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Alleviation of Cadmium and Nickel Toxicity and Phyto-Stimulation of Tomato Plant L. by Endophytic Micrococcus luteus and Enterobacter cloacae. PLANTS 2022; 11:plants11152018. [PMID: 35956496 PMCID: PMC9370581 DOI: 10.3390/plants11152018] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 01/22/2023]
Abstract
Cadmium (Cd) and nickel (Ni) are two of the most toxic metals, wreaking havoc on human health and agricultural output. Furthermore, high levels of Cd and Ni in the soil environment, particularly in the root zone, may slow plant development, resulting in lower plant biomass. On the other hand, endophytic bacteria offer great promise for reducing Cd and Ni. Moreover, they boost plants’ resistance to heavy metal stress. Different bacterium strains were isolated from tomato roots. These isolates were identified as Micrococcus luteus and Enterobacter cloacae using 16SrDNA and were utilized to investigate their involvement in mitigating the detrimental effects of heavy metal stress. The two bacterial strains can solubilize phosphorus and create phytohormones as well as siderophores. Therefore, the objective of this study was to see how endophytic bacteria (Micrococcus luteus and Enterobactercloacae) affected the mitigation of stress from Cd and Ni in tomato plants grown in 50 μM Cd or Ni-contaminated soil. According to the findings, Cd and Ni considerably lowered growth, biomass, chlorophyll (Chl) content, and photosynthetic properties. Furthermore, the content of proline, phenol, malondialdehyde (MDA), H2O2, OH, O2, the antioxidant defense system, and heavy metal (HM) contents were significantly raised under HM-stress conditions. However, endophytic bacteria greatly improved the resistance of tomato plants to HM stress by boosting enzymatic antioxidant defenses (i.e., catalase, peroxidase, superoxide dismutase, glutathione reductase, ascorbate peroxidase, lipoxygenase activity, and nitrate reductase), antioxidant, non-enzymatic defenses, and osmolyte substances such as proline, mineral content, and specific regulatory defense genes. Moreover, the plants treated had a higher value for bioconcentration factor (BCF) and translocation factor (TF) due to more extensive loss of Cd and Ni content from the soil. To summarize, the promotion of endophytic bacterium-induced HM resistance in tomato plants is essentially dependent on the influence of endophytic bacteria on antioxidant capacity and osmoregulation.
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Laranjeira SS, Alves IG, Marques G. Chickpea (Cicer arietinum L.) Seeds as a Reservoir of Endophytic Plant Growth-Promoting Bacteria. Curr Microbiol 2022; 79:277. [PMID: 35907956 DOI: 10.1007/s00284-022-02942-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 06/17/2022] [Indexed: 11/30/2022]
Abstract
The seed microbiome, the primary source of inoculum for plants, may play an important role in plant growth, health and productivity. However, the structure and function of chickpea seed endophytes are poorly characterized. Bacteria with beneficial characteristics can be selected by the plant and transmitted vertically via the seed to benefit the next generation. Studying the diversity and multifunctionality of seed microbial communities can provide innovative opportunities in the field of plant-microbe interaction. This study aimed to isolate, identify and characterize culturable endophytic bacteria from chickpea (Cicer arietinum L.) seeds. Phylogenetic analysis based on 16S rDNA showed that the endophytic bacteria belong to the genera Mesorhizobium, Burkholderia, Bacillus, Priestia, Paenibacillus, Alcaligenes, Acinetobacter, Rahnella, Enterobacter, Tsukamurella, and Microbacterium. The most frequently observed genus was Bacillus; however, rhizobia typically associated with chickpea roots were also found, which is a novel finding of this study. Siderophore production and phosphorus solubilization were the most widespread plant growth-promoting features, while hydrogen cyanide production was relatively rare among the isolates. Most of the isolates possess two or more plant growth-promoting features; however, only Bacillus thuringiensis Y2B, a well-known entomopathogenic bacteria, exhibited the presence of all plant growth-promoting traits evaluated. Results suggest that endophytic bacteria such as Bacillus, Mesorhizobium, and Burkholderia may be vertically transferred from inoculated plants to seeds to benefit the next generation.
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Affiliation(s)
- Sara S Laranjeira
- Centre for Research and Technology of Agro-Environmental and Biological Sciences, CITAB, University of Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, 5000-801, Vila Real, Portugal
| | - Isabel G Alves
- Centre for Research and Technology of Agro-Environmental and Biological Sciences, CITAB, University of Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, 5000-801, Vila Real, Portugal
| | - Guilhermina Marques
- Centre for Research and Technology of Agro-Environmental and Biological Sciences, CITAB, University of Trás-os-Montes e Alto Douro, UTAD, Quinta de Prados, 5000-801, Vila Real, Portugal.
