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Bi YL, Tan H, Zhang SS, Kang JP. Response Mechanism of Extracellular Polymeric Substances Synthesized by Alternaria sp. on Drought Stress in Alfalfa ( Medicago sativa L.). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 39021158 DOI: 10.1021/acs.jafc.4c04009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
This study investigates how extracellular polymeric substances (EPS) synthesized by dark septate endophytic (DSE) improve alfalfa's drought resistance. Drought stress was simulated in hydroponic culture, and roots were treated with different EPS concentrations to determine their effects on drought tolerance and applicable concentrations. Hydroponic solutions with 0.25 and 0.50% EPS concentrations alleviated leaf wilting and increased total plant fresh weight by 35.8 and 57.7%, respectively. SEM shows that EPS attached to the roots and may have served to protect the root system. EPS treatment significantly depressed the MDA contents of the roots, stems, and leaves. Roots responded to drought stress by increasing soluble sugar contents and antioxidant enzyme activities, while mitigating stem and leaf stress by synthesizing lipid compounds, amino acids, and organic acid metabolites. Five metabolites in the stem have been reported to be associated with plant stress tolerance and growth, namely 3-O-methyl 5-O-(2-methyl propyl) (4S)-2,6-dimethyl-4-(2-nitrophenyl)-3,4-dihydropyridine-3,5-dicarboxylate, malic acid, PA (20:1(11Z)/15:0), N-methyl-4,6,7-trihydroxy-1,2,3,4-tetrahydroisoquinoline, and 2-(S-glutathionyl) acetyl glutathione. In summary, EPS treatment induced oxidative stress and altered plant metabolism, and this in turn increased plant antioxidant capacity. The results provide a theoretical basis for the application of EPS in commercial products that increase plant resistance and ecological restoration.
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Affiliation(s)
- Yin-Li Bi
- Institute of Ecological and Environment Restoration in Mine Areas of West China, Xi'an University of Science and Technology, Xi'an 710054, China
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology (Beijing), Beijing 100083, China
| | - Hai Tan
- Institute of Ecological and Environment Restoration in Mine Areas of West China, Xi'an University of Science and Technology, Xi'an 710054, China
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China
| | - Shi-Shuang Zhang
- Institute of Ecological and Environment Restoration in Mine Areas of West China, Xi'an University of Science and Technology, Xi'an 710054, China
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China
| | - Jia-Peng Kang
- Institute of Ecological and Environment Restoration in Mine Areas of West China, Xi'an University of Science and Technology, Xi'an 710054, China
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China
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Alam M, Pandit B, Moin A, Iqbal UN. Invisible Inhabitants of Plants and a Sustainable Planet: Diversity of Bacterial Endophytes and their Potential in Sustainable Agriculture. Indian J Microbiol 2024; 64:343-366. [PMID: 39011025 PMCID: PMC11246410 DOI: 10.1007/s12088-024-01225-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 02/07/2024] [Indexed: 07/17/2024] Open
Abstract
Uncontrolled usage of chemical fertilizers, climate change due to global warming, and the ever-increasing demand for food have necessitated sustainable agricultural practices. Removal of ever-increasing environmental pollutants, treatment of life-threatening diseases, and control of drug-resistant pathogens are also the need of the present time to maintain the health and hygiene of nature, as well as human beings. Research on plant-microbe interactions is paving the way to ameliorate all these sustainably. Diverse bacterial endophytes inhabiting the internal tissues of different parts of the plants promote the growth and development of their hosts by different mechanisms, such as through nutrient acquisition, phytohormone production and modulation, protection from biotic or abiotic challenges, assisting in flowering and root development, etc. Notwithstanding, efficient exploitation of endophytes in human welfare is hindered due to scarce knowledge of the molecular aspects of their interactions, community dynamics, in-planta activities, and their actual functional potential. Modern "-omics-based" technologies and genetic manipulation tools have empowered scientists to explore the diversity, dynamics, roles, and functional potential of endophytes, ultimately empowering humans to better use them in sustainable agricultural practices, especially in future harsh environmental conditions. In this review, we have discussed the diversity of bacterial endophytes, factors (biotic as well as abiotic) affecting their diversity, and their various plant growth-promoting activities. Recent developments and technological advancements for future research, such as "-omics-based" technologies, genetic engineering, genome editing, and genome engineering tools, targeting optimal utilization of the endophytes in sustainable agricultural practices, or other purposes, have also been discussed.
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Affiliation(s)
- Masrure Alam
- Microbial Ecology and Physiology Lab, Department of Biological Sciences, Aliah University, IIA/27 New Town, Kolkata, West Bengal 700160 India
| | - Baishali Pandit
- Microbial Ecology and Physiology Lab, Department of Biological Sciences, Aliah University, IIA/27 New Town, Kolkata, West Bengal 700160 India
- Department of Botany, Surendranath College, 24/2 MG Road, Kolkata, West Bengal 700009 India
| | - Abdul Moin
- Microbial Ecology and Physiology Lab, Department of Biological Sciences, Aliah University, IIA/27 New Town, Kolkata, West Bengal 700160 India
| | - Umaimah Nuzhat Iqbal
- Microbial Ecology and Physiology Lab, Department of Biological Sciences, Aliah University, IIA/27 New Town, Kolkata, West Bengal 700160 India
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Zhao Y, Ding WJ, Xu L, Sun JQ. A comprehensive comparative genomic analysis revealed that plant growth promoting traits are ubiquitous in strains of Stenotrophomonas. Front Microbiol 2024; 15:1395477. [PMID: 38817968 PMCID: PMC11138164 DOI: 10.3389/fmicb.2024.1395477] [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: 03/05/2024] [Accepted: 04/29/2024] [Indexed: 06/01/2024] Open
Abstract
Stenotrophomonas strains, which are often described as plant growth promoting (PGP) bacteria, are ubiquitous in many environments. A total of 213 genomes of strains of Stenotrophomonas were analyzed using comparative genomics to better understand the ecological roles of these bacteria in the environment. The pan-genome of the 213 strains of Stenotrophomonas consists of 27,186 gene families, including 710 core gene families, 11,039 unique genes and 15,437 accessory genes. Nearly all strains of Stenotrophomonas harbor the genes for GH3-family cellulose degradation and GH2- and GH31-family hemicellulose hydrolase, as well as intact glycolysis and tricarboxylic acid cycle pathways. These abilities suggest that the strains of this genus can easily obtain carbon and energy from the environment. The Stenotrophomonas strains can respond to oxidative stress by synthesizing catalase, superoxide dismutase, methionine sulfoxide reductase, and disulfide isomerase, as well as managing their osmotic balance by accumulating potassium and synthesizing compatible solutes, such as betaine, trehalose, glutamate, and proline. Each Stenotrophomonas strain also contains many genes for resistance to antibiotics and heavy metals. These genes that mediate stress tolerance increase the ability of Stenotrophomonas strains to survive in extreme environments. In addition, many functional genes related to attachment and plant colonization, growth promotion and biocontrol were identified. In detail, the genes associated with flagellar assembly, motility, chemotaxis and biofilm formation enable the strains of Stenotrophomonas to effectively colonize host plants. The presence of genes for phosphate-solubilization and siderophore production and the polyamine, indole-3-acetic acid, and cytokinin biosynthetic pathways confer the ability to promote plant growth. These strains can produce antimicrobial compounds, chitinases, lipases and proteases. Each Stenotrophomonas genome contained 1-9 prophages and 17-60 genomic islands, and the genes related to antibiotic and heavy metal resistance and the biosynthesis of polyamines, indole-3-acetic acid, and cytokinin may be acquired by horizontal gene transfer. This study demonstrates that strains of Stenotrophomonas are highly adaptable for different environments and have strong potential for use as plant growth-promoting bacteria.
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Affiliation(s)
- Yang Zhao
- Lab for Microbial Resources, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Wen-Jing Ding
- Lab for Microbial Resources, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
| | - Lian Xu
- Jiangsu Key Lab for Organic Solid Waste Utilization, Educational Ministry Engineering Center of Resource-saving Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
| | - Ji-Quan Sun
- Lab for Microbial Resources, School of Ecology and Environment, Inner Mongolia University, Hohhot, China
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Huang D, Sun X, Ghani MU, Li B, Yang J, Chen Z, Kong T, Xiao E, Liu H, Wang Q, Sun W. Bacteria associated with Comamonadaceae are key arsenite oxidizer associated with Pteris vittata root. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 349:123909. [PMID: 38582183 DOI: 10.1016/j.envpol.2024.123909] [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: 12/28/2023] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 04/08/2024]
Abstract
Pteris vittata (P. vittata), an arsenic (As) hyperaccumulator commonly used in the phytoremediation of As-contaminated soils, contains root-associated bacteria (RAB) including those that colonize the root rhizosphere and endosphere, which can adapt to As contamination and improve plant health. As(III)-oxidizing RAB can convert the more toxic arsenite (As(III)) to less toxic arsenate (As(V)) under As-rich conditions, which may promote plant survial. Previous studies have shown that microbial As(III) oxidation occurs in the rhizospheres and endospheres of P. vittata. However, knowledge of RAB of P. vittata responsible for As(III) oxidation remained limited. In this study, members of the Comamonadaceae family were identified as putative As(III) oxidizers, and the core microbiome associated with P. vittata roots using DNA-stable isotope probing (SIP), amplicon sequencing and metagenomic analysis. Metagenomic binning revealed that metagenome assembled genomes (MAGs) associated with Comamonadaceae contained several functional genes related to carbon fixation, arsenic resistance, plant growth promotion and bacterial colonization. As(III) oxidation and plant growth promotion may be key features of RAB in promoting P. vittata growth. These results extend the current knowledge of the diversity of As(III)-oxidizing RAB and provide new insights into improving the efficiency of arsenic phytoremediation.
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Affiliation(s)
- Duanyi Huang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Xiaoxu Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Muhammad Usman Ghani
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan
| | - Baoqin Li
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Jinchan Yang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; School of Environment, Henan Normal University, Xinxiang 453007, China
| | - Zhenyu Chen
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; School of Environment, Henan Normal University, Xinxiang 453007, China
| | - Tianle Kong
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
| | - Enzong Xiao
- Key Laboratory of Water Quality and Conservation in the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Huaqing Liu
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Qi Wang
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China
| | - Weimin Sun
- National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
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Zhang B, Zhang J, Wang Y, Qu J, Jiang Z, Zhang X, Tao Y, Wang Y, Kang Z, Han S, Zhang J, Zhang Y. Biodegradation of atrazine with biochar-mediated functional bacterial biofilm: Construction, characterization and mechanisms. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133237. [PMID: 38113741 DOI: 10.1016/j.jhazmat.2023.133237] [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: 09/20/2023] [Revised: 11/05/2023] [Accepted: 12/10/2023] [Indexed: 12/21/2023]
Abstract
The abuse and residue of herbicides in the black soil area had seriously affected the soil structure, function and crop growth, posing severe threats to agricultural soil environment and public health. Given the limitation of routine microbial remediation, innovative and eco-friendly functional bacterial biofilm which could adapt under adverse conditions was developed on the biochar to investigate its enhanced bioremediation and metabolic characteristics of typical herbicide atrazine. Results revealed that the atrazine degrading strain Acinetobacter lwoffii had competitive advantage in soil indigenous microorganisms and formed dense biofilms on the biochar which was beneficial to cell viability maintenance and aggregations. Metatranscriptomics and RT-qPCR analysis demonstrated that the biochar-mediated biofilm improved the frequency of intercellular communications through quorum sensing and two-component signal regulation systems, and enhanced the atrazine biodegradation efficiency through horizontal gene transfer in co-metabolism mode, providing important scientific basis for the biological remediation of farmland soil non-point source pollution.
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Affiliation(s)
- Bo Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Jingdan Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Yuping Wang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Jianhua Qu
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Zhao Jiang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Xu Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Yue Tao
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Yifan Wang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Zhonghui Kang
- Longjiang Environmental Protection Group Co.,Ltd., Harbin 150050, PR China
| | - Songting Han
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Jingyi Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China
| | - Ying Zhang
- School of Resources and Environment, Northeast Agricultural University, Harbin 150030, PR China.
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Fu B, Yan Q. Exopolysaccharide is required for motility, stress tolerance, and plant colonization by the endophytic bacterium Paraburkholderia phytofirmans PsJN. Front Microbiol 2023; 14:1218653. [PMID: 37670984 PMCID: PMC10475733 DOI: 10.3389/fmicb.2023.1218653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 07/24/2023] [Indexed: 09/07/2023] Open
Abstract
Paraburkholderia phytofirmans PsJN is an endophytic bacterium and has been shown to promote the growth and health of many different plants. Exopolysaccharide (EPS) plays important roles in plant-bacteria interaction and tolerance to environmental stresses. However, the function of EPS in PsJN and its interaction with plants remain largely unknown. In this study, a deletion mutation of bceQ gene, encoding a putative flippase for the EPS biosynthesis, was introduced in the genome of PsJN. The ΔbceQ mutant produced a significantly lower level of EPS than the wild type strain in culture media. Compared to the wild type PsJN, the ΔbceQ mutant was more sensitive to desiccation, UV damage, salt (NaCl) and iron (FeCl3) stresses, and bacteriophage infection. More importantly, the mutation of bceQ decreased the endophytic colonization of PsJN in camelina (Camelina sativa) and pea (Camelina sativa) under plant drought stress conditions. To the best of our knowledge, this is the first report that EPS production is required for the maximal colonization of an endophytic bacterium in the plant tissues under stress conditions.
