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Calderón AA, Almagro L, Martínez-Calderón A, Ferrer MA. Transcriptional reprogramming in sound-treated Micro-Tom plants inoculated with Pseudomonas syringae pv. tomato DC3000. PHYSIOLOGIA PLANTARUM 2024; 176:e14335. [PMID: 38705728 DOI: 10.1111/ppl.14335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 04/18/2024] [Accepted: 04/23/2024] [Indexed: 05/07/2024]
Abstract
Sound vibrations (SV) are known to influence molecular and physiological processes that can improve crop performance and yield. In this study, the effects of three audible frequencies (100, 500 and 1000 Hz) at constant amplitude (90 dB) on tomato Micro-Tom physiological responses were evaluated 1 and 3 days post-treatment. Moreover, the potential use of SV treatment as priming agent for improved Micro-Tom resistance to Pseudomonas syringae pv. tomato DC3000 was tested by microarray. Results showed that the SV-induced physiological changes were frequency- and time-dependent, with the largest changes registered at 1000 Hz at day 3. SV treatments tended to alter the foliar content of photosynthetic pigments, soluble proteins, sugars, phenolic composition, and the enzymatic activity of polyphenol oxidase, peroxidase, superoxide dismutase and catalase. Microarray data revealed that 1000 Hz treatment is effective in eliciting transcriptional reprogramming in tomato plants grown under normal conditions, but particularly after the infection with Pst DC3000. Broadly, in plants challenged with Pst DC3000, the 1000 Hz pretreatment provoked the up-regulation of unique differentially expressed genes (DEGs) involved in cell wall reinforcement, phenylpropanoid pathway and defensive proteins. In addition, in those plants, DEGs associated with enhancing plant basal immunity, such as proteinase inhibitors, pathogenesis-related proteins, and carbonic anhydrase 3, were notably up-regulated in comparison with non-SV pretreated, infected plants. These findings provide new insights into the modulation of Pst DC3000-tomato interaction by sound and open up prospects for further development of strategies for plant disease management through the reinforcement of defense mechanisms in Micro-Tom plants.
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Affiliation(s)
- Antonio A Calderón
- Departamento de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
| | - Lorena Almagro
- Departamento de Biología Vegetal, Universidad de Murcia, Murcia, Spain
| | | | - María A Ferrer
- Departamento de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
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Raja Gopalan NS, Yegna Priya S, Mohapatra S. The rhizobacterial strain, Pseudomonas putida AKMP7, causes conditional pathogenesis in Arabidopsis thaliana via negative regulation of salicylic acid signaling, under water stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 206:108262. [PMID: 38091931 DOI: 10.1016/j.plaphy.2023.108262] [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: 10/07/2023] [Revised: 11/27/2023] [Accepted: 12/05/2023] [Indexed: 02/15/2024]
Abstract
We have previously reported a phenomenon of "conditional pathogenesis", in which, a drought-tolerant rhizobacterium, Pseudomonas putida AKMP7, promotes plant growth under well-watered conditions, while, deteriorating plant health under water-stressed conditions, in Arabidopsis thaliana seedlings. To understand the molecular mechanisms behind this phenomenon, we studied the modulation of salicylic acid (SA) biosynthesis as well as SA-responsive gene expression, involved in systemic acquired resistance (SAR), in A. thaliana, by AKMP7, under well-watered and water-stressed conditions. We found that, the plant SA levels were upregulated by AKMP7, both under, well-watered as well as water-stressed conditions. However, the SA signaling gene, Non-expressor of Pathogenesis Related gene 1 (NPR1) and Pathogenesis Related gene 1 (PR1) were upregulated under well-watered conditions and suppressed under water-stress, in AKMP7 inoculated seedlings. To understand the reason for this, we studied the expression of NPR4, a negative regulator of NPR1, and, NPR3, a negative regulator of PR1. We observed that, AKMP7 suppresses NPR1 and, consequently, PR1 genes, by upregulating NPR4 under water stress. To understand the potential role of NPR4 in conditional-pathogenesis, we performed physiological studies with NPR4 knockout mutants of A. thaliana and found that the NPR4 mutants did not exhibit any signs of the characteristic growth retardation caused by AKMP7 inoculation, under water stress. Preliminary studies with the model pathogen, Pseudomonas syringae, indicate that AKMP7 may lead to enhanced disease suppression under well-watered conditions, but not under water-stress. Taken together, our data suggest that, AKMP7 causes conditional pathogenesis by an overall compromise in plant immune response under water-stress.
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Affiliation(s)
- N S Raja Gopalan
- Department of Biological Sciences, Birla Institute of Technology and Science (Pilani), Hyderabad Campus, Hyderabad, India
| | - S Yegna Priya
- Department of Biological Sciences, Birla Institute of Technology and Science (Pilani), Hyderabad Campus, Hyderabad, India
| | - Sridev Mohapatra
- Department of Biological Sciences, Birla Institute of Technology and Science (Pilani), Hyderabad Campus, Hyderabad, India.
