - Eugene D Sverdlov
- Kurchatov Center for Genome Research, National Research Center Kurchatov Institute, 123182 Moscow, Russia
- Institute of Molecular Genetics, National Research Center Kurchatov Institute, 123182 Moscow, Russia
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63
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Schulte CCM, Borah K, Wheatley RM, Terpolilli JJ, Saalbach G, Crang N, de Groot DH, Ratcliffe RG, Kruger NJ, Papachristodoulou A, Poole PS. Metabolic control of nitrogen fixation in rhizobium-legume symbioses. SCIENCE ADVANCES 2021; 7:7/31/eabh2433. [PMID: 34330708 PMCID: PMC8324050 DOI: 10.1126/sciadv.abh2433] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/14/2021] [Indexed: 05/16/2023]
Abstract
Rhizobia induce nodule formation on legume roots and differentiate into bacteroids, which catabolize plant-derived dicarboxylates to reduce atmospheric N2 into ammonia. Despite the agricultural importance of this symbiosis, the mechanisms that govern carbon and nitrogen allocation in bacteroids and promote ammonia secretion to the plant are largely unknown. Using a metabolic model derived from genome-scale datasets, we show that carbon polymer synthesis and alanine secretion by bacteroids facilitate redox balance in microaerobic nodules. Catabolism of dicarboxylates induces not only a higher oxygen demand but also a higher NADH/NAD+ ratio than sugars. Modeling and 13C metabolic flux analysis indicate that oxygen limitation restricts the decarboxylating arm of the tricarboxylic acid cycle, which limits ammonia assimilation into glutamate. By tightly controlling oxygen supply and providing dicarboxylates as the energy and electron source donors for N2 fixation, legumes promote ammonia secretion by bacteroids. This is a defining feature of rhizobium-legume symbioses.
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Affiliation(s)
- Carolin C M Schulte
- Department of Plant Sciences, University of Oxford, Oxford, UK
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Khushboo Borah
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | | | | | | | - Nick Crang
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Daan H de Groot
- Systems Biology Lab, AIMMS, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | | | | | | | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford, UK.
- John Innes Centre, Norwich Research Park, Norwich, UK
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64
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Leger D, Matassa S, Noor E, Shepon A, Milo R, Bar-Even A. Photovoltaic-driven microbial protein production can use land and sunlight more efficiently than conventional crops. Proc Natl Acad Sci U S A 2021; 118:e2015025118. [PMID: 34155098 PMCID: PMC8255800 DOI: 10.1073/pnas.2015025118] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Population growth and changes in dietary patterns place an ever-growing pressure on the environment. Feeding the world within sustainable boundaries therefore requires revolutionizing the way we harness natural resources. Microbial biomass can be cultivated to yield protein-rich feed and food supplements, collectively termed single-cell protein (SCP). Yet, we still lack a quantitative comparison between traditional agriculture and photovoltaic-driven SCP systems in terms of land use and energetic efficiency. Here, we analyze the energetic efficiency of harnessing solar energy to produce SCP from air and water. Our model includes photovoltaic electricity generation, direct air capture of carbon dioxide, electrosynthesis of an electron donor and/or carbon source for microbial growth (hydrogen, formate, or methanol), microbial cultivation, and the processing of biomass and proteins. We show that, per unit of land, SCP production can reach an over 10-fold higher protein yield and at least twice the caloric yield compared with any staple crop. Altogether, this quantitative analysis offers an assessment of the future potential of photovoltaic-driven microbial foods to supplement conventional agricultural production and support resource-efficient protein supply on a global scale.
