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Del Castillo-González L, Soudani S, De La Cruz-Gómez N, Manzanera JA, Berrocal-Lobo M. An improved method to study Phytophthora cinnamomi Rands zoospores interactions with host. BMC PLANT BIOLOGY 2024; 24:508. [PMID: 38844843 PMCID: PMC11154991 DOI: 10.1186/s12870-024-05205-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 05/27/2024] [Indexed: 06/10/2024]
Abstract
Phytophthora cinnamomi Rands is a highly prevalent phytopathogen worldwide, ranking among the top ten in terms of distribution. It inflicts crown rot, canker, and root rot on numerous plant species, significantly impacting the biodiversity of both flora and fauna within affected environments. With a host range spanning over 5,000 species, including important plants like Quercus suber, Quercus ilex, Castanea sativa, and commercially significant crops such as avocado (Persea americana), maize (Zea mays), and tomato (Solanum lycopersicum), Phytophthora cinnamomi poses a substantial threat to agriculture and ecosystems. The efficient dissemination of the oomycete relies on its short-lived asexually motile zoospores, which depend on water currents to infect host roots. However, managing these zoospores in the laboratory has long been challenging due to the complexity of the life cycle. Current protocols involve intricate procedures, including alternating cycles of growth, drought, and flooding. Unfortunately, these artificial conditions often result in a rapid decline in virulence, necessitating additional steps to maintain infectivity during cultivation. In our research, we sought to address this challenge by investigating zoospore survival under various conditions. Our goal was to develop a stable stock of zoospores that is both easily deployable and highly infective. Through direct freezing in liquid nitrogen, we have successfully preserved their virulence. This breakthrough eliminates the need for repeated culture transfers, simplifying the process of plant inoculation. Moreover, it enables more comprehensive studies of Phytophthora cinnamomi and its interactions with host plants.
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Affiliation(s)
- Lucía Del Castillo-González
- Centro para la Biodiversidad y Desarrollo Sostenible (CBDS), ETSIMontes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, Madrid, 28040, Spain
| | - Serine Soudani
- Centro para la Biodiversidad y Desarrollo Sostenible (CBDS), ETSIMontes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, Madrid, 28040, Spain
| | - Noelia De La Cruz-Gómez
- Centro para la Biodiversidad y Desarrollo Sostenible (CBDS), ETSIMontes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, Madrid, 28040, Spain
| | - José Antonio Manzanera
- Centro para la Biodiversidad y Desarrollo Sostenible (CBDS), ETSIMontes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, Madrid, 28040, Spain
| | - Marta Berrocal-Lobo
- Centro para la Biodiversidad y Desarrollo Sostenible (CBDS), ETSIMontes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, Ciudad Universitaria s/n, Madrid, 28040, Spain.
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Li C, Liao H, Xu L, Wang C, Yao M, Wang J, Li X. Comparative genomics reveals the adaptation of ammonia-oxidising Thaumarchaeota to arid soils. Environ Microbiol 2024; 26:e16601. [PMID: 38454574 DOI: 10.1111/1462-2920.16601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 02/09/2024] [Indexed: 03/09/2024]
Abstract
Thaumarchaeota are predominant in oligotrophic habitats such as deserts and arid soils, but their adaptations to these arid conditions are not well understood. In this study, we assembled 23 Thaumarchaeota genomes from arid and semi-arid soils collected from the Inner Mongolia Steppe and the Qinghai-Tibet Plateau. Using a comparative genomics approach, integrated with 614 Thaumarchaeota genomes from public databases, we identified the traits and evolutionary forces that contribute to their adaptations to aridity. Our results showed that the newly assembled genomes represent an early diverging group within the lineage of ammonia-oxidising Thaumarchaeota. While the genomic functions previously identified in arid soil lineages were conserved across terrestrial, shallow-ocean and deep-ocean lineages, several traits likely contribute to Thaumarchaeota's adaptation to aridity. These include chlorite dismutase, arsenate reductase, V-type ATPase and genes dealing with oxidative stresses. The acquisition and loss of traits at the last common ancestor of arid soil lineages may have facilitated the specialisation of Thaumarchaeota in arid soils. Additionally, the acquisition of unique adaptive traits, such as a urea transporter, Ca2+ :H+ antiporter, mannosyl-3-phosphoglycerate synthase and phosphatase, DNA end-binding protein Ku and phage shock protein A, further distinguishes arid soil Thaumarchaeota. This study provides evidence for the adaptations of Thaumarchaeota to arid soil, enhancing our understanding of the nitrogen and carbon cycling driven by Thaumarchaeota in drylands.