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Liu D, Lin L, Zhang T, Xu Q, Wang M, Gao M, Bhople P, Pritchard HW, Yang X, Yu F. Wild Panax plants adapt to their thermal environment by harboring abundant beneficial seed endophytic bacteria. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.967692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The seed microbiome of crop wild relatives is a potential reservoir of beneficial traits that potentially improve their host plant resilience to fluctuating environments and pathogenic threats. Herein, we studied the seed microbiome of three species of the medicinal genus Panax (P. vietnamensis, P. japonicas, and P. stipuleanatus) collected from seven locations in Southwest China. We used qPCR and metabarcoding high-throughput sequencing to target both endophytic bacteria and fungi. Seed bacterial absolute abundance (1.1 × 109∼1.0 × 107 gene copy numbers per gram seed) was substantially higher than that of fungi (7.6 × 105∼3.7 × 102). Host plant genotype was the main driver of seed microbiome composition for both bacteria and fungi. Panax growing hypothermal environments significantly shaped their seed endophytic bacterial but not fungal microbiota. The three Panax species’ seeds harbored unique microbes [averaged ∼150 amplicon sequence variants (ASVs)], sharing only 12 bacterial ASVs (half affiliated to Halomonas) and four fungal ASVs. Network analysis showed that the Panax seed endophytic bacteria tend to form inter-weaved functional modules that are majorly connected by core members from the genus Halomonas, Pseudomonas, and Pantoea. These genera have been associated with nutrient cycling, plant, disease suppression, and tolerance to environmental fluctuation. Together, these novel insights may shade light on the ecological strategies of wild Panax plants adaptation to their thermal environment by possessing abundant beneficial seed endophytic bacteria.
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Liu D, Cai J, He H, Yang S, Chater CCC, Yu F. Anemochore Seeds Harbor Distinct Fungal and Bacterial Abundance, Composition, and Functional Profiles. J Fungi (Basel) 2022; 8:89. [PMID: 35050030 PMCID: PMC8778408 DOI: 10.3390/jof8010089] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/13/2022] [Accepted: 01/13/2022] [Indexed: 02/01/2023] Open
Abstract
Many plants adapted to harsh environments have evolved low seed mass ('light seeds') with specific dispersal strategies, primarily either by wind (anemochory) or water (hydrochory). However, the role of their seed microbiota in their survival, and their seed microbial abundance and structure, remain insufficiently studied. Herein, we studied the light seed microbiome of eight anemochores and two hydrochores (as controls) collected from four provinces in China, using qPCR and metagenomic sequencing targeting both bacteria and fungi. Substantial variations were found for seed endophytic fungi (9.9 × 1010~7.3 × 102 gene copy numbers per seed) and bacteria (1.7 × 1010~8.0 × 106). Seed microbial diversity and structure were mainly driven by the plant genotype (species), with weak influences from their host plant classification level or dispersal mode. Seed microbial composition differences were clear at the microbial phylum level, with dominant proportions (~75%) for Proteobacteria and Ascomycota. The light seeds studied harbored unique microbial signatures, sharing only two Halomonas amplicon sequence variants (ASVs) and two fungal ASVs affiliated to Alternaria and Cladosporium. A genome-level functional profile analysis revealed that seed bacterial microbiota were enriched in amino acid, nucleoside, and nucleotide biosynthesis, while in fungal communities the generation of precursor metabolites and respiration were more highly represented. Together, these novel insights provide a deeper understanding of highly diversified plant-specific light seed microbiota and ecological strategies for plants in harsh environments.
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Affiliation(s)
- Dong Liu
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (J.C.); (H.H.); (S.Y.)
| | - Jie Cai
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (J.C.); (H.H.); (S.Y.)
| | - Huajie He
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (J.C.); (H.H.); (S.Y.)
| | - Shimei Yang
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (J.C.); (H.H.); (S.Y.)
| | | | - Fuqiang Yu
- The Germplasm Bank of Wild Species, Yunnan Key Laboratory for Fungal Diversity and Green Development, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China; (J.C.); (H.H.); (S.Y.)
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Sofy MR, Aboseidah AA, Heneidak SA, Ahmed HR. ACC deaminase containing endophytic bacteria ameliorate salt stress in Pisum sativum through reduced oxidative damage and induction of antioxidative defense systems. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:40971-40991. [PMID: 33772716 DOI: 10.1007/s11356-021-13585-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 03/17/2021] [Indexed: 05/07/2023]
Abstract
Approximately 6% of the world's total land area and 20% of the irrigated land are affected by salt stress. Egypt is one such country affected by salt-stress problems. This paper focuses on the role of isolated bacteria, such as Bacillus subtilis and Pseudomonas fluorescens, in alleviating the harmful effects of salt stress. The results show that the irrigation of plants with different concentrations of saline water (0, 75, and 150 mM NaCl) leads to significantly decreased growth criteria, photosynthetic pigments (i.e., chl a, chl b, and carotenoids), and membrane stability index (MSI) values. Moreover, malondialdehyde (MDA), glutathione content, endogenous proline, the antioxidant defense system, 1-aminocyclopropane-1-carboxylic acid (ACC) content, ACC synthase (ACS), ACC oxidase (ACO), and Na+ content were significantly increased under NaCl-stress exposure. On the contrary, treatment with endophytic bacteria significantly increased the resistance of pea plants to salt stress by increasing the enzymatic antioxidant defenses (i.e., superoxide dismutase, catalase, peroxidase, and glutathione reductase), non-enzymatic antioxidant defenses (i.e., glutathione), osmolyte substances such as proline, and antioxidant enzyme gene expression. As a result, endophytic bacteria's use was significantly higher compared to control values for indole-3-acetic acid (IAA), gibberellic acid GA3, MSI, and photosynthetic pigments. The use of endophytic bacteria significantly decreased Na+ accumulation while, at the same time, promoting K+ uptake. In conclusion, the induction of endophytic bacterium-induced salt tolerance in pea plants depends primarily on the effect of endophytic bacteria on osmoregulation, the antioxidant capacity, and ion uptake adjustment by limiting the uptake of Na+ and, alternatively, increasing the accumulation of K+ in plant tissue.