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Affiliation(s)
- Dorian Leger
- Systems and Synthetic Metabolism, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany;
| | - Silvio Matassa
- Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, 80125 Naples, Italy
| | - Elad Noor
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Alon Shepon
- Department of Environmental Studies, The Porter School of the Environment and Earth Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- The Steinhardt Museum of Natural History, Israel National Center for Biodiversity Studies, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Ron Milo
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Arren Bar-Even
- Systems and Synthetic Metabolism, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam, Germany
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Galindo FS, Pagliari PH, Buzetti S, Rodrigues WL, Fernandes GC, Biagini ALC, Marega EMR, Tavanti RFR, Jalal A, Teixeira Filho MCM. Corn shoot and grain nutrient uptake affected by silicon application combined with Azospirillum brasilense inoculation and nitrogen rates. JOURNAL OF PLANT NUTRITION 2021. [DOI: 10.1080/01904167.2021.1943436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Fernando Shintate Galindo
- Department of Plant Health, Rural Engineering, and Soils, São Paulo State University, Ilha Solteira, Brazil
| | - Paulo Humberto Pagliari
- Department of Soil, Water, and Climate, University of Minnesota, Southwest Research and Outreach Center, Lamberton, MN, USA
| | - Salatiér Buzetti
- Department of Plant Health, Rural Engineering, and Soils, São Paulo State University, Ilha Solteira, Brazil
| | - Willian Lima Rodrigues
- Department of Plant Health, Rural Engineering, and Soils, São Paulo State University, Ilha Solteira, Brazil
| | - Guilherme Carlos Fernandes
- Department of Plant Health, Rural Engineering, and Soils, São Paulo State University, Ilha Solteira, Brazil
| | | | - Evelyn Maria Rocha Marega
- Department of Plant Health, Rural Engineering, and Soils, São Paulo State University, Ilha Solteira, Brazil
| | | | - Arshad Jalal
- Department of Plant Health, Rural Engineering, and Soils, São Paulo State University, Ilha Solteira, Brazil
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Schnabel T, Sattely E. Engineering Posttranslational Regulation of Glutamine Synthetase for Controllable Ammonia Production in the Plant Symbiont Azospirillum brasilense. Appl Environ Microbiol 2021; 87:e0058221. [PMID: 33962983 PMCID: PMC8231714 DOI: 10.1128/aem.00582-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 04/27/2021] [Indexed: 11/20/2022] Open
Abstract
Nitrogen requirements for modern agriculture far exceed the levels of bioavailable nitrogen in most arable soils. As a result, the addition of nitrogen fertilizer is necessary to sustain productivity and yields, especially for cereal crops, the planet's major calorie suppliers. Given the unsustainability of industrial fertilizer production and application, engineering biological nitrogen fixation directly at the roots of plants has been a grand challenge for biotechnology. Here, we designed and tested a potentially broadly applicable metabolic engineering strategy for the overproduction of ammonia in the diazotrophic symbiont Azospirillum brasilense. Our approach is based on an engineered unidirectional adenylyltransferase (uAT) that posttranslationally modifies and deactivates glutamine synthetase (GS), a key regulator of nitrogen metabolism in the cell. We show that this circuit can be controlled inducibly, and we leveraged the inherent self-contained nature of our posttranslational approach to demonstrate that multicopy redundancy can improve strain evolutionary stability. uAT-engineered Azospirillum is capable of producing ammonia at rates of up to 500 μM h-1 unit of OD600 (optical density at 600 nm)-1. We demonstrated that when grown in coculture with the model monocot Setaria viridis, these strains increase the biomass and chlorophyll content of plants up to 54% and 71%, respectively, relative to the wild type (WT). Furthermore, we rigorously demonstrated direct transfer of atmospheric nitrogen to extracellular ammonia and then plant biomass using isotopic labeling: after 14 days of cocultivation with engineered uAT strains, 9% of chlorophyll nitrogen in Setaria seedlings was derived from diazotrophically fixed dinitrogen, whereas no nitrogen was incorporated in plants cocultivated with WT controls. This rational design for tunable ammonia overproduction is modular and flexible, and we envision that it could be deployable in a consortium of nitrogen-fixing symbiotic diazotrophs for plant fertilization. IMPORTANCE Nitrogen is the most limiting nutrient in modern agriculture. Free-living diazotrophs, such as Azospirillum, are common colonizers of cereal grasses and have the ability to fix nitrogen but natively do not release excess ammonia. Here, we used a rational engineering approach to generate ammonia-excreting strains of Azospirillum. Our design features posttranslational control of highly conserved central metabolism, enabling tunability and flexibility of circuit placement. We found that our strains promote the growth and health of the model grass S. viridis and rigorously demonstrated that in comparison to WT controls, our engineered strains can transfer nitrogen from 15N2 gas to plant biomass. Unlike previously reported ammonia-producing mutants, our rationally designed approach easily lends itself to further engineering opportunities and has the potential to be broadly deployable.
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Affiliation(s)
- Tim Schnabel
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Elizabeth Sattely
- Department of Chemical Engineering, Stanford University and HHMI, Stanford, California, USA
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67
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R. Cope K, B. Irving T, Chakraborty S, Ané JM. Perception of lipo-chitooligosaccharides by the bioenergy crop Populus. PLANT SIGNALING & BEHAVIOR 2021; 16:1903758. [PMID: 33794743 PMCID: PMC8143229 DOI: 10.1080/15592324.2021.1903758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/12/2021] [Indexed: 06/12/2023]
Abstract
Populus sp. is a developing feedstock for second-generation biofuel production. To ensure its success as a sustainable biofuel source, it is essential to capitalize on the ability of Populus sp. to associate with beneficial plant-associated microbes (e.g., mycorrhizal fungi) and engineer Populus sp. to associate with non-native symbionts (e.g., rhizobia). Here, we review recent research into the molecular mechanisms that control ectomycorrhizal associations in Populus sp. with particular emphasis on the discovery that ectomycorrhizal fungi produce lipochitooligosaccharides capable of activating the common symbiosis pathway. We also present new evidence that lipo-chitooligosaccharides produced by both ectomycorrhizal fungi and various species of rhizobia that do not associate with Populus sp. can induce nuclear calcium spiking in the roots of Populus sp. Thus, we argue Populus sp. already possesses the molecular machinery necessary for perceiving rhizobia, and the next step in engineering symbiosis with rhizobia should be focused on inducing bacterial accommodation and nodule organogenesis. The gene Nodule INception is central to these processes, and several putative orthologs are present in Populus sp. Manipulating the promoters of these genes to match that of plants in the nitrogen-fixing clade may be sufficient to introduce nodulation in Populus sp.
