1
|
Jeong JH, Jeon EY, Hwang MK, Song YJ, Kim JY. Development of super-infective ternary vector systems for enhancing the Agrobacterium-mediated plant transformation and genome editing efficiency. HORTICULTURE RESEARCH 2024; 11:uhae187. [PMID: 39247884 PMCID: PMC11377189 DOI: 10.1093/hr/uhae187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2024] [Accepted: 07/01/2024] [Indexed: 09/10/2024]
Abstract
Agrobacterium-mediated transformation remains a cornerstone of plant biology, fueling advancements in molecular genetics, new genomic techniques (NGTs), and the biotech industry. However, recalcitrant crops and technical hurdles persist as bottlenecks. The goal was to develop super-infective ternary vector systems that integrate a novel salicylic acid-degrading enzyme, GABA, and ethylene-degrading enzymes, targeting the transformation of crops by neutralizing plant defense system on Agrobacterium. Firstly, both the effect and activity of introducing enzymes were validated in EHA105, an important Agrobacterium strain. Our study demonstrates that all ternary vector (Tv) system variants significantly enhance reporter expression in transient assays with Nicotiana benthamiana and Cannabis sativa. Specifically, incorporating a constitutive virG mutation with novel enzyme combinations increased GFP and RUBY expression in C. sativa by >5-fold and 13-fold, respectively. The Tv system, combined with a geminivirus replicon, markedly boosted GUS gene expression in tomato, enhancing genome editing efficiency. Notably, compared to controls, Tv-VS demonstrated up to 18-fold and 4.5-fold increases in genome editing efficiency in C. sativa and tomato, respectively. Additionally, stable transformation rates in tomato and Arabidopsis improved significantly, with Tv-VS showing a remarkable 2.5-fold increase in transformation efficiency compared to control strains. The research marks notable progress in Agrobacterium-mediated plant transformation. The innovative ternary vectors overcome plant defense mechanisms, enabling genetic manipulation in previously challenging plant species. This development is anticipated to broaden the applications of plant genetic engineering, contributing to advancements in crop genome editing.
Collapse
Affiliation(s)
- Jin-Hee Jeong
- Nulla Bio Inc., 501 Jinjudaero, Jinju 660-701, Republic of Korea
- Division of Applied Life Science (BK21 Four program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Eun-Young Jeon
- Nulla Bio Inc., 501 Jinjudaero, Jinju 660-701, Republic of Korea
- Division of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Min Ki Hwang
- Division of Applied Life Science (BK21 Four program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Young Jong Song
- Division of Applied Life Science (BK21 Four program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
| | - Jae-Yean Kim
- Nulla Bio Inc., 501 Jinjudaero, Jinju 660-701, Republic of Korea
- Division of Applied Life Science (BK21 Four program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Republic of Korea
- Division of Life Science, Gyeongsang National University, 501 Jinju-daero, Jinju 52828, Republic of Korea
| |
Collapse
|
2
|
Rico-Jiménez M, Udaondo Z, Krell T, Matilla MA. Auxin-mediated regulation of susceptibility to toxic metabolites, c-di-GMP levels, and phage infection in the rhizobacterium Serratia plymuthica. mSystems 2024; 9:e0016524. [PMID: 38837409 PMCID: PMC11264596 DOI: 10.1128/msystems.00165-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 04/26/2024] [Indexed: 06/07/2024] Open
Abstract
The communication between plants and their microbiota is highly dynamic and involves a complex network of signal molecules. Among them, the auxin indole-3-acetic acid (IAA) is a critical phytohormone that not only regulates plant growth and development, but is emerging as an important inter- and intra-kingdom signal that modulates many bacterial processes that are important during interaction with their plant hosts. However, the corresponding signaling cascades remain largely unknown. Here, we advance our understanding of the largely unknown mechanisms by which IAA carries out its regulatory functions in plant-associated bacteria. We showed that IAA caused important changes in the global transcriptome of the rhizobacterium Serratia plymuthica and multidisciplinary approaches revealed that IAA sensing interferes with the signaling mediated by other pivotal plant-derived signals such as amino acids and 4-hydroxybenzoic acid. Exposure to IAA caused large alterations in the transcript levels of genes involved in amino acid metabolism, resulting in significant metabolic alterations. IAA treatment also increased resistance to toxic aromatic compounds through the induction of the AaeXAB pump, which also confers resistance to IAA. Furthermore, IAA promoted motility and severely inhibited biofilm formation; phenotypes that were associated with decreased c-di-GMP levels and capsule production. IAA increased capsule gene expression and enhanced bacterial sensitivity to a capsule-dependent phage. Additionally, IAA induced the expression of several genes involved in antibiotic resistance and led to changes in the susceptibility and responses to antibiotics with different mechanisms of action. Collectively, our study illustrates the complexity of IAA-mediated signaling in plant-associated bacteria. IMPORTANCE Signal sensing plays an important role in bacterial adaptation to ecological niches and hosts. This communication appears to be particularly important in plant-associated bacteria since they possess a large number of signal transduction systems that respond to a wide diversity of chemical, physical, and biological stimuli. IAA is emerging as a key inter- and intra-kingdom signal molecule that regulates a variety of bacterial processes. However, despite the extensive knowledge of the IAA-mediated regulatory mechanisms in plants, IAA signaling in bacteria remains largely unknown. Here, we provide insight into the diversity of mechanisms by which IAA regulates primary and secondary metabolism, biofilm formation, motility, antibiotic susceptibility, and phage sensitivity in a biocontrol rhizobacterium. This work has important implications for our understanding of bacterial ecology in plant environments and for the biotechnological and clinical applications of IAA, as well as related molecules.
Collapse
Affiliation(s)
- Miriam Rico-Jiménez
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Zulema Udaondo
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, Spain
| | - Tino Krell
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Miguel A. Matilla
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| |
Collapse
|
3
|
Cerna‐Vargas JP, Krell T. Exploring solute binding proteins in Pseudomonas aeruginosa that bind to γ-aminobutyrate and 5-aminovalerate and their role in activating sensor kinases. Microbiologyopen 2024; 13:e1415. [PMID: 38780167 PMCID: PMC11113362 DOI: 10.1002/mbo3.1415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
The standard method of receptor activation involves the binding of signals or signal-loaded solute binding proteins (SBPs) to sensor domains. Many sensor histidine kinases (SHKs), which are activated by SBP binding, are encoded adjacent to their corresponding sbp gene. We examined three SBPs of Pseudomonas aeruginosa PAO1, encoded near the genes for the AgtS (PA0600) and AruS (PA4982) SHKs, to determine how common this arrangement is. Ligand screening and microcalorimetric studies revealed that the SBPs PA0602 and PA4985 preferentially bind to GABA (KD = 2.3 and 0.58 μM, respectively), followed by 5-aminovalerate (KD = 30 and 1.6 μM, respectively) and ethanoldiamine (KD = 2.3 and 0.58 μM, respectively). In contrast, AgtB (PA0604) exclusively recognizes 5-aminovaleric acid (KD = 2.9 μM). However, microcalorimetric titrations did not show any binding between the AgtS sensor domain and AgtB or PA0602, regardless of the presence of ligands. Similarly, bacterial two-hybrid assays did not demonstrate an interaction between PA4985 and the AruS sensor domain. Therefore, sbp and shk genes located nearby are not always functionally linked. We previously identified PA0222 as a GABA-specific SBP. The presence of three SBPs for GABA may be linked to GABA's role as a trigger for P. aeruginosa virulence.
Collapse
Affiliation(s)
- Jean Paul Cerna‐Vargas
- Department of Biotechnology and Environmental Protection, Estación Experimental del ZaidínConsejo Superior de Investigaciones CientíficasGranadaSpain
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria/Consejo Superior de Investigaciones CientíficasParque Científico y Tecnológico de la Universidad Politécnica de Madrid, Pozuelo de AlarcónMadridSpain
| | - Tino Krell
- Department of Biotechnology and Environmental Protection, Estación Experimental del ZaidínConsejo Superior de Investigaciones CientíficasGranadaSpain
| |
Collapse
|
4
|
Yin R, Cheng J, Lin J. The role of the type VI secretion system in the stress resistance of plant-associated bacteria. STRESS BIOLOGY 2024; 4:16. [PMID: 38376647 PMCID: PMC10879055 DOI: 10.1007/s44154-024-00151-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 01/26/2024] [Indexed: 02/21/2024]
Abstract
The type VI secretion system (T6SS) is a powerful bacterial molecular weapon that can inject effector proteins into prokaryotic or eukaryotic cells, thereby participating in the competition between bacteria and improving bacterial environmental adaptability. Although most current studies of the T6SS have focused on animal bacteria, this system is also significant for the adaptation of plant-associated bacteria. This paper briefly introduces the structure and biological functions of the T6SS. We summarize the role of plant-associated bacterial T6SS in adaptability to host plants and the external environment, including resistance to biotic stresses such as host defenses and competition from other bacteria. We review the role of the T6SS in response to abiotic factors such as acid stress, oxidation stress, and osmotic stress. This review provides an important reference for exploring the functions of the T6SS in plant-associated bacteria. In addition, characterizing these anti-stress functions of the T6SS may provide new pathways toward eliminating plant pathogens and controlling agricultural losses.
Collapse
Affiliation(s)
- Rui Yin
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Juanli Cheng
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, 716000, Shaanxi, China
| | - Jinshui Lin
- Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, 716000, Shaanxi, China.
| |
Collapse
|
5
|
Bhardwaj R, Lone JK, Pandey R, Mondal N, Dhandapani R, Meena SK, Khan S. Insights into morphological and physio-biochemical adaptive responses in mungbean ( Vigna radiata L.) under heat stress. Front Genet 2023; 14:1206451. [PMID: 37396038 PMCID: PMC10308031 DOI: 10.3389/fgene.2023.1206451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 06/05/2023] [Indexed: 07/04/2023] Open
Abstract
Mungbean (Vigna radiata L. Wilczek) is an important food legume crop which contributes significantly to nutritional and food security of South and Southeast Asia. The crop thrives in hot and humid weather conditions, with an optimal temperature range of 28°-35°C, and is mainly cultivated under rainfed environments. However, the rising global temperature has posed a serious threat to mungbean cultivation. Optimal temperature is a vital factor in cellular processes, and every crop species has evolved with its specific temperature tolerance ability. Moreover, variation within a crop species is inevitable, given the diverse environmental conditions under which it has evolved. For instance, various mungbean germplasm can grow and produce seeds in extreme ambient temperatures as low as 20°C or as high as 45°C. This range of variation in mungbean germplasm for heat tolerance plays a crucial role in developing heat tolerant and high yielding mungbean cultivars. However, heat tolerance is a complex mechanism which is extensively discussed in this manuscript; and at the same time individual genotypes have evolved with various ways of heat stress tolerance. Therefore, to enhance understanding towards such variability in mungbean germplasm, we studied morphological, anatomical, physiological, and biochemical traits which are responsive to heat stress in plants with more relevance to mungbean. Understanding heat stress tolerance attributing traits will help in identification of corresponding regulatory networks and associated genes, which will further help in devising suitable strategies to enhance heat tolerance in mungbean. The major pathways responsible for heat stress tolerance in plants are also discussed.