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3
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Scholz P, Chapman KD, Ischebeck T, Guzha A. Quantification of Botrytis cinerea Growth in Arabidopsis thaliana. Bio Protoc 2023; 13:e4740. [PMID: 37638304 PMCID: PMC10450733 DOI: 10.21769/bioprotoc.4740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/06/2023] [Accepted: 06/19/2023] [Indexed: 08/29/2023] Open
Abstract
Yield losses attributed to plant pathogens pose a serious threat to plant productivity and food security. Botrytis cinerea is one of the most devastating plant pathogens, infecting a wide array of plant species; it has also been established as a model organism to study plant-pathogen interactions. In this context, development of different assays to follow the relative success of B. cinerea infections is required. Here, we describe two methods to quantify B. cinerea development in Arabidopsis thaliana genotypes through measurements of lesion development and quantification of fungal genomic DNA in infected tissues. This provides two independent techniques that are useful in assessing the susceptibility or tolerance of different Arabidopsis genotypes to B. cinerea. Key features Protocol for the propagation of the necrotrophic plant pathogen fungus Botrytis cinerea and spore production. Two methods of Arabidopsis thaliana infection with the pathogen using droplet and spray inoculation. Two readouts, either by measuring lesion size or by the quantification of fungal DNA using quantitative PCR. The two methods are applicable across plant species susceptible the B. cinerea. Graphical overview A simplified overview of the droplet and spray infection methods used for the determination of B. cinerea growth in different Arabidopsis genotypes.
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Affiliation(s)
- Patricia Scholz
- University of Goettingen, Albrecht-von-Haller-Institute for Plant Sciences, Department for Plant Biochemistry, Goettingen, Germany
| | - Kent D Chapman
- Department of Biological Sciences, BioDiscovery Institute, University of North Texas, Denton, TX, USA
| | - Till Ischebeck
- Institute of Plant Biology and Biotechnology (IBBP), Green Biotechnology, University of Münster, Münster, Germany
| | - Athanas Guzha
- University of Goettingen, Albrecht-von-Haller-Institute for Plant Sciences, Department for Plant Biochemistry, Goettingen, Germany
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Kopczewski T, Kuźniak E, Ciereszko I, Kornaś A. Alterations in Primary Carbon Metabolism in Cucumber Infected with Pseudomonas syringae pv lachrymans: Local and Systemic Responses. Int J Mol Sci 2022; 23:ijms232012418. [PMID: 36293272 PMCID: PMC9603868 DOI: 10.3390/ijms232012418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 11/23/2022] Open
Abstract
The reconfiguration of the primary metabolism is essential in plant–pathogen interactions. We compared the local metabolic responses of cucumber leaves inoculated with Pseudomonas syringae pv lachrymans (Psl) with those in non-inoculated systemic leaves, by examining the changes in the nicotinamide adenine dinucleotides pools, the concentration of soluble carbohydrates and activities/gene expression of carbohydrate metabolism-related enzymes, the expression of photosynthesis-related genes, and the tricarboxylic acid cycle-linked metabolite contents and enzyme activities. In the infected leaves, Psl induced a metabolic signature with an altered [NAD(P)H]/[NAD(P)+] ratio; decreased glucose and sucrose contents, along with a changed invertase gene expression; and increased glucose turnover and accumulation of raffinose, trehalose, and myo-inositol. The accumulation of oxaloacetic and malic acids, enhanced activities, and gene expression of fumarase and l-malate dehydrogenase, as well as the increased respiration rate in the infected leaves, indicated that Psl induced the tricarboxylic acid cycle. The changes in gene expression of ribulose-l,5-bis-phosphate carboxylase/oxygenase large unit, phosphoenolpyruvate carboxylase and chloroplast glyceraldehyde-3-phosphate dehydrogenase were compatible with a net photosynthesis decline described earlier. Psl triggered metabolic changes common to the infected and non-infected leaves, the dynamics of which differed quantitatively (e.g., malic acid content and metabolism, glucose-6-phosphate accumulation, and glucose-6-phosphate dehydrogenase activity) and those specifically related to the local or systemic response (e.g., changes in the sugar content and turnover). Therefore, metabolic changes in the systemic leaves may be part of the global effects of local infection on the whole-plant metabolism and also represent a specific acclimation response contributing to balancing growth and defense.