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Affiliation(s)
- Kevin R. Cope
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, WI,United States
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin, WI,United States
| | - Thomas B. Irving
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, WI,United States
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin, WI,United States
| | - Sanhita Chakraborty
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, WI,United States
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin, WI,United States
| | - Jean-Michel Ané
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, WI,United States
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin, WI,United States
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Galindo FS, Bellotte JLM, Santini JMK, Buzetti S, Rosa PAL, Jalal A, Teixeira Filho MCM. Zinc use efficiency of maize-wheat cropping after inoculation with Azospirillum brasilense. NUTRIENT CYCLING IN AGROECOSYSTEMS 2021. [DOI: 10.1007/s10705-021-10149-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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69
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Pankievicz VCS, do Amaral FP, Ané JM, Stacey G. Diazotrophic Bacteria and Their Mechanisms to Interact and Benefit Cereals. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:491-498. [PMID: 33543986 DOI: 10.1094/mpmi-11-20-0316-fi] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Plant-growth-promoting bacteria (PGPB) stimulate plant growth through diverse mechanisms. In addition to biological nitrogen fixation, diazotrophic PGPB can improve nutrient uptake efficiency from the soil, produce and release phytohormones to the host, and confer resistance against pathogens. The genetic determinants that drive the success of biological nitrogen fixation in nonlegume plants are understudied. These determinants include recognition and signaling pathways, bacterial colonization, and genotype specificity between host and bacteria. This review presents recent discoveries of how nitrogen-fixing PGPB interact with cereals and promote plant growth. We suggest adopting an experimental model system, such as the Setaria-diazotrophic bacteria association, as a reliable way to better understand the associated mechanisms and, ultimately, increase the use of PGPB inoculants for sustainable agriculture.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
| | - Fernanda Plucani do Amaral
- Divisions of Plant Sciences and Biochemistry, C. S. Bond Life Science Center, University of Missouri, Columbia, MO, U.S.A
| | - Jean-Michel Ané
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, U.S.A
| | - Gary Stacey
- Divisions of Plant Sciences and Biochemistry, C. S. Bond Life Science Center, University of Missouri, Columbia, MO, U.S.A
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70
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Costa SR, Ng JLP, Mathesius U. Interaction of Symbiotic Rhizobia and Parasitic Root-Knot Nematodes in Legume Roots: From Molecular Regulation to Field Application. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:470-490. [PMID: 33471549 DOI: 10.1094/mpmi-12-20-0350-fi] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Legumes form two types of root organs in response to signals from microbes, namely, nodules and root galls. In the field, these interactions occur concurrently and often interact with each other. The outcomes of these interactions vary and can depend on natural variation in rhizobia and nematode populations in the soil as well as abiotic conditions. While rhizobia are symbionts that contribute fixed nitrogen to their hosts, parasitic root-knot nematodes (RKN) cause galls as feeding structures that consume plant resources without a contribution to the plant. Yet, the two interactions share similarities, including rhizosphere signaling, repression of host defense responses, activation of host cell division, and differentiation, nutrient exchange, and alteration of root architecture. Rhizobia activate changes in defense and development through Nod factor signaling, with additional functions of effector proteins and exopolysaccharides. RKN inject large numbers of protein effectors into plant cells that directly suppress immune signaling and manipulate developmental pathways. This review examines the molecular control of legume interactions with rhizobia and RKN to elucidate shared and distinct mechanisms of these root-microbe interactions. Many of the molecular pathways targeted by both organisms overlap, yet recent discoveries have singled out differences in the spatial control of expression of developmental regulators that may have enabled activation of cortical cell division during nodulation in legumes. The interaction of legumes with symbionts and parasites highlights the importance of a comprehensive view of root-microbe interactions for future crop management and breeding strategies.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Sofia R Costa
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Jason Liang Pin Ng
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra ACT 2601, Australia
| | - Ulrike Mathesius
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra ACT 2601, Australia
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71
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Bioelectrochemical Fixation of Nitrogen to Extracellular Ammonium by Pseudomonas stutzeri. Appl Environ Microbiol 2021; 87:e0199820. [PMID: 33310714 DOI: 10.1128/aem.01998-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diazotrophs can produce bioavailable nitrogen from inert N2 gas by bioelectrochemical nitrogen fixation (e-BNF), which is emerging as an energy-saving and highly selective strategy for agriculture and industry. However, current e-BNF technology is impeded by requirements for NH4+ assimilation inhibitors to facilitate intracellular ammonia secretion and precious metal catalysts to generate H2 as the energy-carrying intermediate. Here, we initially demonstrate inhibitor- and catalystless extracellular NH4+ production by the diazotroph Pseudomonas stutzeri A1501 using an electrode as the sole electron donor. Multiple lines of evidence revealed that P. stutzeri produced 2.32 ± 0.25 mg/liter extracellular NH4+ at a poised potential of -0.3 V (versus standard hydrogen electrode [SHE]) without the addition of inhibitors or expensive catalysts. The electron uptake mechanism was attributed to the endogenous electron