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Uko MP, Umana SI, Iwatt IJ, Udoekong NS, Mgbechidinma CL, Adie FU, Akan OD. Microbial ice-binding structures: A review of their applications. Int J Biol Macromol 2024; 275:133670. [PMID: 38971293 DOI: 10.1016/j.ijbiomac.2024.133670] [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: 03/12/2024] [Revised: 06/02/2024] [Accepted: 07/02/2024] [Indexed: 07/08/2024]
Abstract
Microorganisms' ice-binding structures (IBS) are macromolecules with potential commercial value in agriculture, food technology, material technology, cryobiology, and medicine. Microbial ice-structuring or microbial ice-binding particles, with their multi-applications, are simple to use, effective in low amounts, non-toxic, and environmentally friendly. Due to their source and composition diversities, microbial ice-binding structures are gaining attention because they are useable in various conditions. Some microorganisms also produce structures with dual ice-nucleating and anti-freezing properties. Structures that promote ice formation (ice nucleating particles- INPs) act as ice nuclei, lowering the energy barrier between supercooled liquid and ice, causing ice crystals to form. In contrast, anti-freeze particles (AFPs) prevent ice formation and recrystallization through several mechanisms, including disturbing the formation of string hydrogen bonds amongst water molecules, melting already formed ice crystals, and preventing crystal formation by binding to specific sites. Knowledge of the type and function of microbial ice-binding structures lends fundamental insight for possible scaling the production of cheap, functional, and advanced microbial structure-inspired mimics and by-products. This review focuses on microbial ice-binding structures and their potential uses in the food, medicinal, environmental, and agricultural sectors.
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Affiliation(s)
- Mfoniso Peter Uko
- Faculty of Biological Science, Akwa-Ibom State University, Akwa-Ibom State, Uyo 1167, Nigeria
| | - Senyene Idorenyin Umana
- Faculty of Biological Science, Akwa-Ibom State University, Akwa-Ibom State, Uyo 1167, Nigeria; Department of Microbiology, Faculty of Michael Okpara of Agriculture, Umudike, Nigeria
| | - Ifiok Joseph Iwatt
- Center for Wetlands and Wastes Management Studies, Faculty of Agriculture, University of Uyo, Uyo, Nigeria
| | | | - Chiamaka Linda Mgbechidinma
- School of Life Sciences, Centre for Cell and Development Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China; Department of Microbiology, University of Ibadan, Ibadan 200243, Nigeria
| | - Francisca Upekiema Adie
- Department of Microbiology, Faculty of Biological Sciences, Cross River State University of Technology, Calabar, Nigeria
| | - Otobong Donald Akan
- Faculty of Biological Science, Akwa-Ibom State University, Akwa-Ibom State, Uyo 1167, Nigeria; College of Food Science and Engineering, Central South University of Forestry and Technology, 498 South Shaoshan Road, Changsha 410004, China.
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Etesami H, Glick BR. Bacterial indole-3-acetic acid: A key regulator for plant growth, plant-microbe interactions, and agricultural adaptive resilience. Microbiol Res 2024; 281:127602. [PMID: 38228017 DOI: 10.1016/j.micres.2024.127602] [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: 11/29/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 01/18/2024]
Abstract
Indole-3-acetic acid (IAA), a fundamental phytohormone categorized under auxins, not only influences plant growth and development but also plays a critical role in plant-microbe interactions. This study reviews the role of IAA in bacteria-plant communication, with a focus on its biosynthesis, regulation, and the subsequent effects on host plants. Bacteria synthesize IAA through multiple pathways, which include the indole-3-acetamide (IAM), indole-3-pyruvic acid (IPyA), and several other routes, whose full mechanisms remain to be fully elucidated. The production of bacterial IAA affects root architecture, nutrient uptake, and resistance to various abiotic stresses such as drought, salinity, and heavy metal toxicity, enhancing plant resilience and thus offering promising routes to sustainable agriculture. Bacterial IAA synthesis is regulated through complex gene networks responsive to environmental cues, impacting plant hormonal balances and symbiotic relationships. Pathogenic bacteria have adapted mechanisms to manipulate the host's IAA dynamics, influencing disease outcomes. On the other hand, beneficial bacteria utilize IAA to promote plant growth and mitigate abiotic stresses, thereby enhancing nutrient use efficiency and reducing dependency on chemical fertilizers. Advancements in analytical methods, such as liquid chromatography-tandem mass spectrometry, have improved the quantification of bacterial IAA, enabling accurate measurement and analysis. Future research focusing on molecular interactions between IAA-producing bacteria and host plants could facilitate the development of biotechnological applications that integrate beneficial bacteria to improve crop performance, which is essential for addressing the challenges posed by climate change and ensuring global food security. This integration of bacterial IAA producers into agricultural practice promises to revolutionize crop management strategies by enhancing growth, fostering resilience, and reducing environmental impact.
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Affiliation(s)
- Hassan Etesami
- Soil Science Department, University of Tehran, Tehran, Iran.
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Neupane A, Shahzad F, Bernardini C, Levy A, Vashisth T. Poor shoot and leaf growth in Huanglongbing-affected sweet orange is associated with increased investment in defenses. FRONTIERS IN PLANT SCIENCE 2023; 14:1305815. [PMID: 38179481 PMCID: PMC10766359 DOI: 10.3389/fpls.2023.1305815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/21/2023] [Indexed: 01/06/2024]
Abstract
Citrus disease Huanglongbing (HLB) causes sparse (thinner) canopies due to reduced leaf and shoot biomass. Herein, we present results demonstrating the possible mechanisms behind compromised leaf growth of HLB-affected 'Valencia' sweet orange trees by comparing morphological, transcriptome, and phytohormone profiles at different leaf development phases (1. buds at the start of the experiment; 2. buds on day 5; . 3. leaf emergence; 4. leaf expansion; and 5. leaf maturation) to healthy trees. Over a period of 3 months (in greenhouse conditions), HLB-affected trees had ≈40% reduction in growth traits such as tree height, number of shoots per tree, shoot length, internode length, and leaf size compared to healthy trees. In addition, buds from HLB-affected trees lagged by ≈1 week in sprouting as well as leaf growth. Throughout the leaf development, high accumulation of defense hormones, salicylic acid (SA) and abscisic acid (ABA), and low levels of growth-promoting hormone (auxin) were found in HLB-affected trees compared to healthy trees. Concomitantly, HLB-affected trees had upregulated differentially expressed genes (DEGs) encoding SA, ABA, and ethylene-related proteins in comparison to healthy trees. The total number of cells per leaf was lower in HLB-affected trees compared to healthy trees, which suggests that reduced cell division may coincide with low levels of growth-promoting hormones leading to small leaf size. Both bud dieback and leaf drop were higher in HLB-affected trees than in healthy trees, with concomitant upregulated DEGs encoding senescence-related proteins in HLB-affected trees that possibly resulted in accelerated aging and cell death. Taken together, it can be concluded that HLB-affected trees had a higher tradeoff of resources on defense over growth, leading to sparse canopies and a high tree mortality rate with HLB progression.
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Affiliation(s)
- Answiya Neupane
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Faisal Shahzad
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
| | - Chiara Bernardini
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | - Amit Levy
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
- Department of Plant Pathology, University of Florida, Gainesville, FL, United States
| | - Tripti Vashisth
- Citrus Research and Education Center, University of Florida, Lake Alfred, FL, United States
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Geraffi N, Gupta P, Wagner N, Barash I, Pupko T, Sessa G. Comparative sequence analysis of pPATH pathogenicity plasmids in Pantoea agglomerans gall-forming bacteria. FRONTIERS IN PLANT SCIENCE 2023; 14:1198160. [PMID: 37583594 PMCID: PMC10425158 DOI: 10.3389/fpls.2023.1198160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/10/2023] [Indexed: 08/17/2023]
Abstract
Acquisition of the pathogenicity plasmid pPATH that encodes a type III secretion system (T3SS) and effectors (T3Es) has likely led to the transition of a non-pathogenic bacterium into the tumorigenic pathogen Pantoea agglomerans. P. agglomerans pv. gypsophilae (Pag) forms galls on gypsophila (Gypsophila paniculata) and triggers immunity on sugar beet (Beta vulgaris), while P. agglomerans pv. betae (Pab) causes galls on both gypsophila and sugar beet. Draft sequences of the Pag and Pab genomes were previously generated using the MiSeq Illumina technology and used to determine partial T3E inventories of Pab and Pag. Here, we fully assembled the Pab and Pag genomes following sequencing with PacBio technology and carried out a comparative sequence analysis of the Pab and Pag pathogenicity plasmids pPATHpag and pPATHpab. Assembly of Pab and Pag genomes revealed a ~4 Mbp chromosome with a 55% GC content, and three and four plasmids in Pab and Pag, respectively. pPATHpag and pPATHpab share 97% identity within a 74% coverage, and a similar GC content (51%); they are ~156 kb and ~131 kb in size and consist of 198 and 155 coding sequences (CDSs), respectively. In both plasmids, we confirmed the presence of highly similar gene clusters encoding a T3SS, as well as auxin and cytokinins biosynthetic enzymes. Three putative novel T3Es were identified in Pab and one in Pag. Among T3SS-associated proteins encoded by Pag and Pab, we identified two novel chaperons of the ShcV and CesT families that are present in both pathovars with high similarity. We also identified insertion sequences (ISs) and transposons (Tns) that may have contributed to the evolution of the two pathovars. These include seven shared IS elements, and three ISs and two transposons unique to Pab. Finally, comparative sequence analysis revealed plasmid regions and CDSs that are present only in pPATHpab or in pPATHpag. The high similarity and common features of the pPATH plasmids support the hypothesis that the two strains recently evolved into host-specific pathogens.