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Affiliation(s)
- Tomasz Kopczewski
- Department of Plant Physiology and Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland
| | - Elżbieta Kuźniak
- Department of Plant Physiology and Biochemistry, Faculty of Biology and Environmental Protection, University of Lodz, 90-237 Lodz, Poland
- Correspondence:
| | - Iwona Ciereszko
- Department of Plant Biology and Ecology, Faculty of Biology, University of Bialystok, 15-245 Bialystok, Poland
| | - Andrzej Kornaś
- Institute of Biology, Pedagogical University of Krakow, 30-084 Kraków, Poland
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5
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Basu D, Codjoe JM, Veley KM, Haswell ES. The Mechanosensitive Ion Channel MSL10 Modulates Susceptibility to Pseudomonas syringae in Arabidopsis thaliana. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2022; 35:567-582. [PMID: 34775835 DOI: 10.1094/mpmi-08-21-0207-fi] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Plants sense and respond to molecular signals associated with the presence of pathogens and their virulence factors. Mechanical signals generated during pathogenic invasion may also be important, but their contributions have rarely been studied. Here, we investigate the potential role of a mechanosensitive ion channel, MscS-like (MSL)10, in defense against the bacterial pathogen Pseudomonas syringae in Arabidopsis thaliana. We previously showed that overexpression of MSL10-GFP, phospho-mimetic versions of MSL10, and the gain-of-function allele msl10-3G all produce dwarfing, spontaneous cell death, and the hyperaccumulation of reactive oxygen species. These phenotypes are shared by many autoimmune mutants and are frequently suppressed by growth at high temperature in those lines. We found that the same was true for all three MSL10 hypermorphs. In addition, we show that the SGT1/RAR1/HSP90 cochaperone complex was required for dwarfing and ectopic cell death, PAD4 and SID2 were partially required, and the immune regulators EDS1 and NDR1 were dispensable. All MSL10 hypermorphs exhibited reduced susceptibility to infection by P. syringae strain Pto DC3000 and Pto DC3000 expressing the avirulence genes avrRpt2 or avrRpm1 but not Pto DC3000 hrpL and showed an accelerated induction of PR1 expression compared with wild-type plants. Null msl10-1 mutants were delayed in PR1 induction and displayed modest susceptibility to infection by coronatine-deficient P. syringae pv. tomato. Finally, stomatal closure was reduced in msl10-1 loss-of-function mutants in response to P. syringae pv. tomato COR-. These data show that MSL10 modulates pathogen responses and begin to address the possibility that mechanical signals are exploited by the plant for pathogen perception.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Debarati Basu
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
- NSF Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
| | - Jennette M Codjoe
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
- NSF Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
| | - Kira M Veley
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
| | - Elizabeth S Haswell
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
- NSF Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, MO 63130, U.S.A
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6
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Oblessuc PR, Bridges DF, Melotto M. Pseudomonas phaseolicola preferentially modulates genes encoding leucine-rich repeat and malectin domains in the bean landrace G2333. PLANTA 2022; 256:25. [PMID: 35768557 PMCID: PMC9242968 DOI: 10.1007/s00425-022-03943-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/11/2022] [Indexed: 06/15/2023]
Abstract
Candidate resistance genes encoding malectin-like and LRR domains mapped to halo blight resistance loci throughout the common bean genome are co-expressed to fight a range of Pph races. Common bean (Phaseolus vulgaris L.) is an important crop both as a source of protein and other nutrients for human nutrition and as a nitrogen fixer that benefits sustainable agriculture. This crop is affected by halo blight disease, caused by the bacterium Pseudomonas syringae pv. phaseolicola (Pph), which can lead to 45% yield losses. Common bean resistance to Pph is conferred by six loci (Pse-1 to Pse-6) and minor-effect quantitative trait loci (QTLs); however, information is lacking on the molecular mechanisms implicated in this resistance. Here, we describe an in-depth RNA-sequencing (RNA-seq) analysis of the tolerant G2333 bean line in response to the Pph strain NPS3121. We identified 275 upregulated and 357 downregulated common bean genes in response to Pph infection. These differentially expressed genes were mapped to all 11 chromosomes of P. vulgaris. The upregulated genes were primarily components of plant immune responses and negative regulation of photosynthesis, with enrichment for leucine-rich repeat (LRRs) and/or malectin-like carbohydrate-binding domains. Interestingly, LRRs and malectin genes mapped to the same location as previously identified Pph resistance loci or QTLs. For instance, the major loci Pse-6/HB4.2 involved in broad-resistance to many Pph races co-located with induced LRR-encoding genes on Pv04. These findings indicate a coordinated modulation of genes involved in pathogen perception and signal transduction. In addition, the results further support these LRR/malectin loci as resistance genes in response to halo blight. Thus, these genes are potential targets for future genetic manipulation, enabling the introduction of resistance to Pph into elite cultivars of common bean.
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Affiliation(s)
- Paula Rodrigues Oblessuc
- Department of Plant Sciences, University of California, Davis, CA, USA
- Department of Protection of Specific Crops, InnovPlantProtection Collaborative Laboratory, Elvas, Portalegre, Portugal
| | - David F Bridges
- Department of Plant Sciences, University of California, Davis, CA, USA
- Plant Biology Graduate Group, University of California, Davis, CA, USA
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, CA, USA.