Collapse
Affiliation(s)
- Ragini Bhardwaj
- ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
- Department of Bioscience and Biotechnology, Banasthali Vidyapith University, Tonk Rajasthan, India
| | - Jafar K Lone
- ICAR-National Bureau of Plant Genetic Resources, New Delhi, India
| | - Renu Pandey
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Nupur Mondal
- Shivaji College, University of Delhi, New Delhi, India
| | - R Dhandapani
- Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Surendra Kumar Meena
- Division of Crop Improvement, ICAR-Indian Grassland and Research Institute, Jhansi, India
| | - Suphiya Khan
- Department of Bioscience and Biotechnology, Banasthali Vidyapith University, Tonk Rajasthan, India
| |
Collapse
|
6
|
Albicoro FJ, Vacca C, Cafiero JH, Draghi WO, Martini MC, Goulian M, Lagares A, Del Papa MF. Comparative Proteomic Analysis Revealing ActJ-Regulated Proteins in Sinorhizobium meliloti. J Proteome Res 2023; 22:1682-1694. [PMID: 37017314 PMCID: PMC10834056 DOI: 10.1021/acs.jproteome.2c00731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
To adapt to different environmental conditions, Sinorhizobium meliloti relies on finely tuned regulatory networks, most of which are unexplored to date. We recently demonstrated that deletion of the two-component system ActJK renders an acid-vulnerable phenotype in S. meliloti and negatively impacts bacteroid development and nodule occupancy as well. To fully understand the role of ActJ in acid tolerance, S. meliloti wild-type and S. meliloti ΔactJ proteomes were compared in the presence or absence of acid stress by nanoflow ultrahigh-performance liquid chromatography coupled to mass spectrometry. The analysis demonstrated that proteins involved in the synthesis of exopolysaccharides (EPSs) were notably enriched in ΔactJ cells in acid pH. Total EPS quantification further revealed that although EPS production was augmented at pH 5.6 in both the ΔactJ and the parental strain, the lack of ActJ significantly enhanced this difference. Moreover, several efflux pumps were found to be downregulated in the ΔactJ strain. Promoter fusion assays suggested that ActJ positively modulated its own expression in an acid medium but not at under neutral conditions. The results presented here identify several ActJ-regulated genes in S. meliloti, highlighting key components associated with ActJK regulation that will contribute to a better understanding of rhizobia adaptation to acid stress.
Collapse
Affiliation(s)
- Francisco Javier Albicoro
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Carolina Vacca
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Juan Hilario Cafiero
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Walter Omar Draghi
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - María Carla Martini
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Mark Goulian
- Department of Biology, University of Pennsylvania, Philadelphia, PA. USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA. USA
| | - Antonio Lagares
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| | - María Florencia Del Papa
- Instituto de Biotecnología y Biologia Molecular -CONICET CCT La Plata - Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
| |
Collapse
|
7
|
Carrillo‐Carrasco VP, Hernandez‐Garcia J, Mutte SK, Weijers D. The birth of a giant: evolutionary insights into the origin of auxin responses in plants. EMBO J 2023; 42:e113018. [PMID: 36786017 PMCID: PMC10015382 DOI: 10.15252/embj.2022113018] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/20/2023] [Accepted: 01/25/2023] [Indexed: 02/15/2023] Open
Abstract
The plant signaling molecule auxin is present in multiple kingdoms of life. Since its discovery, a century of research has been focused on its action as a phytohormone. In land plants, auxin regulates growth and development through transcriptional and non-transcriptional programs. Some of the molecular mechanisms underlying these responses are well understood, mainly in Arabidopsis. Recently, the availability of genomic and transcriptomic data of green lineages, together with phylogenetic inference, has provided the basis to reconstruct the evolutionary history of some components involved in auxin biology. In this review, we follow the evolutionary trajectory that allowed auxin to become the "giant" of plant biology by focusing on bryophytes and streptophyte algae. We consider auxin biosynthesis, transport, physiological, and molecular responses, as well as evidence supporting the role of auxin as a chemical messenger for communication within ecosystems. Finally, we emphasize that functional validation of predicted orthologs will shed light on the conserved properties of auxin biology among streptophytes.
Collapse
Affiliation(s)
| | | | - Sumanth K Mutte
- Laboratory of BiochemistryWageningen UniversityWageningenthe Netherlands
| | - Dolf Weijers
- Laboratory of BiochemistryWageningen UniversityWageningenthe Netherlands
| |
Collapse
|
8
|
Wang H, Zhang M, Wang E, Xiao R, Zhang S, Guo M. Agrobacterium fabrum gene atu1420 regulates the pathogenicity by affecting the degradation of growth- and virulence-associated phenols. Res Microbiol 2023; 174:104011. [PMID: 36455782 DOI: 10.1016/j.resmic.2022.104011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/30/2022]
Abstract
Agrobacterium fabrum is a phytopathogen that causes the crown gall disease. Some plant-derived molecules, e.g. phenols, directly affect A. fabrum-plant interactions. Here, we characterize a phenolic catabolism-related gene, atu1420, that affects the pathogenicity of A. fabrum. Atu1420 is predicted to be an O-demethylase with high structural homology to Sphingomonas paucimobilis LigM. The HPLC-UV analysis showed that atu1420 affected the degradation of acetosyringone (AS). The deletion of atu1420 gene significantly enhanced the AS-induced virulence (vir) gene expression. atu1420 was shown to relieve the inhibitory effect of vanillic acid on the AS-induced vir gene expression and the growth of A. fabrum. The expression of atu1420 and the degradation of AS in A. fabrum C58 was up-regulated by the addition of indole acetic acid (IAA). The inhibitory effect of IAA on the AS-induced vir gene expression was partially relieved by the deletion of atu1420 gene, indicating that accelerating the degradation of AS is one of the ways that IAA inhibits vir genes induction. Furthermore, atu1420 mutant produced more pronounced tumors on kalanchoe leaves than the wild-type strain. These findings reveal the role of atu1420 in A. fabrum-host interactions and will broaden our understanding of the regulatory network of the interactions.
Collapse
Affiliation(s)
- Hao Wang
- Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
| | - Mengqi Zhang
- Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
| | - Erya Wang
- Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
| | - Ruoxuan Xiao
- Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
| | - Shuhang Zhang
- Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
| | - Minliang Guo
- Department of Biotechnology, College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
| |
Collapse
|
9
|
Williams MA, Bouchier JM, Mason AK, Brown PJB. Activation of ChvG-ChvI regulon by cell wall stress confers resistance to β-lactam antibiotics and initiates surface spreading in Agrobacterium tumefaciens. PLoS Genet 2022; 18:e1010274. [PMID: 36480495 PMCID: PMC9731437 DOI: 10.1371/journal.pgen.1010274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/28/2022] [Indexed: 12/13/2022] Open
Abstract
A core component of nearly all bacteria, the cell wall is an ideal target for broad spectrum antibiotics. Many bacteria have evolved strategies to sense and respond to antibiotics targeting cell wall synthesis, especially in the soil where antibiotic-producing bacteria compete with one another. Here we show that cell wall stress caused by both chemical and genetic inhibition of the essential, bifunctional penicillin-binding protein PBP1a prevents microcolony formation and activates the canonical host-invasion two-component system ChvG-ChvI in Agrobacterium tumefaciens. Using RNA-seq, we show that depletion of PBP1a for 6 hours results in a downregulation in transcription of flagellum-dependent motility genes and an upregulation in transcription of type VI secretion and succinoglycan biosynthesis genes, a hallmark of the ChvG-ChvI regulon. Depletion of PBP1a for 16 hours, results in differential expression of many additional genes and may promote a stress response, resembling those of sigma factors in other bacteria. Remarkably, the overproduction of succinoglycan causes cell spreading and deletion of the succinoglycan biosynthesis gene exoA restores microcolony formation. Treatment with cefsulodin phenocopies depletion of PBP1a and we correspondingly find that chvG and chvI mutants are hypersensitive to cefsulodin. This hypersensitivity only occurs in response to treatment with β-lactam antibiotics, suggesting that the ChvG-ChvI pathway may play a key role in resistance to antibiotics targeting cell wall synthesis. Finally, we provide evidence that ChvG-ChvI likely has a conserved role in conferring resistance to cell wall stress within the Alphaproteobacteria that is independent of the ChvG-ChvI repressor ExoR.
Collapse
Affiliation(s)
- Michelle A. Williams
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, United States of America
| | - Jacob M. Bouchier
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, United States of America
| | - Amara K. Mason
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, United States of America
| | - Pamela J. B. Brown
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, Missouri, United States of America
| |
Collapse
|
10
|
Tiwari M, Mishra AK, Chakrabarty D. Agrobacterium-mediated gene transfer: recent advancements and layered immunity in plants. PLANTA 2022; 256:37. [PMID: 35819629 PMCID: PMC9274631 DOI: 10.1007/s00425-022-03951-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 06/19/2022] [Indexed: 05/15/2023]
Abstract
Plant responds to Agrobacterium via three-layered immunity that determines its susceptibility or resistance to Agrobacterium infection. Agrobacterium tumefaciens is a soil-borne Gram-negative bacterium that causes crown gall disease in plants. The remarkable feat of interkingdom gene transfer has been extensively utilised in plant biotechnology to transform plant as well as non-host systems. In the past two decades, the molecular mode of the pathogenesis of A. tumefaciens has been extensively studied. Agrobacterium has also been utilised as a premier model to understand the defence response of plants during plant-Agrobacterium interaction. Nonetheless, the threat of Agrobacterium-mediated crown gall disease persists and is associated with a huge loss of plant vigour in agriculture. Understanding the molecular dialogues between these two interkingdom species might provide a cure for crown gall disease. Plants respond to A. tumefaciens by mounting a three-layered immune response, which is manipulated by Agrobacterium via its virulence effector proteins. Comparative studies on plant defence proteins versus the counter-defence of Agrobacterium have shed light on plant susceptibility and tolerance. It is possible to manipulate a plant's immune system to overcome the crown gall disease and increase its competence via A. tumefaciens-mediated transformation. This review summarises the recent advances in the molecular mode of Agrobacterium pathogenesis as well as the three-layered immune response of plants against Agrobacterium infection.
Collapse
Affiliation(s)
- Madhu Tiwari
- Biotechnology and Molecular Biology Division, CSIR-National Botanical Research Institute, Lucknow, 226001, India
- Laboratory of Microbial Genetics, Department of Botany, Banaras Hindu University, Varanasi, 221005, India
| | - Arun Kumar Mishra
- Laboratory of Microbial Genetics, Department of Botany, Banaras Hindu University, Varanasi, 221005, India
| | - Debasis Chakrabarty
- Biotechnology and Molecular Biology Division, CSIR-National Botanical Research Institute, Lucknow, 226001, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
| |
Collapse
|
11
|
Native Rhizospheric and Endophytic Fungi as Sustainable Sources of Plant Growth Promoting Traits to Improve Wheat Growth under Low Nitrogen Input. J Fungi (Basel) 2022; 8:jof8020094. [PMID: 35205849 PMCID: PMC8875171 DOI: 10.3390/jof8020094] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 01/15/2022] [Indexed: 02/06/2023] Open
Abstract
Wheat crops require effective nitrogen fertilization to produce high yields. Only half of chemical N2 fertilizers are absorbed into plants while the rest remains in the soil, causing environmental problems. Fungi could maximize nitrogen absorption, and from an environmental and biodiversity point of view, there is an urgent necessity for bioprospecting native fungi associated with wild plants growing in harsh environments, e.g., St. Katherine Protectorate (SKP) in the arid Sinai. Recovered taxa, either endophytic and/or rhizospheric, were screened for their plant growth-promoting (PGP) traits. Eighteen fungal isolates (15 rhizospheric and 3 endophytic) belonging to anamorphic ascomycetes were recovered from 9 different wild plants, and their PGP traits (indole-3-acetic acid [IAA] production, phosphate solubilization, siderophore production, and hydrolytic enzyme production) were measured. Rhizospheric isolate NGB-WS14 (Chaetosphaeronema achilleae) produced high levels of IAA (119.1 μg mL−1) in the presence of tryptophan, while NGB-WS 8 (Acrophialophora levis) produced high IAA levels (42.4 μg mL−1) in the absence of tryptophan. The highest phosphate-solubilizing activity (181.9 μg mL−1) was recorded by NGB-WFS2 (Penicillium chrysogenum). Endophytic isolate NGB-WFE16 (Fusarium petersiae) exhibited a high percentage level of Siderophore Unit (96.5% SU). All isolates showed variability in the secretion of extracellular hydrolytic enzymes. Remarkably, all isolates had antagonistic activity (55.6% to 87.3% suppression of pathogen growth) against the pathogenic taxon Alternaria alternata (SCUF00001378) in the dual-assay results. Out of the 18 isolates, 4 rhizospheric and 1 endophytic isolate showed significant increases in shoot dry weight and shoot nitrogen and chlorophyll content of wheat plants subjected to low inputs of chemical nitrogen (N) fertilizers (50% reduction) compared with the non-inoculated control in a pot experiment. Potent taxa were subjected to sequencing for molecular confirmation of phenotypic identification. The retrieved ITS sequences in this study have been deposited in GenBank under accession numbers from LC642736 to LC642740. This study considered the first report of endophytic fungi of Cheilanthes vellea, a wild plant with PGPF which improves wheat growth. These results recommend using PGPF as inoculants to alleviate low nitrogen fertilization.