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Affiliation(s)
- Naama Geraffi
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Priya Gupta
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Naama Wagner
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Isaac Barash
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Tal Pupko
- The Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Guido Sessa
- School of Plant Sciences and Food Security, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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Zhang BX, Li PS, Wang YY, Wang JJ, Liu XL, Wang XY, Hu XM. Characterization and synthesis of indole-3-acetic acid in plant growth promoting Enterobacter sp. RSC Adv 2021; 11:31601-31607. [PMID: 35496854 PMCID: PMC9041686 DOI: 10.1039/d1ra05659j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 09/11/2021] [Indexed: 11/21/2022] Open
Abstract
Indole-3-acetic acid (IAA) plays an important role in the growth and development of plants. In this study, a series of predominant strains were isolated and identified as Enterobacter sp. with remarkable IAA-producing capabilities. The IAA-producing strains are mainly tryptophan-dependent and have significantly high yields of IAA (3477 μg mL−1 and 3378 μg mL−1). The ipdC gene encoding indole-3-pyruvate decarboxylase was identified by genomic analysis and RT-qPCR analysis, indicating the involvement of the indole-3-pyruvic acid (IPyA) pathway of IAA biosynthesis. The IPyA pathway was also confirmed by the intermediate assay. The IAA product of microbial metabolites was isolated, purified and characterized. These microbes exhibiting IAA production significantly promoted the growth of maize, increasing root length, plant height, fresh weight and dry weight. Thus, Enterobacter sp. with high IAA production has great prospects in agricultural and industrial applications. The strains have remarkable IAA-producing capabilities. Genomic analysis and intermediate assay indicated the involvement of the indole-3-pyruvic acid pathway of IAA biosynthesis. These microbes significantly promoted the growth of maize.![]()
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Affiliation(s)
- Bi-Xian Zhang
- Heilongjiang Academy of Agricultural Sciences Harbin 150086 China
| | - Pei-Shan Li
- Northeast Agricultural University Harbin 150030 China
| | | | - Jia-Jun Wang
- Heilongjiang Academy of Agricultural Sciences Harbin 150086 China
| | - Xiu-Lin Liu
- Heilongjiang Academy of Agricultural Sciences Harbin 150086 China
| | - Xue-Yang Wang
- Heilongjiang Academy of Agricultural Sciences Harbin 150086 China
| | - Xiao-Mei Hu
- Northeast Agricultural University Harbin 150030 China
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Investigating the reaction and substrate preference of indole-3-acetaldehyde dehydrogenase from the plant pathogen Pseudomonas syringae PtoDC3000. Biosci Rep 2021; 40:227102. [PMID: 33325526 PMCID: PMC7745063 DOI: 10.1042/bsr20202959] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/24/2020] [Accepted: 12/01/2020] [Indexed: 12/14/2022] Open
Abstract
Aldehyde dehydrogenases (ALDHs) catalyze the conversion of various aliphatic and aromatic aldehydes into corresponding carboxylic acids. Traditionally considered as housekeeping enzymes, new biochemical roles are being identified for members of ALDH family. Recent work showed that AldA from the plant pathogen Pseudomonas syringae strain PtoDC3000 (PtoDC3000) functions as an indole-3-acetaldehyde dehydrogenase for the synthesis of indole-3-acetic acid (IAA). IAA produced by AldA allows the pathogen to suppress salicylic acid-mediated defenses in the model plant Arabidopsis thaliana. Here we present a biochemical and structural analysis of the AldA indole-3-acetaldehyde dehydrogenase from PtoDC3000. Site-directed mutants targeting the catalytic residues Cys302 and Glu267 resulted in a loss of enzymatic activity. The X-ray crystal structure of the catalytically inactive AldA C302A mutant in complex with IAA and NAD+ showed the cofactor adopting a conformation that differs from the previously reported structure of AldA. These structures suggest that NAD+ undergoes a conformational change during the AldA reaction mechanism similar to that reported for human ALDH. Site-directed mutagenesis of the IAA binding site indicates that changes in the active site surface reduces AldA activity; however, substitution of Phe169 with a tryptophan altered the substrate selectivity of the mutant to prefer octanal. The present study highlights the inherent biochemical versatility of members of the ALDH enzyme superfamily in P. syringae.
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Isolation and Characterization of Fungal Endophytes Isolated from Medicinal Plant Ephedra pachyclada as Plant Growth-Promoting. Biomolecules 2021; 11:biom11020140. [PMID: 33499067 PMCID: PMC7911138 DOI: 10.3390/biom11020140] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/17/2022] Open
Abstract
Endophytic fungi are widely present in internal plant tissues and provide different benefits to their host. Medicinal plants have unexplored diversity of functional fungal association; therefore, this study aimed to isolate endophytic fungi associated with leaves of medicinal plants Ephedra pachyclada and evaluate their plant growth-promoting properties. Fifteen isolated fungal endophytes belonging to Ascomycota, with three different genera, Penicillium, Alternaria, and Aspergillus, were obtained from healthy leaves of E. pachyclada. These fungal endophytes have varied antimicrobial activity against human pathogenic microbes and produce ammonia and indole acetic acid (IAA), in addition to their enzymatic activity. The results showed that Penicillium commune EP-5 had a maximum IAA productivity of 192.1 ± 4.04 µg mL−1 in the presence of 5 µg mL−1 tryptophan. The fungal isolates of Penicillium crustosum EP-2, Penicillium chrysogenum EP-3, and Aspergillus flavus EP-14 exhibited variable efficiency for solubilizing phosphate salts. Five representative fungal endophytes of Penicillium crustosum EP-2, Penicillium commune EP-5, Penicillium caseifulvum EP-11, Alternaria tenuissima EP-13, and Aspergillus flavus EP-14 and their consortium were selected and applied as bioinoculant to maize plants. The results showed that Penicillium commune EP-5 increased root lengths from 15.8 ± 0.8 to 22.1 ± 0.6. Moreover, the vegetative growth features of inoculated maize plants improved more than the uninoculated ones.
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Weiten A, Kalvelage K, Becker P, Reinhardt R, Hurek T, Reinhold-Hurek B, Rabus R. Complete Genomes of the Anaerobic Degradation Specialists Aromatoleum petrolei ToN1T and Aromatoleum bremense PbN1T. Microb Physiol 2021; 31:16-35. [PMID: 33477134 DOI: 10.1159/000513167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 11/17/2020] [Indexed: 11/19/2022]
Abstract
The betaproteobacterial genus Aromatoleum comprises facultative denitrifiers specialized in the anaerobic degradation of recalcitrant organic compounds (aromatic and terpenoid). This study reports on the complete and manually annotated genomes of Ar. petrolei ToN1T (5.41 Mbp) and Ar. bremense PbN1T (4.38 Mbp), which cover the phylogenetic breadth of the genus Aromatoleum together with previously genome sequenced Ar. aromaticum EbN1T [Rabus et al., Arch Microbiol. 2005 Jan;183(1):27-36]. The gene clusters for the anaerobic degradation of aromatic and terpenoid (strain ToN1T only) compounds are scattered across the genomes of strains ToN1T and PbN1T. The richness in mobile genetic elements is shared with other Aromatoleum spp., substantiating that horizontal gene transfer should have been a major driver in shaping the genomes of this genus. The composite catabolic network of strains ToN1T and PbN1T comprises 88 proteins, the coding genes of which occupy 86.1 and 76.4 kbp (1.59 and 1.75%) of the respective genome. The strain-specific gene clusters for anaerobic degradation of ethyl-/propylbenzene (strain PbN1T) and toluene/monoterpenes (strain ToN1T) share high similarity with their counterparts in Ar. aromaticum strains EbN1T and pCyN1, respectively. Glucose is degraded via the ED-pathway in strain ToN1T, while gluconeogenesis proceeds via the reverse EMP-pathway in strains ToN1T, PbN1T, and EbN1T. The diazotrophic, endophytic lifestyle of closest related genus Azoarcus is known to be associated with nitrogenase and type-6 secretion system (T6SS). By contrast, strains ToN1T, PbN1T, and EbN1T lack nif genes for nitrogenase (including cofactor synthesis and enzyme maturation). Moreover, strains PbN1T and EbN1T do not possess tss genes for T6SS, while strain ToN1T does and facultative endophytic "Aromatoleum" sp. CIB is known to even have both. These findings underpin the functional heterogeneity among Aromatoleum members, correlating with the high plasticity of their genomes.
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Affiliation(s)
- Arne Weiten
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Kristin Kalvelage
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Patrick Becker
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Richard Reinhardt
- Max-Planck-Genome-Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Thomas Hurek
- Department of Microbe-Plant Interactions, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Barbara Reinhold-Hurek
- Department of Microbe-Plant Interactions, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Ralf Rabus
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany,
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Van Zhang N, Thi Thu N, Thi Linh V, Pylnev V, Popchenko M. Influence of cultivation conditions on IAA - producing activity of endophytic bacterial strains isolated from morning-glory ( IPOMOEA PES-CAPRAE (L.) R.Br.). BIO WEB OF CONFERENCES 2021. [DOI: 10.1051/bioconf/20213605003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This work presents the experimental study results of the influence of the culture medium on the ability to IAA synthesis of three endophytic strains TH10R, TH11T, and TH13T from roots of Ipomoea pes-caprae. Three investigated strains give the highest IAA concentration after 96 h of cultivation. A significant increase in IAA biosynthesis was obtained by cultivating the TH10R strain in a medium containing lactose or starch as a carbon source and NH4Cl or KNO3 as a nitrogen source. The TH11T strain produces the maximum amount of IAA, using glucose or xylose and KNO3 or NH4NO3 as carbon and nitrogen sources, respectively. Sucrose is a suitable carbon source for the TH13T strain; on a sucrose-containing medium, the TH13T strain produces the highest IAA amount. The most active strain is TH10R, identified as Bacillus mycoides and named Bacillus mycoides TH10R.
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Yarlagadda V, Medina R, Johnson TA, Koteva KP, Cox G, Thaker MN, Wright GD. Resistance-Guided Discovery of Elfamycin Antibiotic Producers with Antigonococcal Activity. ACS Infect Dis 2020; 6:3163-3173. [PMID: 33164482 DOI: 10.1021/acsinfecdis.0c00467] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The rise of bacterial antibiotic resistance coupled with a diminished antibiotic drug pipeline underlines the importance of developing rational strategies to discover new antimicrobials. Microbially derived natural products are the basis for most of the antibiotic arsenal available to modern medicine. Here, we demonstrate a resistance-based approach to identify producers of elfamycins, an under-explored class of natural product antibiotics that target the essential translation factor EF-Tu. Antibiotic producers carry self-resistance genes to avoid suicide. These genes are often found within the same biosynthetic gene cluster (BGC) responsible for making the antibiotic, and we exploited this trait to identify members of the kirromycin class of elfamycin producers. Genome mining of Streptomyces spp. led to the identification of three isolates that harbor kirromycin-resistant EF-Tu (EF-TuKirR) within predicted natural product BGCs. Activity-guided purification on extracts of one of the Streptomyces isolates, which was not known to produce an elfamycin, identified it as a producer of phenelfamycin B, a linear polyketide. Phenelfamycin B demonstrates impressive antibacterial activity (MIC ∼ 1 μg/mL) against multidrug-resistant Neisseria gonorrhoeae, a clinically important Gram negative pathogen. The antigonococcal activity of phenelfamycin was shown to be the result of inhibition of protein biosynthesis by binding to EF-Tu. These results indicate that a resistance-based approach of identifying elfamycin producers is translatable to other antibiotic classes that can identify new and overlooked antibiotics necessary to address the antibiotic crisis.