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7
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Jacob C, Velásquez AC, Josh NA, Settles M, He SY, Melotto M. Dual transcriptomic analysis reveals metabolic changes associated with differential persistence of human pathogenic bacteria in leaves of Arabidopsis and lettuce. G3 (BETHESDA, MD.) 2021; 11:jkab331. [PMID: 34550367 PMCID: PMC8664426 DOI: 10.1093/g3journal/jkab331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 09/09/2021] [Indexed: 11/14/2022]
Abstract
Understanding the molecular determinants underlying the interaction between the leaf and human pathogenic bacteria is key to provide the foundation to develop science-based strategies to prevent or decrease the pathogen contamination of leafy greens. In this study, we conducted a dual RNA-sequencing analysis to simultaneously define changes in the transcriptomic profiles of the plant and the bacterium when they come in contact. We used an economically relevant vegetable crop, lettuce (Lactuca sativa L. cultivar Salinas), and a model plant, Arabidopsis thaliana Col-0, as well as two pathogenic bacterial strains that cause disease outbreaks associated with fresh produce, Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium 14028s (STm 14028s). We observed commonalities and specificities in the modulation of biological processes between Arabidopsis and lettuce and between O157:H7 and STm 14028s during early stages of the interaction. We detected a larger alteration of gene expression at the whole transcriptome level in lettuce and Arabidopsis at 24 h post inoculation with STm 14028s compared to that with O157:H7. In addition, bacterial transcriptomic adjustments were substantially larger in Arabidopsis than in lettuce. Bacterial transcriptome was affected at a larger extent in the first 4 h compared to the subsequent 20 h after inoculation. Overall, we gained valuable knowledge about the responses and counter-responses of both bacterial pathogen and plant host when these bacteria are residing in the leaf intercellular space. These findings and the public genomic resources generated in this study are valuable for additional data mining.
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Affiliation(s)
- Cristián Jacob
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
- Department of Plant Sciences, Horticulture and Agronomy Graduate Group, University of California, Davis, Davis, CA 95616, USA
- Departamento de Ciencias Vegetales, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago 7820436, Chile
| | - André C Velásquez
- Department of Biology, Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
| | - Nikhil A Josh
- Bioinformatics Core Facility in the Genome Center, University of California, Davis, Davis, CA 95616, USA
| | - Matthew Settles
- Bioinformatics Core Facility in the Genome Center, University of California, Davis, Davis, CA 95616, USA
| | - Sheng Yang He
- Department of Biology, Howard Hughes Medical Institute, Duke University, Durham, NC 27708, USA
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA 95616, USA
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8
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Zhao J, Bi W, Zhao S, Su J, Li M, Ma L, Yu X, Wang X. Wheat Apoplast-Localized Lipid Transfer Protein TaLTP3 Enhances Defense Responses Against Puccinia triticina. FRONTIERS IN PLANT SCIENCE 2021; 12:771806. [PMID: 34899796 PMCID: PMC8657149 DOI: 10.3389/fpls.2021.771806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/19/2021] [Indexed: 05/29/2023]
Abstract
Plant apoplast serves as the frontier battlefield of plant defense in response to different types of pathogens. Many pathogenesis-related (PR) proteins are accumulated in apoplastic space during the onset of plant-pathogen interaction, where they act to suppress pathogen infection. In this study, we found the expression of Triticum aestivum lipid transfer protein 3 (TaLTP3) gene was unregulated during incompatible interaction mediated by leaf rust resistance genes Lr39/41 at the early infection stage. Stable transgenic wheat lines overexpressing TaLTP3 exhibited enhanced resistance to leaf rust pathogen Puccinia triticina. Transcriptome analysis revealed that overexpression of TaLTP3 specifically activated the transcription of pathogenesis-related protein 1a (TaPR1a) and multiple plant hormone pathways, including salicylic acid (SA), jasmonic acid (JA), and auxin, in response to the infection of the model bacterial pathogen Pseudomonas syringae pv. tomato DC3000. Further investigation indicated that TaLTP3 physically associated with wheat TaPR1a protein in the apoplast. Transgenic wheat lines overexpressing TaLTP3 and TaPR1a showed higher accumulations of reactive oxygen species (ROS) during plant defense responses. All these findings suggested that TaLTP3 is involved in wheat resistance against leaf rust pathogen infection and forming a TaLTP3-TaPR1a complex in apoplast against this pathogen, which provides new insights into the functional roles of PR proteins.
