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Zhao A, Xian L, Franco Ortega S, Yu G, Macho AP. A bacterial effector manipulates plant metabolism, cell death, and immune responses via independent mechanisms. THE NEW PHYTOLOGIST 2024. [PMID: 38877712 DOI: 10.1111/nph.19899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 05/19/2024] [Indexed: 06/16/2024]
Abstract
Bacterial pathogens inject effector proteins inside plant cells to manipulate cellular functions and achieve a successful infection. The soil-borne pathogen Ralstonia solanacearum (Smith), the causal agent of bacterial wilt disease, secretes > 70 different effectors inside plant cells, although only a handful of them have been thoroughly characterized. One of these effectors, named RipI, is required for full R. solanacearum pathogenicity. RipI associates with plant glutamate decarboxylases (GADs) to promote the accumulation of gamma-aminobutyric acid (GABA), which serves as bacterial nutrient. In this work, we found that RipI can also suppress plant immune responses to bacterial elicitors, which seems to be unrelated to the ability of RipI to induce GABA accumulation and plant cell death. A detailed characterization of the RipI features that contribute to its virulence activities identified two residues at the C-terminal domain that mediate RipI interaction with plant GADs and the subsequent promotion of GABA accumulation. These residues are also required for the appropriate homeostasis of RipI in plant cells and the induction of cell death, although they are partially dispensable for the suppression of plant immune responses. Altogether, we decipher and uncouple the virulence activities of an important bacterial effector at the biochemical level.
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Affiliation(s)
- Achen Zhao
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Liu Xian
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Sara Franco Ortega
- Department of Biology, Centre for Novel Agricultural Products (CNAP), University of York, York, YO10 5DD, UK
| | - Gang Yu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Alberto P Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, 201602, China
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Roussin-Léveillée C, Mackey D, Ekanayake G, Gohmann R, Moffett P. Extracellular niche establishment by plant pathogens. Nat Rev Microbiol 2024; 22:360-372. [PMID: 38191847 DOI: 10.1038/s41579-023-00999-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2023] [Indexed: 01/10/2024]
Abstract
The plant extracellular space, referred to as the apoplast, is inhabited by a variety of microorganisms. Reflecting the crucial nature of this compartment, both plants and microorganisms seek to control, exploit and respond to its composition. Upon sensing the apoplastic environment, pathogens activate virulence programmes, including the delivery of effectors with well-established roles in suppressing plant immunity. We posit that another key and foundational role of effectors is niche establishment - specifically, the manipulation of plant physiological processes to enrich the apoplast in water and nutritive metabolites. Facets of plant immunity counteract niche establishment by restricting water, nutrients and signals for virulence activation. The complex competition to control and, in the case of pathogens, exploit the apoplast provides remarkable insights into the nature of virulence, host susceptibility, host defence and, ultimately, the origin of phytopathogenesis. This novel framework focuses on the ecology of a microbial niche and highlights areas of future research on plant-microorganism interactions.
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Affiliation(s)
| | - David Mackey
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, USA.
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA.
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH, USA.
| | - Gayani Ekanayake
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, USA
| | - Reid Gohmann
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH, USA
| | - Peter Moffett
- Centre SÈVE, Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec, Canada.
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Inoue K, Tsuchida N, Saijo Y. Modulation of plant immunity and biotic interactions under phosphate deficiency. JOURNAL OF PLANT RESEARCH 2024; 137:343-357. [PMID: 38693461 DOI: 10.1007/s10265-024-01546-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 04/17/2024] [Indexed: 05/03/2024]
Abstract
Phosphorus (P) is an essential macronutrient for plant life and growth. P is primarily acquired in the form of inorganic phosphate (Pi) from soil. To cope with Pi deficiency, plants have evolved an elaborate system to improve Pi acquisition and utilization through an array of developmental and physiological changes, termed Pi starvation response (PSR). Plants also assemble and manage mutualistic microbes to enhance Pi uptake, through integrating PSR and immunity signaling. A trade-off between plant growth and defense favors the notion that plants lower a cellular state of immunity to accommodate host-beneficial microbes for nutrition and growth at the cost of infection risk. However, the existing data indicate that plants selectively activate defense responses against pathogens, but do not or less against non-pathogens, even under nutrient deficiency. In this review, we highlight recent advances in the principles and mechanisms with which plants balance immunity and growth-related processes to optimize their adaptation to Pi deficiency.