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Affiliation(s)
| | - Qing Yan
- Plant Sciences and Plant Pathology Department, Montana State University, Bozeman, MT, United States
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Fajardo C, Sánchez-Fortún S, Videira-Quintela D, Martin C, Nande M, D Ors A, Costa G, Guillen F, Montalvo G, Martin M. Biofilm formation on polyethylene microplastics and their role as transfer vector of emerging organic pollutants. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:84462-84473. [PMID: 37368211 DOI: 10.1007/s11356-023-28278-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023]
Abstract
Microplastic (MP)-colonizing microorganisms are important links for the potential impacts on environmental, health, and biochemical circulation in various ecosystems but are not yet well understood. In addition, biofilms serve as bioindicators for the evaluation of pollutant effects on ecosystems. This study describes the ability of three polyethylene-type microplastics, white (W-), blue (B-), and fluorescent blue (FB-) MPs, to support microbial colonization of Pseudomonas aeruginosa, the effect of mixed organic contaminants (OCs: amoxicillin, ibuprofen, sertraline, and simazine) on plastic-associated biofilms, and the role of biofilms as transfer vectors of such emerging pollutants. Our results showed that P. aeruginosa had a strong ability to produce biofilms on MPs, although the protein amount of biomass formed on FB-MP was 1.6- and 2.4-fold higher than that on B- and W-MP, respectively. When OCs were present in the culture medium, a decrease in cell viability was observed in the W-MP biofilm (65.0%), although a general impairing effect of OCs on biofilm formation was ruled out. Microbial colonization influenced the ability of MPs to accumulate OCs, which was higher for FB-MP. In particular, the sorption of amoxicillin was lower for all bacterial-colonized MPs than for the bare MPs. Moreover, we analysed oxidative stress production to assess the impact of MPs or MPs/OCs on biofilm development. The exposure of biofilms to OCs induced an adaptive stress response reflected in the upregulation of the katB gene and ROS production, particularly on B- and FB-MP. This study improves our understanding of MP biofilm formation, which modifies the ability of MPs to interact with some organic pollutants. However, such pollutants could hinder microbial colonization through oxidative stress production, and thus, considering the key role of biofilms in biogeochemical cycles or plastic degradation, the co-occurrence of MPs/OCs should be considered to assess the potential risks of MPs in the environment.
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Affiliation(s)
- Carmen Fajardo
- Department of Biomedicine and Biotechnology, Faculty of Pharmacy, University of Alcala, Ctra. Madrid-Barcelona Km 33.600, Alcala de Henares, Madrid, Spain.
| | - Sebastián Sánchez-Fortún
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University Complutense of Madrid, W/N Puerta de Hierro Ave, Madrid, Spain
| | - Diogo Videira-Quintela
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Pharmacy, University of Alcala, Ctra. Madrid-Barcelona Km 33.600, Alcala de Henares, Madrid, Spain
| | - Carmen Martin
- Department of Biotechnology-Plant Biology, School of Agricultural, Food and Biosystems Engineering, Technical University of Madrid, 3 Complutense Ave, Madrid, Spain
| | - Mar Nande
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, University Complutense of Madrid, W/N Puerta de Hierro Ave, Madrid, Spain
| | - Ana D Ors
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University Complutense of Madrid, W/N Puerta de Hierro Ave, Madrid, Spain
| | - Gonzalo Costa
- Department of Animal Physiology, Faculty ofVeterinary, University Complutense of Madrid, W/N Puerta de Hierro Ave, 28040, Madrid, Spain
| | - Francisco Guillen
- Department of Biomedicine and Biotechnology, Faculty of Pharmacy, University of Alcala, Ctra. Madrid-Barcelona Km 33.600, Alcala de Henares, Madrid, Spain
| | - Gemma Montalvo
- Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, Faculty of Pharmacy, University of Alcala, Ctra. Madrid-Barcelona Km 33.600, Alcala de Henares, Madrid, Spain
| | - Margarita Martin
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, University Complutense of Madrid, W/N Puerta de Hierro Ave, Madrid, Spain
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Bhattacharyya A, Mavrodi O, Bhowmik N, Weller D, Thomashow L, Mavrodi D. Bacterial biofilms as an essential component of rhizosphere plant-microbe interactions. METHODS IN MICROBIOLOGY 2023; 53:3-48. [PMID: 38415193 PMCID: PMC10898258 DOI: 10.1016/bs.mim.2023.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Affiliation(s)
- Ankita Bhattacharyya
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Olga Mavrodi
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Niladri Bhowmik
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - David Weller
- USDA-ARS Wheat Health, Genetics and Quality Research Unit, Pullman, WA, United States
| | - Linda Thomashow
- USDA-ARS Wheat Health, Genetics and Quality Research Unit, Pullman, WA, United States
| | - Dmitri Mavrodi
- School of Biological, Environmental and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
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Exploring the Role of Salicylic Acid in Regulating the Colonization Ability of Bacillus subtilis 26D in Potato Plants and Defense against Phytophthora infestans. INTERNATIONAL JOURNAL OF PLANT BIOLOGY 2023. [DOI: 10.3390/ijpb14010020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Plant colonization by endophytic bacteria is mediated by different biomolecules that cause dynamic changes in gene expression of both bacteria and plant. Phytohormones, in particular, salicylic acid, play a key role in the regulation of endophytic colonization and diversity of bacteria in methaphytobiome. For the first time it was found that salicylic acid influenced motility in biofilms and transcription of the surfactin synthetase gene of the endophytic strain Bacillus subtilis 26D in vitro. Treatment of Solanum tuberosum plants with salicylic acid, along with B. subtilis 26D, increased the number of endophytic cells of bacteria in potato internal tissues and level of transcripts of bacterial surfactin synthetase gene and decreased transcription of plant PR genes on the stage of colonisation with endophytes. Thus, the production of surfactin plays an important role in endophytic colonization of plants, and salicylic acid has an ability to influence this mechanism. Here we firstly show that plants treated with salicylic acid and B. subtilis 26D showed enhanced resistance to the late blight pathogen Phytophthora infestans, which was accompanied by increase in transcriptional activity of plant PR-genes and bacterial surfactin synthetase gene after pathogen inoculation. Therefore, it is suggested that salicylic acid can modulate physiological status of the whole plant–endophyte system and improve biocontrol potential of endophytic strains.
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Becker R, Ulrich K, Behrendt U, Schneck V, Ulrich A. Genomic Characterization of Aureimonas altamirensis C2P003-A Specific Member of the Microbiome of Fraxinus excelsior Trees Tolerant to Ash Dieback. PLANTS (BASEL, SWITZERLAND) 2022; 11:3487. [PMID: 36559599 PMCID: PMC9781493 DOI: 10.3390/plants11243487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Some European ash trees show tolerance towards dieback caused by the invasive pathogen Hymenoscyphus fraxineus. The microbiome of these trees harbours a range of specific bacterial groups. One of these groups belonging to the species Aureimonas altamirensis was studied in detail by genome analysis and a plant inoculation trial. The strain group was shown to be phylogenetically distinct from clinical isolates by 16S rRNA analysis and phylogenomics. Genome analysis of a representative strain C2P003 resulted in a large number of unique gene sequences in comparison to other well-studied strains of the species. A functional analysis of the genome revealed features associated with the synthesis of exopolysaccharides, protein secretion and biofilm production as well as genes for stress adaptation, suggesting the ability of C2P003 to effectively colonize ash leaves. The inoculation of ash seedlings with C2P003 showed a significant positive effect on the plant health of the seedlings that were exposed to H. fraxineus infection. This effect was maintained over a period of three years and was accompanied by a significant shift in the bacterial microbiome composition one year after inoculation. Overall, the results indicate that C2P003 may suppress H. fraxineus in or on ash leaves via colonization resistance or indirectly by affecting the microbiome.
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Affiliation(s)
- Regina Becker
- Microbial Biogeochemistry, Research Area Landscape Functioning, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
| | - Kristina Ulrich
- Institute of Forest Genetics, Johann Heinrich von Thünen Institute, 15377 Waldsieversdorf, Germany
| | - Undine Behrendt
- Microbial Biogeochemistry, Research Area Landscape Functioning, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
| | - Volker Schneck
- Institute of Forest Genetics, Johann Heinrich von Thünen Institute, 15377 Waldsieversdorf, Germany
| | - Andreas Ulrich
- Microbial Biogeochemistry, Research Area Landscape Functioning, Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany
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11
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Lv F, Zhan Y, Lu W, Ke X, Shao Y, Ma Y, Zheng J, Yang Z, Jiang S, Shang L, Ma Y, Cheng L, Elmerich C, Yan Y, Lin M. Regulation of hierarchical carbon substrate utilization, nitrogen fixation, and root colonization by the Hfq/Crc/CrcZY genes in Pseudomonas stutzeri. iScience 2022; 25:105663. [PMID: 36505936 PMCID: PMC9730152 DOI: 10.1016/j.isci.2022.105663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 09/08/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022] Open
Abstract
Bacteria of the genus Pseudomonas consume preferred carbon substrates in nearly reverse order to that of enterobacteria, and this process is controlled by RNA-binding translational repressors and regulatory ncRNA antagonists. However, their roles in microbe-plant interactions and the underlying mechanisms remain uncertain. Here we show that root-associated diazotrophic Pseudomonas stutzeri A1501 preferentially catabolizes succinate, followed by the less favorable substrate citrate, and ultimately glucose. Furthermore, the Hfq/Crc/CrcZY regulatory system orchestrates this preference and contributes to optimal nitrogenase activity and efficient root colonization. Hfq has a central role in this regulatory network through different mechanisms of action, including repressing the translation of substrate-specific catabolic genes, activating the nitrogenase gene nifH posttranscriptionally, and exerting a positive effect on the transcription of an exopolysaccharide gene cluster. Our results illustrate an Hfq-mediated mechanism linking carbon metabolism to nitrogen fixation and root colonization, which may confer rhizobacteria competitive advantages in rhizosphere environments.
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Affiliation(s)
- Fanyang Lv
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuhua Zhan
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wei Lu
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiubin Ke
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yahui Shao
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yiyuan Ma
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Juan Zheng
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhimin Yang
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Shanshan Jiang
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Liguo Shang
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yao Ma
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lei Cheng
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
| | | | - Yongliang Yan
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China,Corresponding author
| | - Min Lin
- Biotechnology Research Institute/Key Laboratory of Agricultural Microbiome (MARA), Chinese Academy of Agricultural Sciences, Beijing, China,Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China,Corresponding author
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12
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Saini MR, Chandran LP, Barbadikar KM, Sevanthi AMV, Chawla G, Kaushik M, Mulani E, Phule AS, Govindannagari R, Sonth B, Sinha SK, Sundaram RM, Mandal PK. Understanding plant-microbe interaction of rice and soybean with two contrasting diazotrophic bacteria through comparative transcriptome analysis. FRONTIERS IN PLANT SCIENCE 2022; 13:939395. [PMID: 36483966 PMCID: PMC9724235 DOI: 10.3389/fpls.2022.939395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
Understanding the beneficial plant-microbe interactions is becoming extremely critical for deploying microbes imparting plant fitness and achieving sustainability in agriculture. Diazotrophic bacteria have the unique ability to survive without external sources of nitrogen and simultaneously promote host plant growth, but the mechanisms of endophytic interaction in cereals and legumes have not been studied extensively. We have studied the early interaction of two diazotrophic bacteria, Gluconacetobacter diazotrophicus (GAB) and Bradyrhizobium japonicum (BRH), in 15-day-old seedlings of rice and soybean up to 120 h after inoculation (hai) under low-nitrogen medium. Root colonization of GAB in rice was higher than that of BRH, and BRH colonization was higher in soybean roots as observed from the scanning electron microscopy at 120 hai. Peroxidase enzyme was significantly higher at 24 hai but thereafter was reduced sharply in soybean and gradually in rice. The roots of rice and soybean inoculated with GAB and BRH harvested from five time points were pooled, and transcriptome analysis was executed along with control. Two pathways, "Plant pathogen interaction" and "MAPK signaling," were specific to Rice-Gluconacetobacter (RG), whereas the pathways related to nitrogen metabolism and plant hormone signaling were specific to Rice-Bradyrhizobium (RB) in rice. Comparative transcriptome analysis of the root tissues revealed that several plant-diazotroph-specific differentially expressed genes (DEGs) and metabolic pathways of plant-diazotroph-specific transcripts, viz., chitinase, brassinosteroid, auxin, Myeloblastosis (MYB), nodulin, and nitrate transporter (NRT), were common in all plant-diazotroph combinations; three transcripts, viz., nitrate transport accessory protein (NAR), thaumatin, and thionin, were exclusive in rice and another three transcripts, viz., NAC (NAM: no apical meristem, ATAF: Arabidopsis thaliana activating factor, and CUC: cup-shaped cotyledon), ABA (abscisic acid), and ammonium transporter, were exclusive in soybean. Differential expression of these transcripts and reduction in pathogenesis-related (PR) protein expression show the early interaction. Based on the interaction, it can be inferred that the compatibility of rice and soybean is more with GAB and BRH, respectively. We propose that rice is unable to identify the diazotroph as a beneficial microorganism or a pathogen from an early response. So, it expressed the hypersensitivity-related transcripts along with PR proteins. The molecular mechanism of diazotrophic associations of GAB and BRH with rice vis-à-vis soybean will shed light on the basic understanding of host responses to beneficial microorganisms.