Collapse
|
12
|
Identification of IAA-regulated genes in Pseudomonas syringae pv. tomato strain DC3000. J Bacteriol 2021; 204:e0038021. [PMID: 34662236 DOI: 10.1128/jb.00380-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The auxin indole-3-acetic acid (IAA) is a plant hormone that not only regulates plant growth and development but also plays important roles in plant-microbe interactions. We previously reported that IAA alters expression of several virulence-related genes in the plant pathogen Pseudomonas syringae pv. tomato strain DC3000 (PtoDC3000). To learn more about the impact of IAA on regulation of PtoDC3000 gene expression we performed a global transcriptomic analysis of bacteria grown in culture, in the presence or absence of exogenous IAA. We observed that IAA repressed expression of genes involved in the Type III secretion (T3S) system and motility and promoted expression of several known and putative transcriptional regulators. Several of these regulators are orthologs of factors known to regulate stress responses and accordingly expression of several stress response-related genes was also upregulated by IAA. Similar trends in expression for several genes were also observed by RT-qPCR. Using an Arabidopsis thaliana auxin receptor mutant that accumulates elevated auxin, we found that many of the P. syringae genes regulated by IAA in vitro were also regulated by auxin in planta. Collectively the data indicate that IAA modulates many aspects of PtoDC3000 biology, presumably to promote both virulence and survival under stressful conditions, including those encountered in or on plant leaves. IMPORTANCE Indole-3-acetic acid (IAA), a form of the plant hormone auxin, is used by many plant-associated bacteria as a cue to sense the plant environment. Previously, we showed that IAA can promote disease in interactions between the plant pathogen Pseudomonas syringae strain PtoDC000 and one of its hosts, Arabidopsis thaliana. However, the mechanisms by which IAA impacts the biology of PtoDC3000 and promotes disease are not well understood. Here we demonstrate that IAA is a signal molecule that regulates gene expression in PtoDC3000. The presence of exogenous IAA affects expression of over 700 genes in the bacteria, including genes involved in Type III secretion and genes involved in stress response. This work offers insight into the roles of auxin promoting pathogenesis.
Collapse
|
13
|
Kunkel BN, Johnson JMB. Auxin Plays Multiple Roles during Plant-Pathogen Interactions. Cold Spring Harb Perspect Biol 2021; 13:a040022. [PMID: 33782029 PMCID: PMC8411954 DOI: 10.1101/cshperspect.a040022] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The plant hormone auxin governs many aspects of normal plant growth and development. Auxin also plays an important role in plant-microbe interactions, including interactions between plant hosts and pathogenic microorganisms that cause disease. It is now well established that indole-3-acetic acid (IAA), the most well-studied form of auxin, promotes disease in many plant-pathogen interactions. Recent studies have shown that IAA can act both as a plant hormone that modulates host signaling and physiology to increase host susceptibility and as a microbial signal that directly impacts the pathogen to promote virulence, but large gaps in our understanding remain. In this article, we review recent studies on the roles that auxin plays during plant-pathogen interactions and discuss the virulence mechanisms that many plant pathogens have evolved to manipulate host auxin signaling and promote pathogenesis.
Collapse
Affiliation(s)
- Barbara N Kunkel
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Joshua M B Johnson
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| |
Collapse
|
14
|
Matilla MA, Ortega Á, Krell T. The role of solute binding proteins in signal transduction. Comput Struct Biotechnol J 2021; 19:1786-1805. [PMID: 33897981 PMCID: PMC8050422 DOI: 10.1016/j.csbj.2021.03.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 12/13/2022] Open
Abstract
The solute binding proteins (SBPs) of prokaryotes are present in the extracytosolic space. Although their primary function is providing substrates to transporters, SBPs also stimulate different signaling proteins, including chemoreceptors, sensor kinases, diguanylate cyclases/phosphodiesterases and Ser/Thr kinases, thereby causing a wide range of responses. While relatively few such systems have been identified, several pieces of evidence suggest that SBP-mediated receptor activation is a widespread mechanism. (1) These systems have been identified in Gram-positive and Gram-negative bacteria and archaea. (2) There is a structural diversity in the receptor domains that bind SBPs. (3) SBPs belonging to thirteen different families interact with receptor ligand binding domains (LBDs). (4) For the two most abundant receptor LBD families, dCache and four-helix-bundle, there are different modes of interaction with SBPs. (5) SBP-stimulated receptors carry out many different functions. The advantage of SBP-mediated receptor stimulation is attributed to a strict control of SBP levels, which allows a precise adjustment of the systeḿs sensitivity. We have compiled information on the effect of ligands on the transcript/protein levels of their cognate SBPs. In 87 % of the cases analysed, ligands altered SBP expression levels. The nature of the regulatory effect depended on the ligand family. Whereas inorganic ligands typically downregulate SBP expression, an upregulation was observed in response to most sugars and organic acids. A major unknown is the role that SBPs play in signaling and in receptor stimulation. This review attempts to summarize what is known and to present new information to narrow this gap in knowledge.
Collapse
Affiliation(s)
- Miguel A Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, Granada 18008, Spain
| | - Álvaro Ortega
- Department of Biochemistry and Molecular Biology 'B' and Immunology, Faculty of Chemistry, University of Murcia, Regional Campus of International Excellence "Campus Mare Nostrum", Murcia, Spain
| | - Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, Granada 18008, Spain
| |
Collapse
|
15
|
Sambyal K, Singh RV. Production of salicylic acid; a potent pharmaceutically active agent and its future prospects. Crit Rev Biotechnol 2021; 41:394-405. [PMID: 33618601 DOI: 10.1080/07388551.2020.1869687] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Salicylic acid is one of the potent pharmaceutical organic acids that have various applications in the medical field. It acts as a plant hormone and helps in plant's growth & defence against pathogens. Beyond its numerous functions in plants, SA has great pharmaceutical importance since it acts as an intermediate for the synthesis of various drugs and dyes e.g. aspirin. At the industrial scale, chemical methods are used for the synthesis of SA but presently, several other sources are available that have the capability to alternate the chemical process which will be a step forward toward green synthesis. Aim of this paper is to provide comprehensive knowledge of SA production and its biological application.
Collapse
Affiliation(s)
- Krishika Sambyal
- University Institute of Biotechnology, Chandigarh University, Gharuan, Punjab
| | | |
Collapse
|
16
|
Effect of γ-Aminobutyric Acid (GABA) on the Metabolome of Two Strains of Lasiodiplodia theobromae Isolated from Grapevine. Molecules 2020; 25:molecules25173833. [PMID: 32842542 PMCID: PMC7503889 DOI: 10.3390/molecules25173833] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/07/2020] [Accepted: 08/19/2020] [Indexed: 02/06/2023] Open
Abstract
The effect of γ-aminobutyric acid (GABA) on the metabolome of two strains of Lasiodiplodia theobromae isolated from grapevine that hold a different degree of virulence to the host plant (LA-SOL3 (more virulent), LA-SV1 (less virulent)) was investigated. The culture filtrates and crude extracts from the two strains grown in the presence and absence of 10 mM of GABA were tested for phytotoxicity on tomato plant cuttings and leaves, respectively. Considering the opportunistic nature of this fungus for humans, crude extracts were also tested for cytotoxicity on mammalian cell lines. We found that culture filtrates and crude extracts have a decreased toxicity in the presence of GABA. Metabolomic analysis, conducted on both strains at both growth conditions, revealed the production of several compounds, such as indole-3-carboxylic acid (ICA, which is the main compound produced by L. theobromae), 3-indolecarboxyaldehyde, (3R,4S)-botryodiplodin, (R)-mellein. Finally, data demonstrate that GABA both induces a decrease in the amount of ICA, and a diversification of the metabolites produced by L. theobromae.
Collapse
|
17
|
Djami-Tchatchou AT, Harrison GA, Harper CP, Wang R, Prigge MJ, Estelle M, Kunkel BN. Dual Role of Auxin in Regulating Plant Defense and Bacterial Virulence Gene Expression During Pseudomonas syringae PtoDC3000 Pathogenesis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:1059-1071. [PMID: 32407150 PMCID: PMC7810136 DOI: 10.1094/mpmi-02-20-0047-r] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Modification of host hormone biology is a common strategy used by plant pathogens to promote disease. For example, the bacterial pathogen strain Pseudomonas syringae DC3000 (PtoDC3000) produces the plant hormone auxin (indole-3-acetic acid [IAA]) to promote PtoDC3000 growth in plant tissue. Previous studies suggest that auxin may promote PtoDC3000 pathogenesis through multiple mechanisms, including both suppression of salicylic acid (SA)-mediated host defenses and via an unknown mechanism that appears to be independent of SA. To test if host auxin signaling is important during pathogenesis, we took advantage of Arabidopsis thaliana lines impaired in either auxin signaling or perception. We found that disruption of auxin signaling in plants expressing an inducible dominant axr2-1 mutation resulted in decreased bacterial growth and that this phenotype was suppressed by introducing the sid2-2 mutation, which impairs SA synthesis. Thus, host auxin signaling is required for normal susceptibility to PtoDC3000 and is involved in suppressing SA-mediated defenses. Unexpectedly, tir1 afb1 afb4 afb5 quadruple-mutant plants lacking four of the six known auxin coreceptors that exhibit decreased auxin perception, supported increased levels of bacterial growth. This mutant exhibited elevated IAA levels and reduced SA-mediated defenses, providing additional evidence that auxin promotes disease by suppressing host defense. We also investigated the hypothesis that IAA promotes PtoDC3000 virulence through a direct effect on the pathogen and found that IAA modulates expression of virulence genes, both in culture and in planta. Thus, in addition to suppressing host defenses, IAA acts as a microbial signaling molecule that regulates bacterial virulence gene expression.