shuttle phenazine-1-carboxylic acid, which was excreted by P. stutzeri and mediated electron transfer from electrodes into cells to directly drive N2 fixation. The faradaic efficiency was 20% ± 3%, which was 2 to 4 times that of previous e-BNF attempts using the H2-mediated pathway. This study reports a diazotroph capable of producing secretable NH4+ via extracellular electron uptake, which has important implications for optimizing the performance of e-BNF systems and exploring the novel nitrogen-fixing mode of syntrophic microbial communities in the natural environment. IMPORTANCE Ammonia greatly affects global ecology, agriculture, and the food industry. Diazotrophs with an enhanced capacity of extracellular NH4+ excretion have been proven to be more beneficial to the growth of microalgae and plants, whereas most previously reported diazotrophs produce intracellular organic nitrogen in the absence of chemical suppression and genetic manipulation. Here, we demonstrate that Pseudomonas stutzeri A1501 is capable of extracellular NH4+ production without chemical suppression or genetic manipulation when the extracellular electrode is used as the sole electron donor. We also reveal the electron uptake pathway from the extracellular electron-donating partner to P. stutzeri A1501 via redox electron shuttle phenazines. Since both P. stutzeri A1501 and potential electron-donating partners (such as electroactive microbes and natural semiconductor minerals) are abundant in diverse soils and sediments, P. stutzeri A1501 has broader implications on the improvement of nitrogen fertilization in the natural environment.
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Goyal RK, Schmidt MA, Hynes MF. Molecular Biology in the Improvement of Biological Nitrogen Fixation by Rhizobia and Extending the Scope to Cereals. Microorganisms 2021; 9:microorganisms9010125. [PMID: 33430332 PMCID: PMC7825764 DOI: 10.3390/microorganisms9010125] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 12/29/2020] [Accepted: 01/06/2021] [Indexed: 11/16/2022] Open
Abstract
The contribution of biological nitrogen fixation to the total N requirement of food and feed crops diminished in importance with the advent of synthetic N fertilizers, which fueled the “green revolution”. Despite being environmentally unfriendly, the synthetic versions gained prominence primarily due to their low cost, and the fact that most important staple crops never evolved symbiotic associations with bacteria. In the recent past, advances in our knowledge of symbiosis and nitrogen fixation and the development and application of recombinant DNA technology have created opportunities that could help increase the share of symbiotically-driven nitrogen in global consumption. With the availability of molecular biology tools, rapid improvements in symbiotic characteristics of rhizobial strains became possible. Further, the technology allowed probing the possibility of establishing a symbiotic dialogue between rhizobia and cereals. Because the evolutionary process did not forge a symbiotic relationship with the latter, the potential of molecular manipulations has been tested to incorporate a functional mechanism of nitrogen reduction independent of microbes. In this review, we discuss various strategies applied to improve rhizobial strains for higher nitrogen fixation efficiency, more competitiveness and enhanced fitness under unfavorable environments. The challenges and progress made towards nitrogen self-sufficiency of cereals are also reviewed. An approach to integrate the genetically modified elite rhizobia strains in crop production systems is highlighted.
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Affiliation(s)
- Ravinder K. Goyal
- Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB T4L 1W1, Canada;
- Correspondence:
| | - Maria Augusta Schmidt
- Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB T4L 1W1, Canada;
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4, Canada;
| | - Michael F. Hynes
- Department of Biological Sciences, University of Calgary, 2500 University Dr NW, Calgary, AB T2N 1N4, Canada;
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Galindo FS, da Silva EC, Pagliari PH, Fernandes GC, Rodrigues WL, Biagini ALC, Baratella EB, da Silva Júnior CA, Moretti Neto MJ, Silva VM, Muraoka T, Teixeira Filho MCM. Nitrogen recovery from fertilizer and use efficiency response to Bradyrhizobium sp. and Azospirillum brasilense combined with N rates in cowpea-wheat crop sequence. APPLIED SOIL ECOLOGY 2021. [DOI: 10.1016/j.apsoil.2020.103764] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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74
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Abstract
There is growing interest in the use of associative, plant growth-promoting bacteria (PGPB) as biofertilizers to serve as a sustainable alternative for agriculture application. While a variety of mechanisms have been proposed to explain bacterial plant growth promotion, the molecular details of this process remain unclear. The plant rhizosphere harbors a diverse population of microorganisms, including beneficial plant growth-promoting bacteria (PGPB), that colonize plant roots and enhance growth and productivity. In order to specifically define bacterial traits that contribute to this beneficial interaction, we used high-throughput transposon mutagenesis sequencing (TnSeq) in two model root-bacterium systems associated with Setaria viridis: Azoarcus olearius DQS4T and Herbaspirillum seropedicae SmR1. This approach identified ∼100 significant genes for each bacterium that appeared to confer a competitive advantage for root colonization. Most of the genes identified specifically in A. olearius encoded metabolism functions, whereas genes identified in H. seropedicae were motility related, suggesting that each strain requires unique functions for competitive root colonization. Genes were experimentally validated by site-directed mutagenesis, followed by inoculation of the mutated bacteria onto S. viridis roots individually, as well as in competition with the wild-type strain. The results identify key bacterial functions involved in iron uptake, polyhydroxybutyrate metabolism, and regulation of aromatic metabolism as important for root colonization. The hope is that by improving our understanding of the molecular mechanisms used by PGPB to colonize plants, we can increase the adoption of these bacteria in agriculture to improve the sustainability of modern cropping systems.