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Affiliation(s)
- Kanako Inoue
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192, Japan
| | - Natsuki Tsuchida
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192, Japan
| | - Yusuke Saijo
- Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara, 630-0192, Japan.
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Qian J, Ibrahim HMM, Erz M, Kümmel F, Panstruga R, Kusch S. Long noncoding RNAs emerge from transposon-derived antisense sequences and may contribute to infection stage-specific transposon regulation in a fungal phytopathogen. Mob DNA 2023; 14:17. [PMID: 37964319 PMCID: PMC10648671 DOI: 10.1186/s13100-023-00305-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/18/2023] [Indexed: 11/16/2023] Open
Abstract
BACKGROUND The genome of the obligate biotrophic phytopathogenic barley powdery mildew fungus Blumeria hordei is inflated due to highly abundant and possibly active transposable elements (TEs). In the absence of the otherwise common repeat-induced point mutation transposon defense mechanism, noncoding RNAs could be key for regulating the activity of TEs and coding genes during the pathogenic life cycle. RESULTS We performed time-course whole-transcriptome shotgun sequencing (RNA-seq) of total RNA derived from infected barley leaf epidermis at various stages of fungal pathogenesis and observed significant transcript accumulation and time point-dependent regulation of TEs in B. hordei. Using a manually curated consensus database of 344 TEs, we discovered phased small RNAs mapping to 104 consensus transposons, suggesting that RNA interference contributes significantly to their regulation. Further, we identified 5,127 long noncoding RNAs (lncRNAs) genome-wide in B. hordei, of which 823 originated from the antisense strand of a TE. Co-expression network analysis of lncRNAs, TEs, and coding genes throughout the asexual life cycle of B. hordei points at extensive positive and negative co-regulation of lncRNAs, subsets of TEs and coding genes. CONCLUSIONS Our work suggests that similar to mammals and plants, fungal lncRNAs support the dynamic modulation of transcript levels, including TEs, during pivotal stages of host infection. The lncRNAs may support transcriptional diversity and plasticity amid loss of coding genes in powdery mildew fungi and may give rise to novel regulatory elements and virulence peptides, thus representing key drivers of rapid evolutionary adaptation to promote pathogenicity and overcome host defense.
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Affiliation(s)
- Jiangzhao Qian
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany
| | - Heba M M Ibrahim
- Department of Biosystems, Division of Plant Biotechnics, Faculty of Bioscience Engineering, Katholieke Universiteit Leuven, 3001, Leuven, Belgium
- Present address: Institute of Bio- and Geosciences IBG-2, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Myriam Erz
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany
| | - Florian Kümmel
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany
- Present address: Department of Plant-Microbe Interactions, Max Planck Institute for Plant Breeding Research, Carl-Von-Linné-Weg 10, 50829, Cologne, Germany
| | - Ralph Panstruga
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany
| | - Stefan Kusch
- Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University, Worringerweg 1, 52056, Aachen, Germany.
- Present address: Institute of Bio- and Geosciences IBG-4, Forschungszentrum Jülich, 52425, Jülich, Germany.