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Affiliation(s)
- Venkateswarlu Yarlagadda
- David Braley Center for Antibiotic Discovery, M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Ricardo Medina
- Department of Microbiology, Chemical Bioactive Center, Central University Marta Abreu de las Villas, Santa Clara 54830, Villa Clara, Cuba
| | - Timothy A. Johnson
- Department of Animal Sciences, Purdue University College of Agriculture, West Lafayette, Indiana 47907, United States
| | - Kalinka P. Koteva
- David Braley Center for Antibiotic Discovery, M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Georgina Cox
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Maulik N. Thaker
- Novartis Institutes for Biomedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Gerard D. Wright
- David Braley Center for Antibiotic Discovery, M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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Swarnalakshmi K, Yadav V, Tyagi D, Dhar DW, Kannepalli A, Kumar S. Significance of Plant Growth Promoting Rhizobacteria in Grain Legumes: Growth Promotion and Crop Production. PLANTS 2020; 9:plants9111596. [PMID: 33213067 PMCID: PMC7698556 DOI: 10.3390/plants9111596] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/24/2020] [Accepted: 10/28/2020] [Indexed: 02/01/2023]
Abstract
Grain legumes are an important component of sustainable agri-food systems. They establish symbiotic association with rhizobia and arbuscular mycorrhizal fungi, thus reducing the use of chemical fertilizers. Several other free-living microbial communities (PGPR—plant growth promoting rhizobacteria) residing in the soil-root interface are also known to influence biogeochemical cycles and improve legume productivity. The growth and function of these microorganisms are affected by root exudate molecules secreted in the rhizosphere region. PGPRs produce the chemicals which stimulate growth and functions of leguminous crops at different growth stages. They promote plant growth by nitrogen fixation, solubilization as well as mineralization of phosphorus, and production of phytohormone(s). The co-inoculation of PGPRs along with rhizobia has shown to enhance nodulation and symbiotic interaction. The recent molecular tools are helpful to understand and predict the establishment and function of PGPRs and plant response. In this review, we provide an overview of various growth promoting mechanisms of PGPR inoculations in the production of leguminous crops.
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Affiliation(s)
| | - Vandana Yadav
- Division of Microbiology, ICAR-Indian Agricultural Research Institute (IARI), New Delhi 110012, India
| | - Deepti Tyagi
- Division of Microbiology, ICAR-Indian Agricultural Research Institute (IARI), New Delhi 110012, India
| | - Dolly Wattal Dhar
- Division of Microbiology, ICAR-Indian Agricultural Research Institute (IARI), New Delhi 110012, India
| | - Annapurna Kannepalli
- Division of Microbiology, ICAR-Indian Agricultural Research Institute (IARI), New Delhi 110012, India
| | - Shiv Kumar
- International Centre for Agricultural Research in the Dry Areas (ICARDA), Rabat 10112, Morocco
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Higdon SM, Pozzo T, Tibbett EJ, Chiu C, Jeannotte R, Weimer BC, Bennett AB. Diazotrophic bacteria from maize exhibit multifaceted plant growth promotion traits in multiple hosts. PLoS One 2020; 15:e0239081. [PMID: 32925972 PMCID: PMC7489573 DOI: 10.1371/journal.pone.0239081] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/28/2020] [Indexed: 11/18/2022] Open
Abstract
Sierra Mixe maize is a geographically remote landrace variety grown on nitrogen-deficient fields in Oaxaca, Mexico that meets its nutritional requirements without synthetic fertilizer by associating with free-living diazotrophs comprising the microbiota of its aerial root mucilage. We selected nearly 500 diazotrophic (N2-fixing) bacteria isolated from Sierra Mixe maize mucilage and sequenced their genomes. Comparative genomic analysis demonstrated that isolates represented diverse genera and composed three major diazotrophic groups based on nitrogen fixation gene content. In addition to nitrogen fixation, we examined deamination of 1-amino-1-cyclopropanecarboxylic acid, biosynthesis of indole-3-acetic acid, and phosphate solubilization as alternative mechanisms of direct plant growth promotion (PGP). Genome mining showed that isolates of all diazotrophic groups possessed marker genes for multiple mechanisms of direct plant growth promotion (PGP). Implementing in vitro assays corroborated isolate genotypes by measuring each isolate's potential to confer the targeted PGP traits and revealed phenotypic variation among isolates based on diazotrophic group assignment. Investigating the ability of mucilage diazotrophs to confer PGP by direct inoculation of clonally propagated potato plants in planta led to the identification of 16 bio-stimulant candidates. Conducting nitrogen-stress greenhouse experiments demonstrated that potato inoculation with a synthetic community of bio-stimulant candidates, as well as with its individual components, resulted in PGP phenotypes. We further demonstrated that one diazotrophic isolate conferred PGP to a conventional maize variety under nitrogen-stress in the greenhouse. These results indicate that, while many diazotrophic isolates from Sierra Mixe maize possessed genotypes and in vitro phenotypes for targeted PGP traits, a subset of these organisms promoted the growth of potato and conventional maize, potentially through the use of multiple promotion mechanisms.
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Affiliation(s)
- Shawn M. Higdon
- Department of Plant Sciences, University of California, Davis, California, United States of America
| | - Tania Pozzo
- Department of Plant Sciences, University of California, Davis, California, United States of America
| | - Emily J. Tibbett
- Department of Plant Sciences, University of California, Davis, California, United States of America
| | - Colleen Chiu
- Department of Plant Sciences, University of California, Davis, California, United States of America
| | - Richard Jeannotte
- Department of Population Health and Reproduction, University of California, Davis, California, United States of America
| | - Bart C. Weimer
- Department of Population Health and Reproduction, University of California, Davis, California, United States of America
| | - Alan B. Bennett
- Department of Plant Sciences, University of California, Davis, California, United States of America
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13
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Duca DR, Glick BR. Indole-3-acetic acid biosynthesis and its regulation in plant-associated bacteria. Appl Microbiol Biotechnol 2020; 104:8607-8619. [PMID: 32875364 DOI: 10.1007/s00253-020-10869-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 08/19/2020] [Accepted: 08/26/2020] [Indexed: 11/28/2022]
Abstract
Numerous studies have reported the stimulation of plant growth following inoculation with an IAA-producing PGPB. However, the specific mode of IAA production by the PGPB is rarely elucidated. In part, this is due to the overwhelming complexity of IAA biosynthesis and regulation. The promiscuity of the enzymes implicated in IAA biosynthesis adds another element of complexity when attempting to decipher their role in IAA biosynthesis. To date, the majority of research on IAA biosynthesis describes three separate pathways classified in terms of their intermediates-indole acetonitrile (IAN), indole acetamide (IAM), and indole pyruvic acid (IPA). Each of these pathways is mediated by a set of enzymes, many of which are traditionally assumed to exist for that specific catalytic role. This lends the possibility of missing other, novel, enzymes that may also incidentally serve that function. Some of these pathways are constitutively expressed, while others are inducible. Some enzymes involved in IAA biosynthesis are known to be regulated by IAA or by IAA precursors, as well as by a multitude of environmental cues. This review aims to provide an update to our current understanding of the biosynthesis and regulation of IAA in bacteria. KEY POINTS: • IAA produced by PGPB improves bacterial stress tolerance and promotes plant growth. • Bacterial IAA biosynthesis is convoluted; multiple interdependent pathways. • Biosynthesis of IAA is regulated by IAA, IAA-precursors, and environmental factors.
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Affiliation(s)
- Daiana R Duca
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada.
| | - Bernard R Glick
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
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14
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Lee SG, Harline K, Abar O, Akadri SO, Bastian AG, Chen HYS, Duan M, Focht CM, Groziak AR, Kao J, Kottapalli JS, Leong MC, Lin JJ, Liu R, Luo JE, Meyer CM, Mo AF, Pahng SH, Penna V, Raciti CD, Srinath A, Sudhakar S, Tang JD, Cox BR, Holland CK, Cascella B, Cruz W, McClerkin SA, Kunkel BN, Jez JM. The plant pathogen enzyme AldC is a long-chain aliphatic aldehyde dehydrogenase. J Biol Chem 2020; 295:13914-13926. [PMID: 32796031 DOI: 10.1074/jbc.ra120.014747] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/11/2020] [Indexed: 12/13/2022] Open
Abstract
Aldehyde dehydrogenases are versatile enzymes that serve a range of biochemical functions. Although traditionally considered metabolic housekeeping enzymes because of their ability to detoxify reactive aldehydes, like those generated from lipid peroxidation damage, the contributions of these enzymes to other biological processes are widespread. For example, the plant pathogen Pseudomonas syringae strain PtoDC3000 uses an indole-3-acetaldehyde dehydrogenase to synthesize the phytohormone indole-3-acetic acid to elude host responses. Here we investigate the biochemical function of AldC from PtoDC3000. Analysis of the substrate profile of AldC suggests that this enzyme functions as a long-chain aliphatic aldehyde dehydrogenase. The 2.5 Å resolution X-ray crystal of the AldC C291A mutant in a dead-end complex with octanal and NAD+ reveals an apolar binding site primed for aliphatic aldehyde substrate recognition. Functional characterization of site-directed mutants targeting the substrate- and NAD(H)-binding sites identifies key residues in the active site for ligand interactions, including those in the "aromatic box" that define the aldehyde-binding site. Overall, this study provides molecular insight for understanding the evolution of the prokaryotic aldehyde dehydrogenase superfamily and their diversity of function.
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Affiliation(s)
- Soon Goo Lee
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA; Department of Chemistry and Biochemistry, University of North Carolina-Wilmington, Wilmington, North Carolina, USA
| | - Kate Harline
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Orchid Abar
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Sakirat O Akadri
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Alexander G Bastian
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Hui-Yuan S Chen
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Michael Duan
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Caroline M Focht
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Amanda R Groziak
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Jesse Kao
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Matthew C Leong
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joy J Lin
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Regina Liu
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joanna E Luo
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Christine M Meyer
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Albert F Mo
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Seong Ho Pahng
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Vinay Penna
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Chris D Raciti
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Abhinav Srinath
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Shwetha Sudhakar
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joseph D Tang
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Brian R Cox
- Department of Chemistry and Biochemistry, University of North Carolina-Wilmington, Wilmington, North Carolina, USA
| | - Cynthia K Holland
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA; Department of Biology, Williams College, Williamstown, Massachusetts, USA
| | - Barrie Cascella
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Wilhelm Cruz
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Sheri A McClerkin
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA; Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, Illinois, USA
| | - Barbara N Kunkel
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Joseph M Jez
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA.
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15
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Saad MM, Eida AA, Hirt H. Tailoring plant-associated microbial inoculants in agriculture: a roadmap for successful application. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3878-3901. [PMID: 32157287 PMCID: PMC7450670 DOI: 10.1093/jxb/eraa111] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 03/09/2020] [Indexed: 05/05/2023]
Abstract
Plants are now recognized as metaorganisms which are composed of a host plant associated with a multitude of microbes that provide the host plant with a variety of essential functions to adapt to the local environment. Recent research showed the remarkable importance and range of microbial partners for enhancing the growth and health of plants. However, plant-microbe holobionts are influenced by many different factors, generating complex interactive systems. In this review, we summarize insights from this emerging field, highlighting the factors that contribute to the recruitment, selection, enrichment, and dynamic interactions of plant-associated microbiota. We then propose a roadmap for synthetic community application with the aim of establishing sustainable agricultural systems that use microbial communities to enhance the productivity and health of plants independently of chemical fertilizers and pesticides. Considering global warming and climate change, we suggest that desert plants can serve as a suitable pool of potentially beneficial microbes to maintain plant growth under abiotic stress conditions. Finally, we propose a framework for advancing the application of microbial inoculants in agriculture.