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Affiliation(s)
- Jiaojie Zhao
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
| | - Weishuai Bi
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
| | - Shuqing Zhao
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
| | - Jun Su
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
| | - Mengyu Li
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
| | - Lisong Ma
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
- College of Horticulture, Hebei Agricultural University, Baoding, China
| | - Xiumei Yu
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Xiaodong Wang
- State Key Laboratory of North China Crop Improvement and Regulation, College of Plant Protection, Hebei Agricultural University, Baoding, China
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9
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Choudhary A, Senthil‐Kumar M. An efficient, high-throughput method for the simultaneous exposure of drought stress and bacterial infection in plants. APPLICATIONS IN PLANT SCIENCES 2020; 8:e11399. [PMID: 33304662 PMCID: PMC7705336 DOI: 10.1002/aps3.11399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/11/2020] [Indexed: 06/12/2023]
Abstract
PREMISE We developed a systematic protocol for the easy, high-throughput, qualitative, and quantitative assessment of the patho-morphological, physiological, and molecular responses of Arabidopsis thaliana plants simultaneously subjected to drought and bacterial infection. This approach will assist studies elucidating plant adaptation strategies to combat combined stresses. METHODS AND RESULTS Plants were grown in small screw-capped containers, individual pots, or pot strips. Watering was withheld from 30-day-old plants, which were subsequently infected with Pseudomonas syringae pv. tomato DC3000 using a dip inoculation. The natural development of both drought and bacterial infection was successfully and rapidly replicated in large numbers of plants, which is difficult to achieve with existing protocols. CONCLUSIONS Our protocol offers a simple, low-cost, high-throughput strategy for the rapid and easy bacterial infection of large numbers of plants. It can be used in large-scale mutant and ecotype screenings under combined stresses and for other foliar pathogens in different plant species.
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Affiliation(s)
- Aanchal Choudhary
- National Institute of Plant Genome ResearchAruna Asaf Ali MargNew Delhi110067India
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10
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Oblessuc PR, Melotto M. A Simple Assay to Assess Salmonella enterica Persistence in Lettuce Leaves After Low Inoculation Dose. Front Microbiol 2020; 11:1516. [PMID: 32765443 PMCID: PMC7381196 DOI: 10.3389/fmicb.2020.01516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 06/10/2020] [Indexed: 11/17/2022] Open
Abstract
Salmonella enterica is an enterobacterium associated with numerous foodborne illnesses worldwide. Leafy greens have been a common vehicle for disease outbreaks caused by S. enterica. This human pathogen can be introduced into crop fields and potentially contaminate fresh produce. Several studies have shown that S. enterica can survive for long periods in the plant tissues. Often, S. enterica population does not reach high titers in leaves; however, it is still relevant for food safety due to the low infective dose of the pathogen. Thus, laboratory procedures to study the survival of S. enterica in fresh vegetables should be adjusted accordingly. Here, we describe a protocol to assess the population dynamics of S. enterica serovar Typhimurium 14028s in the leaf apoplast of three cultivars of lettuce (Lactuca sativa L.). By comparing a range of inoculum concentrations, we showed that vacuum infiltration of a bacterium inoculum level in the range of 3.4 Log CFU ml–1 (with a recovery of approximately 170 cells per gram of fresh leaves 2 h post inoculation) allows for a robust assessment of bacterial persistence in three lettuce cultivars using serial dilution plating and qPCR methods. We anticipate that this method can be applied to other leaf–human pathogen combinations in an attempt to standardize the procedure for future efforts to screen for plant phenotypic variability, which is useful for breeding programs.
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Affiliation(s)
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
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11
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Jacob C, Melotto M. Human Pathogen Colonization of Lettuce Dependent Upon Plant Genotype and Defense Response Activation. FRONTIERS IN PLANT SCIENCE 2020; 10:1769. [PMID: 32082340 PMCID: PMC7002439 DOI: 10.3389/fpls.2019.01769] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 12/18/2019] [Indexed: 05/26/2023]
Abstract
Fresh produce contaminated with human pathogens may result in foodborne disease outbreaks that cause a significant number of illnesses, hospitalizations, and death episodes affecting both public health and the agribusiness every year. The ability of these pathogens to survive throughout the food production chain is remarkable. Using a genetic approach, we observed that leaf colonization by Salmonella enterica serovar Typhimurium 14028s (S. Typhimurium 14028s) and Escherichia coli O157:H7 was significantly affected by genetic diversity of lettuce (Lactuca sativa L. and L. serriola L.). In particular, there was a significant variation among 11 lettuce genotypes in bacterial attachment, internalization, and apoplastic persistence after surface- and syringe-inoculation methods. We observed a significant correlation of the bacterial leaf internalization rate with stomatal pore traits (width and area). Moreover, bacterial apoplastic populations significantly decreased in 9 out of 11 lettuce genotypes after 10 days of surface inoculation. However, after syringe infiltration, populations of E. coli O157:H7 and S. Typhimurium 14028s showed positive, neutral, or negative net growth in a 10-day experimental period among seedlings of different lettuce types. The relative ability of the bacteria to persist in the apoplast of lettuce genotypes after syringe inoculation was minimally altered when assessed during a longer period (20 days) using 3.5- to 4-week-old plants. Interestingly, contrasting bacterial persistence in the lettuce genotypes Red Tide and Lollo Rossa was positively correlated with significant differences in the level of reactive oxygen species burst and callose deposition against S. Typhimurium 14028s and E. coli O157:H7 which are related to plant defense responses. Overall, we characterized the genetic diversity in the interaction between lettuce genotypes and enterobacteria S. Typhimurium 14028s and E. coli O157:H7 and discovered that this genetic diversity is linked to variations in plant immune responses towards these bacteria. These results provide opportunities to capitalize on plant genetics to reduce pathogen contamination of leaves.