Collapse
Affiliation(s)
| | | | - Chris P. Harper
- Department of Biology, Washington University, St. Louis, MO, U.S.A
| | - Renhou Wang
- Division of Biological Sciences, Section of Cell & Developmental Biology, University California San Diego, San Diego, CA, U.S.A
| | - Michael J. Prigge
- Division of Biological Sciences, Section of Cell & Developmental Biology, University California San Diego, San Diego, CA, U.S.A
| | - Mark Estelle
- Division of Biological Sciences, Section of Cell & Developmental Biology, University California San Diego, San Diego, CA, U.S.A
| | - Barbara N. Kunkel
- Department of Biology, Washington University, St. Louis, MO, U.S.A
- Corresponding author: B. N. Kunkel;
| |
Collapse
|
18
|
Nonaka S, Someya T, Kadota Y, Nakamura K, Ezura H. Super- Agrobacterium ver. 4: Improving the Transformation Frequencies and Genetic Engineering Possibilities for Crop Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:1204. [PMID: 31649690 PMCID: PMC6791131 DOI: 10.3389/fpls.2019.01204] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 09/02/2019] [Indexed: 05/07/2023]
Abstract
Agrobacterium tumefaciens has been utilized for both transient and stable transformations of plants. These transformation methods have been used in fields such as breeding GM crops, protein production in plant cells, and the functional analysis of genes. However, some plants have significantly lower transient gene transfer and stable transformation rates, creating a technical barrier that needs to be resolved. In this study, Super-Agrobacterium was updated to ver. 4 by introducing both the ACC deaminase (acdS) and GABA transaminase (gabT) genes, whose resultant enzymes degrade ACC, the ethylene precursor, and GABA, respectively. A. tumefaciens strain GV2260, which is similar to other major strains (EHA105, GV3101, LBA4404, and MP90), was used in this study. The abilities of the Super-Agrobacterium ver. 4 were evaluated in Erianthus ravennae, Solanum lycopersicum "Micro-Tom," Nicotiana benthamiana, and S. torvum. Super-Agrobacterium ver. 4 showed the highest T-DNA transfer (transient transformation) frequencies in E. ravennae and S. lycopersicum, but not in N. benthamiana and S. torvum. In tomato, Super-Agrobacterium ver. 4 increased the stable transformation rate by 3.6-fold compared to the original GV2260 strain. Super-Agrobacterium ver. 4 enables reduction of the amount of time and labor required for transformations by approximately 72%, and is therefore a more effective and powerful tool for plant genetic engineering and functional analysis, than the previously developed strains. As our system has a plasmid containing the acdS and gabT genes, it could be used in combination with other major strains such as EHA105, EHA101, LBA4404, MP90, and AGL1. Super-Agrobacterium ver. 4, could thus possibly be a breakthrough application for improving basic plant science research methods.
Collapse
Affiliation(s)
- Satoko Nonaka
- Tsukuba Plant Innovation Research Center, Gene Research Center, University of Tsukuba, Tsukuba, Japan
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- *Correspondence: Satoko Nonaka, ; Hiroshi Ezura,
| | - Tatsuhiko Someya
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Yasuhiro Kadota
- RIKEN Center for Sustainable Resource Science, Plant Immunity Group, Yokohama, Japan
| | - Kouji Nakamura
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Hiroshi Ezura
- Tsukuba Plant Innovation Research Center, Gene Research Center, University of Tsukuba, Tsukuba, Japan
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
- *Correspondence: Satoko Nonaka, ; Hiroshi Ezura,
| |
Collapse
|
19
|
Kalia VC, Patel SKS, Kang YC, Lee JK. Quorum sensing inhibitors as antipathogens: biotechnological applications. Biotechnol Adv 2018; 37:68-90. [PMID: 30471318 DOI: 10.1016/j.biotechadv.2018.11.006] [Citation(s) in RCA: 185] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 10/19/2018] [Accepted: 11/18/2018] [Indexed: 12/20/2022]
Abstract
The mechanisms through which microbes communicate using signal molecules has inspired a great deal of research. Microbes use this exchange of information, known as quorum sensing (QS), to initiate and perpetuate infectious diseases in eukaryotic organisms, evading the eukaryotic defense system by multiplying and expressing their pathogenicity through QS regulation. The major issue to arise from such networks is increased bacterial resistance to antibiotics, resulting from QS-dependent mediation of the formation of biofilm, the induction of efflux pumps, and the production of antibiotics. QS inhibitors (QSIs) of diverse origins have been shown to act as potential antipathogens. In this review, we focus on the use of QSIs to counter diseases in humans as well as plants and animals of economic importance. We also discuss the challenges encountered in the potential applications of QSIs.
Collapse
Affiliation(s)
- Vipin Chandra Kalia
- Department of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea.
| | - Sanjay K S Patel
- Department of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea
| | - Yun Chan Kang
- Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 02841, Republic of Korea
| | - Jung-Kul Lee
- Department of Chemical Engineering, Konkuk University, Seoul 05029, Republic of Korea.
| |
Collapse
|
20
|
Mehmood A, Hussain A, Irshad M, Hamayun M, Iqbal A, Khan N. In vitro production of IAA by endophytic fungus Aspergillus awamori and its growth promoting activities in Zea mays. Symbiosis 2018. [DOI: 10.1007/s13199-018-0583-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
21
|
iac Gene Expression in the Indole-3-Acetic Acid-Degrading Soil Bacterium Enterobacter soli LF7. Appl Environ Microbiol 2018; 84:AEM.01057-18. [PMID: 30054366 DOI: 10.1128/aem.01057-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/21/2018] [Indexed: 12/14/2022] Open
Abstract
We show for soil bacterium Enterobacter soli LF7 that the possession of an indole-3-acetic acid catabolic (iac) gene cluster is causatively linked to the ability to utilize the plant hormone indole-3-acetic acid (IAA) as a carbon and energy source. Genome-wide transcriptional profiling by mRNA sequencing revealed that these iac genes, chromosomally arranged as iacHABICDEFG and coding for the transformation of IAA to catechol, were the most highly induced (>29-fold) among the relatively few (<1%) differentially expressed genes in response to IAA. Also highly induced and immediately downstream of the iac cluster were genes for a major facilitator superfamily protein (mfs) and enzymes of the β-ketoadipate pathway (pcaIJD-catBCA), which channels catechol into central metabolism. This entire iacHABICDEFG-mfs-pcaIJD-catBCA gene set was constitutively expressed in an iacR deletion mutant, confirming the role of iacR, annotated as coding for a MarR-type regulator and located upstream of iacH, as a repressor of iac gene expression. In E. soli LF7 carrying the DNA region upstream of iacH fused to a promoterless gfp gene, green fluorescence accumulated in response to IAA at concentrations as low as 1.6 μM. The iacH promoter region also responded to chlorinated IAA, but not other aromatics tested, indicating a narrow substrate specificity. In an iacR deletion mutant, gfp expression from the iacH promoter region was constitutive, consistent with the predicted role of iacR as a repressor. A deletion analysis revealed putative -35/-10 promoter sequences upstream of iacH, as well as a possible binding site for the IacR repressor.IMPORTANCE Bacterial iac genes code for the enzymatic conversion of the plant hormone indole-3-acetic acid (IAA) to catechol. Here, we demonstrate that the iac genes of soil bacterium Enterobacter soli LF7 enable growth on IAA by coarrangement and coexpression with a set of pca and cat genes that code for complete conversion of catechol to central metabolites. This work contributes in a number of novel and significant ways to our understanding of iac gene biology in bacteria from (non-)plant environments. More specifically, we show that LF7's response to IAA involves derepression of the MarR-type transcriptional regulator IacR, which is quite fast (less than 25 min upon IAA exposure), highly specific (only in response to IAA and chlorinated IAA, and with few genes other than iac, cat, and pca induced), relatively sensitive (low micromolar range), and seemingly tailored to exploit IAA as a source of carbon and energy.
Collapse
|
22
|
Nobori T, Mine A, Tsuda K. Molecular networks in plant-pathogen holobiont. FEBS Lett 2018; 592:1937-1953. [PMID: 29714033 DOI: 10.1002/1873-3468.13071] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/13/2018] [Accepted: 04/23/2018] [Indexed: 12/31/2022]
Abstract
Plant immune receptors enable detection of a multitude of microbes including pathogens. The recognition of microbes activates various plant signaling pathways, such as those mediated by phytohormones. Over the course of coevolution with microbes, plants have expanded their repertoire of immune receptors and signaling components, resulting in highly interconnected plant immune networks. These immune networks enable plants to appropriately respond to different types of microbes and to coordinate immune responses with developmental programs and environmental stress responses. However, the interconnectivity in plant immune networks is exploited by microbial pathogens to promote pathogen fitness in plants. Analogous to plant immune networks, virulence-related pathways in bacterial pathogens are also interconnected. Accumulating evidence implies that some plant-derived compounds target bacterial virulence networks. Thus, the plant immune and bacterial virulence networks intimately interact with each other. Here, we highlight recent insights into the structures of the plant immune and bacterial virulence networks and the interactions between them. We propose that small molecules derived from plants and/or bacterial pathogens connect the two molecular networks, forming supernetworks in the plant-bacterial pathogen holobiont.
Collapse
Affiliation(s)
- Tatsuya Nobori
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Akira Mine
- Ritsumeikan Global Innovation Research Organization, Ritsumeikan University, Kusatsu, Japan.,JST, PRESTO, Kawaguchi-shi, Japan
| | - Kenichi Tsuda
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| |
Collapse
|
23
|
Dessaux Y, Faure D. Quorum Sensing and Quorum Quenching in Agrobacterium: A "Go/No Go System"? Genes (Basel) 2018; 9:genes9040210. [PMID: 29659511 PMCID: PMC5924552 DOI: 10.3390/genes9040210] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/08/2018] [Accepted: 04/09/2018] [Indexed: 02/02/2023] Open
Abstract
The pathogen Agrobacterium induces gall formation on a wide range of dicotyledonous plants. In this bacteria, most pathogenicity determinants are borne on the tumour inducing (Ti) plasmid. The conjugative transfer of this plasmid between agrobacteria is regulated by quorum sensing (QS). However, processes involved in the disturbance of QS also occur in this bacteria under the molecular form of a protein, TraM, inhibiting the sensing of the QS signals, and two lactonases BlcC (AttM) and AiiB that degrade the acylhomoserine lactone (AHL) QS signal. In the model Agrobacteriumfabrum strain C58, several data, once integrated, strongly suggest that the QS regulation may not be reacting only to cell concentration. Rather, these QS elements in association with the quorum quenching (QQ) activities may constitute an integrated and complex “go/no go system” that finely controls the biologically costly transfer of the Ti plasmid in response to multiple environmental cues. This decision mechanism permits the bacteria to sense whether it is in a gall or not, in a living or decaying tumor, in stressed plant tissues, etc. In this scheme, the role of the lactonases selected and maintained in the course of Ti plasmid and agrobacterial evolution appears to be pivotal.
Collapse
Affiliation(s)
- Yves Dessaux
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif sur Yvette CEDEX, France.
| | - Denis Faure
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Avenue de la terrasse, 91198 Gif sur Yvette CEDEX, France.
| |
Collapse
|
24
|
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.