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Affiliation(s)
- Manish Ranjan Saini
- Indian Council of Agricultural Research (ICAR) National Institute for Plant Biotechnology, New Delhi, India
- Kalinga Institute of Industrial Technology (KIIT) School of Biotechnology, KIIT University, Bhubaneswar, India
| | | | | | - Amitha Mithra V. Sevanthi
- Indian Council of Agricultural Research (ICAR) National Institute for Plant Biotechnology, New Delhi, India
| | - Gautam Chawla
- Division of Nematology, ICAR- Indian Agriculture Research Institute, New Delhi, India
| | - Megha Kaushik
- Indian Council of Agricultural Research (ICAR) National Institute for Plant Biotechnology, New Delhi, India
| | - Ekta Mulani
- Indian Council of Agricultural Research (ICAR) National Institute for Plant Biotechnology, New Delhi, India
| | | | | | - Bandeppa Sonth
- ICAR-Indian Institute of Rice Research, Hyderabad, India
| | - Subodh Kumar Sinha
- Indian Council of Agricultural Research (ICAR) National Institute for Plant Biotechnology, New Delhi, India
| | | | - Pranab Kumar Mandal
- Indian Council of Agricultural Research (ICAR) National Institute for Plant Biotechnology, New Delhi, India
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13
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Kumari M, Qureshi KA, Jaremko M, White J, Singh SK, Sharma VK, Singh KK, Santoyo G, Puopolo G, Kumar A. Deciphering the role of endophytic microbiome in postharvest diseases management of fruits: Opportunity areas in commercial up-scale production. FRONTIERS IN PLANT SCIENCE 2022; 13:1026575. [PMID: 36466226 PMCID: PMC9716317 DOI: 10.3389/fpls.2022.1026575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 10/13/2022] [Indexed: 06/17/2023]
Abstract
As endophytes are widely distributed in the plant's internal compartments and despite having enormous potential as a biocontrol agent against postharvest diseases of fruits, the fruit-endophyte-pathogen interactions have not been studied detail. Therefore, this review aims to briefly discuss the colonization patterns of endophytes and pathogens in the host tissue, the diversity and distribution patterns of endophytes in the carposphere of fruits, and host-endophyte-pathogen interactions and the molecular mechanism of the endophytic microbiome in postharvest disease management in fruits. Postharvest loss management is one of the major concerns of the current century. It is considered a critical challenge to food security for the rising global population. However, to manage the postharvest loss, still, a large population relies on chemical fungicides, which affect food quality and are hazardous to health and the surrounding environment. However, the scientific community has searched for alternatives for the last two decades. In this context, endophytic microorganisms have emerged as an economical, sustainable, and viable option to manage postharvest pathogens with integral colonization properties and eliciting a defense response against pathogens. This review extensively summarizes recent developments in endophytic interactions with harvested fruits and pathogens-the multiple biocontrol traits of endophytes and colonization and diversity patterns of endophytes. In addition, the upscale commercial production of endophytes for postharvest disease treatment is discussed.
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Affiliation(s)
- Madhuree Kumari
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Kamal A. Qureshi
- Department of Pharmaceutics, Unaizah College of Pharmacy, Qassim University, Unaizah, Saudi Arabia
| | - Mariusz Jaremko
- Smart-Health Initiative (SHI) and Red Sea Research Center (R.S.R.C.), Division of Biological and Environmental Sciences and Engineering (B.E.S.E.), King Abdullah University of Science and Technology (K.A.U.S.T.), Thuwal, Saudi Arabia
| | - James White
- Department of Plant Biology, Rutgers University, The State University of New Jersey, New Brunswick, NJ, United States
| | - Sandeep Kumar Singh
- Division of Microbiology, Indian Council of Agricultural Research (ICAR), New Delhi, India
| | - Vijay Kumar Sharma
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, India
| | | | - Gustavo Santoyo
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico
| | - Gerardo Puopolo
- Center Agriculture Food Environment, University of Trento, Trentino, TN, Italy
| | - Ajay Kumar
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, India
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14
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Li Y, Yang R, Häggblom MM, Li M, Guo L, Li B, Kolton M, Cao Z, Soleimani M, Chen Z, Xu Z, Gao W, Yan B, Sun W. Characterization of diazotrophic root endophytes in Chinese silvergrass (Miscanthus sinensis). MICROBIOME 2022; 10:186. [PMID: 36329505 PMCID: PMC9632085 DOI: 10.1186/s40168-022-01379-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 09/22/2022] [Indexed: 05/23/2023]
Abstract
BACKGROUND Phytoremediation is a potentially cost-effective way to remediate highly contaminated mine tailing sites. However, nutrient limitations, especially the deficiency of nitrogen (N), can hinder the growth of plants and impair the phytoremediation of mine tailings. Nevertheless, pioneer plants can successfully colonize mine tailings and exhibit potential for tailing phytoremediation. Diazotrophs, especially diazotrophic endophytes, can promote the growth of their host plants. This was tested in a mine-tailing habitat by a combination of field sampling, DNA-stable isotope probing (SIP) analysis, and pot experiments. RESULTS Bacteria belonging to the genera Herbaspirillum, Rhizobium, Devosia, Pseudomonas, Microbacterium, and Delftia are crucial endophytes for Chinese silvergrass (Miscanthus sinensis) grown in the tailing, the model pioneer plant selected in this study. Further, DNA-SIP using 15N2 identified Pseudomonas, Rhizobium, and Exiguobacterium as putative diazotrophic endophytes of M. sinensis. Metagenomic-binning suggested that these bacteria contained essential genes for nitrogen fixation and plant growth promotion. Finally, two diazotrophic endophytes Rhizobium sp. G-14 and Pseudomonas sp. Y-5 were isolated from M. sinensis. Inoculation of another pioneer plant in mine tailings, Bidens pilosa, with diazotrophic endophytes resulted in successful plant colonization, significantly increased nitrogen fixation activity, and promotion of plant growth. CONCLUSIONS This study indicated that diazotrophic endophytes have the potential to promote the growth of pioneer plant B. pilosa in mine tailings. Video Abstract.
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Affiliation(s)
- Yongbin Li
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Academy of Sciences, Guangzhou, 510650, China
- Joint Laboratory for Environmental Pollution and Control, Guangdong-Hong Kong-Macao, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Rui Yang
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Max M Häggblom
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Mengyan Li
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, 07102, USA
| | - Lifang Guo
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Baoqin Li
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Max Kolton
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Academy of Sciences, Guangzhou, 510650, China
- Joint Laboratory for Environmental Pollution and Control, Guangdong-Hong Kong-Macao, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
- French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Zhiguo Cao
- School of Environment, Key Laboratory of Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Normal University, Xinxiang, 453007, China
| | - Mohsen Soleimani
- Department of Natural Resources, Isfahan University of Technology, Isfahan, Iran
| | - Zheng Chen
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, China
| | - Zhimin Xu
- Engineering and Technology Research Center for Agricultural Land Pollution Prevention and Control of Guangdong Higher Education Institutes, College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Wenlong Gao
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Academy of Sciences, Guangzhou, 510650, China
- Joint Laboratory for Environmental Pollution and Control, Guangdong-Hong Kong-Macao, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Bei Yan
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Academy of Sciences, Guangzhou, 510650, China
- Joint Laboratory for Environmental Pollution and Control, Guangdong-Hong Kong-Macao, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China
| | - Weimin Sun
- Guangdong Key Laboratory of Integrated Agro-Environmental Pollution Control and Management, Institute of Eco-Environmental and Soil Sciences, National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Academy of Sciences, Guangzhou, 510650, China.
- Joint Laboratory for Environmental Pollution and Control, Guangdong-Hong Kong-Macao, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China.
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15
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Yan D, Tajima H, Cline LC, Fong RY, Ottaviani JI, Shapiro H, Blumwald E. Genetic modification of flavone biosynthesis in rice enhances biofilm formation of soil diazotrophic bacteria and biological nitrogen fixation. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:2135-2148. [PMID: 35869808 PMCID: PMC9616522 DOI: 10.1111/pbi.13894] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/05/2022] [Accepted: 07/15/2022] [Indexed: 05/06/2023]
Abstract
Improving biological nitrogen fixation (BNF) in cereal crops is a long-sought objective; however, no successful modification of cereal crops showing increased BNF has been reported. Here, we described a novel approach in which rice plants were modified to increase the production of compounds that stimulated biofilm formation in soil diazotrophic bacteria, promoted bacterial colonization of plant tissues and improved BNF with increased grain yield at limiting soil nitrogen contents. We first used a chemical screening to identify plant-produced compounds that induced biofilm formation in nitrogen-fixing bacteria and demonstrated that apigenin and other flavones induced BNF. We then used CRISPR-based gene editing targeting apigenin breakdown in rice, increasing plant apigenin contents and apigenin root exudation. When grown at limiting soil nitrogen conditions, modified rice plants displayed increased grain yield. Biofilm production also modified the root microbiome structure, favouring the enrichment of diazotrophic bacteria recruitment. Our results support the manipulation of the flavone biosynthetic pathway as a feasible strategy for the induction of biological nitrogen fixation in cereals and a reduction in the use of inorganic nitrogen fertilizers.
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Affiliation(s)
- Dawei Yan
- Department of Plant SciencesUniversity of CaliforniaDavisCaliforniaUSA
| | - Hiromi Tajima
- Department of Plant SciencesUniversity of CaliforniaDavisCaliforniaUSA
| | | | - Reedmond Y. Fong
- Department of NutritionUniversity of CaliforniaDavisCaliforniaUSA
| | - Javier I. Ottaviani
- Department of NutritionUniversity of CaliforniaDavisCaliforniaUSA
- Mars Inc.McLeanVirginiaUSA
| | | | - Eduardo Blumwald
- Department of Plant SciencesUniversity of CaliforniaDavisCaliforniaUSA
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16
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Samet M, Ghazala I, Karray F, Abid C, Chiab N, Nouri-Ellouz O, Sayadi S, Gargouri-Bouzid R. Isolation of bacterial strains from compost teas and screening of their PGPR properties on potato plants. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:75365-75379. [PMID: 35653020 DOI: 10.1007/s11356-022-21046-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
The beneficial effect of compost and compost tea on plant growth and protection is mainly associated with the microbial diversity and the presence of bacteria with plant growth-promoting effect. PGPR are considered as eco-friendly bio-fertilizers that may reduce the use of chemical pesticides and fertilizers. Three composts (AT, A10, and A30) were previously prepared from industrial wastes (olive mill wastewater, olive pomace, coffee ground, and phosphogypsum). In the present study, we isolated three bacterial strains from the compost teas. The phylogenetic identification of these bacterial strains (B.AT, B.A10, and B.A30) showed that they correspond to Serratia liquefaciens (B.AT and B.A10) and Achromobacter spanius (B.A30) species. A further characterization of the PGPR traits of these bacteria showed that they produce siderophore, exopolysaccharides, and IAA. Their effect on potato plant growth, yields, and tuber quality was performed under field culture conditions. Results showed that these strains can be characterized as PGPR, the best effect on potato plant growth was observed with Serratia liquefaciens (B.AT), the best yield and tuber quality was observed with Serratia liquefaciens (B.A10) while bacterial treatment with Achromobacter spanius (B.A30) is a Cd-tolerant PGPR.
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Affiliation(s)
- Mariem Samet
- Laboratory of Plant Improvement and Agro-Resources Valorization, National School of Engineers of Sfax, road of Soukra Km 4, B.P 1173, 3038, Sfax, Tunisia.
| | - Imen Ghazala
- Laboratory of Plant Improvement and Agro-Resources Valorization, National School of Engineers of Sfax, road of Soukra Km 4, B.P 1173, 3038, Sfax, Tunisia
| | - Fatma Karray
- Laboratory of Environmental Bioprocesses, Sfax Biotechnology Center, Road of Sidi Mansour km6, BP 1177, 3018, Sfax, Tunisia
| | - Cyrine Abid
- Laboratory of Plant Improvement and Agro-Resources Valorization, National School of Engineers of Sfax, road of Soukra Km 4, B.P 1173, 3038, Sfax, Tunisia
| | - Nour Chiab
- Laboratory of Plant Improvement and Agro-Resources Valorization, National School of Engineers of Sfax, road of Soukra Km 4, B.P 1173, 3038, Sfax, Tunisia
| | - Oumèma Nouri-Ellouz
- Laboratory of Plant Improvement and Agro-Resources Valorization, National School of Engineers of Sfax, road of Soukra Km 4, B.P 1173, 3038, Sfax, Tunisia
| | - Sami Sayadi
- Biotechnology Program, Center for Sustainable Development, College of Arts and Sciences, Qatar University, 2713, Doha, Qatar
| | - Radhia Gargouri-Bouzid
- Laboratory of Plant Improvement and Agro-Resources Valorization, National School of Engineers of Sfax, road of Soukra Km 4, B.P 1173, 3038, Sfax, Tunisia
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17
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Malviya D, Varma A, Singh UB, Singh S, Saxena AK. Unraveling the mechanism of sulfur nutrition in pigeonpea inoculated with sulfur-oxidizing bacteria. Front Microbiol 2022; 13:927702. [PMID: 36134141 PMCID: PMC9483215 DOI: 10.3389/fmicb.2022.927702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Accepted: 08/11/2022] [Indexed: 11/13/2022] Open
Abstract
An investigation was carried out to understand the mechanism(s) involved in the uptake of sulfur (S) as sulfate in pigeonpea following single inoculation of two sulfur-oxidizing bacteria (SOB), Stenotrophomonas maltophilia and Stenotrophomonas pavanii in the treatments amended with either elemental sulfur (S0) or sulfate (S6). Colonization potential and biofilm formation were analyzed through confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM). Furthermore, the effect of seed inoculation on root architecture, expression of genes involved in sulfur oxidation (sox) in bacterial inoculants, and genes involved in sulfate transport in pigeonpea (PpSULTR) were analyzed to correlate with the higher uptake of S in roots and shoots of pigeonpea. Both the SOB exhibited a good colonization potential and biofilm formation on the roots of pigeonpea. Among the 11 sox genes targeted in rhizosphere of pigeonpea, expression was achieved for seven genes, which showed 2-fold increase in treatments inoculated with S. maltophilia and amended with either S6 or S0. The inoculation of S. maltophilia and amendment of S0 led to increased expression of PpSULTR genes by several folds in roots. The inoculation of SOB had a significant influence on non-enzymatic (osmolytes like proline) and enzymatic (PAL, peroxidase, superoxide dismutase, and catalase) levels. The results revealed a significant increase in sulfur uptake in roots and shoots in treatment inoculated with S. maltophilia and amended with S6. The investigation showed that the SOB-mediated over-expression of PpSULTR genes in roots of pigeonpea and sox genes in the rhizosphere were acting synergistically in facilitating higher uptake and translocation of S in roots and shoots of pigeonpea plants.