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Affiliation(s)
- Cristián Jacob
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
- Horticulture and Agronomy Graduate Group, University of California, Davis, Davis, CA, United States
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
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12
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Montano J, Rossidivito G, Torreano J, Porwollik S, Sela Saldinger S, McClelland M, Melotto M. Salmonella enterica Serovar Typhimurium 14028s Genomic Regions Required for Colonization of Lettuce Leaves. Front Microbiol 2020; 11:6. [PMID: 32038592 PMCID: PMC6993584 DOI: 10.3389/fmicb.2020.00006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 01/03/2020] [Indexed: 11/24/2022] Open
Abstract
Contamination of edible produce leaves with human bacterial pathogens has been associated with serious disease outbreaks and has become a major public health concern affecting all aspects of the market, from farmers to consumers. While pathogen populations residing on the surface of ready-to-eat produce can be potentially removed through thorough washing, there is no disinfection technology available that effectively eliminates internal bacterial populations. By screening 303 multi-gene deletion (MGD) mutants of Salmonella enterica serovar Typhimurium (STm) 14028s, we were able to identify ten genomic regions that play a role in opening the stomatal pore of lettuce leaves. The major metabolic functions of the deleted regions are associated with sensing the environment, bacterium movement, transport through the bacterial membrane, and biosynthesis of surface appendages. Interestingly, at 21 days post inoculation, seven of these mutants showed increased population titers inside the leaf, two mutants showed similar titers as the wild type bacterium, whereas one mutant with a large deletion that includes the Salmonella pathogenicity island 2 (SPI-2) showed significantly impaired persistence in the leaf apoplast. These findings suggest that not all the genomic regions required for initiation of leaf colonization (i.e., epiphytic behavior and tissue penetration) are essential for continuing bacterial survival as an endophyte. We also observed that mutants lacking either SPI-1 (Mut3) or SPI-2 (Mut9) induce callose deposition levels comparable to those of the wild type STm 14028s; therefore, these islands do not seem to affect this lettuce defense mechanism. However, the growth of Mut9, but not Mut3, was significantly impaired in the leaf apoplastic wash fluid (AWF) suggesting that the STm persistence in the apoplast may be linked to nutrient acquisition capabilities or overall bacterial fitness in this niche, which are dependent on the gene(s) deleted in the Mut9 strain. The genetic basis of STm colonization of leaves investigated in this study provides a foundation from which to develop mitigation tactics to enhance food safety.
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Affiliation(s)
- Jeanine Montano
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
- Plant Pathology Graduate Group, University of California, Davis, Davis, CA, United States
| | - Gabrielle Rossidivito
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
- Plant Biology Graduate Group, University of California, Davis, Davis, CA, United States
| | - Joseph Torreano
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
| | - Steffen Porwollik
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA, United States
| | - Shlomo Sela Saldinger
- Microbial Food Safety Research Unit, Department of Food Science, Agricultural Research Organization, Volcani Center, Rishon LeTsiyon, Israel
| | - Michael McClelland
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA, United States
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, Davis, CA, United States
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Oblessuc PR, Matiolli CC, Melotto M. Novel molecular components involved in callose-mediated Arabidopsis defense against Salmonella enterica and Escherichia coli O157:H7. BMC PLANT BIOLOGY 2020; 20:16. [PMID: 31914927 PMCID: PMC6950905 DOI: 10.1186/s12870-019-2232-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 12/30/2019] [Indexed: 05/26/2023]
Abstract
BACKGROUND Food contamination with Salmonella enterica and enterohemorrhagic Escherichia coli is among the leading causes of foodborne illnesses worldwide and crop plants are associated with > 50% of the disease outbreaks. However, the mechanisms underlying the interaction of these human pathogens with plants remain elusive. In this study, we have explored plant resistance mechanisms against these enterobacteria and the plant pathogen Pseudomonas syringae pv. tomato (Pst) DC3118, as an opportunity to improve food safety. RESULTS We found that S. enterica serovar Typhimurium (STm) transcriptionally modulates stress responses in Arabidopsis leaves, including induction of two hallmark processes of plant defense: ROS burst and cell wall modifications. Analyses of plants with a mutation in the potentially STm-induced gene EXO70H4 revealed that its encoded protein is required for stomatal defense against STm and E. coli O157:H7, but not against Pst DC3118. In the apoplast however, EXO70H4 is required for defense against STm and Pst DC3118, but not against E. coli O157:H7. Moreover, EXO70H4 is required for callose deposition, but had no function in ROS burst, triggered by all three bacteria. The salicylic acid (SA) signaling and biosynthesis proteins NPR1 and ICS1, respectively, were involved in stomatal and apoplastic defense, as well as callose deposition, against human and plant pathogens. CONCLUSIONS The results show that EXO70H4 is involved in stomatal and apoplastic defenses in Arabidopsis and suggest that EXO70H4-mediated defense play a distinct role in guard cells and leaf mesophyll cells in a bacteria-dependent manner. Nonetheless, EXO70H4 contributes to callose deposition in response to both human and plant pathogens. NPR1 and ICS1, two proteins involved in the SA signaling pathway, are important to inhibit leaf internalization and apoplastic persistence of enterobacteria and proliferation of phytopathogens. These findings highlight the existence of unique and shared plant genetic components to fight off diverse bacterial pathogens providing specific targets for the prevention of foodborne diseases.