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Affiliation(s)
- Chaonan Li
- Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, China
| | - Haijun Liao
- Engineering Research Center of Chuanxibei RHS Construction at Mianyang Normal University of Sichuan Province, Mianyang Normal University, Mianyang, China
| | - Lin Xu
- National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River & Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - Changting Wang
- Institute of Qinghai-Tibet Plateau, Southwest Minzu University, Chengdu, China
| | - Minjie Yao
- Engineering Research Center of Soil Remediation of Fujian Province University, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Junming Wang
- Section of Climate Science, Illinois State Water Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA
| | - Xiangzhen Li
- Engineering Research Center of Soil Remediation of Fujian Province University, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
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Silva JPD, Veloso TGR, Costa MD, Souza JJLLD, Soares EMB, Gomes LC, Schaefer CEGR. Microbial successional pattern along a glacier retreat gradient from Byers Peninsula, Maritime Antarctica. ENVIRONMENTAL RESEARCH 2024; 241:117548. [PMID: 37939803 DOI: 10.1016/j.envres.2023.117548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/10/2023]
Abstract
The retreat of glaciers in Antarctica has increased in the last decades due to global climate change, influencing vegetation expansion, and soil physico-chemical and biological attributes. However, little is known about soil microbiology diversity in these periglacial landscapes. This study characterized and compared bacterial and fungal diversity using metabarcoding of soil samples from the Byers Peninsula, Maritime Antarctica. We identified bacterial and fungal communities by amplification of bacterial 16 S rRNA region V3-V4 and fungal internal transcribed spacer 1 (ITS1). We also applied 14C dating on soil organic matter (SOM) from six profiles. Physico-chemical analyses and attributes associated with SOM were evaluated. A total of 14,048 bacterial ASVs were obtained, and almost all samples had 50% of their sequences assigned to Actinobacteriota and Proteobacteria. Regarding the fungal community, Mortierellomycota, Ascomycota and Basidiomycota were the main phyla from 1619 ASVs. We found that soil age was more relevant than the distance from the glacier, with the oldest soil profile (late Holocene soil profile) hosting the highest bacterial and fungal diversity. The microbial indices of the fungal community were correlated with nutrient availability, soil reactivity and SOM composition, whereas the bacterial community was not correlated with any soil attribute. The bacterial diversity, richness, and evenness varied according to presence of permafrost and moisture regime. The fungal community richness in the surface horizon was not related to altitude, permafrost, or moisture regime. The soil moisture regime was crucial for the structure, high diversity and richness of the microbial community, specially to the bacterial community. Further studies should examine the relationship between microbial communities and environmental factors to better predict changes in this terrestrial ecosystem.