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75
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Granado-Rodríguez S, Bolaños L, Reguera M. MtNIP5;1, a novel Medicago truncatula boron diffusion facilitator induced under deficiency. BMC PLANT BIOLOGY 2020; 20:552. [PMID: 33297962 PMCID: PMC7724820 DOI: 10.1186/s12870-020-02750-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 11/22/2020] [Indexed: 05/26/2023]
Abstract
BACKGROUND Legumes comprise important crops that offer major agronomic benefits, including the capacity of establishing symbiosis with rhizobia, fixing atmospheric N2. It has been proven that legumes are particularly susceptible to boron (B) stress, which leads to important yield penalties. Boron (B) deficiency or toxicity in plants causes the inhibition of growth and an altered development. Under such conditions, the participation of two distinct protein families (the major intrinsic protein family MIP and the Boron transporter family BOR) is required to minimize detrimental effects caused by B stress. However, in legumes, little is known about the transport mechanisms responsible for B uptake and distribution, especially under deficiency. RESULTS A Medicago truncatula protein, MtNIP5;1 (Medtr1g097840) (homologous to the Arabidopsis thaliana AtNIP5;1) was identified as a novel legume B transporter involved in B uptake under deficiency. Further analyses revealed that this M. truncatula aquaporin expression was boron-regulated in roots, being induced under deficiency and repressed under toxicity. It localizes at the plasma membrane of root epidermal cells and in nodules, where B plays pivotal roles in symbiosis. Furthermore, the partial complementation of the nip5;1-1 A. thaliana mutant phenotype under B deficiency supports a functional role of MtNIP5;1 as a B transporter in this legume model plant. CONCLUSIONS The results here presented support a functional role of MtNIP5;1 in B uptake under deficiency and provides new insights into B transport mechanisms in legume species.
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Affiliation(s)
- Sara Granado-Rodríguez
- Departamento de Biología, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Luis Bolaños
- Departamento de Biología, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Maria Reguera
- Departamento de Biología, Universidad Autónoma de Madrid, c/Darwin 2, Campus de Cantoblanco, 28049, Madrid, Spain.
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Groves NR, Biel A, Moser M, Mendes T, Amstutz K, Meier I. Recent advances in understanding the biological roles of the plant nuclear envelope. Nucleus 2020; 11:330-346. [PMID: 33161800 PMCID: PMC7746247 DOI: 10.1080/19491034.2020.1846836] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/15/2020] [Accepted: 10/29/2020] [Indexed: 02/06/2023] Open
Abstract
The functional organization of the plant nuclear envelope is gaining increasing attention through new connections made between nuclear envelope-associated proteins and important plant biological processes. Animal nuclear envelope proteins play roles in nuclear morphology, nuclear anchoring and movement, chromatin tethering and mechanical signaling. However, how these roles translate to functionality in a broader biological context is often not well understood. A surprising number of plant nuclear envelope-associated proteins are plant-unique, suggesting that separate functionalities evolved after the split of Opisthokonta and Streptophyta. Significant progress has now been made in discovering broader biological roles of plant nuclear envelope proteins, increasing the number of known plant nuclear envelope proteins, and connecting known proteins to chromatin organization, gene expression, and the regulation of nuclear calcium. The interaction of viruses with the plant nuclear envelope is another emerging theme. Here, we survey the recent developments in this still relatively new, yet rapidly advancing field.