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Affiliation(s)
- Deepti Malviya
- Amity Institute of Microbial Technology, Amity University, Noida, Uttar Pradesh, India
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, Uttar Pradesh, India
| | - Ajit Varma
- Amity Institute of Microbial Technology, Amity University, Noida, Uttar Pradesh, India
| | - Udai B. Singh
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, Uttar Pradesh, India
| | - Shailendra Singh
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, Uttar Pradesh, India
| | - Anil K. Saxena
- Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-National Bureau of Agriculturally Important Microorganisms, Maunath Bhanjan, Uttar Pradesh, India
- *Correspondence: Anil K. Saxena,
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18
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Dundas CM, Dinneny JR. Genetic Circuit Design in Rhizobacteria. BIODESIGN RESEARCH 2022; 2022:9858049. [PMID: 37850138 PMCID: PMC10521742 DOI: 10.34133/2022/9858049] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 07/31/2022] [Indexed: 10/19/2023] Open
Abstract
Genetically engineered plants hold enormous promise for tackling global food security and agricultural sustainability challenges. However, construction of plant-based genetic circuitry is constrained by a lack of well-characterized genetic parts and circuit design rules. In contrast, advances in bacterial synthetic biology have yielded a wealth of sensors, actuators, and other tools that can be used to build bacterial circuitry. As root-colonizing bacteria (rhizobacteria) exert substantial influence over plant health and growth, genetic circuit design in these microorganisms can be used to indirectly engineer plants and accelerate the design-build-test-learn cycle. Here, we outline genetic parts and best practices for designing rhizobacterial circuits, with an emphasis on sensors, actuators, and chassis species that can be used to monitor/control rhizosphere and plant processes.
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Affiliation(s)
| | - José R. Dinneny
- Department of Biology, Stanford University, Stanford, CA 94305, USA
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19
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Abdul Hamid NW, Nadarajah K. Microbe Related Chemical Signalling and Its Application in Agriculture. Int J Mol Sci 2022; 23:ijms23168998. [PMID: 36012261 PMCID: PMC9409198 DOI: 10.3390/ijms23168998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 07/31/2022] [Accepted: 08/04/2022] [Indexed: 11/17/2022] Open
Abstract
The agriculture sector has been put under tremendous strain by the world’s growing population. The use of fertilizers and pesticides in conventional farming has had a negative impact on the environment and human health. Sustainable agriculture attempts to maintain productivity, while protecting the environment and feeding the global population. The importance of soil-dwelling microbial populations in overcoming these issues cannot be overstated. Various processes such as rhizospheric competence, antibiosis, release of enzymes, and induction of systemic resistance in host plants are all used by microbes to influence plant-microbe interactions. These processes are largely founded on chemical signalling. Producing, releasing, detecting, and responding to chemicals are all part of chemical signalling. Different microbes released distinct sorts of chemical signal molecules which interacts with the environment and hosts. Microbial chemicals affect symbiosis, virulence, competence, conjugation, antibiotic production, motility, sporulation, and biofilm growth, to name a few. We present an in-depth overview of chemical signalling between bacteria-bacteria, bacteria-fungi, and plant-microbe and the diverse roles played by these compounds in plant microbe interactions. These compounds’ current and potential uses and significance in agriculture have been highlighted.
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20
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Transcriptomic Response of the Diazotrophic Bacteria Gluconacetobacter diazotrophicus Strain PAL5 to Iron Limitation and Characterization of the fur Regulatory Network. Int J Mol Sci 2022; 23:ijms23158533. [PMID: 35955667 PMCID: PMC9368920 DOI: 10.3390/ijms23158533] [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: 06/17/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 01/25/2023] Open
Abstract
Gluconacetobacter diazotrophicus has been the focus of several studies aiming to understand the mechanisms behind this endophytic diazotrophic bacterium. The present study is the first global analysis of the early transcriptional response of exponentially growing G. diazotrophicus to iron, an essential cofactor for many enzymes involved in various metabolic pathways. RNA-seq, targeted gene mutagenesis and computational motif discovery tools were used to define the G. diazotrophicusfur regulon. The data analysis showed that genes encoding functions related to iron homeostasis were significantly upregulated in response to iron limitations. Certain genes involved in secondary metabolism were overexpressed under iron-limited conditions. In contrast, it was observed that the expression of genes involved in Fe-S cluster biosynthesis, flagellar biosynthesis and type IV secretion systems were downregulated in an iron-depleted culture medium. Our results support a model that controls transcription in G. diazotrophicus by fur function. The G. diazotrophicusfur protein was able to complement an E. colifur mutant. These results provide new insights into the effects of iron on the metabolism of G. diazotrophicus, as well as demonstrate the essentiality of this micronutrient for the main characteristics of plant growth promotion by G. diazotrophicus.
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Xue J, Tong T, Wang R, Qiu Y, Gu Y, Sun L, Xu H, Lei P. Secretion of poly-γ-glutamic acid by Bacillus atrophaeus NX-12 enhanced its root colonization and biocontrol activity. Front Microbiol 2022; 13:972393. [PMID: 35966665 PMCID: PMC9372288 DOI: 10.3389/fmicb.2022.972393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 07/04/2022] [Indexed: 11/22/2022] Open
Abstract
Bacilli are used as biocontrol agents (BCAs) against phytopathogens and most of them can produce poly-γ-glutamic acid (γ-PGA) as one of the major extracellular polymeric substances (EPSs). However, the role of γ-PGA in plant biocontrol is still unclear. In this study, Bacillus atrophaeus NX-12 (γ-PGA yield: 16.8 g/l) was screened, which formed a strong biofilm and has been proved to be a promising BCA against Cucumber Fusarium wilt. Then, the γ-PGA synthesis gene cluster pgsBCA was knocked out by CRISPR-Cas9n. Interestingly, the antifungal ability of γ-PGA synthetase-deficient strain NX-12Δpgs (γ-PGA yield: 1.65 g/l) was improved in vitro, while the biocontrol ability of NX-12Δpgs was greatly diminished in situ. Data proved that γ-PGA produced by NX-12 contributes to the biofilm formation and rhizosphere colonization, which effectively improved biocontrol capability. Taken together, these findings prove that the mechanism of γ-PGA promotes the colonization of NX-12 and thus assists in controlling plant diseases, which highlight the key role of γ-PGA produced by BCA in biocontrol.
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Pathania N, Kumar A, Sharma P, Kaur A, Sharma S, Jain R. Harnessing rhizobacteria to fulfil inter-linked nutrient dependency on soil and alleviate stresses in plants. J Appl Microbiol 2022; 133:2694-2716. [PMID: 35656999 DOI: 10.1111/jam.15649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 05/12/2022] [Accepted: 05/31/2022] [Indexed: 11/27/2022]
Abstract
Plant rhizo-microbiome comprises of complex microbial communities that colonizes at the interphase of plant roots and soil. Plant-growth-promoting rhizobacteria (PGPR) in the rhizosphere provides important ecosystem services ranging from release of essential nutrients for enhancing soil quality and improving plant health to imparting protection to plants against rising biotic and abiotic stresses. Hence, PGPR serve as restoring agents to rejuvenate soil health and mediate plant fitness in the facet of changing climate. Though, it is evident that nutrients availability in soil are managed through inter-linked mechanisms, how PGPR expediate these processes remain less recognized. Promising results of PGPR inoculation on plant growth are continually reported in controlled environmental conditions, however, their field application often fails due to competition with native microbiota and low colonization efficiency in roots. The development of highly efficient and smart bacterial synthetic communities by integrating bacterial ecological and genetic features provides better opportunities for successful inoculant formulations. This review provides an overview of the inter-play between nutrient availability and disease suppression governed by rhizobacteria in soil followed by the role of synthetic bacterial communities in developing efficient microbial inoculants. Moreover, an outlook on the beneficial activities of rhizobacteria in modifying soil characteristics to sustainably boost agroecosystem functioning is also provided.
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Affiliation(s)
- Neemisha Pathania
- Department of Soil Science, Punjab Agricultural University, Ludhiana, Punjab 141004, India
| | - Arun Kumar
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India
| | - Poonam Sharma
- Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, Punjab 141004, India
| | - Avneet Kaur
- Department of Soil Science, Punjab Agricultural University, Ludhiana, Punjab 141004, India
| | - Sandeep Sharma
- Department of Soil Science, Punjab Agricultural University, Ludhiana, Punjab 141004, India
| | - Rahul Jain
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India
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Rani S, Kumar P, Dahiya P, Maheshwari R, Dang AS, Suneja P. Endophytism: A Multidimensional Approach to Plant-Prokaryotic Microbe Interaction. Front Microbiol 2022; 13:861235. [PMID: 35633681 PMCID: PMC9135327 DOI: 10.3389/fmicb.2022.861235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 03/11/2022] [Indexed: 11/20/2022] Open
Abstract
Plant growth and development are positively regulated by the endophytic microbiome via both direct and indirect perspectives. Endophytes use phytohormone production to promote plant health along with other added benefits such as nutrient acquisition, nitrogen fixation, and survival under abiotic and biotic stress conditions. The ability of endophytes to penetrate the plant tissues, reside and interact with the host in multiple ways makes them unique. The common assumption that these endophytes interact with plants in a similar manner as the rhizospheric bacteria is a deterring factor to go deeper into their study, and more focus was on symbiotic associations and plant–pathogen reactions. The current focus has shifted on the complexity of relationships between host plants and their endophytic counterparts. It would be gripping to inspect how endophytes influence host gene expression and can be utilized to climb the ladder of “Sustainable agriculture.” Advancements in various molecular techniques have provided an impetus to elucidate the complexity of endophytic microbiome. The present review is focused on canvassing different aspects concerned with the multidimensional interaction of endophytes with plants along with their application.
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Affiliation(s)
- Simran Rani
- Plant Microbe Interaction Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
| | - Pradeep Kumar
- Plant Microbe Interaction Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
| | - Priyanka Dahiya
- Plant Microbe Interaction Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
| | - Rajat Maheshwari
- Plant Microbe Interaction Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
| | - Amita Suneja Dang
- Centre for Medical Biotechnology, Maharshi Dayanand University, Rohtak, India
| | - Pooja Suneja
- Plant Microbe Interaction Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, India
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da Silva MSRDA, Tavares OCH, de Oliveira ISR, da Silva CSRDA, da Silva CSRDA, Vidal MS, Baldani VLD, Jesus EDC. Stimulatory effects of defective and effective 3-indoleacetic acid-producing bacterial strains on rice in an advanced stage of its vegetative cycle. Braz J Microbiol 2022; 53:281-288. [PMID: 35060090 PMCID: PMC8882547 DOI: 10.1007/s42770-021-00651-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 11/02/2021] [Indexed: 01/23/2023] Open
Abstract
The production of 3-indoleacetic acid (IAA) by plant growth-promoting bacteria (PGPR) stimulates root development and plant growth. In addition, morphological changes such as an increased root ramification and root hair production improves nutrient absorption and biomass accumulation. The objective of this work was to evaluate the effect of IAA-producing strains on rice in an advanced stage of its vegetative cycle. Rice was inoculated with Gluconacetobacter diazotrophicus PAL 5 and its lao- mutant, deficient in auxin production, Azospirillum baldaniorum Sp 245, and Escherichia coli DH10b. Both the mutant and wild-type G. diazotrophicus stimulated root elongation, area, volume, and diameter. However, the lao- mutant strain was the only one capable of increasing the number of roots. In turn, inoculation with A. baldaniorum had no significant effect on plant development. The inoculation with E. coli led to changes in root volume, area, and diameter, and a response that may be related to the stress caused by its presence. We conclude that the inoculation with G. diazotrophicus stimulates the root system's growth independently of their IAA production ability, suggesting that a metabolite other than IAA is responsible for this effect at advanced stages of the rice's vegetative cycle.