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Affiliation(s)
- Jônatas Pedro da Silva
- Graduate Program in Soils and Plant Nutrition, Soil Science Department, Universidade Federal de Viçosa - UFV, Viçosa, MG, Brazil; Soil Science Department, Universidade Federal de Viçosa - UFV, Viçosa, MG, Brazil
| | | | - Maurício Dutra Costa
- Microbiology Department, Universidade Federal de Viçosa - UFV, Viçosa, MG, Brazil; Bolsista Pesquisador Do Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, Brasília, DF, Brazil
| | - José João Lelis Leal de Souza
- Soil Science Department, Universidade Federal de Viçosa - UFV, Viçosa, MG, Brazil; Bolsista Pesquisador Do Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, Brasília, DF, Brazil
| | | | | | - Carlos Ernesto G R Schaefer
- Soil Science Department, Universidade Federal de Viçosa - UFV, Viçosa, MG, Brazil; Bolsista Pesquisador Do Conselho Nacional de Desenvolvimento Científico e Tecnológico, CNPq, Brasília, DF, Brazil
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Bao C, Li M, Zhao X, Shi J, Liu Y, Zhang N, Zhou Y, Ma J, Chen G, Zhang S, Chen H. Mining of key genes for cold adaptation from Pseudomonas fragi D12 and analysis of its cold-adaptation mechanism. Front Microbiol 2023; 14:1215837. [PMID: 37485517 PMCID: PMC10358777 DOI: 10.3389/fmicb.2023.1215837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 06/21/2023] [Indexed: 07/25/2023] Open
Abstract
The psychrotroph Pseudomonas fragi D12, which grew strongly under low temperatures, was screened from tundra soil collected from the permanent alpine zone on Changbai Mountain. To mine the genes critical for cold tolerance and to investigate the cold-adaptation mechanism, whole-genome sequencing, comparative genomic analysis, and transcriptome analysis were performed with P. fragi. A total of 124 potential cold adaptation genes were identified, including nineteen unique cold-adaptive genes were detected in the genome of P. fragi D12. Three unique genes associated with pili protein were significantly upregulated at different degrees of low temperature, which may be the key to the strong low-temperature adaptability of P. fragi D12. Meanwhile, we were pleasantly surprised to find that Pseudomonas fragi D12 exhibited different cold-adaptation mechanisms under different temperature changes. When the temperature declined from 30°C to 15°C, the response included maintenance of the fluidity of cell membranes, increased production of extracellular polymers, elevation in the content of compatibility solutes, and reduction in the content of reactive oxygen species, thereby providing a stable metabolic environment. When the temperature decreased from 15°C to 4°C, the response mainly included increases in the expression of molecular chaperones and transcription factors, enabling the bacteria to restore normal transcription and translation. The response mechanism of P. fragi D12 to low-temperature exposure is discussed. The results provide new ideas for the cold-adaptation mechanism of cold-tolerant microorganisms.
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Affiliation(s)
- Changjie Bao
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Muzi Li
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Xuhui Zhao
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Jia Shi
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Yehui Liu
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Na Zhang
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Yuqi Zhou
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Jie Ma
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Guang Chen
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
| | - Sitong Zhang
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, China
| | - Huan Chen
- Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation, Ministry of Education, Changchun, China
- College of Life Science, Jilin Agricultural University, Changchun, China
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Barros-Rodríguez A, García-Gálvez C, Pacheco P, Kalyuzhnaya MG, Manzanera M. Isolation of Methane Enriched Bacterial Communities and Application as Wheat Biofertilizer under Drought Conditions: An Environmental Contribution. PLANTS (BASEL, SWITZERLAND) 2023; 12:2487. [PMID: 37447048 DOI: 10.3390/plants12132487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023]
Abstract
The search for methanotrophs as plant-growth-promoting rhizobacteria (PGPR) presents an important contribution to mitigating the impact of global warming by restoring the natural soil potential for consuming methane while benefiting plants during droughts. Our in silico simulations suggest that water, produced as a byproduct of methane oxidation, can satisfy the cell growth requirement. In addition to water, methanotrophs can produce metabolites that stimulate plant growth. Considering this, we proposed that applying methanotrophs as PGPR can alleviate the effect of droughts on crops, while stimulating atmospheric methane consumption. In this work, we isolated a series of methanotrophic communities from the rhizospheres of different crops, including Italian sweet pepper and zucchini, using an atmosphere enriched with pure methane gas, to determine their potential for alleviating drought stress in wheat plants. Subsequently, 23 strains of nonmethanotrophic bacteria present in the methanotrophic communities were isolated and characterized. We then analyzed the contribution of the methane-consuming consortia to the improvement of plant growth under drought conditions, showing that some communities contributed to increases in the wheat plants' lengths and weights, with statistically significant differences according to ANOVA models. Furthermore, we found that the presence of methane gas can further stimulate the plant-microbe interactions, resulting in larger plants and higher drought tolerance.