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Affiliation(s)
- Norman Reid Groves
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, USA
| | - Alecia Biel
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Morgan Moser
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Tyler Mendes
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Katelyn Amstutz
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - Iris Meier
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH, USA
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Atieno M, Herrmann L, Nguyen HT, Phan HT, Nguyen NK, Srean P, Than MM, Zhiyong R, Tittabutr P, Shutsrirung A, Bräu L, Lesueur D. Assessment of biofertilizer use for sustainable agriculture in the Great Mekong Region. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 275:111300. [PMID: 32871522 DOI: 10.1016/j.jenvman.2020.111300] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/21/2020] [Accepted: 08/22/2020] [Indexed: 06/11/2023]
Abstract
A growing concern on the deleterious effects of chemical inputs to the environment has been on the rise from the excessive use of chemical inputs leading to soil and water pollution, destruction to fauna and microbial communities, reduced soil fertility and increased crop disease susceptibility. In the Great Mekong Region (GMR), a large majority of the population relies on agriculture and faces severe challenges including decline in soil fertility, increased pests and diseases, leading to lower ecosystem productivity. In this region, over-dependence on chemical fertilizers also continues to impact negatively on soil health and the wider ecosystem. Agroecological practices, and beneficial microorganisms in particular, offer an affordable and sustainable alternative to mineral inputs for improved plant nutrition and soil health for optimal crop performance and sustainable production. Biofertilizers are a key component in integrated nutrient management as well as for increased economic benefits from reduced expenditure on chemical fertilizers, holistically leading to sustainable agriculture. To cope with the need for biofertilizer adoption for sustainable agricultural production, the countries in the GMR are putting efforts in promoting development and use of biofertilizers and making them available to farmers at affordable costs. Despite these efforts, farmers continue to use chemical fertilizers at high rates with the hope of increased yields instead of taking advantage of microbial products capable of providing plant nutrients while restoring or improving soil health. This study explored the current agricultural practices in the six countries in the GMR (China, Vietnam, Myanmar, Thailand, Cambodia and Lao PDR), the critical need for sustainable agroecological practices with a special emphasis on biofertilizers. We highlighted the current status, distribution, adoption and gaps of biofertilizer production in the GMR, in order to obtain an insight on the nature of biofertilizers, efficacy and production standards, adoption or lack of biofertilizers in the GMR.
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Affiliation(s)
- Mary Atieno
- Alliance of Bioversity International and CIAT, Asia hub, Common Microbial Biotechnology Platform (CMBP), Hanoi, Viet Nam
| | - Laetitia Herrmann
- Alliance of Bioversity International and CIAT, Asia hub, Common Microbial Biotechnology Platform (CMBP), Hanoi, Viet Nam
| | - Huong Thu Nguyen
- Alliance of Bioversity International and CIAT, Asia hub, Common Microbial Biotechnology Platform (CMBP), Hanoi, Viet Nam
| | - Hoan Thi Phan
- Alliance of Bioversity International and CIAT, Asia hub, Common Microbial Biotechnology Platform (CMBP), Hanoi, Viet Nam
| | - Nghia Khoi Nguyen
- Department of Soil Science, College of Agriculture and Applied Biology, Can Tho University, Viet Nam
| | - Pao Srean
- Faculty of Agriculture and Food Processing, University of Battambang, Battambang, Cambodia
| | - Maw Maw Than
- Department of Agricultural Research, Yezin, NayPyiTaw, Myanmar
| | - Ruan Zhiyong
- Chinese Academy of Agricultural Sciences-CIAT Joint Laboratory in Advanced Technologies for Sustainable Agriculture, Beijing, 100081, PR China
| | - Panlada Tittabutr
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Thailand
| | - Arawan Shutsrirung
- Department of Plant and Soil Science, Faculty of Agriculture, Chiang Mai University, Chiang Mai, Thailand
| | - Lambert Bräu
- School of Life and Environmental Sciences, Faculty of Science, Engineering and Built Environment, Deakin University, Geelong, Australia
| | - Didier Lesueur
- Alliance of Bioversity International and CIAT, Asia hub, Common Microbial Biotechnology Platform (CMBP), Hanoi, Viet Nam; School of Life and Environmental Sciences, Faculty of Science, Engineering and Built Environment, Deakin University, Geelong, Australia; CIRAD, UMR Eco&Sols, Hanoi, Viet Nam; Eco&Sols, Univ Montpellier, CIRAD, INRAE, IRD, Montpellier SupAgro, Montpellier, France.
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78
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Walker L, Lagunas B, Gifford ML. Determinants of Host Range Specificity in Legume-Rhizobia Symbiosis. Front Microbiol 2020; 11:585749. [PMID: 33329456 PMCID: PMC7728800 DOI: 10.3389/fmicb.2020.585749] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/06/2020] [Indexed: 01/24/2023] Open
Abstract
Leguminous plants possess the almost unique ability to enter symbiosis with soil-resident, nitrogen fixing bacteria called rhizobia. During this symbiosis, the bacteria physically colonize specialized organs on the roots of the host plant called nodules, where they reduce atmospheric nitrogen into forms that can be assimilated by the host plant and receive photosynthates in return. In order for nodule development to occur, there is extensive chemical cross-talk between both parties during the formative stages of the symbiosis. The vast majority of the legume family are capable of forming root nodules and typically rhizobia are only able to fix nitrogen within the context of this symbiotic association. However, many legume species only enter productive symbiosis with a few, or even single rhizobial species or strains, and vice-versa. Permitting symbiosis with only rhizobial strains that will be able to fix nitrogen with high efficiency is a crucial strategy for the host plant to prevent cheating by rhizobia. This selectivity is enforced at all stages of the symbiosis, with partner choice beginning during the initial communication between the plant and rhizobia. However, it can also be influenced even once nitrogen-fixing nodules have developed on the root. This review sets out current knowledge about the molecular mechanisms employed by both parties to influence host range during legume-rhizobia symbiosis.