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Affiliation(s)
- Mahmoud R Sofy
- Botany and Microbiology Department, Faculty of Science, Al-Azhar University, 11884 Nasr City, Cairo, Egypt.
| | - Akram A Aboseidah
- Botany and Microbiology Department, Faculty of Science, Suez University, Suez, Egypt
| | - Samia A Heneidak
- Botany and Microbiology Department, Faculty of Science, Suez University, Suez, Egypt
| | - Hoda R Ahmed
- Botany and Microbiology Department, Faculty of Science, Suez University, Suez, Egypt
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Abstract
Pigeon pea, a legume crop native to India, is the primary source of protein for more than a billion people in developing countries. The plant can form symbioses with N2-fixing bacteria; however, reports of poor crop nodulation in agricultural soils abound. We report here a study of the bacterial community associated with pigeon pea, with a special focus on the symbiont population in different soils and vegetative and non-vegetative plant growth. Location with respect to the plant roots was determined to be the main factor controlling the bacterial community, followed by developmental stage and soil type. Plant genotype plays only a minor role. Pigeon pea roots have a reduced microbial diversity compared to the surrounding soil and select for Proteobacteria, especially for Rhizobium spp., during vegetative growth. While Bradyrhizobium, a native symbiont of pigeon pea, can be found associating with roots, its presence is dependent on plant variety and soil conditions. A combination of 16S rRNA gene amplicon survey, strain isolation, and co-inoculation with nodule-forming Bradyrhizobium spp. and non-N2-fixing Rhizobium spp. demonstrated that the latter is a much more successful colonizer of pigeon pea roots. Poor nodulation of pigeon pea in Indian soils may be caused by a poor Bradyrhizobium competitiveness against non-nodulating root colonizers such as Rhizobium. Hence, inoculant strain selection of symbionts for pigeon pea should be based not only on their nitrogen fixation potential but, more importantly, on their competitiveness in agricultural soils.
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Singh K, Dwivedi GR, Sanket AS, Pati S. Therapeutic Potential of Endophytic Compounds: A Special Reference to Drug Transporter Inhibitors. Curr Top Med Chem 2019; 19:754-783. [DOI: 10.2174/1568026619666190412095105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/08/2019] [Accepted: 03/09/2019] [Indexed: 12/11/2022]
Abstract
From the discovery to the golden age of antibiotics (miracle), millions of lives have been saved. The era of negligence towards chemotherapeutic agents gave birth to drug resistance. Among all the regulators of drug resistance, drug transporters are considered to be the key regulators for multidrug resistance. These transporters are prevalent from prokaryotes to eukaryotes. Endophytes are one of the unexplored wealths of nature. Endophytes are a model mutualistic partner of plants. They are the reservoir of novel therapeutics. The present review deals with endophytes as novel drug resistance reversal agents by inhibiting the drug transporters across the genera. This review also focuses on drug transporters, and mutualistic chemical diversity, exploring drug transporter modulating potential of endophytes.
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Affiliation(s)
- Khusbu Singh
- Microbiology Department, ICMR-Regional Medical Research Centre, Bhubaneswar, India
| | - Gaurav Raj Dwivedi
- Microbiology Department, ICMR-Regional Medical Research Centre, Bhubaneswar, India
| | - A. Swaroop Sanket
- Microbiology Department, ICMR-Regional Medical Research Centre, Bhubaneswar, India
| | - Sanghamitra Pati
- Microbiology Department, ICMR-Regional Medical Research Centre, Bhubaneswar, India
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Shahzad R, Khan AL, Bilal S, Asaf S, Lee IJ. What Is There in Seeds? Vertically Transmitted Endophytic Resources for Sustainable Improvement in Plant Growth. FRONTIERS IN PLANT SCIENCE 2018; 9:24. [PMID: 29410675 PMCID: PMC5787091 DOI: 10.3389/fpls.2018.00024] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/08/2018] [Indexed: 05/19/2023]
Abstract
Phytobeneficial microbes, particularly endophytes, such as fungi and bacteria, are concomitant partners of plants throughout its developmental stages, including seed germination, root and stem growth, and fruiting. Endophytic microbes have been identified in plants that grow in a wide array of habitats; however, seed-borne endophytic microbes have not been fully explored yet. Seed-borne endophytes are of great interest because of their vertical transmission; their potential to produce various phytohormones, enzymes, antimicrobial compounds, and other secondary metabolites; and improve plant biomass and yield under biotic and abiotic stresses. This review addresses the current knowledge on endophytes, their ability to produce metabolites, and their influence on plant growth and stress mitigation.