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Affiliation(s)
- Adoración Barros-Rodríguez
- Institute for Water Research and Department of Microbiology, University of Granada, 18071 Granada, Spain
- VitaNtech Biotechnology S.L., 18008 Granada, Spain
| | - Carlos García-Gálvez
- Institute for Water Research and Department of Microbiology, University of Granada, 18071 Granada, Spain
- VitaNtech Biotechnology S.L., 18008 Granada, Spain
| | - Pamela Pacheco
- Institute for Water Research and Department of Microbiology, University of Granada, 18071 Granada, Spain
| | | | - Maximino Manzanera
- Institute for Water Research and Department of Microbiology, University of Granada, 18071 Granada, Spain
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6
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Shree B, Jayakrishnan U, Bhushan S. Impact of key parameters involved with plant-microbe interaction in context to global climate change. Front Microbiol 2022; 13:1008451. [PMID: 36246210 PMCID: PMC9561941 DOI: 10.3389/fmicb.2022.1008451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
Anthropogenic activities have a critical influence on climate change that directly or indirectly impacts plant and microbial diversity on our planet. Due to climate change, there is an increase in the intensity and frequency of extreme environmental events such as temperature rise, drought, and precipitation. The increase in greenhouse gas emissions such as CO2, CH4, NOx, water vapor, increase in global temperature, and change in rainfall patterns have impacted soil–plant-microbe interactions, which poses a serious threat to food security. Microbes in the soil play an essential role in plants’ resilience to abiotic and biotic stressors. The soil microbial communities are sensitive and responsive to these stressors. Therefore, a systemic approach to climate adaptation will be needed which acknowledges the multidimensional nature of plant-microbe-environment interactions. In the last two scores of years, there has been an enhancement in the understanding of plant’s response to microbes at physiological, biochemical, and molecular levels due to the availability of techniques and tools. This review highlights some of the critical factors influencing plant-microbe interactions under stress. The association and response of microbe and plants as a result of several stresses such as temperature, salinity, metal toxicity, and greenhouse gases are also depicted. New tools to study the molecular complexity of these interactions, such as genomic and sequencing approaches, which provide researchers greater accuracy, reproducibility, and flexibility for exploring plant-microbe–environment interactions under a changing climate, are also discussed in the review, which will be helpful in the development of resistant crops/plants in present and future.