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Affiliation(s)
- Maged M Saad
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Abdul Aziz Eida
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Heribert Hirt
- DARWIN21, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Institute of Plant Sciences Paris-Saclay (IPS2), Gif-sur-Yvette Cedex, France
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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16
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Morffy N, Strader LC. Old Town Roads: routes of auxin biosynthesis across kingdoms. CURRENT OPINION IN PLANT BIOLOGY 2020; 55:21-27. [PMID: 32199307 PMCID: PMC7540728 DOI: 10.1016/j.pbi.2020.02.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/28/2020] [Accepted: 02/09/2020] [Indexed: 05/04/2023]
Abstract
Auxin is an important signaling molecule synthesized in organisms from multiple kingdoms of life, including land plants, green algae, and bacteria. In this review, we highlight the similarities and differences in auxin biosynthesis among these organisms. Tryptophan-dependent routes to IAA are found in land plants, green algae and bacteria. Recent sequencing efforts show that the indole-3-pyruvic acid pathway, one of the primary biosynthetic pathways in land plants, is also found in the green algae. These similarities raise questions about the origin of auxin biosynthesis. Future studies comparing auxin biosynthesis across kingdoms will shed light on its origin and role outside of the plant lineage.
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Affiliation(s)
- Nicholas Morffy
- Department of Biology, Washington University, St. Louis, MO 63130, United States; Center for Science and Engineering Living Systems (CSELS), Washington University, St. Louis, MO 63130, United States.
| | - Lucia C Strader
- Department of Biology, Washington University, St. Louis, MO 63130, United States; Center for Science and Engineering Living Systems (CSELS), Washington University, St. Louis, MO 63130, United States; Center for Engineering MechanoBiology, Washington University, St. Louis, MO 63130, United States.
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17
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Dodueva IE, Lebedeva MA, Kuznetsova KA, Gancheva MS, Paponova SS, Lutova LL. Plant tumors: a hundred years of study. PLANTA 2020; 251:82. [PMID: 32189080 DOI: 10.1007/s00425-020-03375-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/11/2020] [Indexed: 05/21/2023]
Abstract
The review provides information on the mechanisms underlying the development of spontaneous and pathogen-induced tumors in higher plants. The activation of meristem-specific regulators in plant tumors of various origins suggests the meristem-like nature of abnormal plant hyperplasia. Plant tumor formation has more than a century of research history. The study of this phenomenon has led to a number of important discoveries, including the development of the Agrobacterium-mediated transformation technique and the discovery of horizontal gene transfer from bacteria to plants. There are two main groups of plant tumors: pathogen-induced tumors (e.g., tumors induced by bacteria, viruses, fungi, insects, etc.), and spontaneous ones, which are formed in the absence of any pathogen in plants with certain genotypes (e.g., interspecific hybrids, inbred lines, and mutants). The causes of the transition of plant cells to tumor growth are different from those in animals, and they include the disturbance of phytohormonal balance and the acquisition of meristematic characteristics by differentiated cells. The aim of this review is to discuss the mechanisms underlying the development of most known examples of plant tumors.
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Affiliation(s)
- Irina E Dodueva
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia.
| | - Maria A Lebedeva
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Kseniya A Kuznetsova
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Maria S Gancheva
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Svetlana S Paponova
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
| | - Ludmila L Lutova
- Department of Genetics and Biotechnology, Saint-Petersburg State University, Saint-Petersburg, Russia
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18
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Nissan G, Chalupowicz L, Sessa G, Manulis‐Sasson S, Barash I. Two Pantoea agglomerans type III effectors can transform nonpathogenic and phytopathogenic bacteria into host-specific gall-forming pathogens. MOLECULAR PLANT PATHOLOGY 2019; 20:1582-1587. [PMID: 31368647 PMCID: PMC6804341 DOI: 10.1111/mpp.12860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Pantoea agglomerans (Pa), a widespread commensal bacterium, has evolved into a host-specific gall-forming pathogen on gypsophila and beet by acquiring a plasmid harbouring a type III secretion system (T3SS) and effectors (T3Es). Pantoea agglomerans pv. gypsophilae (Pag) elicits galls on gypsophila and a hypersensitive response on beet, whereas P. agglomerans pv. betae (Pab) elicits galls on beet and gypsophila. HsvG and HsvB are two paralogous T3Es present in both pathovars and act as host-specific transcription activators on gypsophila and beet, respectively. PthG and PseB are major T3Es that contribute to gall development of Pag and Pab, respectively. To establish the minimal combinations of T3Es that are sufficient to elicit gall symptoms, strains of the nonpathogenic bacteria Pseudomonas fluorescens 55, Pa 3-1, Pa 98 and Escherichia coli, transformed with pHIR11 harbouring a T3SS, and the phytopathogenic bacteria Erwinia amylovora, Dickeya solani and Xanthomonas campestris pv. campestris were transformed with the T3Es hsvG, hsvB, pthG and pseB, either individually or in pairs, and used to infect gypsophila and beet. Strikingly, all the tested nonpathogenic and phytopathogenic bacterial strains harbouring hsvG and pthG incited galls on gypsophila, whereas strains harbouring hsvB and pseB, with the exception of E. coli, incited galls on beet.
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Affiliation(s)
- Gal Nissan
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Laura Chalupowicz
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Guido Sessa
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
| | - Shulamit Manulis‐Sasson
- Department of Plant Pathology and Weed ResearchARO the Volcani CenterRishon LeZion7528809Israel
| | - Isaac Barash
- School of Plant Sciences and Security, Faculty of Life SciencesTel‐Aviv UniversityTel AvivIsrael
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19
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Zhang P, Jin T, Kumar Sahu S, Xu J, Shi Q, Liu H, Wang Y. The Distribution of Tryptophan-Dependent Indole-3-Acetic Acid Synthesis Pathways in Bacteria Unraveled by Large-Scale Genomic Analysis. Molecules 2019; 24:E1411. [PMID: 30974826 PMCID: PMC6479905 DOI: 10.3390/molecules24071411] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 01/08/2023] Open
Abstract
Bacterial indole-3-acetic acid (IAA), an effector molecule in microbial physiology, plays an important role in plant growth-promotion. Here, we comprehensively analyzed about 7282 prokaryotic genomes representing diverse bacterial phyla, combined with root-associated metagenomic data to unravel the distribution of tryptophan-dependent IAA synthesis pathways and to quantify the IAA synthesis-related genes in the plant root environments. We found that 82.2% of the analyzed bacterial genomes were potentially capable of synthesizing IAA from tryptophan (Trp) or intermediates. Interestingly, several phylogenetically diverse bacteria showed a preferential tendency to utilize different pathways and tryptamine and indole-3-pyruvate pathways are most prevalent in bacteria. About 45.3% of the studied genomes displayed multiple coexisting pathways, constituting complex IAA synthesis systems. Furthermore, root-associated metagenomic analyses revealed that rhizobacteria mainly synthesize IAA via indole-3-acetamide (IAM) and tryptamine (TMP) pathways and might possess stronger IAA synthesis abilities than bacteria colonizing other environments. The obtained results refurbished our understanding of bacterial IAA synthesis pathways and provided a faster and less labor-intensive alternative to physiological screening based on genome collections. The better understanding of IAA synthesis among bacterial communities could maximize the utilization of bacterial IAA to augment the crop growth and physiological function.
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Affiliation(s)
- Pengfan Zhang
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China.
- BGI-Shenzhen, Shenzhen 518083, China.
| | - Tao Jin
- BGI-Shenzhen, Shenzhen 518083, China.
| | - Sunil Kumar Sahu
- BGI-Shenzhen, Shenzhen 518083, China.
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China.
| | - Jin Xu
- Citrus Research and Education Center, Department of Microbiology and Cell Science, IFAS, University of Florida, Lake Alfred, FL 33885, USA.
| | - Qiong Shi
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China.
- BGI-Shenzhen, Shenzhen 518083, China.
| | - Huan Liu
- BGI-Shenzhen, Shenzhen 518083, China.
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China.
| | - Yayu Wang
- BGI-Shenzhen, Shenzhen 518083, China.
- State Key Laboratory of Agricultural Genomics, BGI-Shenzhen, Shenzhen 518083, China.
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads 2800 Kgs., 2800 Lyngby, Denmark.
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20
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Marag PS, Suman A. Growth stage and tissue specific colonization of endophytic bacteria having plant growth promoting traits in hybrid and composite maize (Zea mays L.). Microbiol Res 2018; 214:101-113. [PMID: 30031472 DOI: 10.1016/j.micres.2018.05.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/16/2018] [Accepted: 05/26/2018] [Indexed: 10/16/2022]
Abstract
Maize, a crop cultivated worldwide, was investigated for plant tissue and crop stage specific colonization of endophytic bacteria. Such bacterial interactions have high potential to enhance maize grain yield by means of biological nitrogen fixation and/or plant growth promoting activities. In this study endophytic bacteria were isolated from a hybrid PEEHM-5 and composite PC-4 maize varieties using root, stem and leaf tissues of plants at vegetative, flowering and maturity stages of growth. PEEHM-5 harbored higher endophytic bacterial population than PC-4 at all growth stages, with highest in roots and at flowering stage. Morphologically 188 different endophytic isolates (82 from PEEHM-5, 106 from PC-4) were screened for plant growth promoting attributes viz. P, K, Zn solubilization, production of hormones, siderophore, ACC deaminase, HCN, biological nitrogen fixation and biocontrol of two maize fungal pathogens. Thirty one potential PGP isolates on RFLP analysis of their amplified 16S rRNA gene, were clustered in 13 phylogenetic groups. On sequencing and blasting of amplified 16S rRNA gene of representative isolates from each group identified PC-4 endophytic bacterial isolates as Bacillus aryabhattai, Pantoea cypripedii, Bacillus licheniformis, Klebsiella sp., Pantoea dispersa, Klebsiella variicola, Pantoea sp., Agrobacterium larrymoorei and PEEHM-5 endophytic bacterial isolates as Bacillus sp., Bacillus amyloliquefaciens, Lactococcus lactis, Bacillus cereus and Staphylococcus hominis. In planta evaluation of potential isolates at variable chemical fertilizer input indicated their potential in compensating nearly 25% of the fertilizer input as observed on their improvement of shoot and root parameters. Lactococcus lactis inoculation influenced maximum followed by Pantoea and Klebsiella isolates.
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Affiliation(s)
- Premsing Shivsing Marag
- Division of Microbiology, ICAR- Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Archna Suman
- Division of Microbiology, ICAR- Indian Agricultural Research Institute, New Delhi, 110012, India.