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Affiliation(s)
- Paula Rodrigues Oblessuc
- Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA, 95616, USA
| | | | - Maeli Melotto
- Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA, 95616, USA.
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Oblessuc PR, Obulareddy N, DeMott L, Matiolli CC, Thompson BK, Melotto M. JAZ4 is involved in plant defense, growth, and development in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:371-383. [PMID: 31557372 DOI: 10.1111/tpj.14548] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 09/16/2019] [Indexed: 05/25/2023]
Abstract
Jasmonate zim-domain (JAZ) proteins comprise a family of transcriptional repressors that modulate jasmonate (JA) responses. JAZ proteins form a co-receptor complex with the F-box protein coronatine insensitive1 (COI1) that recognizes both jasmonoyl-l-isoleucine (JA-Ile) and the bacterial-produced phytotoxin coronatine (COR). Although several JAZ family members have been placed in this pathway, the role of JAZ4 in this model remains elusive. In this study, we observed that the jaz4-1 mutant of Arabidopsis is hyper-susceptible to Pseudomonas syringae pv. tomato (Pst) DC3000, while Arabidopsis lines overexpressing a JAZ4 protein lacking the Jas domain (JAZ4∆Jas) have enhanced resistance to this bacterium. Our results show that the Jas domain of JAZ4 is required for its physical interaction with COI1, MYC2 or MYC3, but not with the repressor complex adaptor protein NINJA. Furthermore, JAZ4 degradation is induced by COR in a proteasome- and Jas domain-dependent manner. Phenotypic evaluations revealed that expression of JAZ4∆Jas results in early flowering and increased length of root, hypocotyl, and petiole when compared with Col-0 and jaz4-1 plants, although JAZ4∆Jas lines remain sensitive to MeJA- and COR-induced root and hypocotyl growth inhibition. Additionally, jaz4-1 mutant plants have increased anthocyanin accumulation and late flowering compared with Col-0, while JAZ4∆Jas lines showed no alteration in anthocyanin production. These findings suggest that JAZ4 participates in the canonical JA signaling pathway leading to plant defense response in addition to COI1/MYC-independent functions in plant growth and development, supporting the notion that JAZ4-mediated signaling may have distinct branches.
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Affiliation(s)
- Paula R Oblessuc
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | - Nisita Obulareddy
- Department of Biology, University of Texas, Arlington, TX, 76019, USA
| | - Logan DeMott
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
| | | | - Blaine K Thompson
- Department of Biology, University of Texas, Arlington, TX, 76019, USA
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
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Fröschel C, Iven T, Walper E, Bachmann V, Weiste C, Dröge-Laser W. A Gain-of-Function Screen Reveals Redundant ERF Transcription Factors Providing Opportunities for Resistance Breeding Toward the Vascular Fungal Pathogen Verticillium longisporum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:1095-1109. [PMID: 31365325 DOI: 10.1094/mpmi-02-19-0055-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Verticillium longisporum is a vascular fungal pathogen leading to severe crop loss, particular in oilseed rape. Transcription factors (TF) are highly suited for genetic engineering of pathogen-resistant crops, as they control sets of functionally associated genes. Applying the AtTORF-Ex (Arabidopsis thaliana transcription factor open reading frame expression) collection, a simple and robust screen of TF-overexpressing plants was established displaying reduced fungal colonization. Distinct members of the large ethylene response factor (ERF) family, namely ERF96 and the six highly related subgroup IXb members ERF102 to ERF107, were identified. Whereas overexpression of these ERF significantly reduces fungal propagation, single loss-of-function approaches did not reveal altered susceptibility. Hence, this gain-of-function approach is particularly suited to identify redundant family members. Expression analyses disclosed distinct ERF gene activation patterns in roots and leaves, suggesting functional differences. Transcriptome studies performed on chemically induced ERF106 expression revealed an enrichment of genes involved in the biosynthesis of antimicrobial indole glucosinolates (IG), such as CYP81F2 (CYTOCHROME P450-MONOOXYGENASE 81F2), which is directly regulated by IXb-ERF via two GCC-like cis-elements. The impact of IG in restricting fungal propagation was further supported as the cyp81f2 mutant displayed significantly enhanced susceptibility. Taken together, this proof-of-concept approach provides a novel strategy to identify candidate TF that are valuable genetic resources for engineering or breeding pathogen-resistant crop plants.