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Affiliation(s)
- Bharti Shree
- Department of Agricultural Biotechnology, College of Agriculture, Chaudhary Sarwan Kumar Himachal Pradesh Krishi Vishvavidyalaya, Palampur, India
| | | | - Shashi Bhushan
- Department of Agriculture and Biosystem Engineering, North Dakota State University, Fargo, ND, United States
- *Correspondence: Shashi Bhushan,
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Sibanda T, Buys EM. Listeria monocytogenes Pathogenesis: The Role of Stress Adaptation. Microorganisms 2022; 10:microorganisms10081522. [PMID: 36013940 PMCID: PMC9416357 DOI: 10.3390/microorganisms10081522] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/08/2022] [Accepted: 07/19/2022] [Indexed: 12/13/2022] Open
Abstract
Adaptive stress tolerance responses are the driving force behind the survival ability of Listeria monocytogenes in different environmental niches, within foods, and ultimately, the ability to cause human infections. Although the bacterial stress adaptive responses are primarily a necessity for survival in foods and the environment, some aspects of the stress responses are linked to bacterial pathogenesis. Food stress-induced adaptive tolerance responses to acid and osmotic stresses can protect the pathogen against similar stresses in the gastrointestinal tract (GIT) and, thus, directly aid its virulence potential. Moreover, once in the GIT, the reprogramming of gene expression from the stress survival-related genes to virulence-related genes allows L. monocytogenes to switch from an avirulent to a virulent state. This transition is controlled by two overlapping and interlinked transcriptional networks for general stress response (regulated by Sigma factor B, (SigB)) and virulence (regulated by the positive regulatory factor A (PrfA)). This review explores the current knowledge on the molecular basis of the connection between stress tolerance responses and the pathogenesis of L. monocytogenes. The review gives a detailed background on the currently known mechanisms of pathogenesis and stress adaptation. Furthermore, the paper looks at the current literature and theories on the overlaps and connections between the regulatory networks for SigB and PrfA.
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Affiliation(s)
- Thulani Sibanda
- Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa;
- Department of Applied Biology and Biochemistry, National University of Science and Technology, Bulawayo P.O. Box AC939, Zimbabwe
| | - Elna M. Buys
- Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa;
- Correspondence:
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Seed-Encapsulation of Desiccation-Tolerant Microorganisms for the Protection of Maize from Drought: Phenotyping Effects of a New Dry Bioformulation. PLANTS 2022; 11:plants11081024. [PMID: 35448752 PMCID: PMC9024790 DOI: 10.3390/plants11081024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 11/20/2022]
Abstract
Droughts and high temperatures deeply affect crop production. The use of desiccation-tolerant (or xerotolerant) microorganisms able to protect plants from droughts represents a promising alternative. These xerotolerant microorganisms have previously been used to modulate plant responses and improve their tolerance to drought. In addition, these microorganisms could be stored and used in dry formats, which would improve their viability and resilience at a much lower cost than current market alternatives. In the present study we analyze the possibility of using strains of xerotolerant Actinobacteria in encapsulated format on seeds. Under this formulation, we carried out greenhouse with farming soil with maize plants. Under greenhouse conditions, the plants showed greater resistance to drought, as well as increased growth and production yield, but not as well in field trials. This alternative could represent a useful tool to improve water efficiency in crops for drought-affected areas or affected by water scarcity.
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Plant Tolerance to Drought Stress in the Presence of Supporting Bacteria and Fungi: An Efficient Strategy in Horticulture. HORTICULTURAE 2021. [DOI: 10.3390/horticulturae7100390] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Increasing temperature leads to intensive water evaporation, contributing to global warming and consequently leading to drought stress. These events are likely to trigger modifications in plant physiology and microbial functioning due to the altered availability of nutrients. Plants exposed to drought have developed different strategies to cope with stress by morphological, physiological, anatomical, and biochemical responses. First, visible changes influence plant biomass and consequently limit the yield of crops. The presented review was undertaken to discuss the impact of climate change with respect to drought stress and its impact on the performance of plants inoculated with plant growth-promoting microorganisms (PGPM). The main challenge for optimal performance of horticultural plants is the application of selected, beneficial microorganisms which actively support plants during drought stress. The most frequently described biochemical mechanisms for plant protection against drought by microorganisms are the production of phytohormones, antioxidants and xeroprotectants, and the induction of plant resistance. Rhizospheric or plant surface-colonizing (rhizoplane) and interior (endophytic) bacteria and fungi appear to be a suitable alternative for drought-stress management. Application of various biopreparations containing PGPM seems to provide hope for a relatively cheap, easy to apply and efficient way of alleviating drought stress in plants, with implications in productivity and food condition.