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Affiliation(s)
- Raheem Shahzad
- School of Applied Biosciences, Kyungpook National University, Daegu, South Korea
| | - Abdul L. Khan
- Chair of Oman's Medicinal Plants and Marine Natural Products, University of Nizwa, Nizwa, Oman
| | - Saqib Bilal
- School of Applied Biosciences, Kyungpook National University, Daegu, South Korea
| | - Sajjad Asaf
- Chair of Oman's Medicinal Plants and Marine Natural Products, University of Nizwa, Nizwa, Oman
| | - In-Jung Lee
- School of Applied Biosciences, Kyungpook National University, Daegu, South Korea
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9
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Jasim B, Sreelakshmi KS, Mathew J, Radhakrishnan EK. Surfactin, Iturin, and Fengycin Biosynthesis by Endophytic Bacillus sp. from Bacopa monnieri. MICROBIAL ECOLOGY 2016; 72:106-119. [PMID: 27021396 DOI: 10.1007/s00248-016-0753-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/08/2016] [Indexed: 05/15/2023]
Abstract
Endophytic microorganisms which are ubiquitously present in plants may colonize intracellularly or intercellularly without causing any diseases. By living within the unique chemical environment of a host plant, they produce a vast array of compounds with a wide range of biological activities. Because of this, natural products of endophytic origin have been exploited for antimicrobial, antiviral, anticancer, and antioxidant properties. Also, they can be considered to function as an efficient microbial barrier to protect plants from various pathogens. In the present study, endophytic bacterium BmB 9 with antifungal and antibacterial activity isolated from the stem tissue of Bacopa monnieri was studied for the molecular and chemical basis of its activity. PCR-based genome mining for various biosynthetic gene clusters proved the presence of surfactin, iturin, and type I polyketide synthase (PKS) genes in the isolate. The LC-MS/MS based analysis of the extract further confirmed the production of surfactin derivatives (M + H(+)-1008.6602, 1022.6755), iturin (M + H(+)-1043.5697), and fengycin (M + H(+)-1491.8195, 1477.8055) by the selected bacterial isolate. The 16S rDNA sequence similarity based analysis identified the isolate BmB 9 as Bacillus sp. with 100 % identity to Bacillus sp. LCF1 (KP257289).
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Affiliation(s)
- B Jasim
- School of Biosciences, Mahatma Gandhi University, PD Hills (PO), Kottayam, Kerala, 686 560, India
| | - K S Sreelakshmi
- School of Biotechnology, Amrita Vishwa Vidhyapeetham, Clapppana, Kollam, Kerala, 690 525, India
| | - Jyothis Mathew
- School of Biosciences, Mahatma Gandhi University, PD Hills (PO), Kottayam, Kerala, 686 560, India
| | - E K Radhakrishnan
- School of Biosciences, Mahatma Gandhi University, PD Hills (PO), Kottayam, Kerala, 686 560, India.
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Mongiardini EJ, Parisi GD, Quelas JI, Lodeiro AR. The tight-adhesion proteins TadGEF of Bradyrhizobium diazoefficiens USDA 110 are involved in cell adhesion and infectivity on soybean roots. Microbiol Res 2016; 182:80-8. [PMID: 26686616 DOI: 10.1016/j.micres.2015.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/06/2015] [Accepted: 10/10/2015] [Indexed: 01/23/2023]
Abstract
Adhesion of symbiotic bacteria to host plants is an essential early step of the infection process that leads to the beneficial interaction. In the Bradyrhizobium diazoefficiens-soybean symbiosis few molecular determinants of adhesion are known. Here we identified the tight-adhesion gene products TadGEF in the open-reading frames blr3941-blr3943 of the B. diazoefficiens USDA 110 complete genomic sequence. Predicted structure of TadG indicates a transmembrane domain and two extracytosolic domains, from which the C-terminal has an integrin fold. TadE and TadF are also predicted as bearing transmembrane segments. Mutants in tadG or the small cluster tadGEF were impaired in adhesion to soybean roots, and the root infection was delayed. However, nodule histology was not compromised by the mutations, indicating that these effects were restricted to the earliest contact of the B. diazoefficiens and root surfaces. Knowledge of preinfection determinants is important for development of inoculants that are applied to soybean crops worldwide.
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Affiliation(s)
- Elías J Mongiardini
- Laboratorio de Interacciones entre Rizobios y Soja (LIRyS), IBBM-Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT La Plata-CONICET, Calles 47 y 115, B1900AJL La Plata, Argentina
| | - Gustavo D Parisi
- Unidad de Bioinformática Estructural, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Sáenz Peña 352, B1876BXD Bernal, Argentina
| | - Juan I Quelas
- Laboratorio de Interacciones entre Rizobios y Soja (LIRyS), IBBM-Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT La Plata-CONICET, Calles 47 y 115, B1900AJL La Plata, Argentina
| | - Aníbal R Lodeiro
- Laboratorio de Interacciones entre Rizobios y Soja (LIRyS), IBBM-Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata y CCT La Plata-CONICET, Calles 47 y 115, B1900AJL La Plata, Argentina.