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21
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Estenson K, Hurst GB, Standaert RF, Bible AN, Garcia D, Chourey K, Doktycz MJ, Morrell-Falvey JL. Characterization of Indole-3-acetic Acid Biosynthesis and the Effects of This Phytohormone on the Proteome of the Plant-Associated Microbe Pantoea sp. YR343. J Proteome Res 2018; 17:1361-1374. [PMID: 29464956 DOI: 10.1021/acs.jproteome.7b00708] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Indole-3-acetic acid (IAA) plays a central role in plant growth and development, and many plant-associated microbes produce IAA using tryptophan as the precursor. Using genomic analyses, we predicted that Pantoea sp. YR343, a microbe isolated from Populus deltoides, synthesizes IAA using the indole-3-pyruvate (IPA) pathway. To better understand IAA biosynthesis and the effects of IAA exposure on cell physiology, we characterized proteomes of Pantoea sp. YR343 grown in the presence of tryptophan or IAA. Exposure to IAA resulted in upregulation of proteins predicted to function in carbohydrate and amino acid transport and exopolysaccharide (EPS) biosynthesis. Metabolite profiles of wild-type cells showed the production of IPA, IAA, and tryptophol, consistent with an active IPA pathway. Finally, we constructed an Δ ipdC mutant that showed the elimination of tryptophol, consistent with a loss of IpdC activity, but was still able to produce IAA (20% of wild-type levels). Although we failed to detect intermediates from other known IAA biosynthetic pathways, this result suggests the possibility of an alternate pathway or the production of IAA by a nonenzymatic route in Pantoea sp. YR343. The Δ ipdC mutant was able to efficiently colonize poplar, suggesting that an active IPA pathway is not required for plant association.
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Affiliation(s)
- Kasey Estenson
- UT-ORNL Graduate School of Genome Science and Technology , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | | | - Robert F Standaert
- Department of Biochemistry & Cellular and Molecular Biology , University of Tennessee , Knoxville , Tennessee 37996 , United States.,Shull Wollan Center - a Joint Institute for Neutron Sciences , Oak Ridge , Tennessee 37831 , United States
| | - Amber N Bible
- Department of Biochemistry & Cellular and Molecular Biology , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - David Garcia
- Bredesen Center , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | | | - Mitchel J Doktycz
- UT-ORNL Graduate School of Genome Science and Technology , University of Tennessee , Knoxville , Tennessee 37996 , United States.,Bredesen Center , University of Tennessee , Knoxville , Tennessee 37996 , United States
| | - Jennifer L Morrell-Falvey
- UT-ORNL Graduate School of Genome Science and Technology , University of Tennessee , Knoxville , Tennessee 37996 , United States.,Department of Biochemistry & Cellular and Molecular Biology , University of Tennessee , Knoxville , Tennessee 37996 , United States
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22
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Sardar P, Kempken F. Characterization of indole-3-pyruvic acid pathway-mediated biosynthesis of auxin in Neurospora crassa. PLoS One 2018; 13:e0192293. [PMID: 29420579 PMCID: PMC5805262 DOI: 10.1371/journal.pone.0192293] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 01/22/2018] [Indexed: 12/03/2022] Open
Abstract
Plants, bacteria and some fungi are known to produce indole-3-acetic acid (IAA) by employing various pathways. Among these pathways, the indole-3-pyruvic acid (IPA) pathway is the best studied in green plants and plant-associated beneficial microbes. While IAA production circuitry in plants has been studied for decades, little is known regarding the IAA biosynthesis pathway in fungal species. Here, we present the first data for IAA-producing genes and the associated biosynthesis pathway in a non-pathogenic fungus, Neurospora crassa. For this purpose, we used a computational approach to determine the genes and outlined the IAA production circuitry in N. crassa. We then validated these data with experimental evidence. Here, we describe the homologous genes that are present in the IPA pathway of IAA production in N. crassa. High-performance liquid chromatography and thin-layer chromatography unambiguously identified IAA, indole-3-lactic acid (ILA) and tryptophol (TOL) from cultures supplemented with tryptophan. Deletion of the gene (cfp) that encodes the enzyme indole-3-pyruvate decarboxylase, which converts IPA to indole-3-acetaldehyde (IAAld), results in an accumulation of higher levels of ILA in the N. crassa culture medium. A double knock-out strain (Δcbs-3;Δahd-2) for the enzyme IAAld dehydrogenase, which converts IAAld to IAA, shows a many fold decrease in IAA production compared with the wild type strain. The Δcbs-3;Δahd-2 strain also displays slower conidiation and produces many fewer conidiospores than the wild type strain.
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Affiliation(s)
- Puspendu Sardar
- Abteilung Botanische Genetik und Molekularbiologie, Botanisches Institut und Botanischer Garten, Christian-Albrechts-Universität, Kiel, Germany
| | - Frank Kempken
- Abteilung Botanische Genetik und Molekularbiologie, Botanisches Institut und Botanischer Garten, Christian-Albrechts-Universität, Kiel, Germany
- * E-mail:
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Nissan G, Gershovits M, Morozov M, Chalupowicz L, Sessa G, Manulis‐Sasson S, Barash I, Pupko T. Revealing the inventory of type III effectors in Pantoea agglomerans gall-forming pathovars using draft genome sequences and a machine-learning approach. MOLECULAR PLANT PATHOLOGY 2018; 19:381-392. [PMID: 28019708 PMCID: PMC6638007 DOI: 10.1111/mpp.12528] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 12/06/2016] [Accepted: 12/14/2016] [Indexed: 05/03/2023]
Abstract
Pantoea agglomerans, a widespread epiphytic bacterium, has evolved into a hypersensitive response and pathogenicity (hrp)-dependent and host-specific gall-forming pathogen by the acquisition of a pathogenicity plasmid containing a type III secretion system (T3SS) and its effectors (T3Es). Pantoea agglomerans pv. betae (Pab) elicits galls on beet (Beta vulgaris) and gypsophila (Gypsophila paniculata), whereas P. agglomerans pv. gypsophilae (Pag) incites galls on gypsophila and a hypersensitive response (HR) on beet. Draft genome sequences were generated and employed in combination with a machine-learning approach and a translocation assay into beet roots to identify the pools of T3Es in the two pathovars. The genomes of the sequenced Pab4188 and Pag824-1 strains have a similar size (∼5 MB) and GC content (∼55%). Mutational analysis revealed that, in Pab4188, eight T3Es (HsvB, HsvG, PseB, DspA/E, HopAY1, HopX2, HopAF1 and HrpK) contribute to pathogenicity on beet and gypsophila. In Pag824-1, nine T3Es (HsvG, HsvB, PthG, DspA/E, HopAY1, HopD1, HopX2, HopAF1 and HrpK) contribute to pathogenicity on gypsophila, whereas the PthG effector triggers HR on beet. HsvB, HsvG, PthG and PseB appear to endow pathovar specificities to Pab and Pag, and no homologous T3Es were identified for these proteins in other phytopathogenic bacteria. Conversely, the remaining T3Es contribute to the virulence of both pathovars, and homologous T3Es were found in other phytopathogenic bacteria. Remarkably, HsvG and HsvB, which act as host-specific transcription factors, displayed the largest contribution to disease development.
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Affiliation(s)
- Gal Nissan
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Michael Gershovits
- Department of Cell Research and Immunology, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Michael Morozov
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Laura Chalupowicz
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Guido Sessa
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Shulamit Manulis‐Sasson
- Department of Plant Pathology and Weed ResearchAgricultural Research Organization, The Volcani CenterRishonLeZion7528809Israel
| | - Isaac Barash
- Department of Molecular Biology and Ecology of Plants, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
| | - Tal Pupko
- Department of Cell Research and Immunology, Faculty of Life SciencesTel‐Aviv UniversityTel‐Aviv69978Israel
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Cox CE, Brandl MT, de Moraes MH, Gunasekera S, Teplitski M. Production of the Plant Hormone Auxin by Salmonella and Its Role in the Interactions with Plants and Animals. Front Microbiol 2018; 8:2668. [PMID: 29375530 PMCID: PMC5770404 DOI: 10.3389/fmicb.2017.02668] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 12/21/2017] [Indexed: 11/30/2022] Open
Abstract
The ability of human enteric pathogens to colonize plants and use them as alternate hosts is now well established. Salmonella, similarly to phytobacteria, appears to be capable of producing the plant hormone auxin via an indole-3-pyruvate decarboxylase (IpdC), a key enzyme of the IPyA pathway. A deletion of the Salmonella ipdC significantly reduced auxin synthesis in laboratory culture. The Salmonella ipdC gene was expressed on root surfaces of Medicago truncatula. M. truncatula auxin-responsive GH3::GUS reporter was activated by the wild type Salmonella, and not but the ipdC mutant, implying that the bacterially produced IAA (Indole Acetic Acid) was detected by the seedlings. Seedling infections with the wild type Salmonella caused an increase in secondary root formation, which was not observed in the ipdC mutant. The wild type Salmonella cells were detected as aggregates at the sites of lateral root emergence, whereas the ipdC mutant cells were evenly distributed in the rhizosphere. However, both strains appeared to colonize seedlings well in growth pouch experiments. The ipdC mutant was also less virulent in a murine model of infection. When mice were infected by oral gavage, the ipdC mutant was as proficient as the wild type strain in colonization of the intestine, but it was defective in the ability to cross the intestinal barrier. Fewer cells of the ipdC mutant, compared with the wild type strain, were detected in Peyer's patches, spleen and in the liver. Orthologs of ipdC are found in all Salmonella genomes and are distributed among many animal pathogens and plant-associated bacteria of the Enterobacteriaceae, suggesting a broad ecological role of the IpdC-catalyzed pathway.
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Affiliation(s)
- Clayton E Cox
- Department of Soil and Water Science, University of Florida, Gainesville, FL, United States
| | - Maria T Brandl
- Produce Safety and Microbiology Research Unit, United States Department of Agriculture, Agricultural Research Service, Albany, CA, United States
| | - Marcos H de Moraes
- Department of Soil and Water Science, University of Florida, Gainesville, FL, United States
| | | | - Max Teplitski
- Department of Soil and Water Science, University of Florida, Gainesville, FL, United States.,Smithsonian Marine Station, Ft. Pierce, FL, United States
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Kunkel BN, Harper CP. The roles of auxin during interactions between bacterial plant pathogens and their hosts. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:245-254. [PMID: 29272462 DOI: 10.1093/jxb/erx447] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Plant pathogens have evolved several strategies to manipulate the biology of their hosts to facilitate colonization, growth to high levels in plant tissue, and production of disease. One of the less well known of these strategies is the synthesis of plant hormones and hormone analogs, and there is growing evidence that modulation of host hormone signaling is important during pathogenesis. Several plant pathogens produce the auxin indole-3-acetic acid (IAA) and/or virulence factors that modulate host auxin signaling. Auxin is well known for being involved in many aspects of plant growth and development, but recent findings have revealed that elevated IAA levels or enhanced auxin signaling can also promote disease development in some plant-pathogen interactions. In addition to stimulating plant cell growth during infection by gall-forming bacteria, auxin and auxin signaling can antagonize plant defense responses. Auxin can also act as a microbial signaling molecule to impact the biology of some pathogens directly. In this review, we summarize recent progress towards elucidating the roles that auxin production, modification of host auxin signaling, and direct effects of auxin on pathogens play during pathogenesis, with emphasis on the impacts of auxin on interactions with bacterial pathogens.