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Affiliation(s)
- Maura Santos Reis de Andrade da Silva
- Centro Nacional de Pesquisa de Agrobiologia, EMBRAPA, Rodovia BR 465, km 7, s/n, Ecologia, Seropédica, RJ 23.891-000 Brazil
- Departamento de Ciências Do Solo, Universidade Federal Rural Do Rio de Janeiro, Rodovia BR 465, km 7, s/n, Zona Rural, Seropédica, RJ 23890-000 Brazil
| | - Orlando Carlos Huertas Tavares
- Departamento de Ciências Do Solo, Universidade Federal Rural Do Rio de Janeiro, Rodovia BR 465, km 7, s/n, Zona Rural, Seropédica, RJ 23890-000 Brazil
| | - Isabelly Santos Rosado de Oliveira
- Centro Nacional de Pesquisa de Agrobiologia, EMBRAPA, Rodovia BR 465, km 7, s/n, Ecologia, Seropédica, RJ 23.891-000 Brazil
- Departamento de Ciências Ambientais E Florestais, Universidade Federal Rural Do Rio de Janeiro, Rodovia BR 465, km 7, s/n, Zona Rural, Seropédica, RJ 23890-000 Brazil
| | - Camilla Santos Reis de Andrade da Silva
- Centro Nacional de Pesquisa de Agrobiologia, EMBRAPA, Rodovia BR 465, km 7, s/n, Ecologia, Seropédica, RJ 23.891-000 Brazil
- Departamento de Ciências Do Solo, Universidade Federal Rural Do Rio de Janeiro, Rodovia BR 465, km 7, s/n, Zona Rural, Seropédica, RJ 23890-000 Brazil
| | | | - Márcia Soares Vidal
- Centro Nacional de Pesquisa de Agrobiologia, EMBRAPA, Rodovia BR 465, km 7, s/n, Ecologia, Seropédica, RJ 23.891-000 Brazil
| | - Vera Lúcia Divan Baldani
- Centro Nacional de Pesquisa de Agrobiologia, EMBRAPA, Rodovia BR 465, km 7, s/n, Ecologia, Seropédica, RJ 23.891-000 Brazil
| | - Ederson da Conceição Jesus
- Centro Nacional de Pesquisa de Agrobiologia, EMBRAPA, Rodovia BR 465, km 7, s/n, Ecologia, Seropédica, RJ 23.891-000 Brazil
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Systematic optimization of exopolysaccharide production by Gluconacetobacter sp. and use of (crude) glycerol as carbon source. Carbohydr Polym 2022; 276:118769. [PMID: 34823788 DOI: 10.1016/j.carbpol.2021.118769] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/12/2021] [Accepted: 10/12/2021] [Indexed: 11/23/2022]
Abstract
The usage of polysaccharides as biodegradable polymers is of growing interest in the context of a sustainable and ecofriendly economy. For this, the production of exopolysaccharides (EPS) by Gluconacetobacter sp. was investigated. Glycerol as carbon source revealed to be beneficial compared to glucose. In addition, pure glycerol could be substituted by a crude glycerol waste stream from biodiesel production. Systematic analysis of the peptone and phosphate concentrations in glycerol-based media indicated a strong effect of peptone. Optimized parameters resulted in a titer of 25.4 ± 2.4 g/L EPS with a productivity of 0.46 ± 0.04 g*(L*h)-1. With decreasing peptone, a variation in the monomer ratios was observed. An accompanying change in molecular size distribution indicated the production of two different polysaccharides. Intensified analysis revealed the main polysaccharide to be composed of glucose (Glc), galactose (Gal), mannose (Man) and glucuronic acid (GlcA), and the minor polysaccharide of Gal, Man, ribose (Rib).
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Santoyo G. How plants recruit their microbiome? New insights into beneficial interactions. J Adv Res 2021; 40:45-58. [PMID: 36100333 PMCID: PMC9481936 DOI: 10.1016/j.jare.2021.11.020] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/25/2021] [Accepted: 11/30/2021] [Indexed: 01/07/2023] Open
Abstract
Plant-microbiome interaction occurs at the rhizosphere, endosphere, and phyllosphere. Root exudates can favor the recruitment of a beneficial microbiome in the rhizosphere. Plant topology and phytochemistry influence the recruitment of the phyllosphere microbiome. Diverse plant strategies selectively recruit beneficial microbiomes. Multiple plant mechanisms displace potential pathogens from the rhizosphere. The beneficial microbiome helps plants to recruit other beneficial microbiota.
Background Research on beneficial mechanisms by plant-associated microbiomes, such as plant growth stimulation and protection from plant pathogens, has gained considerable attention over the past decades; however, the mechanisms used by plants to recruit their microbiome is largely unknown. Aim of Review Here, we review the latest studies that have begun to reveal plant strategies in selectively recruiting beneficial microbiomes, and how they manage to exclude potential pathogens. Key Scientific concepts of Review: We examine how plants attract beneficial microbiota from the main areas of interaction, such as the rhizosphere, endosphere, and phyllosphere, and demonstrate that such process occurs by producing root exudates, and recognizing molecules produced by the beneficial microbiota or distinguishing pathogens using specific receptors, or by triggering signals that support plant-microbiome homeostasis. Second, we analyzed the main environmental or biotic factors that modulate the structure and successional dynamics of microbial communities. Finally, we review how the associated microbiome is capable of engaging with other synergistic microbes, hence providing an additional element of selection. Collectively, this study reveals the importance of understanding the complex network of plant interactions, which will improve the understanding of bioinoculant application in agriculture, based on a microbiome that interacts efficiently with plant organs under different environmental conditions.
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Affiliation(s)
- Gustavo Santoyo
- Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, 58030 Morelia, Mexico.
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27
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Ahlawat OP, Yadav D, Kashyap PL, Khippal A, Singh G. Wheat endophytes and their potential role in managing abiotic stress under changing climate. J Appl Microbiol 2021; 132:2501-2520. [PMID: 34800309 DOI: 10.1111/jam.15375] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/23/2021] [Accepted: 11/16/2021] [Indexed: 11/30/2022]
Abstract
Wheat (Triticum aestivum L.) cultivation differs considerably in respect of soil type, temperature, pH, organic matter, moisture regime, etc. Among these, rising atmospheric temperature due to global warming is most important as it affects grain yield drastically. Studies have shown that for every 1°C rise in temperature above wheat's optimal growing temperature range of 20-25°C, there is a decrease in 2.8 days and 1.5 mg in the grain filling period and kernel weight, respectively, resulting in wheat yield reduction by 4-6 quintal per hectare. Growing demand for food and multidimensional issues of global warming may further push wheat crop to heat stress environments that can substantially affect heading duration, percent grain setting, maturity duration, grain growth rate and ultimately total grain yield. Considerable genetic variation exists in wheat gene pool with respect to various attributes associated with high temperature and stress tolerance; however, only about 15% of the genetic variability could be incorporated into cultivated wheat so far. Thus, alternative strategies have to be explored and implemented for sustainable, more productive and environment friendly agriculture. One of the feasible and environment friendly option is to look at micro-organisms that reside inside the plant without adversely affecting its growth, known as 'endophytes', and these colonize virtually all plant organs such as roots, stems, leaves, flowers and grains. The relationship between plant and endophytes is vital to the plant health, productivity and overall survival under abiotic stress conditions. Thus, it becomes imperative to enlist the endophytes (bacterial and fungal) isolated till date from wheat cultivars, their mechanism of ingression and establishment inside plant organs, genes involved in ingression, the survival advantages they confer to the plant under abiotic stress conditions and the potential benefits of their use in sustainable wheat cultivation.
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Affiliation(s)
| | - Dhinu Yadav
- ICAR-Indian Institute of Wheat and Barley Research, Karnal, India
| | - Prem Lal Kashyap
- ICAR-Indian Institute of Wheat and Barley Research, Karnal, India
| | - Anil Khippal
- ICAR-Indian Institute of Wheat and Barley Research, Karnal, India
| | - Gyanendra Singh
- ICAR-Indian Institute of Wheat and Barley Research, Karnal, India
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Tyrosine Kinase Self-Phosphorylation Controls Exopolysaccharide Biosynthesis in Gluconacetobacter diazotrophicus Strain Pal5. Life (Basel) 2021; 11:life11111231. [PMID: 34833106 PMCID: PMC8620434 DOI: 10.3390/life11111231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/28/2021] [Accepted: 11/10/2021] [Indexed: 11/16/2022] Open
Abstract
The biosynthesis of exopolysaccharides (EPSs) is essential for endophytic bacterial colonisation in plants bacause this exopolymer both protects bacterial cells against the defence and oxidative systems of plants and acts on the plant colonisation mechanism in Gluconacetobacter diazotrophicus. The pathway involved in the biosynthesis of bacterial EPS has not been fully elucidated, and several areas related to its molecular regulation mechanisms are still lacking. G. diazotrophicus relies heavily on EPS for survival indirectly by protecting plants from pathogen attack as well as for endophytic maintenance and adhesion in plant tissues. Here, we report that EPS from G. diazotrophicus strain Pal5 is a signal polymer that controls its own biosynthesis. EPS production depends on a bacterial tyrosine (BY) kinase (Wzc) that consists of a component that is able to phosphorylate a glycosyltranferase or to self-phosphorylate. EPS interacts with the extracellular domain of Wzc, which regulates kinase activity. In G. diazotrophicus strains that are deficient in EPS production, the Wzc is rendered inoperative by self-phosphorylation. The presence of EPS promotes the phosphorylation of a glycosyltransferase in the pathway, thus producing EPS. Wzc-mediated self-regulation is an attribute for the control of exopolysaccharide biosynthesis in G. diazotrophicus.
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Wang M, Geng L, Xue B, Wang Z, Xu W, Shu C, Zhang J. Structure characteristics and function of a novel extracellular polysaccharide from Bacillus thuringiensis strain 4D19. Int J Biol Macromol 2021; 189:956-964. [PMID: 34478795 DOI: 10.1016/j.ijbiomac.2021.08.193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 01/16/2023]
Abstract
Bacillus thuringiensis (Bt) are entomopathogenic bacteria that produce different kinds of insecticidal proteins. However, studies on Bt exopolysaccharides are lacking. Here, we aimed to explore the characteristics and insecticidal synergism of EPS, an exopolysaccharide from Bt strain 4D19. The molecular weight of EPS-2 was 58.0 kDa, which consisted of mannose (44.2%), GlcN (35.5%), D-GalN (8.0%), glucose (5.5%), arabinose (5.1%), galactose (0.9%), Man-UA (0.3%) and Glc-UA (0.2%). The toxicity of insecticidal proteins against Plutella xylostella was increased by adding EPS. EPS-2 bound to Cry1Ac protoxin and promoted the binding of Cry1Ac protoxin to the gut membrane of P. xylostella, but did not bind to activated toxins. These results suggested that EPS-2 may bind to the protoxin C-terminal region to enhance insecticidal activity. Our findings indicated that Bt strains produce exopolysaccharide to enhance the toxicity of insecticidal crystal proteins, which could be applied in biopesticide research and product development.
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Affiliation(s)
- Meiling Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Lili Geng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bai Xue
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zeyu Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wenyue Xu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Changlong Shu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jie Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
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Zeng Q, Xie J, Li Y, Gao T, Zhang X, Wang Q. Comprehensive Genomic Analysis of the Endophytic Bacillus altitudinis Strain GLB197, a Potential Biocontrol Agent of Grape Downy Mildew. Front Genet 2021; 12:729603. [PMID: 34646305 PMCID: PMC8502975 DOI: 10.3389/fgene.2021.729603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/24/2021] [Indexed: 11/13/2022] Open
Abstract
Bacillus has been extensively studied for agricultural application as a biocontrol agent. B. altitudinis GLB197, an endophytic bacterium isolated from grape leaves, exhibits distinctive inhibition to grape downy mildew based on unknown mechanisms. To determine the genetic traits involved in the mechanism of biocontrol and host-interaction traits, the genome sequence of GLB197 was obtained and further analyzed. The genome of B. altitudinis GLB197 consisted of one plasmid and a 3,733,835-bp circular chromosome with 41.56% G + C content, containing 3,770 protein-coding genes. Phylogenetic analysis of 17 Bacillus strains using the concatenated 1,226 single-copy core genes divided into different clusters was conducted. In addition, average nucleotide identity (ANI) values indicate that the current taxonomy of some B. pumilus group strains is incorrect. Comparative analysis of B. altitudinis GLB197 proteins with other B. altitudinis strains identified 3,157 core genes. Furthermore, we found that the pan-genome of B. altitudinis is open. The genome of B. altitudinis GLB197 contains one nonribosomal peptide synthetase (NRPS) gene cluster which was annotated as lichenysin. Interestingly, the cluster in B. altitudinis has two more genes than other Bacillus strains (lgrD and lgrB). The two genes were probably obtained via horizontal gene transfer (HGT) during the evolutionary process from Brevibacillus. Taken together, these observations enable the future application of B. altitudinis GLB197 as a biocontrol agent for control of grape downy mildew and promote our understanding of the beneficial interactions between B. altitudinis GLB197 and plants.