Collapse
Affiliation(s)
- Barbara N Kunkel
- Department of Biology, Washington University in St. Louis, St. Louis, MO, USA
| | | |
Collapse
|
25
|
Barton IS, Fuqua C, Platt TG. Ecological and evolutionary dynamics of a model facultative pathogen: Agrobacterium and crown gall disease of plants. Environ Microbiol 2018; 20:16-29. [PMID: 29105274 PMCID: PMC5764771 DOI: 10.1111/1462-2920.13976] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 10/20/2017] [Accepted: 10/25/2017] [Indexed: 01/09/2023]
Abstract
Many important pathogens maintain significant populations in highly disparate disease and non-disease environments. The consequences of this environmental heterogeneity in shaping the ecological and evolutionary dynamics of these facultative pathogens are incompletely understood. Agrobacterium tumefaciens, the causative agent for crown gall disease of plants has proven a productive model for many aspects of interactions between pathogens and their hosts and with other microbes. In this review, we highlight how this past work provides valuable context for the use of this system to examine how heterogeneity and transitions between disease and non-disease environments influence the ecology and evolution of facultative pathogens. We focus on several features common among facultative pathogens, such as the physiological remodelling required to colonize hosts from environmental reservoirs and the consequences of competition with host and non-host associated microbiota. In addition, we discuss how the life history of facultative pathogens likely often results in ecological tradeoffs associated with performance in disease and non-disease environments. These pathogens may therefore have different competitive dynamics in disease and non-disease environments and are subject to shifting selective pressures that can result in pathoadaptation or the within-host spread of avirulent phenotypes.
Collapse
Affiliation(s)
- Ian S. Barton
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, IN, USA
| | - Thomas G. Platt
- Division of Biology, Kansas State University, Manhattan, KS, USA
| |
Collapse
|
26
|
Sita K, Sehgal A, HanumanthaRao B, Nair RM, Vara Prasad PV, Kumar S, Gaur PM, Farooq M, Siddique KHM, Varshney RK, Nayyar H. Food Legumes and Rising Temperatures: Effects, Adaptive Functional Mechanisms Specific to Reproductive Growth Stage and Strategies to Improve Heat Tolerance. FRONTIERS IN PLANT SCIENCE 2017; 8:1658. [PMID: 29123532 PMCID: PMC5662899 DOI: 10.3389/fpls.2017.01658] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/08/2017] [Indexed: 05/20/2023]
Abstract
Ambient temperatures are predicted to rise in the future owing to several reasons associated with global climate changes. These temperature increases can result in heat stress- a severe threat to crop production in most countries. Legumes are well-known for their impact on agricultural sustainability as well as their nutritional and health benefits. Heat stress imposes challenges for legume crops and has deleterious effects on the morphology, physiology, and reproductive growth of plants. High-temperature stress at the time of the reproductive stage is becoming a severe limitation for production of grain legumes as their cultivation expands to warmer environments and temperature variability increases due to climate change. The reproductive period is vital in the life cycle of all plants and is susceptible to high-temperature stress as various metabolic processes are adversely impacted during this phase, which reduces crop yield. Food legumes exposed to high-temperature stress during reproduction show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to smaller seeds and poor yields. Through various breeding techniques, heat tolerance in major legumes can be enhanced to improve performance in the field. Omics approaches unravel different mechanisms underlying thermotolerance, which is imperative to understand the processes of molecular responses toward high-temperature stress.
Collapse
Affiliation(s)
- Kumari Sita
- Department of Botany, Panjab University, Chandigarh, India
| | | | | | | | - P. V. Vara Prasad
- Sustainable Intensification Innovation Lab, Kansas State University, Manhattan, KS, United States
| | - Shiv Kumar
- International Center for Agricultural Research in the Dry Areas, Rabat, Morocco
| | - Pooran M. Gaur
- International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India
| | - Muhammad Farooq
- Department of Agronomy, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | | | - Rajeev K. Varshney
- International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India
- The UWA Institute of Agriculture, University of Western Australia, Perth, WA, Australia
| | - Harsh Nayyar
- Department of Botany, Panjab University, Chandigarh, India
| |
Collapse
|
27
|
Nathoo N, Bernards MA, MacDonald J, Yuan ZC. A Hydroponic Co-cultivation System for Simultaneous and Systematic Analysis of Plant/Microbe Molecular Interactions and Signaling. J Vis Exp 2017. [PMID: 28784965 DOI: 10.3791/55955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
An experimental design mimicking natural plant-microbe interactions is very important to delineate the complex plant-microbe signaling processes. Arabidopsis thaliana-Agrobacterium tumefaciens provides an excellent model system to study bacterial pathogenesis and plant interactions. Previous studies of plant-Agrobacterium interactions have largely relied on plant cell suspension cultures, the artificial wounding of plants, or the artificial induction of microbial virulence factors or plant defenses by synthetic chemicals. However, these methods are distinct from the natural signaling in planta, where plants and microbes recognize and respond in spatial and temporal manners. This work presents a hydroponic cocultivation system where intact plants are supported by metal mesh screens and cocultivated with Agrobacterium. In this cocultivation system, no synthetic phytohormone or chemical that induces microbial virulence or plant defense is supplemented. The hydroponic cocultivation system closely resembles natural plant-microbe interactions and signaling homeostasis in planta. Plant roots can be separated from the medium containing Agrobacterium, and the signaling and responses of both the plant hosts and the interacting microbes can be investigated simultaneously and systematically. At any given timepoint/interval, plant tissues or bacteria can be harvested separately for various "omics" analyses, demonstrating the power and efficacy of this system. The hydroponic cocultivation system can be easily adapted to study: 1) the reciprocal signaling of diverse plant-microbe systems, 2) signaling between a plant host and multiple microbial species (i.e. microbial consortia or microbiomes), 3) how nutrients and chemicals are implicated in plant-microbe signaling, and 4) how microbes interact with plant hosts and contribute to plant tolerance to biotic or abiotic stresses.
Collapse
Affiliation(s)
- Naeem Nathoo
- London Research and Development Centre, Agriculture & Agri-Food Canada; Department of Biology, University of Western Ontario
| | | | | | - Ze-Chun Yuan
- London Research and Development Centre, Agriculture & Agri-Food Canada; Department of Microbiology and Immunology, University of Western Ontario;
| |
Collapse
|
28
|
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.
Collapse
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
| |
Collapse
|
29
|
Ramesh SA, Tyerman SD, Gilliham M, Xu B. γ-Aminobutyric acid (GABA) signalling in plants. Cell Mol Life Sci 2017; 74:1577-1603. [PMID: 27838745 PMCID: PMC11107511 DOI: 10.1007/s00018-016-2415-7] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/06/2016] [Accepted: 11/08/2016] [Indexed: 01/11/2023]
Abstract
The role of γ-aminobutyric acid (GABA) as a signal in animals has been documented for over 60 years. In contrast, evidence that GABA is a signal in plants has only emerged in the last 15 years, and it was not until last year that a mechanism by which this could occur was identified-a plant 'GABA receptor' that inhibits anion passage through the aluminium-activated malate transporter family of proteins (ALMTs). ALMTs are multigenic, expressed in different organs and present on different membranes. We propose GABA regulation of ALMT activity could function as a signal that modulates plant growth, development, and stress response. In this review, we compare and contrast the plant 'GABA receptor' with mammalian GABAA receptors in terms of their molecular identity, predicted topology, mode of action, and signalling roles. We also explore the implications of the discovery that GABA modulates anion flux in plants, its role in signal transduction for the regulation of plant physiology, and predict the possibility that there are other GABA interaction sites in the N termini of ALMT proteins through in silico evolutionary coupling analysis; we also explore the potential interactions between GABA and other signalling molecules.
Collapse
Affiliation(s)
- Sunita A Ramesh
- Plant Transport and Signalling Lab, ARC Centre of Excellence in Plant Energy Biology and School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Stephen D Tyerman
- Plant Transport and Signalling Lab, ARC Centre of Excellence in Plant Energy Biology and School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Matthew Gilliham
- Plant Transport and Signalling Lab, ARC Centre of Excellence in Plant Energy Biology and School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia
| | - Bo Xu
- Plant Transport and Signalling Lab, ARC Centre of Excellence in Plant Energy Biology and School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, SA, 5064, Australia.
| |
Collapse
|
30
|
Imam J, Singh PK, Shukla P. Plant Microbe Interactions in Post Genomic Era: Perspectives and Applications. Front Microbiol 2016; 7:1488. [PMID: 27725809 PMCID: PMC5035750 DOI: 10.3389/fmicb.2016.01488] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/07/2016] [Indexed: 01/17/2023] Open
Abstract
Deciphering plant-microbe interactions is a promising aspect to understand the benefits and the pathogenic effect of microbes and crop improvement. The advancement in sequencing technologies and various 'omics' tool has impressively accelerated the research in biological sciences in this area. The recent and ongoing developments provide a unique approach to describing these intricate interactions and test hypotheses. In the present review, we discuss the role of plant-pathogen interaction in crop improvement. The plant innate immunity has always been an important aspect of research and leads to some interesting information like the adaptation of unique immune mechanisms of plants against pathogens. The development of new techniques in the post - genomic era has greatly enhanced our understanding of the regulation of plant defense mechanisms against pathogens. The present review also provides an overview of beneficial plant-microbe interactions with special reference to Agrobacterium tumefaciens-plant interactions where plant derived signal molecules and plant immune responses are important in pathogenicity and transformation efficiency. The construction of various Genome-scale metabolic models of microorganisms and plants presented a better understanding of all metabolic interactions activated during the interactions. This review also lists the emerging repertoire of phytopathogens and its impact on plant disease resistance. Outline of different aspects of plant-pathogen interactions is presented in this review to bridge the gap between plant microbial ecology and their immune responses.
Collapse
Affiliation(s)
| | | | - Pratyoosh Shukla
- Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand UniversityRohtak, India
| |
Collapse
|
31
|
Succinic Semialdehyde Promotes Prosurvival Capability of Agrobacterium tumefaciens. J Bacteriol 2016; 198:930-40. [PMID: 26755630 DOI: 10.1128/jb.00373-15] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 12/10/2015] [Indexed: 01/25/2023] Open
Abstract
UNLABELLED Succinic semialdehyde (SSA), an important metabolite of γ-aminobutyric acid (GABA), is a ligand of the repressor AttJ regulating the expression of the attJ-attKLM gene cluster in the plant pathogen Agrobacterium tumefaciens. While the response of A. tumefaciens to GABA and the function of attKLM have been extensively studied, genetic and physiological responses of A. tumefaciens to SSA remain unknown. In combination with microarray and genetic approaches, this study sets out to explore new roles of the SSA-AttJKLM regulatory mechanism during bacterial infection. The results showed that SSA plays a key role in regulation of several bacterial activities, including C4-dicarboxylate utilization, nitrate assimilation, and resistance to oxidative stress. Interestingly, while the SSA relies heavily on the functional AttKLM in mediating nitrate assimilation and oxidative stress resistance, the compound could regulate utilization of C4-dicarboxylates independent of AttJKLM. We further provide evidence that SSA controls C4-dicarboxylate utilization through induction of an SSA importer and that disruption of attKLM attenuates the tumorigenicity of A. tumefaciens. Taken together, these findings indicate that SSA could be a potent plant signal which, together with AttKLM, plays a vital role in promoting the bacterial prosurvival abilities during infection. IMPORTANCE Agrobacterium tumefaciens is a plant pathogen causing crown gall diseases and has been well known as a powerful tool for plant genetic engineering. During the long history of microbe-host interaction, A. tumefaciens has evolved the capabilities of recognition and response to plant-derived chemical metabolites. Succinic semialdehyde (SSA) is one such metabolite. Previous results have demonstrated that SSA functions to activate a quorum-quenching mechanism and thus to decrease the level of quorum-sensing signals, thereby avoiding the elicitation of a plant defense. Here, we studied the effect of SSA on gene expression at a genome-wide level and reported that SSA also promotes bacterial survival during infection. These findings provide a new insight on the biological significance of chemical signaling between agrobacteria and plant hosts.