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Deivanai S, Bindusara AS, Prabhakaran G, Bhore SJ. Culturable bacterial endophytes isolated from Mangrove tree (Rhizophora apiculata Blume) enhance seedling growth in Rice. J Nat Sci Biol Med 2014; 5:437-44. [PMID: 25097431 PMCID: PMC4121931 DOI: 10.4103/0976-9668.136233] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Endophytic bacteria do have several potential applications in medicine and in other various sectors of biotechnology including agriculture. Bacterial endophytes need to be explored for their potential applications in agricultural biotechnology. One of the potential applications of bacterial endophytes in agricultural is to enhance the growth of the agricultural crops. Hence, this study was undertaken to explore the plant growth promoting potential application of bacterial endophytes. OBJECTIVE The objective of this study was to examine the effect of endophytic bacteria from mangrove tree (Rhizophora apiculata Blume) for their efficacy in promoting seedling growth in rice. MATERIALS AND METHODS Eight endophytic bacterial isolates (EBIs) isolated from twig and petiole tissues of the mangrove were identified based on their 16S ribosomal ribonucleic acid (rRNA) gene sequence homology. Separately, surface sterilized paddy seeds were treated with cell-free broth and cell suspension of the EBIs. Rice seedlings were analyzed by various bioassays and data was recorded. RESULTS The gene sequences of the isolates were closely related to two genera namely, Bacillus and Pantoea. Inoculation of EBIs from R. apiculata with rice seeds resulted in accelerated root and shoot growth with significant increase in chlorophyll content. Among the isolates, Pantoea ananatis (1MSE1) and Bacillus amyloliquefaciens (3MPE1) had shown predominance of activity. Endophytic invasion was recognized by the non-host by rapid accumulation of reactive oxygen species (ROS) and was counteracted by the production of hydrogen peroxide (H2O2) and lipid peroxide. The results demonstrated that EBIs from mangrove tree can increase the fitness of the rice seedlings under controlled conditions. CONCLUSION These research findings could be useful to enhance the seedling growth and could serve as foundation in further research on enhancing the growth of the rice crop using endophytic bacteria.
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Affiliation(s)
- Subramanian Deivanai
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Semeling, Kedah, Malaysia
| | | | - Guruswamy Prabhakaran
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Semeling, Kedah, Malaysia
| | - Subhash Janardhan Bhore
- Department of Biotechnology, Faculty of Applied Sciences, AIMST University, Semeling, Kedah, Malaysia
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Symbiotic influence of endophytic Bacillus pumilus on growth promotion and probiotic potential of the medicinal plant Ocimum sanctum. Symbiosis 2013. [DOI: 10.1007/s13199-013-0244-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Isolation and Characterization of Nodule-Associated Exiguobacterium sp. from the Root Nodules of Fenugreek (Trigonella foenum-graecum) and Their Possible Role in Plant Growth Promotion. Int J Microbiol 2012; 2012:693982. [PMID: 22518149 PMCID: PMC3299478 DOI: 10.1155/2012/693982] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 09/20/2011] [Accepted: 10/23/2011] [Indexed: 11/24/2022] Open
Abstract
One of the ways to increase the competitive survivability of rhizobial biofertilizers and thus achieve better plant growth under such conditions is by modifying the rhizospheric environment or community by addition of nonrhizobial nodule-associated bacteria (NAB) that cause better nodulation and plant growth when coinoculated with rhizobia. A study was performed to investigate the most commonly associated nodule-associated bacteria and the rhizospheric microorganisms associated with the Fenugreek (Trigonella foenum-graecum) plant. Isolation of nonrhizobial isolates from root nodules of Fenugreek was carried out along with the rhizospheric isolates. About 64.7% isolates obtained from Fenugreek nodules were gram-negative coccobacilli, 29.41% were gram-positive bacilli, and all rhizospheric isolates except one were gram-positive bacilli. All the isolates were characterized for their plant growth promoting (PGP) activities. Two of the NAB isolates M2N2c and B1N2b (Exiguobacterium sp.) showed maximum positive PGP features. Those NAB isolates when coinoculated with rhizobial strain—S. meliloti, showed plant growth promotion with respect to increase in plant's root and shoot length, chlorophyll content, nodulation efficiency, and nodule dry weight.
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Dynamics of seed-borne rice endophytes on early plant growth stages. PLoS One 2012; 7:e30438. [PMID: 22363438 PMCID: PMC3281832 DOI: 10.1371/journal.pone.0030438] [Citation(s) in RCA: 235] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 12/20/2011] [Indexed: 11/30/2022] Open
Abstract
Bacterial endophytes are ubiquitous to virtually all terrestrial plants. With the increasing appreciation of studies that unravel the mutualistic interactions between plant and microbes, we increasingly value the beneficial functions of endophytes that improve plant growth and development. However, still little is known on the source of established endophytes as well as on how plants select specific microbial communities to establish associations. Here, we used cultivation-dependent and -independent approaches to assess the endophytic bacterrial community of surface-sterilized rice seeds, encompassing two consecutive rice generations. We isolated members of nine bacterial genera. In particular, organisms affiliated with Stenotrophomonas maltophilia and Ochrobactrum spp. were isolated from both seed generations. PCR-based denaturing gradient gel electrophoresis (PCR-DGGE) of seed-extracted DNA revealed that approximately 45% of the bacterial community from the first seed generation was found in the second generation as well. In addition, we set up a greenhouse experiment to investigate abiotic and biotic factors influencing the endophytic bacterial community structure. PCR-DGGE profiles performed with DNA extracted from different plant parts showed that soil type is a major effector of the bacterial endophytes. Rice plants cultivated in neutral-pH soil favoured the growth of seed-borne Pseudomonas oryzihabitans and Rhizobium radiobacter, whereas Enterobacter-like and Dyella ginsengisoli were dominant in plants cultivated in low-pH soil. The seed-borne Stenotrophomonas maltophilia was the only conspicuous bacterial endophyte found in plants cultivated in both soils. Several members of the endophytic community originating from seeds were observed in the rhizosphere and surrounding soils. Their impact on the soil community is further discussed.