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Affiliation(s)
- Qingchao Zeng
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China.,Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
| | - Jianbo Xie
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
| | - Yan Li
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Tantan Gao
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xun Zhang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
| | - Qi Wang
- Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China
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Wang H, Liu R, You MP, Barbetti MJ, Chen Y. Pathogen Biocontrol Using Plant Growth-Promoting Bacteria (PGPR): Role of Bacterial Diversity. Microorganisms 2021; 9:microorganisms9091988. [PMID: 34576883 PMCID: PMC8470069 DOI: 10.3390/microorganisms9091988] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 09/10/2021] [Accepted: 09/15/2021] [Indexed: 11/16/2022] Open
Abstract
A vast microbial community inhabits in the rhizosphere, among which, specialized bacteria known as Plant Growth-Promoting Rhizobacteria (PGPR) confer benefits to host plants including growth promotion and disease suppression. PGPR taxa vary in the ways whereby they curtail the negative effects of invading plant pathogens. However, a cumulative or synergistic effect does not always ensue when a bacterial consortium is used. In this review, we reassess the disease-suppressive mechanisms of PGPR and present explanations and illustrations for functional diversity and/or stability among PGPR taxa regarding these mechanisms. We also provide evidence of benefits when PGPR mixtures, rather than individuals, are used for protecting crops from various diseases, and underscore the critical determinant factors for successful use of PGPR mixtures. Then, we evaluate the challenges of and limitations to achieving the desired outcomes from strain/species-rich bacterial assemblages, particularly in relation to their role for plant disease management. In addition, towards locating additive or synergistic outcomes, we highlight why and how the benefits conferred need to be categorized and quantified when different strains/species of PGPR are used in combinations. Finally, we highlight the critical approaches needed for developing PGPR mixtures with improved efficacy and stability as biocontrols for utilization in agricultural fields.
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Affiliation(s)
- Hao Wang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Research Center of Soil and Water Conservation and Ecological Environment, Chinese Academy of Sciences, Xianyang 712100, China;
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Runjin Liu
- Institute of Mycorrhizal Biotechnology, Qingdao Agricultural University, Qingdao 266109, China;
| | - Ming Pei You
- The UWA Institute of Agriculture, and School of Agriculture and Environment, The University of Western Australia, LB 5005, Perth, WA 6009, Australia; (M.P.Y.); (M.J.B.)
| | - Martin J. Barbetti
- The UWA Institute of Agriculture, and School of Agriculture and Environment, The University of Western Australia, LB 5005, Perth, WA 6009, Australia; (M.P.Y.); (M.J.B.)
| | - Yinglong Chen
- The UWA Institute of Agriculture, and School of Agriculture and Environment, The University of Western Australia, LB 5005, Perth, WA 6009, Australia; (M.P.Y.); (M.J.B.)
- Correspondence:
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The Potential Application of Endophytes in Management of Stress from Drought and Salinity in Crop Plants. Microorganisms 2021; 9:microorganisms9081729. [PMID: 34442808 PMCID: PMC8398416 DOI: 10.3390/microorganisms9081729] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 01/05/2023] Open
Abstract
Endophytic microorganisms present inside the host plant play an essential role in host fitness, nutrient supply and stress tolerance. Endophytes are often used in sustainable agriculture as biofertilizers, biopesticides and as inoculants to mitigate abiotic stresses including salinity, drought, cold and pH variation in the soil. In changing climatic conditions, abiotic stresses create global challenges to achieve optimum crop yields in agricultural production. Plants experience stress conditions that involve endogenous boosting of their immune system or the overexpression of their defensive redox regulatory systems with increased reactive oxygen species (ROS). However, rising stress factors overwhelm the natural redox protection systems of plants, which leads to massive internal oxidative damage and death. Endophytes are an integral internal partner of hosts and have been shown to mitigate abiotic stresses via modulating local or systemic mechanisms and producing antioxidants to counteract ROS in plants. Advancements in omics and other technologies have been made, but potential application of endophytes remains largely unrealized. In this review article, we will discuss the diversity, population and interaction of endophytes with crop plants as well as potential applications in abiotic stress management.
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A regulatory network involving Rpo, Gac and Rsm for nitrogen-fixing biofilm formation by Pseudomonas stutzeri. NPJ Biofilms Microbiomes 2021; 7:54. [PMID: 34210981 PMCID: PMC8249394 DOI: 10.1038/s41522-021-00230-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/16/2021] [Indexed: 02/06/2023] Open
Abstract
Biofilm and nitrogen fixation are two competitive strategies used by many plant-associated bacteria; however, the mechanisms underlying the formation of nitrogen-fixing biofilms remain largely unknown. Here, we examined the roles of multiple signalling systems in the regulation of biofilm formation by root-associated diazotrophic P. stutzeri A1501. Physiological analysis, construction of mutant strains and microscale thermophoresis experiments showed that RpoN is a regulatory hub coupling nitrogen fixation and biofilm formation by directly activating the transcription of pslA, a major gene involved in the synthesis of the Psl exopolysaccharide component of the biofilm matrix and nifA, the transcriptional activator of nif gene expression. Genetic complementation studies and determination of the copy number of transcripts by droplet digital PCR confirmed that the regulatory ncRNA RsmZ serves as a signal amplifier to trigger biofilm formation by sequestering the translational repressor protein RsmA away from pslA and sadC mRNAs, the latter of which encodes a diguanylate cyclase that synthesises c-di-GMP. Moreover, RpoS exerts a braking effect on biofilm formation by transcriptionally downregulating RsmZ expression, while RpoS expression is repressed posttranscriptionally by RsmA. These findings provide mechanistic insights into how the Rpo/Gac/Rsm regulatory networks fine-tune nitrogen-fixing biofilm formation in response to the availability of nutrients.
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Adeleke BS, Ayangbenro AS, Babalola OO. Genomic assessment of Stenotrophomonas indicatrix for improved sunflower plant. Curr Genet 2021; 67:891-907. [PMID: 34195871 DOI: 10.1007/s00294-021-01199-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 06/21/2021] [Accepted: 06/21/2021] [Indexed: 11/29/2022]
Abstract
Diverse agriculturally important microbes have been studied with known potential in plant growth promotion. Providing several opportunities, Stenotrophomonas species are characterized as promising plant enhancers, inducers, and protectors against environmental stressors. The S. indicatrix BOVIS40 isolated from the sunflower root endosphere possessed unique features, as genome insights into the Stenotrophomonas species isolated from oilseed crops in Southern Africa have not been reported. Plant growth-promotion screening and genome analysis of S. indicatrix BOVIS40 were presented in this study. The genomic information reveals various genes underlining plant growth promotion and resistance to environmental stressors. The genome of S. indicatrix BOVIS40 harbors genes involved in the degradation and biotransformation of organic molecules. Also, other genes involved in biofilm production, chemotaxis, and flagellation that facilitate bacterial colonization in the root endosphere and phytohormone genes that modulate root development and stress response in plants were detected in strain BOVIS40. IAA activity of the bacterial strain may be a factor responsible for root formation. A measurable approach to the S. indicatrix BOVIS40 lifestyle can strategically provide several opportunities in their use as bioinoculants in developing environmentally friendly agriculture sustainably. The findings presented here provide insights into the genomic functions of S. indicatrix BOVIS40, which has set a foundation for future comparative studies for a better understanding of the synergism among microbes inhabiting plant endosphere. Hence, highlighting the potential of S. indicatrix BOVIS40 upon inoculation under greenhouse experiment, thus suggesting its application in enhancing plant and soil health sustainably.
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Affiliation(s)
- Bartholomew Saanu Adeleke
- Food Security and Safety Niche Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho, 2735, South Africa
| | - Ayansina Segun Ayangbenro
- Food Security and Safety Niche Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho, 2735, South Africa
| | - Olubukola Oluranti Babalola
- Food Security and Safety Niche Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho, 2735, South Africa.
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Santoyo G, Urtis-Flores CA, Loeza-Lara PD, Orozco-Mosqueda MDC, Glick BR. Rhizosphere Colonization Determinants by Plant Growth-Promoting Rhizobacteria (PGPR). BIOLOGY 2021; 10:biology10060475. [PMID: 34072072 PMCID: PMC8229920 DOI: 10.3390/biology10060475] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Plant growth-promoting rhizobacteria (PGPR) are an eco-friendly alternative to the use of chemicals in agricultural production and crop protection. However, the efficacy of PGPR as bioinoculants can be diminished by a low capacity to colonize spaces in the rhizosphere. In this work, we review pioneering and recent developments on several important functions that rhizobacteria exhibit in order to compete, colonize, and establish themselves in the plant rhizosphere. Therefore, the use of highly competitive strains in open field trials should be a priority, in order to have consistent and better results in agricultural production activities. Abstract The application of plant growth-promoting rhizobacteria (PGPR) in the field has been hampered by a number of gaps in the knowledge of the mechanisms that improve plant growth, health, and production. These gaps include (i) the ability of PGPR to colonize the rhizosphere of plants and (ii) the ability of bacterial strains to thrive under different environmental conditions. In this review, different strategies of PGPR to colonize the rhizosphere of host plants are summarized and the advantages of having highly competitive strains are discussed. Some mechanisms exhibited by PGPR to colonize the rhizosphere include recognition of chemical signals and nutrients from root exudates, antioxidant activities, biofilm production, bacterial motility, as well as efficient evasion and suppression of the plant immune system. Moreover, many PGPR contain secretion systems and produce antimicrobial compounds, such as antibiotics, volatile organic compounds, and lytic enzymes that enable them to restrict the growth of potentially phytopathogenic microorganisms. Finally, the ability of PGPR to compete and successfully colonize the rhizosphere should be considered in the development and application of bioinoculants.
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Affiliation(s)
- Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico;
- Correspondence:
| | - Carlos Alberto Urtis-Flores
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico;
| | - Pedro Damián Loeza-Lara
- Licenciatura en Genómica Alimentaria, Universidad de La Ciénega del Estado de Michoacán de Ocampo, Sahuayo 59103, Mexico;
| | - Ma. del Carmen Orozco-Mosqueda
- Facultad de Agrobiología “Presidente Juárez”, Universidad Michoacana de San Nicolás de Hidalgo, Melchor Ocampo, Uruapan 60170, Mexico;
| | - Bernard R. Glick
- Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada;
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Antunes VDC, Freitag D, Serrato RV. Differential exopolysaccharide production and composition by Herbaspirillum strains from diverse ecological environments. Arch Microbiol 2021; 203:3883-3892. [PMID: 34009446 DOI: 10.1007/s00203-021-02371-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/22/2021] [Accepted: 05/08/2021] [Indexed: 11/26/2022]
Abstract
Bacteria belonging to the genus Herbaspirillum are found in many different ecological niches. Some species are typically endophytic, while others were reported as free-living organisms that occupy various environments. Also, opportunistic herbaspirilli have been found infecting humans affected by several diseases. We have analyzed the production of exopolysaccharides (EPS) by Herbaspirillum strains isolated from different sources and with distinct ecological characteristics. The monosaccharide composition was determined for the EPS obtained for selected strains including free-living, plant-associated and clinical isolates, and the relationship with the ecological niches occupied by Herbaspirillum spp. is proposed.
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Affiliation(s)
- Valquíria D C Antunes
- Department of Biochemistry and Molecular Biology, Setor de Ciências Biológicas-Centro Politécnico, Universidade Federal do Paraná , R. Francisco H. dos Santos, 100 , PO Box 19046, Curitiba, PR, 81531-980, Brazil
| | - Daniela Freitag
- Department of Biochemistry and Molecular Biology, Setor de Ciências Biológicas-Centro Politécnico, Universidade Federal do Paraná , R. Francisco H. dos Santos, 100 , PO Box 19046, Curitiba, PR, 81531-980, Brazil
| | - Rodrigo V Serrato
- Department of Biochemistry and Molecular Biology, Setor de Ciências Biológicas-Centro Politécnico, Universidade Federal do Paraná , R. Francisco H. dos Santos, 100 , PO Box 19046, Curitiba, PR, 81531-980, Brazil.
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Verma SK, Sahu PK, Kumar K, Pal G, Gond SK, Kharwar RN, White JF. Endophyte roles in nutrient acquisition, root system architecture development and oxidative stress tolerance. J Appl Microbiol 2021; 131:2161-2177. [PMID: 33893707 DOI: 10.1111/jam.15111] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/06/2021] [Accepted: 04/16/2021] [Indexed: 01/01/2023]
Abstract
Plants associate with communities of microbes (bacteria and fungi) that play critical roles in plant development, nutrient acquisition and oxidative stress tolerance. The major share of plant microbiota is endophytes which inhabit plant tissues and help them in various capacities. In this article, we have reviewed what is presently known with regard to how endophytic microbes interact with plants to modulate root development, branching, root hair formation and their implications in overall plant development. Endophytic microbes link the interactions of plants, rhizospheric microbes and soil to promote nutrient solubilization and further vectoring these nutrients to the plant roots making the soil-plant-microbe continuum. Further, plant roots internalize microbes and oxidatively extract nutrients from microbes in the rhizophagy cycle. The oxidative interactions between endophytes and plants result in the acquisition of nutrients by plants and are also instrumental in oxidative stress tolerance of plants. It is evident that plants actively cultivate microbes internally, on surfaces and in soils to acquire nutrients, modulate development and improve health. Understanding this continuum could be of greater significance in connecting endophytes with the hidden half of the plant that can also be harnessed in applied terms to enhance nutrient acquisition through the development of favourable root system architecture for sustainable production under stress conditions.