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Affiliation(s)
- Barbara N Kunkel
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
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McClerklin SA, Lee SG, Harper CP, Nwumeh R, Jez JM, Kunkel BN. Indole-3-acetaldehyde dehydrogenase-dependent auxin synthesis contributes to virulence of Pseudomonas syringae strain DC3000. PLoS Pathog 2018; 14:e1006811. [PMID: 29293681 PMCID: PMC5766252 DOI: 10.1371/journal.ppat.1006811] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/12/2018] [Accepted: 12/14/2017] [Indexed: 12/02/2022] Open
Abstract
The bacterial pathogen Pseudomonas syringae modulates plant hormone signaling to promote infection and disease development. P. syringae uses several strategies to manipulate auxin physiology in Arabidopsis thaliana to promote pathogenesis, including its synthesis of indole-3-acetic acid (IAA), the predominant form of auxin in plants, and production of virulence factors that alter auxin responses in the host; however, the role of pathogen-derived auxin in P. syringae pathogenesis is not well understood. Here we demonstrate that P. syringae strain DC3000 produces IAA via a previously uncharacterized pathway and identify a novel indole-3-acetaldehyde dehydrogenase, AldA, that functions in IAA biosynthesis by catalyzing the NAD-dependent formation of IAA from indole-3-acetaldehyde (IAAld). Biochemical analysis and solving of the 1.9 Å resolution x-ray crystal structure reveal key features of AldA for IAA synthesis, including the molecular basis of substrate specificity. Disruption of aldA and a close homolog, aldB, lead to reduced IAA production in culture and reduced virulence on A. thaliana. We use these mutants to explore the mechanism by which pathogen-derived auxin contributes to virulence and show that IAA produced by DC3000 suppresses salicylic acid-mediated defenses in A. thaliana. Thus, auxin is a DC3000 virulence factor that promotes pathogenicity by suppressing host defenses. Pathogens have evolved multiple strategies for suppressing host defenses and modulating host physiology to promote colonization and disease development. For example, the plant pathogen Pseudomonas syringae uses several strategies to the manipulate hormone signaling of its hosts, including production of virulence factors that alter hormone responses in and synthesis of plant hormones or hormone mimics. Synthesis of indole-3-acetic acid (IAA), a common form of the plant hormone auxin, by many plant pathogens has been implicated in virulence. However, the role of pathogen-derived IAA during pathogenesis by leaf spotting pathogens such as P. syringae strain DC3000 is not well understood. Here, we demonstrate that P. syringae strain DC3000 uses a previously uncharacterized biochemical pathway to synthesize IAA, catalyzed by a novel aldehyde dehydrogenase, AldA, and carry out biochemical and structural studies of the AldA protein to investigate AldA activity and substrate specificity. We also generate an aldA mutant disrupted in IAA synthesis to show that IAA is a DC3000 virulence factor that promotes pathogenesis by suppressing host defense responses.
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Affiliation(s)
- Sheri A. McClerklin
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Soon Goo Lee
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Christopher P. Harper
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Ron Nwumeh
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Joseph M. Jez
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Barbara N. Kunkel
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
- * E-mail:
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Aswathy SK, Sridar R, Sivakumar U. Mitigation of drought in rice by a phyllosphere bacterium Bacillus altitudinis FD48. ACTA ACUST UNITED AC 2017. [DOI: 10.5897/ajmr2017.8610] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Thapa S, Prasanna R, Ranjan K, Velmourougane K, Ramakrishnan B. Nutrients and host attributes modulate the abundance and functional traits of phyllosphere microbiome in rice. Microbiol Res 2017; 204:55-64. [PMID: 28870292 DOI: 10.1016/j.micres.2017.07.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 07/11/2017] [Accepted: 07/15/2017] [Indexed: 02/04/2023]
Abstract
The abundance of phyllosphere bacterial communities of seven genotypes of rice ADT- 38, ADT-43, CR-1009, PB-1, PS-5, P-44, and PB-1509 was investigated, in relation to nutrient dynamics of rhizosphere and leaves. P-44 genotype recorded highest pigment accumulation, while genotypes CR-1009 and P-44 exhibited most number of different bacterial morphotypes, Colony forming units in two media (Nutrient agar and R2A) varied significantly and ranged from 106-107 per g plant tissues. Among the selected 60 distinct morphotypes, IAA and siderophore producers were the dominant functional types. Biocontrol activity against Drechslera oryzae was shown by 38 isolates, while 17 and 9 isolates were potent against Rhizoctonia solani and Magnaporthe oryzae respectively. Principal Component Analysis (PCA) illustrated the significant effects of selected soil and leaf nutrients of seven rice varieties on the culturable phyllospheric population (log CFU), particularly in the R2A medium. Eigen values revealed that 83% of the variance observed could be assigned to Leaf-Fe, Leaf-Mn, chlorophyll b and soil organic carbon (OC). Quantitative PCR analyses of abundance of bacteria, cyanobacteria and archaebacteria revealed a host-specific response, with CR-1009 showing highest number of 16S rRNA copies of bacterial members, while both P-44 and PS-5 had higher cyanobacterial abundance, but lowest number of those belonging to archaebacteria. Nutritional aspects of leaf and soil influenced the abundance of bacteria and their functional attributes; this is of interest for enhancing the efficacy of foliar inoculants, thereby, improving plant growth and disease tolerance.
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Affiliation(s)
- Shobit Thapa
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India
| | - Radha Prasanna
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India.
| | - Kunal Ranjan
- Division of Microbiology, ICAR-Indian Agricultural Research Institute, New Delhi 110012, India
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Caballo-Ponce E, Murillo J, Martínez-Gil M, Moreno-Pérez A, Pintado A, Ramos C. Knots Untie: Molecular Determinants Involved in Knot Formation Induced by Pseudomonas savastanoi in Woody Hosts. FRONTIERS IN PLANT SCIENCE 2017; 8:1089. [PMID: 28680437 PMCID: PMC5478681 DOI: 10.3389/fpls.2017.01089] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/06/2017] [Indexed: 05/10/2023]
Abstract
The study of the molecular basis of tree diseases is lately receiving a renewed attention, especially with the emerging perception that pathogens require specific pathogenicity and virulence factors to successfully colonize woody hosts. Pathosystems involving woody plants are notoriously difficult to study, although the use of model bacterial strains together with genetically homogeneous micropropagated plant material is providing a significant impetus to our understanding of the molecular determinants leading to disease. The gammaproteobacterium Pseudomonas savastanoi belongs to the intensively studied Pseudomonas syringae complex, and includes three pathogenic lineages causing tumorous overgrowths (knots) in diverse economically relevant trees and shrubs. As it occurs with many other bacteria, pathogenicity of P. savastanoi is dependent on a type III secretion system, which is accompanied by a core set of at least 20 effector genes shared among strains isolated from olive, oleander, and ash. The induction of knots of wild-type size requires that the pathogen maintains adequate levels of diverse metabolites, including the phytohormones indole-3-acetic acid and cytokinins, as well as cyclic-di-GMP, some of which can also regulate the expression of other pathogenicity and virulence genes and participate in bacterial competitiveness. In a remarkable example of social networking, quorum sensing molecules allow for the communication among P. savastanoi and other members of the knot microbiome, while at the same time are essential for tumor formation. Additionally, a distinguishing feature of bacteria from the P. syringae complex isolated from woody organs is the possession of a 15 kb genomic island (WHOP) carrying four operons and three other genes involved in degradation of phenolic compounds. Two of these operons mediate the catabolism of anthranilate and catechol and, together with another operon, are required for the induction of full-size tumors in woody hosts, but not in non-woody micropropagated plants. The use of transposon mutagenesis also uncovered a treasure trove of additional P. savastanoi genes affecting virulence and participating in diverse bacterial processes. Although there is still much to be learned on what makes a bacterium a successful pathogen of trees, we are already untying the knots.
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Affiliation(s)
- Eloy Caballo-Ponce
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga–Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Jesús Murillo
- Departamento de Producción Agraria, ETS de Ingenieros Agrónomos, Universidad Pública de NavarraPamplona, Spain
| | - Marta Martínez-Gil
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga–Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Alba Moreno-Pérez
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga–Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Adrián Pintado
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga–Consejo Superior de Investigaciones CientíficasMálaga, Spain
| | - Cayo Ramos
- Área de Genética, Facultad de Ciencias, Instituto de Hortofruticultura Subtropical y Mediterránea ‘La Mayora’, Universidad de Málaga–Consejo Superior de Investigaciones CientíficasMálaga, Spain
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Phytohormone production endowed with antagonistic potential and plant growth promoting abilities of culturable endophytic bacteria isolated from Clerodendrum colebrookianum Walp. Microbiol Res 2016; 193:57-73. [PMID: 27825487 DOI: 10.1016/j.micres.2016.09.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/23/2016] [Accepted: 09/23/2016] [Indexed: 11/23/2022]
Abstract
In this study, culturable endophytic bacterial isolates obtained from an ethnomedicinal plant Clerodendrum colebrookianum Walp., were assessed for their diversity, in vitro screening for their plant growth promoting (PGP) activities and to use them as inoculant for in vivo PGP activities with biocontrol potential. Totally, 73 isolates were recovered from different tissues of C. colebrookianum were identified by 16S rRNA gene sequencing and phylogenetically analyzed by using BOX-PCR fingerprinting. Out of 73 isolates, 52 exhibited varying extents of antagonistic potential were selected for screening for various PGP traits. Concerning the PGP activities, the percentage of isolates positive for P-solubilisation, indolic compounds production, siderophore and ammonia production were 84.6, 92.3, 78.8 and 98.0 respectively. All isolates were positive for the production of hydrocyanic acid (HCN) and 86.5%, 84.6% and 90.3% of isolates showed significant cellulase, amylase and protease production respectively. Further, the top 10 bacterial isolates based on a bonitur scale with multiple PGP activities were screened for root surface colonization and biofilm formation ability. Out of selected 10 isolates, 9 showed significant potential for root surface colonization on tomato roots. Isolate BPSAC6 identified as Bacillus sp. was most efficient in biofilm formation as assessed with respect to the intensity of crystal violet, which further showed their potential to withstand various biotic and abiotic stresses. Furthermore, Bacillus sp. strain BPSAC6 showed a significant increase in shoot and root height as well as fresh weight after 45 and 60 d of inoculation with tomato seedlings. Additionally, biosynthetic potential of antagonistic isolate was detection by using PKSI, PKSII and NRPS biosynthetic genes. Two isolates Pseudomonas psychrotolerans and Labrys wisconsinensis were reported first time as an endophyte. At last, first time an endophytic bacterial strain Bacillus sp. BPSAC6 was reported to produce altogether three phytohormones (IAA, Kinetin and 6-Benzyladenine). This study is the first report that bacteria isolated from C. colebrookianum has biocontrol as well as PGP abilities endowed with phytohormones production and can be used for the preparation of bioinoculant for plant growth promotion.