Collapse
|
32
|
Grandclément C, Tannières M, Moréra S, Dessaux Y, Faure D. Quorum quenching: role in nature and applied developments. FEMS Microbiol Rev 2015; 40:86-116. [PMID: 26432822 DOI: 10.1093/femsre/fuv038] [Citation(s) in RCA: 353] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2015] [Indexed: 12/11/2022] Open
Abstract
Quorum sensing (QS) refers to the capacity of bacteria to monitor their population density and regulate gene expression accordingly: the QS-regulated processes deal with multicellular behaviors (e.g. growth and development of biofilm), horizontal gene transfer and host-microbe (symbiosis and pathogenesis) and microbe-microbe interactions. QS signaling requires the synthesis, exchange and perception of bacterial compounds, called autoinducers or QS signals (e.g. N-acylhomoserine lactones). The disruption of QS signaling, also termed quorum quenching (QQ), encompasses very diverse phenomena and mechanisms which are presented and discussed in this review. First, we surveyed the QS-signal diversity and QS-associated responses for a better understanding of the targets of the QQ phenomena that organisms have naturally evolved and are currently actively investigated in applied perspectives. Next the mechanisms, targets and molecular actors associated with QS interference are presented, with a special emphasis on the description of natural QQ enzymes and chemicals acting as QS inhibitors. Selected QQ paradigms are detailed to exemplify the mechanisms and biological roles of QS inhibition in microbe-microbe and host-microbe interactions. Finally, some QQ strategies are presented as promising tools in different fields such as medicine, aquaculture, crop production and anti-biofouling area.
Collapse
Affiliation(s)
- Catherine Grandclément
- Institut for Integrative Biology of the Cell, Department of Microbiology, CNRS CEA Paris-Sud University, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Mélanie Tannières
- Institut for Integrative Biology of the Cell, Department of Microbiology, CNRS CEA Paris-Sud University, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Solange Moréra
- Institut for Integrative Biology of the Cell, Department of Structural Biology, CNRS CEA Paris-Sud University, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Yves Dessaux
- Institut for Integrative Biology of the Cell, Department of Microbiology, CNRS CEA Paris-Sud University, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| | - Denis Faure
- Institut for Integrative Biology of the Cell, Department of Microbiology, CNRS CEA Paris-Sud University, Saclay Plant Sciences, Avenue de la Terrasse, 91198 Gif-sur-Yvette cedex, France
| |
Collapse
|
33
|
Characterization of a nitrilase and a nitrile hydratase from Pseudomonas sp. strain UW4 that converts indole-3-acetonitrile to indole-3-acetic acid. Appl Environ Microbiol 2015; 80:4640-9. [PMID: 24837382 DOI: 10.1128/aem.00649-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Indole-3-acetic acid (IAA) is a fundamental phytohormone with the ability to control many aspects of plant growth and development. Pseudomonas sp. strain UW4 is a rhizospheric plant growth-promoting bacterium that produces and secretes IAA. While several putative IAA biosynthetic genes have been reported in this bacterium, the pathways leading to the production of IAA in strain UW4 are unclear. Here, the presence of the indole-3-acetamide (IAM) and indole-3-acetaldoxime/indole-3-acetonitrile (IAOx/IAN) pathways of IAA biosynthesis is described, and the specific role of two of the enzymes (nitrilase and nitrile hydratase) that mediate these pathways is assessed. The genes encoding these two enzymes were expressed in Escherichia coli, and the enzymes were isolated and characterized. Substrate-feeding assays indicate that the nitrilase produces both IAM and IAA from the IAN substrate, while the nitrile hydratase only produces IAM. The two nitrile-hydrolyzing enzymes have very different temperature and pH optimums. Nitrilase prefers a temperature of 50°C and a pH of 6, while nitrile hydratase prefers 4°C and a pH of 7.5. Based on multiple sequence alignments and motif analyses, physicochemical properties and enzyme assays, it is concluded that the UW4 nitrilase has an aromatic substrate specificity. The nitrile hydratase is identified as an iron-type metalloenzyme that does not require the help of a P47K activator protein to be active. These data are interpreted in terms of a preliminary model for the biosynthesis of IAA in this bacterium.
Collapse
|
34
|
Song GC, Lee S, Hong J, Choi HK, Hong GH, Bae DW, Mysore KS, Park YS, Ryu CM. Aboveground insect infestation attenuates belowground Agrobacterium-mediated genetic transformation. THE NEW PHYTOLOGIST 2015; 207:148-158. [PMID: 25676198 DOI: 10.1111/nph.13324] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 01/07/2015] [Indexed: 05/08/2023]
Abstract
Agrobacterium tumefaciens causes crown gall disease. Although Agrobacterium can be popularly used for genetic engineering, the influence of aboveground insect infestation on Agrobacterium induced gall formation has not been investigated. Nicotiana benthamiana leaves were exposed to a sucking insect (whitefly) infestation and benzothiadiazole (BTH) for 7 d, and these exposed plants were inoculated with a tumorigenic Agrobacterium strain. We evaluated, both in planta and in vitro, how whitefly infestation affects crown gall disease. Whitefly-infested plants exhibited at least a two-fold reduction in gall formation on both stem and crown root. Silencing of isochorismate synthase 1 (ICS1), required for salicylic acid (SA) synthesis, compromised gall formation indicating an involvement of SA in whitefly-derived plant defence against Agrobacterium. Endogenous SA content was augmented in whitefly-infested plants upon Agrobacterium inoculation. In addition, SA concentration was three times higher in root exudates from whitefly-infested plants. As a consequence, Agrobacterium-mediated transformation of roots of whitefly-infested plants was clearly inhibited when compared to control plants. These results suggest that aboveground whitefly infestation elicits systemic defence responses throughout the plant. Our findings provide new insights into insect-mediated leaf-root intra-communication and a framework to understand interactions between three organisms: whitefly, N. benthamiana and Agrobacterium.
Collapse
Affiliation(s)
- Geun Cheol Song
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
- Biosystems and Bioengineering Program, University of Science and Technology (UST), Daejeon, 305-350, South Korea
| | - Soohyun Lee
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
| | - Jaehwa Hong
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
- Department of Plant Pathology, Chungnam National University, Daejeon, 305-764, South Korea
| | - Hye Kyung Choi
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
| | - Gun Hyong Hong
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
- Biosystems and Bioengineering Program, University of Science and Technology (UST), Daejeon, 305-350, South Korea
| | - Dong-Won Bae
- Central Instrument Facility, Gyeongsang National University, Jinju, 660-701, South Korea
| | - Kirankumar S Mysore
- Plant Biology Division, The Samuel Roberts Noble Foundation, Ardmore, OK, 73401, USA
| | - Yong-Soon Park
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
| | - Choong-Min Ryu
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
- Biosystems and Bioengineering Program, University of Science and Technology (UST), Daejeon, 305-350, South Korea
| |
Collapse
|
35
|
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]
|
36
|
Park YS, Ryu CM. Inter-organ defense networking: Leaf whitefly sucking elicits plant immunity to crown gall disease caused by Agrobacterium tumefaciens. PLANT SIGNALING & BEHAVIOR 2015; 10:e1081325. [PMID: 26357873 PMCID: PMC4883951 DOI: 10.1080/15592324.2015.1081325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 08/04/2015] [Accepted: 08/05/2015] [Indexed: 05/17/2023]
Abstract
Plants have elaborate defensive machinery to protect against numerous pathogens and insects. Plant hormones function as modulators of defensive mechanisms to maintain plant resistance to natural enemies. Our recent study suggests that salicylic acid (SA) is the primary phytohormone regulating plant responses to Agrobacterium tumefaciens infection. Tobacco (Nicotiana benthamiana Domin.) immune responses against Agrobacterium-mediated crown gall disease were activated by exposure to the sucking insect whitefly, which stimulated SA biosynthesis in aerial tissues; in turn, SA synthesized in aboveground tissues systemically modulated SA secretion in root tissues. Further investigation revealed that endogenous SA biosynthesis negatively modulated Agrobacterium-mediated plant genetic transformation. Our study provides novel evidence that activation of the SA-signaling pathway mediated by a sucking insect infestation has a pivotal role in subsequently attenuating Agrobacterium infection. These results demonstrate new insights into interspecies cross-talking among insects, plants, and soil bacteria.
Collapse
Affiliation(s)
- Yong-Soon Park
- Agricultural Microbiology Division; National Academy of Agricultural Science; Wanju, South Korea
| | - Choong-Min Ryu
- Molecular Phytobacteriology Laboratory; Superbacteria Research Center; Daejeon, South Korea
- Biosystem and Bioengineering Program; University of Science and Technology (UST); Daejeon, South Korea
| |
Collapse
|
37
|
Farrar K, Bryant D, Cope-Selby N. Understanding and engineering beneficial plant-microbe interactions: plant growth promotion in energy crops. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:1193-206. [PMID: 25431199 PMCID: PMC4265282 DOI: 10.1111/pbi.12279] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 08/22/2014] [Accepted: 10/09/2014] [Indexed: 05/16/2023]
Abstract
Plant production systems globally must be optimized to produce stable high yields from limited land under changing and variable climates. Demands for food, animal feed, and feedstocks for bioenergy and biorefining applications, are increasing with population growth, urbanization and affluence. Low-input, sustainable, alternatives to petrochemical-derived fertilizers and pesticides are required to reduce input costs and maintain or increase yields, with potential biological solutions having an important role to play. In contrast to crops that have been bred for food, many bioenergy crops are largely undomesticated, and so there is an opportunity to harness beneficial plant-microbe relationships which may have been inadvertently lost through intensive crop breeding. Plant-microbe interactions span a wide range of relationships in which one or both of the organisms may have a beneficial, neutral or negative effect on the other partner. A relatively small number of beneficial plant-microbe interactions are well understood and already exploited; however, others remain understudied and represent an untapped reservoir for optimizing plant production. There may be near-term applications for bacterial strains as microbial biopesticides and biofertilizers to increase biomass yield from energy crops grown on land unsuitable for food production. Longer term aims involve the design of synthetic genetic circuits within and between the host and microbes to optimize plant production. A highly exciting prospect is that endosymbionts comprise a unique resource of reduced complexity microbial genomes with adaptive traits of great interest for a wide variety of applications.
Collapse
Affiliation(s)
- Kerrie Farrar
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth UniversityAberystwyth, UK
- *Correspondence (Tel +0044 (0)1970 823097; fax 0044 (0)1970 828357; email )
| | - David Bryant
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth UniversityAberystwyth, UK
| | - Naomi Cope-Selby
- Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth UniversityAberystwyth, UK
| |
Collapse
|
38
|
Tiwari V, Chaturvedi AK, Mishra A, Jha B. An efficient method of agrobacterium-mediated genetic transformation and regeneration in local Indian cultivar of groundnut (Arachis hypogaea) using grafting. Appl Biochem Biotechnol 2014; 175:436-53. [PMID: 25308617 DOI: 10.1007/s12010-014-1286-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 10/02/2014] [Indexed: 01/05/2023]
Abstract
Groundnut (Arachis hypogaea L.) is an industrial crop used as a source of edible oil and nutrients. In this study, an efficient method of regeneration and Agrobacterium-mediated genetic transformation is reported for a local cultivar GG-20 using de-embryonated cotyledon explant. A high regeneration 52.69 ± 2.32 % was achieved by this method with 66.6 μM 6-benzylaminopurine (BAP), while the highest number of shoot buds per explant, 17.67 ± 3.51, was found with 20 μM BAP and 10 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The bacterial culture OD, acetosyringone and L-cysteine concentration were optimized as 1.8, 200 μM and 50 mg L(-1), respectively, in co-cultivation media. It was observed that the addition of 2,4-D in co-cultivation media induced accumulation of endogenous indole-3-acetic acid (IAA). The optimized protocol exhibited 85 % transformation efficiency followed by 14.65 ± 1.06 % regeneration, of which 3.82 ± 0.6 % explants were survived on hygromycin after selection. Finally, 14.58 ± 2.95 % shoots (regenerated on survived explants) were rooted on rooting media (RM3). In grafting method, regenerated shoots (after hygromycin selection) were grafted on the non-transformed stocks with 100 % survival and new leaves emerged in 3 weeks. The putative transgenic plants were then confirmed by PCR, Southern hybridization, reverse transcriptase PCR (RT-PCR) and β-glucuronidase (GUS) histochemical assay. The reported method is efficient and rapid and can also be applied to other crops which are recalcitrant and difficult in rooting.