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Dudeja SS, Giri R, Saini R, Suneja-Madan P, Kothe E. Interaction of endophytic microbes with legumes. J Basic Microbiol 2011; 52:248-60. [DOI: 10.1002/jobm.201100063] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 04/27/2011] [Indexed: 11/11/2022]
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Böltner D, Godoy P, Muñoz-Rojas J, Duque E, Moreno-Morillas S, Sánchez L, Ramos JL. Rhizoremediation of lindane by root-colonizing Sphingomonas. Microb Biotechnol 2011; 1:87-93. [PMID: 21261825 PMCID: PMC3864435 DOI: 10.1111/j.1751-7915.2007.00004.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
We used a two‐step enrichment approach to isolate root‐colonizing hexachlorocyclohexane (HCH)‐degrading microorganisms. The first step consists of the use of classical liquid enrichment to isolate γ‐HCH degraders. The γ‐HCH‐degrading microbes were attached in mass to corn seeds sown in soil with γ‐HCH, and after plant development we rescued bacteria growing on root tips. Bacteria were then subjected to a second enrichment round in which growth on liquid medium with γ‐HCH and inoculation of corn seeds were repeated. We then isolated bacteria on M9 minimal medium with γ‐HCH from root tips. We were able to isolate four Sphingomonas strains, all of which degraded α‐, β‐, γ‐ and δ‐HCH. Two of the strains were particularly good colonizers of corn roots, reaching high cell density in vegetated soil and partly removing γ‐HCH. In contrast, these bacteria performed poorly in unplanted soils. This study supports the hypothesis that the removal of persistent toxic chemicals can be accelerated by combinations of plants and bacteria, a process generally known as rhizoremediation.
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Affiliation(s)
- Dietmar Böltner
- Consejo Superior de Investigaciones Cientificas, Eslación Experimental del Zaidin, Department of Environmental Protection, C/ Prof. Albareda, 1, E-18008 Granada, Spain
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Zhao L, Xu Y, Sun R, Deng Z, Yang W, Wei G. Identification and characterization of the endophytic plant growth prompter Bacillus Cereus strain mq23 isolated from Sophora Alopecuroides root nodules. Braz J Microbiol 2011; 42:567-75. [PMID: 24031669 PMCID: PMC3769835 DOI: 10.1590/s1517-838220110002000022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Accepted: 01/13/2011] [Indexed: 11/25/2022] Open
Abstract
Endophytes MQ23 and MQ23R isolated from Sophora alopecuroides root nodules were characterized by observing their ability to promote plant growth and employing molecular analysis techniques. Results showed that MQ23 and MQ23R are potential N2-fixing endophytes and belong to the same species as Bacillus cereus. MQ23 was shown to be able to produce siderophores, IAA, and demonstrate certain antifungal activity to plant pathogenic fungi. Co-inoculation with MQ23+MQ23II showed a more significant effect than inoculation alone in vitro for most of positive actions suggesting they have a cooperative interaction. Results of plant inoculation with endophytes indicated that the growth indexes of co-inoculated MQ23+MQ23II were higher than those of inoculated alone (p<0.05) (the exception being for root fresh weight) when compared to negative control. There have been little of any studies of nonrhizobial putative endophytes with growth-promotion attributes in S. alopecuroides root nodules. This could be exploited as potential bio-inoculants and biocontrol agents in agriculture.
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Affiliation(s)
- Longfei Zhao
- College of Life Sciences, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A & F University, Yangling, Shaanxi, 712100, China
- College of Life Sciences, Shangqiu Normal University, Shangqiu, Henan, 476000, China
| | - Yajun Xu
- College of Life Sciences, Shangqiu Normal University, Shangqiu, Henan, 476000, China
| | - Ran Sun
- College of Life Sciences, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A & F University, Yangling, Shaanxi, 712100, China
| | - Zhenshan Deng
- College of Life Sciences, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A & F University, Yangling, Shaanxi, 712100, China
| | - Wenquan Yang
- College of Life Sciences, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A & F University, Yangling, Shaanxi, 712100, China
| | - Gehong Wei
- College of Life Sciences, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A & F University, Yangling, Shaanxi, 712100, China
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Oehrle NW, Sarma AD, Waters JK, Emerich DW. Proteomic analysis of soybean nodule cytosol. PHYTOCHEMISTRY 2008; 69:2426-38. [PMID: 18757068 DOI: 10.1016/j.phytochem.2008.07.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 06/24/2008] [Accepted: 07/18/2008] [Indexed: 05/13/2023]
Abstract
An isolation procedure for soybean (Glycine max L. cv Williams 82) nodule cytosol proteins was developed which greatly improved protein resolution by two-dimensional polyacrylamide gel electrophoresis. The most abundant proteins were selected and analyzed by mass spectrometry. The identified proteins were categorized by function (% of total proteins analyzed): carbon metabolism (28%), nitrogen metabolism (12%), reactive oxygen metabolism (12%) and vesicular trafficking (11%). The first three categories were expected based on the known physiological functions of the symbiotic nitrogen fixation process. The number of proteins involved in vesicular trafficking suggests a very active exchange of macromolecules and membrane components. Among the 69 identified proteins were the enzymes of the three carbon portion of glycolysis, which were further characterized to support their roles in the sucrose synthase pathway to provide malate for the bacteroids. Proteomic analysis provides a functional tool by which to understand and further investigate nodule function.