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Affiliation(s)
- S K Verma
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - P K Sahu
- National Bureau of Agriculturally Important Microorganism, Mau, Uttar Pradesh, India
| | - K Kumar
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - G Pal
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - S K Gond
- Botany Section, MMV, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - R N Kharwar
- Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - J F White
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA
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Santos RMD, Rigobelo EC. Growth-Promoting Potential of Rhizobacteria Isolated From Sugarcane. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2021. [DOI: 10.3389/fsufs.2021.596269] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The search for plant growth-promoting rhizobacteria (PGPRs) addresses the ongoing need for new bioinoculants to be used on various agricultural crop species, including sugarcane. Bacterial strains were isolated from the rhizosphere of sugarcane plants and identified by sequencing the 16S ribosomal gene. The main indole acetic acid producers were Enterobacter sp. IP11, Enterobacter sp. IP14, and E. asburiae IP24. Achromobacter spanius IP23 presented the highest levels of cellulolytic activity and potassium solubilization. Bacillus thuringiensis IP21 and Staphylococcus saprophyticus IJ8 showed the highest levels of fixed nitrogen. The levels of calcium phosphate and aluminum phosphate in B. thuringiensis IP21 were notable, as this strain solubilized 481.00 and 39.33 mg of phosphorus mL−1, respectively; however, for Araxá apatite, the results for B. anthracis IP17 were notable (622.99 mg phosphorus mL−1), while for iron phosphate solubilization, Enterobacter sp. IP14, which solubilized 105.66 mg phosphorus mL−1 was notable. The B. thuringiensis IP21 and Enterobacter sp. IP11 isolates promoted the growth of the tallest sugarcane plants, inducing increases of 14.1 and 10.4% relative to the control plants, respectively. For shoot dry matter, root dry matter, and total dry matter, plants inoculated with Enterobacter sp. IP14, B. anthracis IP17, and A. spanius IP23 presented higher values than the controls. Furthermore, plants inoculated with B. thuringiensis IP21 presented higher root dry matter and total dry matter values, and those inoculated with Enterobacter sp. IP14 also presented higher total dry matter values. These results indicate that bacteria with the potential for use as future inoculants should be investigated since bacteria with plant growth-related characteristics may not impact growth promotion.
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Computational characterizations of GDP-mannose 4,6-dehydratase (NoeL) Rhizobial proteins. Curr Genet 2021; 67:769-784. [PMID: 33837815 DOI: 10.1007/s00294-021-01184-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/19/2021] [Accepted: 03/29/2021] [Indexed: 10/21/2022]
Abstract
A growing body of evidence suggests that Nod Factors molecules are the critical structural components in nitrogen fixation. These molecules have been implicated in plant-microbe signaling. Many enzymes involved in Nod factors biosynthesis; however, the enzymes that decorate (modify) nod factor main structure play a vital role. Here, the computational analysis of GDP-mannose 4,6-dehydratase (NoeL) proteins with great impact in modification of nod factor structure in four genomes of agriculturally important rhizobia (Bradyrhizobium, Mesorhizobium, Rhizobium, Sinorhizobium) presented. The NoeL number of amino acids was in the range of 147 (M5AMF5) to 372 (A0A023XWX0, Q89TZ1). The molecular weights were around 41 KDa. The results showed that the strain-specific purification strategy should apply as the pI of the sequences varied significantly (in the range of 5.59 to 9.12). The enzyme sequences and eight 3-dimensional structures predicted with homology modeling and machine learning representing the phylogenetic tree revealed the stability of enzymes in different conditions (Instability and Aliphatic index); however, this stability is also strain-specific. Disulphide bonds were observed in some species; however, the pattern was not detected in all members of the same species. Alpha helix was the dominant secondary structure predicted in all cytoplasmic NoeL. All models were homo-tetramer with acceptable sequence identity, GMEAN and coverage (60, - 1.80, 88, respectively). Additionally, Ramachandran maps showed that more than 94% of residues are in favored regions. We also highlight several key characterizations of NoeL from four rhizobia genomes annotation. These findings provide novel insights into the complexity and diversity of NoeL enzymes among important rhizobia and suggest considering a broader framework of biofilm for future research.
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Dudeja SS, Suneja-Madan P, Paul M, Maheswari R, Kothe E. Bacterial endophytes: Molecular interactions with their hosts. J Basic Microbiol 2021; 61:475-505. [PMID: 33834549 DOI: 10.1002/jobm.202000657] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 03/07/2021] [Accepted: 03/16/2021] [Indexed: 01/19/2023]
Abstract
Plant growth promotion has been found associated with plants on the surface (epiphytic), inside (endophytic), or close to the plant roots (rhizospheric). Endophytic bacteria mainly have been researched for their beneficial activities in terms of nutrient availability, plant growth hormones, and control of soil-borne and systemic pathogens. Molecular communications leading to these interactions between plants and endophytic bacteria are now being unrevealed using multidisciplinary approaches with advanced techniques such as metagenomics, metaproteomics, metatranscriptomics, metaproteogenomic, microRNAs, microarray, chips as well as the comparison of complete genome sequences. More than 400 genes in both the genomes of host plant and bacterial endophyte are up- or downregulated for the establishment of endophytism and plant growth-promoting activity. The involvement of more than 20 genes for endophytism, about 50 genes for direct plant growth promotion, about 25 genes for biocontrol activity, and about 10 genes for mitigation of different stresses has been identified in various bacterial endophytes. This review summarizes the progress that has been made in recent years by these modern techniques and approaches.
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Affiliation(s)
- Surjit S Dudeja
- Department of Bio & Nanotechnology, Guru Jambeshwar University of Science & Technology, Hisar, India
| | - Pooja Suneja-Madan
- Department of Microbiology, Maharishi Dayanand University, Rohtak, India
| | - Minakshi Paul
- Department of Bio & Nanotechnology, Guru Jambeshwar University of Science & Technology, Hisar, India
| | - Rajat Maheswari
- Department of Microbiology, Maharishi Dayanand University, Rohtak, India
| | - Erika Kothe
- Microbial Communication, Institute of Microbiology, Faculty for Biosciences, Friedrich Schiller University of Jena, Jena, Germany
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Fernández-Llamosas H, Díaz E, Carmona M. Motility, Adhesion and c-di-GMP Influence the Endophytic Colonization of Rice by Azoarcus sp. CIB. Microorganisms 2021; 9:microorganisms9030554. [PMID: 33800326 PMCID: PMC7998248 DOI: 10.3390/microorganisms9030554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 02/18/2021] [Accepted: 03/05/2021] [Indexed: 01/26/2023] Open
Abstract
Proficient crop production is needed to ensure the feeding of a growing global population. The association of bacteria with plants plays an important role in the health state of the plants contributing to the increase of agricultural production. Endophytic bacteria are ubiquitous in most plant species providing, in most cases, plant promotion properties. However, the knowledge on the genetic determinants involved in the colonization of plants by endophytic bacteria is still poorly understood. In this work we have used a genetic approach based on the construction of fliM, pilX and eps knockout mutants to show that the motility mediated by a functional flagellum and the pili type IV, and the adhesion modulated by exopolysaccarides are required for the efficient colonization of rice roots by the endophyte Azoarcus sp. CIB. Moreover, we have demonstrated that expression of an exogenous diguanylate cyclase or phophodiesterase, which causes either an increase or decrease of the intracellular levels of the second messenger cyclic di-GMP (c-di-GMP), respectively, leads to a reduction of the ability of Azoarcus sp. CIB to colonize rice plants. Here we present results demonstrating the unprecedented role of the universal second messenger cyclic-di-GMP in plant colonization by an endophytic bacterium, Azoarcus sp. CIB. These studies pave the way to further strategies to modulate the interaction of endophytes with their target plant hosts.
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Acetan and Acetan-Like Polysaccharides: Genetics, Biosynthesis, Structure, and Viscoelasticity. Polymers (Basel) 2021; 13:polym13050815. [PMID: 33799945 PMCID: PMC7961339 DOI: 10.3390/polym13050815] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
Abstract
Bacteria produce a variety of multifunctional polysaccharides, including structural, intracellular, and extracellular polysaccharides. They are attractive for the industrial sector due to their natural origin, sustainability, biodegradability, low toxicity, stability, unique viscoelastic properties, stable cost, and supply. When incorporated into different matrices, they may control emulsification, stabilization, crystallization, water release, and encapsulation. Acetan is an important extracellular water-soluble polysaccharide produced mainly by bacterial species of the genera Komagataeibacter and Acetobacter. Since its original description in Komagataeibacter xylinus, acetan-like polysaccharides have also been described in other species of acetic acid bacteria. Our knowledge on chemical composition of different acetan-like polysaccharides, their viscoelasticity, and the genetic basis for their production has expanded during the last years. Here, we review data on acetan biosynthesis, its molecular structure, genetic organization, and mechanical properties. In addition, we have performed an extended bioinformatic analysis on acetan-like polysaccharide genetic clusters in the genomes of Komagataeibacter and Acetobacter species. The analysis revealed for the first time a second acetan-like polysaccharide genetic cluster, that is widespread in both genera. All species of the Komagataeibacter possess at least one acetan genetic cluster, while it is present in only one third of the Acetobacter species surveyed.
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Kumawat KC, Sharma P, Nagpal S, Gupta RK, Sirari A, Nair RM, Bindumadhava H, Singh S. Dual Microbial Inoculation, a Game Changer? - Bacterial Biostimulants With Multifunctional Growth Promoting Traits to Mitigate Salinity Stress in Spring Mungbean. Front Microbiol 2021; 11:600576. [PMID: 33584566 PMCID: PMC7874087 DOI: 10.3389/fmicb.2020.600576] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 12/16/2020] [Indexed: 11/13/2022] Open
Abstract
Soil microbes play a vital role in improving plant growth, soil health, ameliorate biotic/abiotic stress and enhance crop productivity. The present study was aimed to investigate a coordinated effect of compatible consortium [salt tolerating Rhizobium and rhizobacterium with 1-aminocyclopropane-1-carboxylate (ACC) deaminase] in enhancing plant growth promoting (PGP) traits, symbiotic efficiency, nutrient acquisition, anti-oxidative enzymes, grain yield and associated profitability in spring mungbean. We identified a non-pathogenic compatible Rhizobium sp. LSMR-32 (MH644039.1) and Enterococcus mundtii LSMRS-3 (MH644178.1) from salt affected areas of Punjab, India and the same were assessed to develop consortium biofertilizer based on salt tolerance, multifarious PGP traits, antagonistic defense activities and presence of nifH, acds, pqq, and ipdc genes. Indole Acetic acid (IAA), P-solubilization, biofilm formation, exo-polysaccharides, siderophore, salt tolerance, ACC deaminase activities were all found highly significant in dual inoculant (LSMR-32 + LSMRS-3) treatment compared to LSMR-32 alone. Under saline soil conditions, dual inoculant showed a higher seed germination, plant height, biomass, chlorophyll content and macro and micro-nutrient uptake, than un-inoculated control. However, symbiotic (nodulation, nodule biomass and leghaemoglobin content) and soil quality parameters (phosphatase and soil dehydrogenase enzymes) increased numerically with LSMR-32 + LSMRS-3 over Rhizobium sp. LSMR-32 alone. Dual bacterial inoculation (LSMR-32 + LSMRS-3) increased the proline content (2.05 fold), anti-oxidative enzymes viz., superoxide dismutase (1.50 fold), catalase (1.43 fold) and peroxidase (3.88 folds) in contrast to control treatment. Decreased Na+ accumulation and increased K+ uptake resulted in favorable K+/Na+ ratio through ion homeostasis. Co-inoculation of Rhizobium sp. LSMR-32 and Enterococcus mundtii LSMRS-3 significantly improved the grain yield by 8.92% and led to superior B: C ratio over Rhizobium sp. alone under salt stress. To best of our knowledge this is perhaps the first field report from Indian soils that largely describes dual inoculation of Rhizobium sp. LSMR-32 and Enterococcus mundtii LSMRS-3 and the same can be considered as a game-changer approach to simultaneously induce salt tolerance and improve productivity in spring mungbean under saline stress conditions.
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Affiliation(s)
| | - Poonam Sharma
- Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, India
| | - Sharon Nagpal
- Department of Microbiology, Punjab Agricultural University, Ludhiana, India
| | - R K Gupta
- Department of Soil Science, Punjab Agricultural University, Ludhiana, India
| | - Asmita Sirari
- Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana, India
| | | | | | - Sudeep Singh
- Regional Research Station, Punjab Agricultural University, Bathinda, India
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Insights into the early stages of plant-endophytic bacteria interaction. World J Microbiol Biotechnol 2021; 37:13. [PMID: 33392741 DOI: 10.1007/s11274-020-02966-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/21/2020] [Indexed: 12/11/2022]
Abstract
The plant holobiont is a complex entity composed of the plant and the organisms that live in and on it including its microbiota. The plant microbiota includes, among other microorganisms, bacterial endophytes, which are bacteria that can invade living plant tissues without causing symptoms of disease. The interaction between the endophytic bacterial microbiota and their plant host has profound influences on their fitness and depends on biotic and abiotic factors. For these interactions to be established, the bacteria have to be present at the right time, in the right place either colonizing the soil or the seed. In this review we summarize the current knowledge regarding the sources of the bacterial endophytic microbiome and the processes involved in the assemblage of the resulting community during the initial stages of plant development. The adaptations that allow the spatial approximation of soil- and seed-borne bacteria towards infection and colonization of the internal tissues of plants will be addressed in this review.