Collapse
Affiliation(s)
- Vivekanand Tiwari
- Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, G.B. Road, Bhavnagar, 364002, Gujarat, India
| | | | | | | |
Collapse
|
39
|
Subramoni S, Nathoo N, Klimov E, Yuan ZC. Agrobacterium tumefaciens responses to plant-derived signaling molecules. FRONTIERS IN PLANT SCIENCE 2014; 5:322. [PMID: 25071805 PMCID: PMC4086400 DOI: 10.3389/fpls.2014.00322] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 06/18/2014] [Indexed: 05/24/2023]
Abstract
As a special phytopathogen, Agrobacterium tumefaciens infects a wide range of plant hosts and causes plant tumors also known as crown galls. The complexity of Agrobacterium-plant interaction has been studied for several decades. Agrobacterium pathogenicity is largely attributed to its evolved capabilities of precise recognition and response to plant-derived chemical signals. Agrobacterium perceives plant-derived signals to activate its virulence genes, which are responsible for transferring and integrating its Transferred DNA (T-DNA) from its Tumor-inducing (Ti) plasmid into the plant nucleus. The expression of T-DNA in plant hosts leads to the production of a large amount of indole-3-acetic acid (IAA), cytokinin (CK), and opines. IAA and CK stimulate plant growth, resulting in tumor formation. Agrobacterium utilizes opines as nutrient sources as well as signals in order to activate its quorum sensing (QS) to further promote virulence and opine metabolism. Intriguingly, Agrobacterium also recognizes plant-derived signals including γ-amino butyric acid and salicylic acid (SA) to activate quorum quenching that reduces the level of QS signals, thereby avoiding the elicitation of plant defense and preserving energy. In addition, Agrobacterium hijacks plant-derived signals including SA, IAA, and ethylene to down-regulate its virulence genes located on the Ti plasmid. Moreover, certain metabolites from corn (Zea mays) also inhibit the expression of Agrobacterium virulence genes. Here we outline the responses of Agrobacterium to major plant-derived signals that impact Agrobacterium-plant interactions.
Collapse
Affiliation(s)
- Sujatha Subramoni
- Southern Crop Protection and Food Research Centre, Agriculture & Agri-Food CanadaLondon, ON, Canada
| | - Naeem Nathoo
- Southern Crop Protection and Food Research Centre, Agriculture & Agri-Food CanadaLondon, ON, Canada
- Department of Biology, University of Western OntarioLondon, ON, Canada
| | - Eugene Klimov
- Southern Crop Protection and Food Research Centre, Agriculture & Agri-Food CanadaLondon, ON, Canada
| | - Ze-Chun Yuan
- Southern Crop Protection and Food Research Centre, Agriculture & Agri-Food CanadaLondon, ON, Canada
- Department of Microbiology and Immunology, University of Western OntarioLondon, ON, Canada
| |
Collapse
|
40
|
Overlöper A, Kraus A, Gurski R, Wright PR, Georg J, Hess WR, Narberhaus F. Two separate modules of the conserved regulatory RNA AbcR1 address multiple target mRNAs in and outside of the translation initiation region. RNA Biol 2014; 11:624-40. [PMID: 24921646 PMCID: PMC4152367 DOI: 10.4161/rna.29145] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The small RNA AbcR1 regulates the expression of ABC transporters in the plant pathogen Agrobacterium tumefaciens, the plant symbiont Sinorhizobium meliloti, and the human pathogen Brucella abortus. A combination of proteomic and bioinformatic approaches suggested dozens of AbcR1 targets in A. tumefaciens. Several of these newly discovered targets are involved in the uptake of amino acids, their derivatives, and sugars. Among the latter is the periplasmic sugar-binding protein ChvE, a component of the virulence signal transduction system. We examined 16 targets and their interaction with AbcR1 in close detail. In addition to the previously described mRNA interaction site of AbcR1 (M1), the CopraRNA program predicted a second functional module (M2) as target-binding site. Both M1 and M2 contain single-stranded anti-SD motifs. Using mutated AbcR1 variants, we systematically tested by band shift experiments, which sRNA region is responsible for mRNA binding and gene regulation. On the target site, we find that AbcR1 interacts with some mRNAs in the translation initiation region and with others far into their coding sequence. Our data show that AbcR1 is a versatile master regulator of nutrient uptake systems in A. tumefaciens and related bacteria.
Collapse
Affiliation(s)
| | | | | | - Patrick R Wright
- Genetics and Experimental Bioinformatics; University of Freiburg; Germany
| | - Jens Georg
- Genetics and Experimental Bioinformatics; University of Freiburg; Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics; University of Freiburg; Germany
| | | |
Collapse
|
41
|
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.
Collapse
Affiliation(s)
- Daiana Duca
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada,
| | | | | | | | | |
Collapse
|
42
|
Lang J, Faure D. Functions and regulation of quorum-sensing in Agrobacterium tumefaciens. FRONTIERS IN PLANT SCIENCE 2014; 5:14. [PMID: 24550924 PMCID: PMC3907764 DOI: 10.3389/fpls.2014.00014] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/12/2014] [Indexed: 05/05/2023]
Abstract
In Agrobacterium tumefaciens, horizontal transfer and vegetative replication of oncogenic Ti plasmids involve a cell-to-cell communication process called quorum-sensing (QS). The determinants of the QS-system belong to the LuxR/LuxI class. The LuxI-like protein TraI synthesizes N-acyl-homoserine lactone molecules which act as diffusible QS-signals. Beyond a threshold concentration, these molecules bind and activate the LuxR-like transcriptional regulator TraR, thereby initiating the QS-regulatory pathway. For the last 20 years, A. tumefaciens has stood as a prominent model in the understanding of the LuxR/LuxI type of QS systems. A number of studies also unveiled features which are unique to A. tumefaciens QS, some of them being directly related to the phytopathogenic lifestyle of the bacteria. In this review, we will present the current knowledge of QS in A. tumefaciens at both the genetic and molecular levels. We will also describe how interactions with plant host modulate the QS pathway of A. tumefaciens, and discuss what could be the advantages for the agrobacteria to use such a tightly regulated QS-system to disseminate the Ti plasmids.
Collapse
Affiliation(s)
| | - Denis Faure
- *Correspondence: Denis Faure, Institut des Sciences du Végétal, UPR2355, Centre National de la Recherche Scientifique, 1 Avenue de la Terrasse, 91 198 Gif-sur-Yvette, France e-mail:
| |
Collapse
|
43
|
Abstract
Cell-cell communication, or quorum sensing, is a widespread phenomenon in bacteria that is used to coordinate gene expression among local populations. Its use by bacterial pathogens to regulate genes that promote invasion, defense, and spread has been particularly well documented. With the ongoing emergence of antibiotic-resistant pathogens, there is a current need for development of alternative therapeutic strategies. An antivirulence approach by which quorum sensing is impeded has caught on as a viable means to manipulate bacterial processes, especially pathogenic traits that are harmful to human and animal health and agricultural productivity. The identification and development of chemical compounds and enzymes that facilitate quorum-sensing inhibition (QSI) by targeting signaling molecules, signal biogenesis, or signal detection are reviewed here. Overall, the evidence suggests that QSI therapy may be efficacious against some, but not necessarily all, bacterial pathogens, and several failures and ongoing concerns that may steer future studies in productive directions are discussed. Nevertheless, various QSI successes have rightfully perpetuated excitement surrounding new potential therapies, and this review highlights promising QSI leads in disrupting pathogenesis in both plants and animals.
Collapse
|
44
|
Repar J, Šućurović S, Zahradka K, Zahradka D, Ćurković-Perica M. Stress resistance of Escherichia coli and Bacillus subtilis is modulated by auxins. Can J Microbiol 2013; 59:766-70. [PMID: 24206360 DOI: 10.1139/cjm-2013-0266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two bacterial species, Gram-negative Escherichia coli and Gram-positive Bacillus subtilis, were exposed to different auxins to examine possible effects of these substances on bacterial stress tolerance. Bacterial resistance to UV irradiation, heat shock, and streptomycin was assessed with and without previous exposure to the following auxins: indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and 1-naphthalene acetic acid (NAA). Escherichia coli and B. subtilis cultures pretreated with any of the 3 auxins survived UV irradiation better than the untreated cultures. Also, B. subtilis cultures pretreated with IBA or NAA survived prolonged heat exposure better than the untreated cultures, while IAA pretreatment had no effect on heat shock survival. In contrast, auxin pretreatment rendered E. coli more sensitive to heat shock. Escherichia coli cultures pretreated with auxins were also more sensitive to streptomycin, while auxin pretreatment had no effect on sensitivity of B. subtilis to streptomycin. These results show that auxins may either enhance or reduce bacterial tolerance to different stressors, depending on the bacterial species and the type and level of the stress. Auxins usually had similar effects on the same bacterial species in cases when the same type and level of stress were applied.
Collapse
Affiliation(s)
- J Repar
- a Department of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | | | | | | | | |
Collapse
|
45
|
Donati AJ, Lee HI, Leveau JHJ, Chang WS. Effects of indole-3-acetic acid on the transcriptional activities and stress tolerance of Bradyrhizobium japonicum. PLoS One 2013; 8:e76559. [PMID: 24098533 PMCID: PMC3788728 DOI: 10.1371/journal.pone.0076559] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/28/2013] [Indexed: 11/18/2022] Open
Abstract
A genome-wide transcriptional profile of Bradyrhizobium japonicum, the nitrogen-fixing endosymbiont of the soybean plant, revealed differential expression of approximately 15% of the genome after a 1 mM treatment with the phytohormone indole-3-acetic acid (IAA). A total of 1,323 genes were differentially expressed (619 up-regulated and 704 down-regulated) at a two-fold cut off with q value ≤ 0.05. General stress response genes were induced, such as those involved in response to heat, cold, oxidative, osmotic, and desiccation stresses and in exopolysaccharide (EPS) biosynthesis. This suggests that IAA is effective in activating a generalized stress response in B. japonicum. The transcriptional data were corroborated by the finding that stress tolerance of B. japonicum in cell viability assays was enhanced when pre-treated with 1 mM IAA compared to controls. The IAA treatment also stimulated biofilm formation and EPS production by B. japonicum, especially acidic sugar components in the total EPS. The IAA pre-treatment did not influence the nodulation ability of B. japonicum. The data provide a comprehensive overview of the potential transcriptional responses of the symbiotic bacterium when exposed to the ubiquitous hormone of its plant host.