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Affiliation(s)
- Nathan W Oehrle
- United States Department of Agriculture, Curtis Hall, University of Missouri, Columbia, MO 65211, United States
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Rajendran G, Sing F, Desai AJ, Archana G. Enhanced growth and nodulation of pigeon pea by co-inoculation of Bacillus strains with Rhizobium spp. BIORESOURCE TECHNOLOGY 2008; 99:4544-50. [PMID: 17826983 DOI: 10.1016/j.biortech.2007.06.057] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 04/30/2007] [Accepted: 06/27/2007] [Indexed: 05/17/2023]
Abstract
Endophytic bacteria which are known to reside in plant tissues have often been shown to promote plant growth. Present study deals with the isolation of putative endophytes from the surface sterilized root nodules of pigeon pea (Cajanus cajan) designated as non-rhizobial (NR) isolates. Three of these non-rhizobial isolates called NR2, NR4 and NR6 showed plant growth promotion with respect to increase in plant fresh weight, chlorophyll content, nodule number and nodule fresh weight when co-inoculated with the rhizobial bioinoculant strain IC3123. The three isolates were neither able to nodulate C. cajan nor did they show significant plant growth promotion when inoculated alone without Rhizobium spp. IC3123. All the three isolates were gram positive rods with NR2 and NR4 showing endospore formation and formed one single cluster in Amplified Ribosomal DNA Restriction Analysis (ARDRA). Partial sequences of 16S rRNA genes of NR4 and NR6 showed 97% similarity to Bacillus megaterium. The Bacillus strains NR4 and NR6 were able to produce siderophores which the rhizobial bioinoculant IC3123 was able to cross-utilize. Under iron starved conditions IC3123 showed enhanced growth in the presence of the Bacillus isolates indicating that siderophore mediated interactions may be underlying mechanism of beneficial effect of the NR isolates on nodulation by IC3123.
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Affiliation(s)
- Geetha Rajendran
- Department of Microbiology and Biotechnology Centre, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara 390 002, Gujarat, India.
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Shah R, Emerich DW. Isocitrate dehydrogenase of Bradyrhizobium japonicum is not required for symbiotic nitrogen fixation with soybean. J Bacteriol 2006; 188:7600-8. [PMID: 16936027 PMCID: PMC1636263 DOI: 10.1128/jb.00671-06] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2006] [Accepted: 08/08/2006] [Indexed: 11/20/2022] Open
Abstract
A mutant strain of Bradyrhizobium japonicum USDA110 lacking isocitrate dehydrogenase activity was created to determine whether this enzyme was required for symbiotic nitrogen fixation with soybean (Glycine max cv. Williams 82). The isocitrate dehydrogenase mutant, strain 5051, was constructed by insertion of a streptomycin resistance gene cassette. The mutant was devoid of isocitrate dehydrogenase activity and of immunologically detectable protein, indicating there is only one copy in the genome. Strain 5051 grew well on a variety of carbon sources, including arabinose, pyruvate, succinate, and malate, but, unlike many microorganisms, was a glutamate auxotroph. Although the formation of nodules was slightly delayed, the mutant was able to form nodules on soybean and reduce atmospheric dinitrogen as well as the wild type, indicating that the plant was able to supply sufficient glutamate to permit infection. Combined with the results of other citric acid cycle mutants, these results suggest a role for the citric acid cycle in the infection and colonization stage of nodule development but not in the actual fixation of atmospheric dinitrogen.
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Affiliation(s)
- Ritu Shah
- Department of Biochemistry, University of Missouri, Columbia, 65211, USA
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Ramos-González MI, Campos MJ, Ramos JL. Analysis of Pseudomonas putida KT2440 gene expression in the maize rhizosphere: in vivo [corrected] expression technology capture and identification of root-activated promoters. J Bacteriol 2005; 187:4033-41. [PMID: 15937166 PMCID: PMC1151710 DOI: 10.1128/jb.187.12.4033-4041.2005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pseudomonas putida KT2440, a paradigm organism in biodegradation and a good competitive colonizer of the maize rhizosphere, was the subject of studies undertaken to establish the genetic determinants important for its rhizospheric lifestyle. By using in vivo expression technology (IVET) to positively select single cell survival, we identified 28 rap genes (root-activated promoters) preferentially expressed in the maize rhizosphere. The IVET system had two components: a mutant affected in aspartate-beta-semialdehyde dehydrogenase (asd), which was unable to survive in the rhizosphere, and plasmid pOR1, which carries a promoter-less asd gene. pOR1-borne transcriptional fusions of the rap promoters to the essential gene asd, which were integrated into the chromosome at the original position of the corresponding rap gene, were active and allowed growth of the asd strain in the rhizosphere. The fact that five of the rap genes identified in the course of this work had been formerly characterized as being related to root colonization reinforced the IVET approach. Up to nine rap genes encoded proteins either of unknown function or that had been assigned an unspecific role based on conservation of the protein family domains. Rhizosphere-induced fusions included genes with probable functions in the cell envelope, chemotaxis and motility, transport, secretion, DNA metabolism and defense mechanism, regulation, energy metabolism, stress, detoxification, and protein synthesis.
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Affiliation(s)
- María Isabel Ramos-González
- Department of Plant Biochemistry and Molecular and Cell Biology, Estación Experimental de Zaidín, CSIC, Profesor Albareda, 1, Granada 18008, Spain.