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Affiliation(s)
- Liam Walker
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Beatriz Lagunas
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Miriam L Gifford
- School of Life Sciences, University of Warwick, Coventry, United Kingdom.,Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, United Kingdom
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79
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Sharma M, Sudheer S, Usmani Z, Rani R, Gupta P. Deciphering the Omics of Plant-Microbe Interaction: Perspectives and New Insights. Curr Genomics 2020; 21:343-362. [PMID: 33093798 PMCID: PMC7536805 DOI: 10.2174/1389202921999200515140420] [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: 02/02/2020] [Revised: 03/29/2020] [Accepted: 04/17/2020] [Indexed: 12/19/2022] Open
Abstract
Introduction Plants do not grow in isolation, rather they are hosts to a variety of microbes in their natural environments. While, few thrive in the plants for their own benefit, others may have a direct impact on plants in a symbiotic manner. Unraveling plant-microbe interactions is a critical component in recognizing the positive and negative impacts of microbes on plants. Also, by affecting the environment around plants, microbes may indirectly influence plants. The progress in sequencing technologies in the genomics era and several omics tools has accelerated in biological science. Studying the complex nature of plant-microbe interactions can offer several strategies to increase the productivity of plants in an environmentally friendly manner by providing better insights. This review brings forward the recent works performed in building omics strategies that decipher the interactions between plant-microbiome. At the same time, it further explores other associated mutually beneficial aspects of plant-microbe interactions such as plant growth promotion, nitrogen fixation, stress suppressions in crops and bioremediation; as well as provides better insights on metabolic interactions between microbes and plants through omics approaches. It also aims to explore advances in the study of Arabidopsis as an important avenue to serve as a baseline tool to create models that help in scrutinizing various factors that contribute to the elaborate relationship between plants and microbes. Causal relationships between plants and microbes can be established through systematic gnotobiotic experimental studies to test hypotheses on biologically derived interactions. Conclusion This review will cover recent advances in the study of plant-microbe interactions keeping in view the advantages of these interactions in improving nutrient uptake and plant health.
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Affiliation(s)
- Minaxi Sharma
- 1Department of Food Technology, ACA, Eternal University, Baru Sahib (173001), Himachal Pradesh, India; 2Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, Estonia; 3Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn12612, Estonia; 4Applied Microbiology Laboratory, Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad, India
| | - Surya Sudheer
- 1Department of Food Technology, ACA, Eternal University, Baru Sahib (173001), Himachal Pradesh, India; 2Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, Estonia; 3Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn12612, Estonia; 4Applied Microbiology Laboratory, Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad, India
| | - Zeba Usmani
- 1Department of Food Technology, ACA, Eternal University, Baru Sahib (173001), Himachal Pradesh, India; 2Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, Estonia; 3Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn12612, Estonia; 4Applied Microbiology Laboratory, Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad, India
| | - Rupa Rani
- 1Department of Food Technology, ACA, Eternal University, Baru Sahib (173001), Himachal Pradesh, India; 2Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, Estonia; 3Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn12612, Estonia; 4Applied Microbiology Laboratory, Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad, India
| | - Pratishtha Gupta
- 1Department of Food Technology, ACA, Eternal University, Baru Sahib (173001), Himachal Pradesh, India; 2Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, Estonia; 3Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn12612, Estonia; 4Applied Microbiology Laboratory, Department of Environmental Science and Engineering, Indian Institute of Technology (ISM), Dhanbad, India
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80
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Bloch SE, Clark R, Gottlieb SS, Wood LK, Shah N, Mak SM, Lorigan JG, Johnson J, Davis-Richardson AG, Williams L, McKellar M, Soriano D, Petersen M, Horton A, Smith O, Wu L, Tung E, Broglie R, Tamsir A, Temme K. Biological nitrogen fixation in maize: optimizing nitrogenase expression in a root-associated diazotroph. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4591-4603. [PMID: 32267497 PMCID: PMC7382387 DOI: 10.1093/jxb/eraa176] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 04/09/2020] [Indexed: 05/04/2023]
Abstract
Plants depend upon beneficial interactions between roots and root-associated microorganisms for growth promotion, disease suppression, and nutrient availability. This includes the ability of free-living diazotrophic bacteria to supply nitrogen, an ecological role that has been long underappreciated in modern agriculture for efficient crop production systems. Long-term ecological studies in legume-rhizobia interactions have shown that elevated nitrogen inputs can lead to the evolution of less cooperative nitrogen-fixing mutualists. Here we describe how reprogramming the genetic regulation of nitrogen fixation and assimilation in a novel root-associated diazotroph can restore ammonium production in the presence of exogenous nitrogen inputs. We isolated a strain of the plant-associated proteobacterium Kosakonia sacchari from corn roots, characterized its nitrogen regulatory network, and targeted key nodes for gene editing to optimize nitrogen fixation in corn. While the wild-type strain exhibits repression of nitrogen fixation in conditions replete with bioavailable nitrogen, such as fertilized greenhouse and field experiments, remodeled strains show elevated levels in the rhizosphere of corn in the greenhouse and field even in the presence of exogenous nitrogen. Such strains could be used in commercial applications to supply fixed nitrogen to cereal crops.