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Affiliation(s)
- Christian Fröschel
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institut, Biozentrum, Julius-Maximilians-Universität Würzburg, Würzburg, 97082, Germany
| | - Tim Iven
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institut, Biozentrum, Julius-Maximilians-Universität Würzburg, Würzburg, 97082, Germany
| | - Elisabeth Walper
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institut, Biozentrum, Julius-Maximilians-Universität Würzburg, Würzburg, 97082, Germany
| | - Vanessa Bachmann
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institut, Biozentrum, Julius-Maximilians-Universität Würzburg, Würzburg, 97082, Germany
| | - Christoph Weiste
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institut, Biozentrum, Julius-Maximilians-Universität Würzburg, Würzburg, 97082, Germany
| | - Wolfgang Dröge-Laser
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institut, Biozentrum, Julius-Maximilians-Universität Würzburg, Würzburg, 97082, Germany
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Matiolli CC, Melotto M. A Comprehensive Arabidopsis Yeast Two-Hybrid Library for Protein-Protein Interaction Studies: A Resource to the Plant Research Community. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:899-902. [PMID: 29547357 DOI: 10.1094/mpmi-02-18-0047-a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Yeast-two-hybrid (Y2H) cDNA library screening is a valuable tool to uncover protein-protein interactions and represents a widely used method to investigate protein function. However, low transcript representation in cDNA libraries limits the depth of the screening. We have developed a Y2H library with cDNA made from Arabidopsis leaves exposed to several stressors as well as untreated leaves. The library was built using pooled mRNA extracted from plants challenged with plant and human bacterial pathogens, the flg22 elicitor, the phytotoxin coronatine, and several hormones associated with environmental stress responses. The purpose of such a library is to maximize the discovery of protein-protein interactions that occur under optimum conditions as well as during biotic and abiotic stresses.
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Affiliation(s)
| | - Maeli Melotto
- Department of Plant Sciences, University of California, Davis, 95616, U.S.A
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Azevedo RF, Gonçalves‐Vidigal MC, Oblessuc PR, Melotto M. The common bean COK-4 and the Arabidopsis FER kinase domain share similar functions in plant growth and defence. MOLECULAR PLANT PATHOLOGY 2018; 19:1765-1778. [PMID: 29352746 PMCID: PMC6638044 DOI: 10.1111/mpp.12659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/08/2018] [Accepted: 01/15/2018] [Indexed: 05/30/2023]
Abstract
Receptor-like kinases are membrane proteins that can be shared by diverse signalling pathways. Among them, the Arabidopsis thaliana FERONIA (FER) plays a role in the balance between distinct signals to control growth and defence. We have found that COK-4, a putative kinase encoded in the common bean anthracnose resistance locus Co-4, which is transcriptionally regulated during the immune response, is highly similar to the kinase domain of FER. To assess whether COK-4 is a functional orthologue of FER, we expressed COK-4 in the wild-type Col-0 and the fer-5 mutant of Arabidopsis and evaluated FER-associated traits. We observed that fer-5 plants show an enhanced apoplastic and stomatal defence against Pseudomonas syringae. In addition, the fer-5 mutant shows reduced biomass, smaller guard cell size, greater number of stomata per leaf area, fewer leaves, faster transition to reproductive stage and lower seed weight per plant than the wild-type Col-0. Except for the stomatal complex length and number of stomata, COK-4 expression in fer-5 lines partially or completely rescued both defence and developmental defects of fer-5 to the wild-type level. Notably, COK-4 may have an additive effect to FER, as the expression of COK-4 in Col-0 resulted in enhanced defence and growth phenotypes in comparison with wild-type Col-0 plants. Altogether, these findings indicate that the common bean COK-4 shares at least some of the multiple functions of the Arabidopsis FER kinase domain, acting in both the induction of plant growth and regulation of plant defence.
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Affiliation(s)
- Rafhael Felipin Azevedo
- Department of Plant SciencesUniversity of California, DavisDavisCA 95616USA
- Departamento de AgronomiaUniversidade Estadual de MaringáMaringáPR 87020‐900Brazil
| | | | | | - Maeli Melotto
- Department of Plant SciencesUniversity of California, DavisDavisCA 95616USA
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