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Hoo H, Hashidoko Y, Islam MT, Tahara S. Requirement of a relatively high threshold level of Mg(2+) for cell growth of a rhizoplane bacterium, Sphingomonas yanoikuyae EC-S001. Appl Environ Microbiol 2004; 70:5214-21. [PMID: 15345402 PMCID: PMC520926 DOI: 10.1128/aem.70.9.5214-5221.2004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Accepted: 04/06/2004] [Indexed: 11/20/2022] Open
Abstract
Mg(2+) is one of the essential elements for bacterial cell growth. The presence of the magnesium cation (Mg(2+)) in various concentrations often affects cell growth restoration in plant-associating bacteria. This study attempted to determine whether Mg(2+) levels in Sphingomonas yanoikuyae EC-S001 affected cell growth restoration in the host plant and what the threshold level is. S. yanoikuyae EC-S001, isolated from the rhizoplane of spinach seedlings grown from surface-sterilized seeds under aseptic conditions, displayed uniform dispersion and attachment throughout the rhizoplane and phylloplane of the host seedlings. S. yanoikuyae EC-S001 did not grow in potato-dextrose broth medium but grew well in an aqueous extract of spinach leaves. Chemical investigation of the growth factor in the spinach leaf extract led to identification of the active principle as the magnesium cation. A concentration of ca. 0.10 mM Mg(2+) or more allowed S. yanoikuyae EC-S001 to grow in potato-dextrose broth medium. Some saprophytic and/or diazotrophic bacteria used in our experiment were found to have diverse threshold levels for their Mg(2+) requirements. For example, Burkholderia cepacia EC-K014, originally isolated from the rhizoplane of a Melastoma sp., could grow even in Mg(2+)-free Hoagland's no. 2 medium with saccharose and glutamine (HSG medium) and requires a trace level of Mg(2+) for its growth. In contrast, S. yanoikuyae EC-S001, together with Bacillus subtilis IFO12113, showed the most drastic restoring responses to subsequent addition of 0.98 mM Mg(2+) to Mg(2+)-free HSG medium. Our studies concluded that Mg(2+) is more than just the essential trace element needed for cell growth restoration in S. yanoikuyae EC-S001 and that certain nonculturable bacteria may require a higher concentration of Mg(2+) or another specific essential element for their growth.
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Affiliation(s)
- Henny Hoo
- Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo 060-8589, Japan
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Bai Y, D'Aoust F, Smith DL, Driscoll BT. Isolation of plant-growth-promoting Bacillus strains from soybean root nodules. Can J Microbiol 2002; 48:230-8. [PMID: 11989767 DOI: 10.1139/w02-014] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Endophytic bacteria reside within plant tissues and have often been found to promote plant growth. Fourteen strains of putative endophytic bacteria, not including endosymbiotic Bradyrhizobium strains, were isolated from surface-sterilized soybean (Glycine max. (L.) Merr.) root nodules. These isolates were designated as non-Bradyrhizobium endophytic bacteria (NEB). Three isolates (NEB4, NEB5, and NEB17) were found to increase soybean weight when plants were co-inoculated with one of the isolates and Bradyrhizobium japonicum under nitrogen-free conditions, compared with plants inoculated with B. japonicum alone. In the absence of B. japonicum, these isolates neither nodulated soybean, nor did they affect soybean growth. All three isolates were Gram-positive spore-forming rods. While Biolog tests indicated that the three isolates belonged to the genus Bacillus, it was not possible to determine the species. Phylogenetic analysis of 16S rRNA gene hypervariant region sequences demonstrated that both NEB4 and NEB5 are Bacillus subtilis strains, and that NEB17 is a Bacillus thuringiensis strain.
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Affiliation(s)
- Yuming Bai
- Department of Plant Science, McGill University, Ste-Anne-de-Bellevue, QC, Canada
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Henselová M, Hudecová D. Differences in the microflora of scarified and unscarified seeds of Karwinskia humboldtiana (Rhamnaceae). Folia Microbiol (Praha) 2001; 46:543-8. [PMID: 11898346 DOI: 10.1007/bf02818000] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Seeds of Karwinskia humboldtiana obtained from a 1997 collection in the locality of Villa de Gracía Nuevo (León, Mexico) were contaminated with spores of filamentous fungi, bacteria and yeasts. The concentration of microorganisms in unscarified seeds ranged from 3.0 x 10(3) to 7.5 x 10(3) CFU/g. Predominant were bacterial isolates of the genera Aeromonas sp., Bacillus, and Pseudomonas; from filamentous fungi were identified Alternaria, Aspergillus niger, Cladosporium sp., Fusarium sp., Mucor sp., Penicillium commune, Trichothecium sp.; from yeasts Rhodotorula sp. and Saccharomyces cerevisiae. Seed scarification significantly reduced the microbial contamination. Of the original fungal isolates, only two were identified on scarified seeds, viz. Cladosporium sp. and Saccharomyces cerevisiae; although a relatively high incidence of a unidentifiable of Penicillium sp. was found, the bacterial spectrum was not altered. Treatment of scarified seeds with Vitavax 200 WP and Pomarsol Forte 80 WP (3 mg/g seeds) augmented germination by 10-19% compared to treated unscarified seeds, and by 16-31% compared to untreated unscarified seeds.
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Affiliation(s)
- M Henselová
- Department of Plant Physiology, Faculty of Science, Comenius University, 842 15 Bratislava, Slovakia.
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