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Dos Santos TC, Leandro MR, Maia CY, Rangel P, Soares FS, Reis R, Passamani L, Silveira V, de Souza Filho GA. Arabidopsis thaliana exudates induce growth and proteomic changes in Gluconacetobacter diazotrophicus. PeerJ 2020; 8:e9600. [PMID: 33240578 PMCID: PMC7676354 DOI: 10.7717/peerj.9600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/03/2020] [Indexed: 12/17/2022] Open
Abstract
Background Plants interact with a variety of microorganisms during their life cycle, among which beneficial bacteria deserve special attention. Gluconacetobacter diazotrophicus is a beneficial bacterium able to fix nitrogen and promote plant growth. Despite its biotechnological potential, the mechanisms regulating the interaction between G. diazotrophicus and host plants remain unclear. Methods We analyzed the response of G. diazotrophicus to cocultivation with Arabidopsis thaliana seedlings. Bacterial growth in response to cocultivation and plant exudates was analyzed. Through comparative proteomic analysis, G. diazotrophicus proteins regulated during cocultivation were investigated. Finally, the role of some up-accumulated proteins in the response G. diazotrophicus to cocultivation was analyzed by reverse genetics, using insertion mutants. Results Our results revealed the induction of bacterial growth in response to cocultivation. Comparative proteomic analysis identified 450 bacterial proteins, with 39 up-accumulated, and 12 down-accumulated in response to cocultivation. Among the up-accumulated pathways, the metabolism of pentoses and protein synthesis were highlighted. Proteins potentially relevant to bacterial growth response such as ABC-F-Etta, ClpX, Zwf, MetE, AcnA, IlvC, and AccC were also increased. Reverse genetics analysis, using insertion mutants, revealed that the lack of ABC-F-Etta and AccC proteins severely affects G. diazotrophicus response to cocultivation. Our data demonstrated that specific mechanisms are activated in the bacterial response to plant exudates, indicating the essential role of “ribosomal activity” and “fatty acid biosynthesis” in such a process. This is the first study to demonstrate the participation of EttA and AccC proteins in plant-bacteria interactions, and open new perspectives for understanding the initial steps of such associations.
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Affiliation(s)
- Tamires Cruz Dos Santos
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Mariana Ramos Leandro
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Clara Yohana Maia
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Patrícia Rangel
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Fabiano S Soares
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Ricardo Reis
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Lucas Passamani
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Vanildo Silveira
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
| | - Gonçalo Apolinário de Souza Filho
- Laboratório de Biotecnologia/Unidade de Biologia Integrativa, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Rio de Janeiro, Brazil
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Dos-Santos CM, Nascimento WBA, do Nascimento BP, Schwab S, Baldani JI, Vidal MS. Temporal assessment of root and shoot colonization of elephant grass (Pennisetum purpureum Schum.) host seedlings by Gluconacetobacter diazotrophicus strain LP343. Microbiol Res 2020; 244:126651. [PMID: 33383369 DOI: 10.1016/j.micres.2020.126651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/09/2020] [Accepted: 11/13/2020] [Indexed: 11/18/2022]
Abstract
Gluconacetobacter diazotrophicus is a species of great agronomic potential due to its growth-promotion traits. Its colonization process in different plants has been reported. However, there have been no studies regarding its structural colonization in elephant grass. This is a fast-growing C4-Poaceae plant, and its application in Brazil is mainly aimed at feeding dairy cattle, due to its high nutritional value. Also, in the last decade, this grass has been applied in the production of biofuels. The present study aimed to monitor the colonization process of strain LP343 of G. diazotrophicus inoculated in elephant grass seedlings of PCEA genotype, by using a mCherry-tagged bacterium. Samples of roots and shoots collected at different periods were visualized by confocal laser-scanning microscopy. The colony-counting assay was used to compare the number of cells recovered in different niches and a qPCR was performed for the quantification of endophytic cells in root and shoot tissues. Results suggested that the strain LP343 quickly recognized the PCEA roots as host, attached to the elephant grass roots at 6 h, and 7 days after inoculation were able to colonize the xylem vessels of roots and shoots of elephant grass. This study advances our knowledge about the colonization process of G. diazotrophicus species in elephant grass, contributing to future studies involving the plant-bacteria interaction cultivated under gnotobiotic conditions.
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Affiliation(s)
- Carlos M Dos-Santos
- Embrapa Agrobiologia, Rodovia BR 465, km 7, CEP 23891-000, Seropédica, RJ, Brazil
| | - Wiglison B A Nascimento
- Embrapa Agrobiologia, Rodovia BR 465, km 7, CEP 23891-000, Seropédica, RJ, Brazil; Instituto de Agronomia, Departamento de Agronomia, Universidade Federal Rural do Rio de Janeiro, Rodovia BR 465, km 7, CEP 23897-000, Seropédica, RJ, Brazil
| | - Bruna P do Nascimento
- Embrapa Agrobiologia, Rodovia BR 465, km 7, CEP 23891-000, Seropédica, RJ, Brazil; Instituto de Tecnologia, Departamento de Química, Universidade Federal Rural do Rio de Janeiro, Rodovia BR 465, km 7, CEP 23897-000, Seropédica, RJ, Brazil
| | - Stefan Schwab
- Embrapa Agrobiologia, Rodovia BR 465, km 7, CEP 23891-000, Seropédica, RJ, Brazil
| | - José I Baldani
- Embrapa Agrobiologia, Rodovia BR 465, km 7, CEP 23891-000, Seropédica, RJ, Brazil
| | - Marcia S Vidal
- Embrapa Agrobiologia, Rodovia BR 465, km 7, CEP 23891-000, Seropédica, RJ, Brazil.
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Chlebek D, Pinski A, Żur J, Michalska J, Hupert-Kocurek K. Genome Mining and Evaluation of the Biocontrol Potential of Pseudomonas fluorescens BRZ63, a New Endophyte of Oilseed Rape ( Brassica napus L.) against Fungal Pathogens. Int J Mol Sci 2020; 21:ijms21228740. [PMID: 33228091 PMCID: PMC7699435 DOI: 10.3390/ijms21228740] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/12/2020] [Accepted: 11/16/2020] [Indexed: 11/30/2022] Open
Abstract
Endophytic bacteria hold tremendous potential for use as biocontrol agents. Our study aimed to investigate the biocontrol activity of Pseudomonas fluorescens BRZ63, a new endophyte of oilseed rape (Brassica napus L.) against Rhizoctonia solani W70, Colletotrichum dematium K, Sclerotinia sclerotiorum K2291, and Fusarium avenaceum. In addition, features crucial for biocontrol, plant growth promotion, and colonization were assessed and linked with the genome sequences. The in vitro tests showed that BRZ63 significantly inhibited the mycelium growth of all tested pathogens and stimulated germination and growth of oilseed rape seedlings treated with fungal pathogens. The BRZ63 strain can benefit plants by producing biosurfactants, siderophores, indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and ammonia as well as phosphate solubilization. The abilities of exopolysaccharide production, autoaggregation, and biofilm formation additionally underline its potential to plant colonization and hence biocontrol. The effective colonization properties of the BRZ63 strain were confirmed by microscopy observations of EGFP-expressing cells colonizing the root surface and epidermal cells of Arabidopsis thaliana Col-0. Genome mining identified many genes related to the biocontrol process, such as transporters, siderophores, and other secondary metabolites. All analyses revealed that the BRZ63 strain is an excellent endophytic candidate for biocontrol of various plant pathogens and plant growth promotion.
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Affiliation(s)
- Daria Chlebek
- Correspondence: (D.C.); (K.H.-K.); Tel.: +48-32-2009-462 (K.H.-K.)
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Papik J, Folkmanova M, Polivkova-Majorova M, Suman J, Uhlik O. The invisible life inside plants: Deciphering the riddles of endophytic bacterial diversity. Biotechnol Adv 2020; 44:107614. [PMID: 32858117 DOI: 10.1016/j.biotechadv.2020.107614] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/14/2020] [Accepted: 08/15/2020] [Indexed: 10/25/2022]
Abstract
Endophytic bacteria often promote plant growth and protect their host plant against pathogens, herbivores, and abiotic stresses including drought, increased salinity or pollution. Current agricultural practices are being challenged in terms of climate change and the ever-increasing demand for food. Therefore, the rational exploitation of bacterial endophytes to increase the productivity and resistance of crops appears to be very promising. However, the efficient and larger-scale use of bacterial endophytes for more effective and sustainable agriculture is hindered by very little knowledge on molecular aspects of plant-endophyte interactions and mechanisms driving bacterial communities in planta. In addition, since most of the information on bacterial endophytes has been obtained through culture-dependent techniques, endophytic bacterial diversity and its full biotechnological potential still remain highly unexplored. In this study, we discuss the diversity and role of endophytic populations as well as complex interactions that the endophytes have with the plant and vice versa, including the interactions leading to plant colonization. A description of biotic and abiotic factors influencing endophytic bacterial communities is provided, along with a summary of different methodologies suitable for determining the diversity of bacterial endophytes, mechanisms governing the assembly and structure of bacterial communities in the endosphere, and potential biotechnological applications of endophytes in the future.
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Affiliation(s)
- Jakub Papik
- University of Chemistry and Technology, Prague, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Prague, Czech Republic
| | - Magdalena Folkmanova
- University of Chemistry and Technology, Prague, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Prague, Czech Republic
| | - Marketa Polivkova-Majorova
- University of Chemistry and Technology, Prague, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Prague, Czech Republic
| | - Jachym Suman
- University of Chemistry and Technology, Prague, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Prague, Czech Republic
| | - Ondrej Uhlik
- University of Chemistry and Technology, Prague, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Prague, Czech Republic.
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Fadiji AE, Babalola OO. Exploring the potentialities of beneficial endophytes for improved plant growth. Saudi J Biol Sci 2020; 27:3622-3633. [PMID: 33304173 PMCID: PMC7714962 DOI: 10.1016/j.sjbs.2020.08.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 11/23/2022] Open
Abstract
Pathogen affects plant growth, host health and productivity. Endophytes, presumed to live inside the plant tissues, might be helpful in sustaining the future of agriculture. Although recent studies have proven that endophytes can be pathogenic, commensal, non-pathogenic, and/or beneficial, this review will focus on the beneficial category only. Beneficial endophytes produce a number of compounds which are useful for protecting plants from environmental conditions, enhancing plant growth and sustainability, while living conveniently inside the hosts. The population of endophytes is majorly controlled by location, and climatic conditions where the host plant grows. Often the most frequently isolated endophytes from the tissues of the plant are fungi, but sometimes greater numbers of bacteria are isolated. Beneficial endophytes stand a chance to replace the synthetic chemicals currently being used for plant growth promotion if carefully explored by researchers and embraced by policymakers. However, the roles of endophytes in plant growth improvement and their behavior in the host plant have not been fully understood. This review presents the current development of research into beneficial endophytes and their effect in improving plant growth.
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Affiliation(s)
- Ayomide Emmanuel Fadiji
- Food Security and Safety Niche, Faculty of Natural and Agricultural Sciences, Private Mail Bag X2046, North-West University, South Africa
| | - Olubukola Oluranti Babalola
- Food Security and Safety Niche, Faculty of Natural and Agricultural Sciences, Private Mail Bag X2046, North-West University, South Africa
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Fatima T, Mishra I, Verma R, Arora NK. Mechanisms of halotolerant plant growth promoting Alcaligenes sp. involved in salt tolerance and enhancement of the growth of rice under salinity stress. 3 Biotech 2020; 10:361. [PMID: 32832323 PMCID: PMC7392994 DOI: 10.1007/s13205-020-02348-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/20/2020] [Indexed: 02/06/2023] Open
Abstract
In the present study halotolerant bacteria were isolated from saline soil (EC ~ 11.9). Based on salt tolerance and plant growth promoting characteristics isolate AF7 was selected for further study. It was identified as Alcaligenes sp. on the basis of protein profiling and 16S rRNA sequence homology. Interestingly, AF7 showed diverse PGP characters at different salinity levels. While phosphate solubilization activity was expressed up to 300 mM NaCl, siderophore production was shown up to 700 mM, zinc solubilization up to 1000 mM and indole acetic acid (IAA), gibberellic acid (GA) and exopolysaccharides (EPS) production were depicted till 1400 mM. Correlative and regression analysis suggested positive relation between IAA, GA, EPS, siderophore production and zinc solubilization capability of AF7 and salinity up to 300 mM NaCl. EPS was found to be the most significant response and there was 263% increment in presence of 300 mM NaCl when compared to non-saline control. Analysis also showed that while growth promoting attributes were significant up to a threshold salinity level, further increasing the stress deviates the mechanism towards survival involving proline, antioxidant and hydroxyl scavenging activities. Combination of halotolerant AF7 and EPS showed more than twofold increase in the vegetative growth parameters of rice at ~ 170 mM NaCl (EC 9 dS/m). The study shows the mechanisms/metabolites of the plant growth promoting bacterium (PGPB) AF7 prominently involved during the salinity stress. Study also proves that novel bioformulations can be developed by integrative use of EPS and salt tolerant-PGPB which can be effective for saline soils.
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Affiliation(s)
- Tahmish Fatima
- Department of Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Isha Mishra
- Department of Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Renu Verma
- Department of Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
| | - Naveen Kumar Arora
- Department of Environmental Science, School for Environmental Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow, India
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