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81
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Yadav R, Ror P, Rathore P, Ramakrishna W. Bacteria from native soil in combination with arbuscular mycorrhizal fungi augment wheat yield and biofortification. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 150:222-233. [PMID: 32155450 DOI: 10.1016/j.plaphy.2020.02.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 05/16/2023]
Abstract
Plant growth promoting bacteria (PGPB) have been used to enhance crop productivity. The effect of native PGPB and arbuscular mycorrhizal (AM) fungi in combination on wheat yield, biofortification and soil enzymatic activity is a relatively unexplored area. Twenty seven bacterial isolates from three different soils were characterized for their plant growth promoting traits. A total of three native and five non-native bacteria were used with and without arbuscular mycorrhizal (AM) fungi in an open greenhouse pot experiment with two wheat varieties to evaluate their effect on wheat yield, nutrient uptake, and soil health parameters. Wheat plants subjected to native PGPB (CP4) (Bacillus subtilis) and AM fungi treatment gave the best results with reference to macronutrient (nitrogen and phosphorus), micronutrient (iron and zinc) content in wheat grains and yield-related parameters, including thousand grain weight, number of grains per spike and total tillers per plant in both wheat cultivars. Treatment with CP4 and CP4 plus AM fungi enhanced total chlorophyll in wheat leaves indicating higher photosynthetic activity. Significant improvement in soil health-related parameters, including soil organic matter and dehydrogenase activity, was observed. Significant correlation among grain yield-related parameters, nutrient enhancement, and soil health parameters was observed in PGPB and AM fungi treated plants, especially HD-3086. These results provide a roadmap for utilizing native PGPB and AM fungi for enhancing wheat production in Punjab state of India and exploring their utility in other parts of the country with different soil and environmental conditions.
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Affiliation(s)
| | - Pankaj Ror
- Department of Biochemistry, Central University of Punjab, India
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Pereira NCM, Galindo FS, Gazola RPD, Dupas E, Rosa PAL, Mortinho ES, Filho MCMT. Corn Yield and Phosphorus Use Efficiency Response to Phosphorus Rates Associated With Plant Growth Promoting Bacteria. FRONTIERS IN ENVIRONMENTAL SCIENCE 2020. [DOI: 10.3389/fenvs.2020.00040] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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83
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Doin de Moura GG, Remigi P, Masson-Boivin C, Capela D. Experimental Evolution of Legume Symbionts: What Have We Learnt? Genes (Basel) 2020; 11:E339. [PMID: 32210028 PMCID: PMC7141107 DOI: 10.3390/genes11030339] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
Rhizobia, the nitrogen-fixing symbionts of legumes, are polyphyletic bacteria distributed in many alpha- and beta-proteobacterial genera. They likely emerged and diversified through independent horizontal transfers of key symbiotic genes. To replay the evolution of a new rhizobium genus under laboratory conditions, the symbiotic plasmid of Cupriavidus taiwanensis was introduced in the plant pathogen Ralstonia solanacearum, and the generated proto-rhizobium was submitted to repeated inoculations to the C. taiwanensis host, Mimosa pudica L.. This experiment validated a two-step evolutionary scenario of key symbiotic gene acquisition followed by genome remodeling under plant selection. Nodulation and nodule cell infection were obtained and optimized mainly via the rewiring of regulatory circuits of the recipient bacterium. Symbiotic adaptation was shown to be accelerated by the activity of a mutagenesis cassette conserved in most rhizobia. Investigating mutated genes led us to identify new components of R. solanacearum virulence and C. taiwanensis symbiosis. Nitrogen fixation was not acquired in our short experiment. However, we showed that post-infection sanctions allowed the increase in frequency of nitrogen-fixing variants among a non-fixing population in the M. pudica-C. taiwanensis system and likely allowed the spread of this trait in natura. Experimental evolution thus provided new insights into rhizobium biology and evolution.
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Affiliation(s)
| | | | | | - Delphine Capela
- LIPM, Université de Toulouse, INRAE, CNRS, Castanet-Tolosan 31320, France; (G.G.D.d.M.); (P.R.); (C.M.-B.)
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