Collapse
Affiliation(s)
- Andrew J. Donati
- Department of Biology, University of Texas, Arlington, Texas, United States of America
| | - Hae-In Lee
- Department of Biology, University of Texas, Arlington, Texas, United States of America
| | - Johan H. J. Leveau
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Woo-Suk Chang
- Department of Biology, University of Texas, Arlington, Texas, United States of America
| |
Collapse
|
46
|
Lee K, Huang X, Yang C, Lee D, Ho V, Nobuta K, Fan JB, Wang K. A genome-wide survey of highly expressed non-coding RNAs and biological validation of selected candidates in Agrobacterium tumefaciens. PLoS One 2013; 8:e70720. [PMID: 23950988 PMCID: PMC3738593 DOI: 10.1371/journal.pone.0070720] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 06/26/2013] [Indexed: 12/31/2022] Open
Abstract
Agrobacterium tumefaciens is a plant pathogen that has the natural ability of delivering and integrating a piece of its own DNA into plant genome. Although bacterial non-coding RNAs (ncRNAs) have been shown to regulate various biological processes including virulence, we have limited knowledge of how Agrobacterium ncRNAs regulate this unique inter-Kingdom gene transfer. Using whole transcriptome sequencing and an ncRNA search algorithm developed for this work, we identified 475 highly expressed candidate ncRNAs from A. tumefaciens C58, including 101 trans-encoded small RNAs (sRNAs), 354 antisense RNAs (asRNAs), 20 5' untranslated region (UTR) leaders including a RNA thermosensor and 6 riboswitches. Moreover, transcription start site (TSS) mapping analysis revealed that about 51% of the mapped mRNAs have 5' UTRs longer than 60 nt, suggesting that numerous cis-acting regulatory elements might be encoded in the A. tumefaciens genome. Eighteen asRNAs were found on the complementary strands of virA, virB, virC, virD, and virE operons. Fifteen ncRNAs were induced and 7 were suppressed by the Agrobacterium virulence (vir) gene inducer acetosyringone (AS), a phenolic compound secreted by the plants. Interestingly, fourteen of the AS-induced ncRNAs have putative vir box sequences in the upstream regions. We experimentally validated expression of 36 ncRNAs using Northern blot and Rapid Amplification of cDNA Ends analyses. We show functional relevance of two 5' UTR elements: a RNA thermonsensor (C1_109596F) that may regulate translation of the major cold shock protein cspA, and a thi-box riboswitch (C1_2541934R) that may transcriptionally regulate a thiamine biosynthesis operon, thiCOGG. Further studies on ncRNAs functions in this bacterium may provide insights and strategies that can be used to better manage pathogenic bacteria for plants and to improve Agrobacterum-mediated plant transformation.
Collapse
Affiliation(s)
- Keunsub Lee
- Center for Plant Transformation, Plant Sciences Institute, Iowa State University, Ames, Iowa, United States of America
- Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| | - Xiaoqiu Huang
- Department of Computer Science, Iowa State University, Ames, Iowa, United States of America
| | - Chichun Yang
- Center for Plant Transformation, Plant Sciences Institute, Iowa State University, Ames, Iowa, United States of America
- Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| | - Danny Lee
- Scientific Research, Illumina Inc., San Diego, California, United States of America
| | - Vincent Ho
- Scientific Research, Illumina Inc., San Diego, California, United States of America
| | - Kan Nobuta
- Scientific Research, Illumina Inc., San Diego, California, United States of America
| | - Jian-Bing Fan
- Scientific Research, Illumina Inc., San Diego, California, United States of America
| | - Kan Wang
- Center for Plant Transformation, Plant Sciences Institute, Iowa State University, Ames, Iowa, United States of America
- Department of Agronomy, Iowa State University, Ames, Iowa, United States of America
| |
Collapse
|
47
|
Criscitiello MF, Dickman MB, Samuel JE, de Figueiredo P. Tripping on acid: trans-kingdom perspectives on biological acids in immunity and pathogenesis. PLoS Pathog 2013; 9:e1003402. [PMID: 23874196 PMCID: PMC3715416 DOI: 10.1371/journal.ppat.1003402] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Michael F Criscitiello
- Comparative Immunogenetics Laboratory, Texas A&M University, College Station, Texas, United States of America.
| | | | | | | |
Collapse
|
48
|
Planamente S, Moréra S, Faure D. In planta fitness-cost of the Atu4232-regulon encoding for a selective GABA-binding sensor in Agrobacterium. Commun Integr Biol 2013; 6:e23692. [PMID: 23710277 PMCID: PMC3656012 DOI: 10.4161/cib.23692] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 01/21/2013] [Accepted: 01/21/2013] [Indexed: 12/01/2022] Open
Abstract
GABA (gamma-aminobutyric acid) mediates cell-to-cell communication in eukaryotes and interspecies communication in host-microbe interactions. Agrobacterium tumefaciens induces the development of plant tumor in which GABA accumulates. Two periplasmic binding proteins Atu2422 and Atu4243 and their appropriate ABC-transporter are involved in the binding and importation of GABA. The structure of the selective GABA-binding Atu4243 reveals a GABA conformation similar to a proposed model of GABA bound to the mammalian GABAC receptor. The A. tumefaciens atu4243 mutant is affected for GABA uptake, aggressiveness on plant host and GABA-induced degradation of the quorum-sensing signal, hence for horizontal transfer of the tumor-inducing plasmid. Here, we report that a de-repression of atu4243 and its co-regulated neighbor genes affect the fitness of A. tumefaciens during tumor colonization. Atu4243-orthologs are present in several species of the Agrobacterium genus. This addendum highlights the recent data on the GABA transport in the A. tumefaciens plant-pathogen.
Collapse
Affiliation(s)
- Sara Planamente
- Institut des Sciences du Végétal (ISV); CNRS; Gif-sur-Yvette, France ; Laboratoire d'Enzymologie et Biochimie Structurales (LEBS); CNRS; Gif-sur-Yvette, France
| | | | | |
Collapse
|
49
|
Zúñiga A, Poupin MJ, Donoso R, Ledger T, Guiliani N, Gutiérrez RA, González B. Quorum sensing and indole-3-acetic acid degradation play a role in colonization and plant growth promotion of Arabidopsis thaliana by Burkholderia phytofirmans PsJN. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:546-53. [PMID: 23301615 DOI: 10.1094/mpmi-10-12-0241-r] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Although not fully understood, molecular communication in the rhizosphere plays an important role regulating traits involved in plant-bacteria association. Burkholderia phytofirmans PsJN is a well-known plant-growth-promoting bacterium, which establishes rhizospheric and endophytic colonization in different plants. A competent colonization is essential for plant-growth-promoting effects produced by bacteria. Using appropriate mutant strains of B. phytofirmans, we obtained evidence for the importance of N-acyl homoserine lactone-mediated (quorum sensing) cell-to-cell communication in efficient colonization of Arabidopsis thaliana plants and the establishment of a beneficial interaction. We also observed that bacterial degradation of the auxin indole-3-acetic acid (IAA) plays a key role in plant-growth-promoting traits and is necessary for efficient rhizosphere colonization. Wildtype B. phytofirmans but not the iacC mutant in IAA mineralization is able to restore promotion effects in roots of A. thaliana in the presence of exogenously added IAA, indicating the importance of this trait for promoting primary root length. Using a transgenic A. thaliana line with suppressed auxin signaling (miR393) and analyzing the expression of auxin receptors in wild-type inoculated plants, we provide evidence that auxin signaling in plants is necessary for the growth promotion effects produced by B. phytofirmans. The interplay between ethylene and auxin signaling was also confirmed by the response of the plant to a 1-aminocyclopropane-1-carboxylate deaminase bacterial mutant strain.
Collapse
Affiliation(s)
- Ana Zúñiga
- Universidad Adolfo Ibanez, Santiago, Chile
| | | | | | | | | | | | | |
Collapse
|
50
|
Rasamiravaka T, Jedrzejowski A, Kiendrebeogo M, Rajaonson S, Randriamampionona D, Rabemanantsoa C, Andriantsimahavandy A, Rasamindrakotroka A, Duez P, El Jaziri M, Vandeputte OM. Endemic malagasy Dalbergia species inhibit quorum sensing in Pseudomonas aeruginosa PAO1. MICROBIOLOGY-SGM 2013; 159:924-938. [PMID: 23449917 DOI: 10.1099/mic.0.064378-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Various species of the plant genus Dalbergia are traditionally used as medicine for sundry ailments and some of them have been shown recently to quench the virulence of Gram-positive and Gram-negative bacteria. Cell-to-cell communication mechanisms, quorum sensing (QS) in particular, are key regulators of virulence in many pathogenic bacteria. Screening n-hexane extracts of leaves, roots and bark of endemic Malagasy Dalbergia species for their capacity to antagonize QS mechanisms in Pseudomonas aeruginosa PAO1 showed that many reduced the expression of the QS-regulated genes lasB and rhlA. However, only the extract of Dalbergia trichocarpa bark (DTB) showed a significant reduction of QS gene expression without any effect on the aceA gene encoding a QS-independent isocitrate lyase. Further characterization of DTB impact on QS revealed that the QS systems las and rhl are inhibited and that swarming, twitching, biofilm formation and the production of pyocyanin, elastase and proteases are also hampered in the presence of the DTB extract. Importantly, compared with the known QS inhibitor naringenin, the DTB extract showed a stronger negative effect on twitching, biofilm formation and tobramycin resistance. Preliminary structural characterization of these potent biofilm disrupters suggests that they belong to the phytosterols. The strong inhibition of motility and biofilm formation suggests that the DTB extract contains agents disrupting biofilm architecture, which is an important observation in the context of the design of new drugs targeting biofilm-encapsulated pathogens.
Collapse
Affiliation(s)
- Tsiry Rasamiravaka
- Laboratoire de Formation et de Recherche en Biologie Médicale, Université d'Antananarivo, B.P. 566 Antananarivo 101, Madagascar.,Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Anaïs Jedrzejowski
- Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Martin Kiendrebeogo
- Laboratoire de Biochimie et de Chimie Appliquées, Université de Ouagadougou, 09 BP 848 Ouagadougou 09, Burkina Faso.,Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Sanda Rajaonson
- Laboratoire de Physiologie Végétale, Université d'Antananarivo, B.P. 906 Antananarivo 101, Madagascar.,Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Denis Randriamampionona
- Laboratoire de Physiologie Végétale, Université d'Antananarivo, B.P. 906 Antananarivo 101, Madagascar.,Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Christian Rabemanantsoa
- Laboratoire de Biodiversité et de Biotechnologie, Institut Malgache de Recherches Appliquées (IMRA), B.P. 3833 Avarabohitra Itaosy, Antananarivo 102, Madagascar
| | - Abel Andriantsimahavandy
- Laboratoire de Formation et de Recherche en Biologie Médicale, Université d'Antananarivo, B.P. 566 Antananarivo 101, Madagascar
| | - Andry Rasamindrakotroka
- Laboratoire de Formation et de Recherche en Biologie Médicale, Université d'Antananarivo, B.P. 566 Antananarivo 101, Madagascar
| | - Pierre Duez
- Laboratoire de Pharmacognosie, de Bromatologie et de Nutrition Humaine, Université Libre de Bruxelles, CP 205/9, Boulevard du Triomphe, B-1050 Brussels, Belgium
| | - Mondher El Jaziri
- Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Olivier M Vandeputte
- Laboratoire de Biotechnologie Végétale, Université Libre de Bruxelles, 12 rue des Professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| |
Collapse
|