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Ribone AI, Fass M, Gonzalez S, Lia V, Paniego N, Rivarola M. Co-Expression Networks in Sunflower: Harnessing the Power of Multi-Study Transcriptomic Public Data to Identify and Categorize Candidate Genes for Fungal Resistance. PLANTS (BASEL, SWITZERLAND) 2023; 12:2767. [PMID: 37570920 PMCID: PMC10421300 DOI: 10.3390/plants12152767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/19/2023] [Accepted: 07/21/2023] [Indexed: 08/13/2023]
Abstract
Fungal plant diseases are a major threat to food security worldwide. Current efforts to identify and list loci involved in different biological processes are more complicated than originally thought, even when complete genome assemblies are available. Despite numerous experimental and computational efforts to characterize gene functions in plants, about ~40% of protein-coding genes in the model plant Arabidopsis thaliana L. are still not categorized in the Gene Ontology (GO) Biological Process (BP) annotation. In non-model organisms, such as sunflower (Helianthus annuus L.), the number of BP term annotations is far fewer, ~22%. In the current study, we performed gene co-expression network analysis using eight terabytes of public transcriptome datasets and expression-based functional prediction to categorize and identify loci involved in the response to fungal pathogens. We were able to construct a reference gene network of healthy green tissue (GreenGCN) and a gene network of healthy and stressed root tissues (RootGCN). Both networks achieved robust, high-quality scores on the metrics of guilt-by-association and selective constraints versus gene connectivity. We were able to identify eight modules enriched in defense functions, of which two out of the three modules in the RootGCN were also conserved in the GreenGCN, suggesting similar defense-related expression patterns. We identified 16 WRKY genes involved in defense related functions and 65 previously uncharacterized loci now linked to defense response. In addition, we identified and classified 122 loci previously identified within QTLs or near candidate loci reported in GWAS studies of disease resistance in sunflower linked to defense response. All in all, we have implemented a valuable strategy to better describe genes within specific biological processes.
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Affiliation(s)
| | | | | | | | | | - Máximo Rivarola
- Instituto de Agrobiotecnología y Biología Molecular (IABIMO), CICVyA—Instituto Nacional de Tecnología Agropecuaria (INTA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Los Reseros y Nicolás Repetto, Hurlingham 1686, Argentina; (A.I.R.); (M.F.); (S.G.); (V.L.); (N.P.)
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Liu Q, Zhang C, Fang H, Yi L, Li M. Indispensable Biomolecules for Plant Defense Against Pathogens: NBS-LRR and "nitrogen pool" Alkaloids. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023:111752. [PMID: 37268110 DOI: 10.1016/j.plantsci.2023.111752] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/04/2023]
Abstract
In a complex natural environment, plants have evolved intricate and subtle defense response regulatory mechanisms for survival. Plant specific defenses, including the disease resistance protein nucleotide-binding site leucine-rich repeat (NBS-LRR) protein and metabolite derived alkaloids, are key components of these complex mechanisms. The NBS-LRR protein can specifically recognize the invasion of pathogenic microorganisms to trigger the immune response mechanism. Alkaloids, synthesized from amino acids or their derivatives, can also inhibit pathogens. This study reviews NBS-LRR protein activation, recognition, and downstream signal transduction in plant protection, as well as the synthetic signaling pathways and regulatory defense mechanisms associated with alkaloids. In addition, we clarify the basic regulation mechanism and summarize their current applications and the development of future applications in biotechnology for these plant defense molecules. Studies on the NBS-LRR protein and alkaloid plant disease resistance molecules may provide a theoretical foundation for the cultivation of disease resistant crops and the development of botanical pesticides.
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Affiliation(s)
- Qian Liu
- Inner Mongolia Hospital of Traditional Chinese Medicine, Hohhot, China; Baotou Medical College, Inner Mongolia Key Laboratory of Characteristic Geoherbs Resources Protection and Utilization, Inner Mongolia Engineering Research Center of The Planting and Development of Astragalus membranaceus of the Geoherbs, Baotou, China
| | - Chunhong Zhang
- Baotou Medical College, Inner Mongolia Key Laboratory of Characteristic Geoherbs Resources Protection and Utilization, Inner Mongolia Engineering Research Center of The Planting and Development of Astragalus membranaceus of the Geoherbs, Baotou, China
| | - Huiyong Fang
- Hebei University of Chinese Medicine, Traditional Chinese Medicine Processing Technology Innovation Center of Hebei Province, Shijiazhuang, China.
| | - Letai Yi
- Inner Mongolia Medical University, Hohhot, China.
| | - Minhui Li
- Inner Mongolia Hospital of Traditional Chinese Medicine, Hohhot, China; Baotou Medical College, Inner Mongolia Key Laboratory of Characteristic Geoherbs Resources Protection and Utilization, Inner Mongolia Engineering Research Center of The Planting and Development of Astragalus membranaceus of the Geoherbs, Baotou, China; Inner Mongolia Institute of Traditional Chinese and Mongolian Medicine, Hohhot, China.
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