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10
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Deep-Sea Actinobacteria Mitigate Salinity Stress in Tomato Seedlings and Their Biosafety Testing. PLANTS 2021; 10:plants10081687. [PMID: 34451732 PMCID: PMC8401925 DOI: 10.3390/plants10081687] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/04/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022]
Abstract
Soil salinity is an enormous problem affecting global agricultural productivity. Deep-sea actinobacteria are interesting due to their salt tolerance mechanisms. In the present study, we aim to determine the ability of deep-sea Dermacoccus (D. barathri MT2.1T and D. profundi MT2.2T) to promote tomato seedlings under 150 mM NaCl compared with the terrestrial strain D. nishinomiyaensis DSM20448T. All strains exhibit in vitro plant growth-promoting traits of indole-3-acetic acid production, phosphate solubilization, and siderophore production. Tomato seedlings inoculated with D. barathri MT2.1T showed higher growth parameters (shoot and root length, dry weight, and chlorophyll content) than non-inoculated tomato and the terrestrial strain under 150 mM NaCl. In addition, hydrogen peroxide (H2O2) in leaves of tomatoes inoculated with deep-sea Dermacoccus was lower than the control seedlings. This observation suggested that deep-sea Dermacoccus mitigated salt stress by reducing oxidative stress caused by hydrogen peroxide. D. barathri MT2.1T showed no harmful effects on Caenorhabditis elegans, Daphnia magna, Eisenia foetida, and Escherichia coli MC4100 in biosafety tests. This evidence suggests that D. barathri MT2.1T would be safe for use in the environment. Our results highlight the potential of deep-sea Dermacoccus as a plant growth promoter for tomatoes under salinity stress.
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Bosch J, Varliero G, Hallsworth JE, Dallas TD, Hopkins D, Frey B, Kong W, Lebre P, Makhalanyane TP, Cowan DA. Microbial anhydrobiosis. Environ Microbiol 2021; 23:6377-6390. [PMID: 34347349 DOI: 10.1111/1462-2920.15699] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/29/2021] [Accepted: 07/31/2021] [Indexed: 12/28/2022]
Abstract
The loss of cellular water (desiccation) and the resulting low cytosolic water activity are major stress factors for life. Numerous prokaryotic and eukaryotic taxa have evolved molecular and physiological adaptions to periods of low water availability or water-limited environments that occur across the terrestrial Earth. The changes within cells during the processes of desiccation and rehydration, from the activation (and inactivation) of biosynthetic pathways to the accumulation of compatible solutes, have been studied in considerable detail. However, relatively little is known on the metabolic status of organisms in the desiccated state; that is, in the sometimes extended periods between the drying and rewetting phases. During these periods, which can extend beyond decades and which we term 'anhydrobiosis', organismal survival could be dependent on a continued supply of energy to maintain the basal metabolic processes necessary for critical functions such as macromolecular repair. Here, we review the state of knowledge relating to the function of microorganisms during the anhydrobiotic state, highlighting substantial gaps in our understanding of qualitative and quantitative aspects of molecular and biochemical processes in desiccated cells.
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Affiliation(s)
- Jason Bosch
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0002, South Africa
| | - Gilda Varliero
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0002, South Africa
| | - John E Hallsworth
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland, BT9 5DL, UK
| | - Tiffany D Dallas
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, Northern Ireland, BT9 5DL, UK
| | | | - Beat Frey
- Rhizosphere Processes Group, Swiss Federal Research Institute WSL, Birmensdorf, 8903, Switzerland
| | - Weidong Kong
- State Key Laboratory of Tibetan Plateau Earth System Science (LATPES), Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing, 100101, China
| | - Pedro Lebre
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0002, South Africa
| | - Thulani P Makhalanyane
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0002, South Africa
| | - Don A Cowan
- Centre for Microbial Ecology and Genomics, Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, 0002, South Africa
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12
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Morcillo RJL, Manzanera M. The Effects of Plant-Associated Bacterial Exopolysaccharides on Plant Abiotic Stress Tolerance. Metabolites 2021; 11:337. [PMID: 34074032 PMCID: PMC8225083 DOI: 10.3390/metabo11060337] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 11/16/2022] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) are beneficial soil microorganisms that can stimulate plant growth and increase tolerance to biotic and abiotic stresses. Some PGPR are capable of secreting exopolysaccharides (EPS) to protect themselves and, consequently, their plant hosts against environmental fluctuations and other abiotic stresses such as drought, salinity, or heavy metal pollution. This review focuses on the enhancement of plant abiotic stress tolerance by bacterial EPS. We provide a comprehensive summary of the mechanisms through EPS to alleviate plant abiotic stress tolerance, including salinity, drought, temperature, and heavy metal toxicity. Finally, we discuss how these abiotic stresses may affect bacterial EPS production and its role during plant-microbe interactions.