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Davis II EW, Weisberg AJ, Tabima JF, Grunwald NJ, Chang JH. Gall-ID: tools for genotyping gall-causing phytopathogenic bacteria. PeerJ 2016; 4:e2222. [PMID: 27547538 PMCID: PMC4958008 DOI: 10.7717/peerj.2222] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 06/15/2016] [Indexed: 11/20/2022] Open
Abstract
Understanding the population structure and genetic diversity of plant pathogens, as well as the effect of agricultural practices on pathogen evolution, is important for disease management. Developments in molecular methods have contributed to increase the resolution for accurate pathogen identification, but those based on analysis of DNA sequences can be less straightforward to use. To address this, we developed Gall-ID, a web-based platform that uses DNA sequence information from 16S rDNA, multilocus sequence analysis and whole genome sequences to group disease-associated bacteria to their taxonomic units. Gall-ID was developed with a particular focus on gall-forming bacteria belonging to Agrobacterium, Pseudomonas savastanoi, Pantoea agglomerans, and Rhodococcus. Members of these groups of bacteria cause growth deformation of plants, and some are capable of infecting many species of field, orchard, and nursery crops. Gall-ID also enables the use of high-throughput sequencing reads to search for evidence for homologs of characterized virulence genes, and provides downloadable software pipelines for automating multilocus sequence analysis, analyzing genome sequences for average nucleotide identity, and constructing core genome phylogenies. Lastly, additional databases were included in Gall-ID to help determine the identity of other plant pathogenic bacteria that may be in microbial communities associated with galls or causative agents in other diseased tissues of plants. The URL for Gall-ID is http://gall-id.cgrb.oregonstate.edu/.
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Affiliation(s)
- Edward W. Davis II
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, United States
| | - Alexandra J. Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Javier F. Tabima
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Niklaus J. Grunwald
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, United States
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, United States
- Horticultural Crops Research Laboratory, USDA-ARS, Corvallis, OR, United States
| | - Jeff H. Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, OR, United States
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, United States
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Bible AN, Fletcher SJ, Pelletier DA, Schadt CW, Jawdy SS, Weston DJ, Engle NL, Tschaplinski T, Masyuko R, Polisetti S, Bohn PW, Coutinho TA, Doktycz MJ, Morrell-Falvey JL. A Carotenoid-Deficient Mutant in Pantoea sp. YR343, a Bacteria Isolated from the Rhizosphere of Populus deltoides, Is Defective in Root Colonization. Front Microbiol 2016; 7:491. [PMID: 27148182 PMCID: PMC4834302 DOI: 10.3389/fmicb.2016.00491] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/24/2016] [Indexed: 11/13/2022] Open
Abstract
The complex interactions between plants and their microbiome can have a profound effect on the health and productivity of the plant host. A better understanding of the microbial mechanisms that promote plant health and stress tolerance will enable strategies for improving the productivity of economically important plants. Pantoea sp. YR343 is a motile, rod-shaped bacterium isolated from the roots of Populus deltoides that possesses the ability to solubilize phosphate and produce the phytohormone indole-3-acetic acid (IAA). Pantoea sp. YR343 readily colonizes plant roots and does not appear to be pathogenic when applied to the leaves or roots of selected plant hosts. To better understand the molecular mechanisms involved in plant association and rhizosphere survival by Pantoea sp. YR343, we constructed a mutant in which the crtB gene encoding phytoene synthase was deleted. Phytoene synthase is responsible for converting geranylgeranyl pyrophosphate to phytoene, an important precursor to the production of carotenoids. As predicted, the ΔcrtB mutant is defective in carotenoid production, and shows increased sensitivity to oxidative stress. Moreover, we find that the ΔcrtB mutant is impaired in biofilm formation and production of IAA. Finally we demonstrate that the ΔcrtB mutant shows reduced colonization of plant roots. Taken together, these data suggest that carotenoids are important for plant association and/or rhizosphere survival in Pantoea sp. YR343.
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Affiliation(s)
- Amber N. Bible
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Sarah J. Fletcher
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Dale A. Pelletier
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | | | - Sara S. Jawdy
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - David J. Weston
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | - Nancy L. Engle
- Biosciences Division, Oak Ridge National LaboratoryOak Ridge, TN, USA
| | | | - Rachel Masyuko
- Department of Chemical and Biomolecular Engineering, University of Notre DameNotre Dame, IN, USA
| | - Sneha Polisetti
- Department of Chemical and Biomolecular Engineering, University of Notre DameNotre Dame, IN, USA
| | - Paul W. Bohn
- Department of Chemical and Biomolecular Engineering, University of Notre DameNotre Dame, IN, USA
| | - Teresa A. Coutinho
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of PretoriaPretoria, South Africa
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Lin GH, Chang CY, Lin HR. Systematic profiling of indole-3-acetic acid biosynthesis in bacteria using LC-MS/MS. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 988:53-8. [PMID: 25746752 DOI: 10.1016/j.jchromb.2015.02.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 01/23/2015] [Accepted: 02/17/2015] [Indexed: 01/24/2023]
Abstract
Indole-3-acetic acid (IAA) is produced from tryptophan through five synthesis pathways. A comprehensive method for the quantification of IAA and biosynthesis-related intermediates in a culture medium was developed. Sample preparation was simple with protein precipitation. The analytes were separated on a superficially porous C18 silica column and detected by electrospray ionization-tandem mass spectrometry in the positive ion multiple reaction monitoring mode. The limit of detection was 0.05 μM, and the lower limits of quantification ranged from 0.05 to 2 μM. The intra-day and inter-day precision and accuracy were less than 13.96%. Ion suppression was observed, and the deuterated internal standards were used to compensate for the matrix effect. The method was applied to analyze changes in tryptophan catabolism in a culture medium of Pseudomonas putida. The proposed method is robust and suitable for the systematic profiling of IAA biosynthesis in culture supernatant.
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Affiliation(s)
- Guang-Huey Lin
- Department of Microbiology, Tzu Chi University, Hualien, Taiwan
| | - Chung-Yu Chang
- Institute of Medical Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Huei-Ru Lin
- Institute of Medical Biotechnology, Tzu Chi University, Hualien, Taiwan; Department of Laboratory Medicine and Biotechnology, Tzu Chi University, 701 Section 3, Jhongyang Road, Hualien 970, Taiwan.
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35
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Etesami H, Alikhani HA, Mirseyed Hosseini H. Indole-3-Acetic Acid and 1-Aminocyclopropane-1-Carboxylate Deaminase: Bacterial Traits Required in Rhizosphere, Rhizoplane and/or Endophytic Competence by Beneficial Bacteria. BACTERIAL METABOLITES IN SUSTAINABLE AGROECOSYSTEM 2015. [DOI: 10.1007/978-3-319-24654-3_8] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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36
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Techniques to Study Microbial Phytohormones. BACTERIAL METABOLITES IN SUSTAINABLE AGROECOSYSTEM 2015. [DOI: 10.1007/978-3-319-24654-3_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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37
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Microbial Life on Green Biomass and Their Use for Production of Platform Chemicals. MICROORGANISMS IN BIOREFINERIES 2015. [DOI: 10.1007/978-3-662-45209-7_2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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38
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Duca D, Lorv J, Patten CL, Rose D, Glick BR. Indole-3-acetic acid in plant-microbe interactions. Antonie van Leeuwenhoek 2014; 106:85-125. [PMID: 24445491 DOI: 10.1007/s10482-013-0095-y] [Citation(s) in RCA: 325] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 12/07/2013] [Indexed: 01/04/2023]
Abstract
Indole-3-acetic acid (IAA) is an important phytohormone with the capacity to control plant development in both beneficial and deleterious ways. The ability to synthesize IAA is an attribute that many bacteria including both plant growth-promoters and phytopathogens possess. There are three main pathways through which IAA is synthesized; the indole-3-pyruvic acid, indole-3-acetamide and indole-3-acetonitrile pathways. This chapter reviews the factors that effect the production of this phytohormone, the role of IAA in bacterial physiology and in plant-microbe interactions including phytostimulation and phytopathogenesis.
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Affiliation(s)
- Daiana Duca
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada,
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39
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Lorv JSH, Rose DR, Glick BR. Bacterial ice crystal controlling proteins. SCIENTIFICA 2014; 2014:976895. [PMID: 24579057 PMCID: PMC3918373 DOI: 10.1155/2014/976895] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 12/15/2013] [Indexed: 05/31/2023]
Abstract
Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions.
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Affiliation(s)
- Janet S. H. Lorv
- Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - David R. Rose
- Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1
| | - Bernard R. Glick
- Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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40
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Abstract
In this article, I briefly recount the historical events in my native country that led me to become a plant pathologist. I started as a field pathologist specializing in fungal diseases of legumes, moved to biochemical research on virulence factors, and then on to molecular plant-microbe interactions. I describe the impact my graduate studies at the University of California (UC)-Davis had on my career. My life's work and teaching can be said to reflect the development in plant pathology during the past 40 years. I have included a concise review of the development of plant pathology in Israel and the ways it is funded. Dealing with administrative duties while conducting research has contributed to my belief in the importance of multidisciplinary approaches and of preserving the applied approach in the teaching of plant pathology.
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Affiliation(s)
- Isaac Barash
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv 69978, Israel;
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41
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Distribution pattern analysis of epiphytic bacteria on ethnomedicinal plant surfaces: A micrographical and molecular approach. J Microsc Ultrastruct 2014. [DOI: 10.1016/j.jmau.2014.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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42
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Panijel M, Chalupowicz L, Sessa G, Manulis-Sasson S, Barash I. Global regulatory networks control the hrp regulon of the gall-forming bacterium Pantoea agglomerans pv. gypsophilae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:1031-1043. [PMID: 23745675 DOI: 10.1094/mpmi-04-13-0097-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Gall formation by Pantoea agglomerans pv. gypsophilae is dependent on the hypersensitive response and pathogenicity (hrp) system. Previous studies demonstrated that PagR and PagI, regulators of the quorum-sensing system, induce expression of the hrp regulatory cascade (i.e., hrpXY, hrpS, and hrpL) that activates the HrpL regulon. Here, we isolated the genes of the Gac/Rsm global regulatory pathway (i.e., gacS, gacA, rsmB, and csrD) and of the post-transcriptional regulator rsmA. Our results demonstrate that PagR and PagI also upregulate expression of the Gac/Rsm pathway. PagR acts as a transcriptional activator of each of the hrp regulatory genes and gacA in a N-butanoyl-L-homoserine lactone-dependent manner as shown by gel shift experiments. Mutants of the Gac/Rsm genes or overexpression of rsmA significantly reduced Pantoea agglomerans virulence and colonization of gypsophila. Overexpression of rsmB sRNA abolished gall formation, colonization, and hypersensitive reaction on nonhost plants and prevented transcription of the hrp regulatory cascade, indicating a lack of functional type III secretion system. Expression of rsmB sRNA in the background of the csrD null mutant suggests that CsrD may act as a safeguard for preventing excessive production of rsmB sRNA. Results presented indicate that the hrp regulatory cascade is controlled directly by PagR and indirectly by RsmA, whereas deficiency in RsmA activity is epistatic to PagR induction.
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Affiliation(s)
- Mary Panijel
- Department of Molecular Biology and Ecology of Plants, Tel-Aviv University, Tel-Aviv, Israel
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43
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Bose A, Shah D, Keharia H. Production of indole-3-acetic-acid (IAA) by the white rot fungusPleurotus ostreatusunder submerged condition of Jatropha seedcake. Mycology 2013. [DOI: 10.1080/21501203.2013.823891] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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44
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Poza-Carrion C, Suslow T, Lindow S. Resident bacteria on leaves enhance survival of immigrant cells of Salmonella enterica. PHYTOPATHOLOGY 2013; 103:341-51. [PMID: 23506362 DOI: 10.1094/phyto-09-12-0221-fi] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Although Salmonella enterica apparently has comparatively low epiphytic fitness on plants, external factors that would influence its ability to survive on plants after contamination would be of significance in the epidemiology of human diseases caused by this human pathogen. Viable population sizes of S. enterica applied to plants preinoculated with Pseudomonas syringae or either of two Erwinia herbicola strains was ≥10-fold higher than that on control plants that were not precolonized by such indigenous bacteria when assessed 24 to 72 h after the imposition of desiccation stress. The protective effect of P. fluorescens, which exhibited antibiosis toward S. enterica in vitro, was only ≈50% that conferred by other bacterial strains. Although S. enterica could produce small cellular aggregates after incubation on wet leaves for several days, and the cells in such aggregates were less susceptible to death upon acute dehydration than solitary cells (as determined by propidium iodide staining), most Salmonella cells were found as isolated cells when it was applied to leaves previously colonized by other bacterial species. The proportion of solitary cells of S. enterica coincident with aggregates of cells of preexisting epiphytic species that subsequently were judged as nonviable by viability staining on dry leaves was as much as 10-fold less than those that had landed on uncolonized portions of the leaf. Thus, survival of immigrant cells of S. enterica on plants appears to be strongly context dependent, and the presence of common epiphytic bacteria on plants can protect such immigrants from at least one key stress (i.e., desiccation) encountered on leaf surfaces.
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Affiliation(s)
- Cesar Poza-Carrion
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
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45
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Scheublin TR, Leveau JHJ. Isolation of Arthrobacter species from the phyllosphere and demonstration of their epiphytic fitness. Microbiologyopen 2013; 2:205-13. [PMID: 23355506 PMCID: PMC3584225 DOI: 10.1002/mbo3.59] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 11/12/2012] [Accepted: 11/13/2012] [Indexed: 11/08/2022] Open
Abstract
Bacteria of the genus Arthrobacter are common inhabitants of the soil environment, but can also be recovered from leaf surfaces (the phyllosphere). Using enrichment cultures on 4-chlorophenol, we succeeded in specifically isolating Arthrobacter bacteria from ground cover vegetation in an apple orchard. Based on 16S rRNA gene sequencing, the isolates were found to belong to at least three different species of Arthrobacter. Compared to the model bacterial epiphyte Pantoea agglomerans, the Arthrobacter isolates performed as well or even better in a standardized laboratory test of phyllosphere fitness. A similar performance was observed with the well-characterized soil isolate Arthrobacter chlorophenolicus A6. These findings suggest that the frequently reported presence of Arthrobacter strains on plant foliage can be explained by the capacity to multiply and persist in the phyllosphere environment. As bacteria from the genus Arthrobacter are known for their ability to degrade a wide variety of organic pollutants, their high phyllosphere competency marks them as a promising group for future studies on phyllosphere-based bioremediation, for example, as foliar bioaugmentation on ground cover or buffer-zone vegetation to prevent pesticides from reaching soil, surface-, or groundwater.
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Affiliation(s)
- Tanja R Scheublin
- Department of Microbial Ecology, Netherlands Institute of Ecology, Droevendaalsesteeg 10, Wageningen, 6708 PB, The Netherlands
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46
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Chalupowicz L, Weinthal D, Gaba V, Sessa G, Barash I, Manulis-Sasson S. Polar auxin transport is essential for gall formation by Pantoea agglomerans on Gypsophila. MOLECULAR PLANT PATHOLOGY 2013; 14:185-90. [PMID: 23083316 PMCID: PMC6638636 DOI: 10.1111/j.1364-3703.2012.00839.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The virulence of the bacterium Pantoea agglomerans pv. gypsophilae (Pag) on Gypsophila paniculata depends on a type III secretion system (T3SS) and its effectors. The hypothesis that plant-derived indole-3-acetic acid (IAA) plays a major role in gall formation was examined by disrupting basipetal polar auxin transport with the specific inhibitors 2,3,5-triiodobenzoic acid (TIBA) and N-1-naphthylphthalamic acid (NPA). On inoculation with Pag, galls developed in gypsophila stems above but not below lanolin rings containing TIBA or NPA, whereas, in controls, galls developed above and below the rings. In contrast, TIBA and NPA could not inhibit tumour formation in tomato caused by Agrobacterium tumefaciens. The colonization of gypsophila stems by Pag was reduced below, but not above, the lanolin-TIBA ring. Following Pag inoculation and TIBA treatment, the expression of hrpL (a T3SS regulator) and pagR (a quorum-sensing transcriptional regulator) decreased four-fold and that of pthG (a T3SS effector) two-fold after 24 h. Expression of PIN2 (a putative auxin efflux carrier) increased 35-fold, 24 h after Pag inoculation. However, inoculation with a mutant in the T3SS effector pthG reduced the expression of PIN2 by two-fold compared with wild-type infection. The results suggest that pthG might govern the elevation of PIN2 expression during infection, and that polar auxin transport-derived IAA is essential for gall initiation.
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Affiliation(s)
- Laura Chalupowicz
- Department of Plant Pathology and Weed Research, ARO, Volcani Center, Bet Dagan 50250, Israel
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47
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Hilbert M, Voll LM, Ding Y, Hofmann J, Sharma M, Zuccaro A. Indole derivative production by the root endophyte Piriformospora indica is not required for growth promotion but for biotrophic colonization of barley roots. THE NEW PHYTOLOGIST 2012; 196:520-534. [PMID: 22924530 DOI: 10.1111/j.1469-8137.2012.04275.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/07/2012] [Indexed: 05/04/2023]
Abstract
Beneficial effects elicited by the root endophyte Piriformospora indica are widely known, but the mechanism by which these are achieved is still unclear. It is proposed that phytohormones produced by the fungal symbiont play a crucial role in the interaction with the plant roots. Biochemical analyses of the underlying biosynthetic pathways for auxin production have shown that, on tryptophan feeding, P. indica can produce the phytohormones indole-3-acetic acid (IAA) and indole-3-lactate (ILA) through the intermediate indole-3-pyruvic acid (IPA). Time course transcriptional analyses after exposure to tryptophan designated the piTam1 gene as a key player. A green fluorescence protein (GFP) reporter study and transcriptional analysis of colonized barley roots showed that piTam1 is induced during the biotrophic phase. Piriformospora indica strains in which the piTam1 gene was silenced via an RNA interference (RNAi) approach were compromised in IAA and ILA production and displayed reduced colonization of barley (Hordeum vulgare) roots in the biotrophic phase, but the elicitation of growth promotion was not affected compared with the wild-type situation. Our results suggest that IAA is involved in the establishment of biotrophy in P. indica-barley symbiosis and might represent a compatibility factor in this system.
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Affiliation(s)
- Magdalena Hilbert
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl von Frisch Str. 10, 35043, Marburg, Germany
| | - Lars M Voll
- Department of Biology, Friedrich-Alexander University Erlangen-Nürnberg, Staudtstr. 5, 91058, Erlangen, Germany
| | - Yi Ding
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl von Frisch Str. 10, 35043, Marburg, Germany
| | - Jörg Hofmann
- Department of Biology, Friedrich-Alexander University Erlangen-Nürnberg, Staudtstr. 5, 91058, Erlangen, Germany
| | - Monica Sharma
- Department of Mycology and Plant Pathology, Dr. YSP UHF, Nauni, Solan, HP, India
| | - Alga Zuccaro
- Department of Organismic Interactions, Max Planck Institute for Terrestrial Microbiology, Karl von Frisch Str. 10, 35043, Marburg, Germany
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48
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Patten CL, Blakney AJC, Coulson TJD. Activity, distribution and function of indole-3-acetic acid biosynthetic pathways in bacteria. Crit Rev Microbiol 2012; 39:395-415. [PMID: 22978761 DOI: 10.3109/1040841x.2012.716819] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The capacity to produce the phytohormone indole-3-acetic acid (IAA) is widespread among bacteria that inhabit diverse environments such as soils, fresh and marine waters, and plant and animal hosts. Three major pathways for bacterial IAA synthesis have been characterized that remove the amino and carboxyl groups from the α-carbon of tryptophan via the intermediates indolepyruvate, indoleacetamide, or indoleacetonitrile; the oxidized end product IAA is typically secreted. The enzymes in these pathways often catabolize a broad range of substrates including aromatic amino acids and in some cases the branched chain amino acids. Moreover, expression of some of the genes encoding key IAA biosynthetic enzymes is induced by all three aromatic amino acids. The broad distribution and substrate specificity of the enzymes suggests a role for these pathways beyond plant-microbe interactions in which bacterial IAA has been best studied.
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Affiliation(s)
- Cheryl L Patten
- Department of Biology, University of New Brunswick , Fredericton, New Brunswick , Canada
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49
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Fedorov DN, Doronina NV, Trotsenko YA. Phytosymbiosis of aerobic methylobacteria: New facts and views. Microbiology (Reading) 2011. [DOI: 10.1134/s0026261711040047] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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50
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Fedorov DN, Doronina NV, Trotsenko YA. Cloning and characterization of indolepyruvate decarboxylase from Methylobacterium extorquens AM1. BIOCHEMISTRY (MOSCOW) 2011; 75:1435-43. [PMID: 21314613 DOI: 10.1134/s0006297910120035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
For the first time for methylotrophic bacteria an enzyme of phytohormone indole-3-acetic acid (IAA) biosynthesis, indole-3-pyruvate decarboxylase (EC 4.1.1.74), has been found. An open reading frame (ORF) was identified in the genome of facultative methylotroph Methylobacterium extorquens AM1 using BLAST. This ORF encodes thiamine diphosphate-dependent 2-keto acid decarboxylase and has similarity with indole-3-pyruvate decarboxylases, which are key enzymes of IAA biosynthesis. The ORF of the gene, named ipdC, was cloned into overexpression vector pET-22b(+). Recombinant enzyme IpdC was purified from Escherichia coli BL21(DE3) and characterized. The enzyme showed the highest k(cat) value for benzoylformate, albeit the indolepyruvate was decarboxylated with the highest catalytic efficiency (k(cat)/K(m)). The molecular mass of the holoenzyme determined using gel-permeation chromatography corresponds to a 245-kDa homotetramer. An ipdC-knockout mutant of M. extorquens grown in the presence of tryptophan had decreased IAA level (46% of wild type strain). Complementation of the mutation resulted in 6.3-fold increase of IAA concentration in the culture medium compared to that of the mutant strain. Thus involvement of IpdC in IAA biosynthesis in M. extorquens was shown.
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Affiliation(s)
- D N Fedorov
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia
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