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Affiliation(s)
- Rafael J L Morcillo
- Institute for Water Research, Department of Microbiology, University of Granada, 18003 Granada, Spain
| | - Maximino Manzanera
- Institute for Water Research, Department of Microbiology, University of Granada, 18003 Granada, Spain
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Frey B, Walthert L, Perez-Mon C, Stierli B, Köchli R, Dharmarajah A, Brunner I. Deep Soil Layers of Drought-Exposed Forests Harbor Poorly Known Bacterial and Fungal Communities. Front Microbiol 2021; 12:674160. [PMID: 34025630 PMCID: PMC8137989 DOI: 10.3389/fmicb.2021.674160] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/12/2021] [Indexed: 12/31/2022] Open
Abstract
Soil microorganisms such as bacteria and fungi play important roles in the biogeochemical cycling of soil nutrients, because they act as decomposers or are mutualistic or antagonistic symbionts, thereby influencing plant growth and health. In the present study, we investigated the vertical distribution of the soil microbiome to a depth of 2 m in Swiss drought-exposed forests of European beech and oaks on calcareous bedrock. We aimed to disentangle the effects of soil depth, tree (beech, oak), and substrate (soil, roots) on microbial abundance, diversity, and community structure. With increasing soil depth, organic carbon, nitrogen, and clay content decreased significantly. Similarly, fine root biomass, microbial biomass (DNA content, fungal abundance), and microbial alpha-diversity decreased and were consequently significantly related to these physicochemical parameters. In contrast, bacterial abundance tended to increase with soil depth, and the bacteria to fungi ratio increased significantly with greater depth. Tree species was only significantly related to the fungal Shannon index but not to the bacterial Shannon index. Microbial community analyses revealed that bacterial and fungal communities varied significantly across the soil layers, more strongly for bacteria than for fungi. Both communities were also significantly affected by tree species and substrate. In deep soil layers, poorly known bacterial taxa from Nitrospirae, Chloroflexi, Rokubacteria, Gemmatimonadetes, Firmicutes and GAL 15 were overrepresented. Furthermore, archaeal phyla such as Thaumarchaeota and Euryarchaeota were more abundant in subsoils than topsoils. Fungal taxa that were predominantly found in deep soil layers belong to the ectomycorrhizal Boletus luridus and Hydnum vesterholtii. Both taxa are reported for the first time in such deep soil layers. Saprotrophic fungal taxa predominantly recorded in deep soil layers were unknown species of Xylaria. Finally, our results show that the microbial community structure found in fine roots was well represented in the bulk soil. Overall, we recorded poorly known bacterial and archaeal phyla, as well as ectomycorrhizal fungi that were not previously known to colonize deep soil layers. Our study contributes to an integrated perspective on the vertical distribution of the soil microbiome at a fine spatial scale in drought-exposed forests.
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Affiliation(s)
- Beat Frey
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Lorenz Walthert
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Carla Perez-Mon
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Beat Stierli
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Roger Köchli
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Alexander Dharmarajah
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Ivano Brunner
- Forest Soils and Biogeochemistry, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
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