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Kharadi RR, Hsueh BY, Waters CM, Sundin GW. pGpG-signaling regulates virulence and global transcriptomic targets in Erwinia amylovora. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.12.575434. [PMID: 38260453 PMCID: PMC10802605 DOI: 10.1101/2024.01.12.575434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Cyclic-di-GMP (c-di-GMP) is a critical bacterial second messenger that enables the physiological phase transition in Erwinia amylovora, the phytopathogenic bacterium that causes fire blight disease. C-di-GMP generation is dependent on diguanylate cyclase enzymes while the degradation of c-di-GMP can occur through the action of phosphodiesterase (PDE) enzymes that contain an active EAL and/or a HD-GYP domain. The HD-GYP-type PDEs, which are absent in E. amylovora, can directly degrade c-di-GMP into two GMP molecules. PDEs that contain an active EAL domain, as found in all active PDEs in E. amylovora, degrade c-di-GMP into pGpG. The signaling function of pGpG is not fully understood in bacterial systems. A transcriptomic approach revealed that elevated levels of pGpG in E. amylovora impacted several genes involved in metabolic and regulatory functions including several type III secretion and extracellular appendage related genes. The heterologous overexpression of an EAL or HD-GYP-type PDE in different background E. amylovora strains with varying c-di-GMP levels revealed that in contrast to the generation of pGpG, the direct breakdown of c-di-GMP into GMP by the HD-GYP-type PDE led to an elevation in amylovoran production and biofilm formation despite a decrease in c-di-GMP levels. The breakdown of c-di-GMP into pGpG (as opposed to GTP) also led to a decrease in virulence in apple shoots. The expression of hrpS was significantly increased in response to the breakdown of c-di-GMP into pGpG. Further, our model suggests that a balance in the intracellular ratio of pGpG and c-di-GMP is essential for biofilm regulation in E. amylovora.
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Affiliation(s)
- Roshni R. Kharadi
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA
| | - Brian Y. Hsueh
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - Christopher M. Waters
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
| | - George W. Sundin
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan, USA
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Wang K, Li W, Cui H, Qin S. Phylogenetic Analysis and Characterization of Diguanylate Cyclase and Phosphodiesterase in Planktonic Filamentous Cyanobacterium Arthrospira sp. Int J Mol Sci 2023; 24:15210. [PMID: 37894891 PMCID: PMC10607523 DOI: 10.3390/ijms242015210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/10/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
Cyclic di-GMP (c-di-GMP) is a second messenger of intracellular communication in bacterial species, which widely modulates diverse cellular processes. However, little is known about the c-di-GMP network in filamentous multicellular cyanobacteria. In this study, we preliminarily investigated the c-di-GMP turnover proteins in Arthrospira based on published protein data. Bioinformatics results indicate the presence of at least 149 potential turnover proteins in five Arthrospira subspecies. Some proteins are highly conserved in all tested Arthrospira, whereas others are specifically found only in certain subspecies. To further validate the protein catalytic activity, we constructed a riboswitch-based c-di-GMP expression assay system in Escherichia coli and confirmed that a GGDEF domain protein, Adc11, exhibits potential diguanylate cyclase activity. Moreover, we also evaluated a protein with a conserved HD-GYP domain, Ahd1, the expression of which significantly improved the swimming ability of E. coli. Enzyme-linked immunosorbent assay also showed that overexpression of Ahd1 reduced the intracellular concentration of c-di-GMP, which is presumed to exhibit phosphodiesterase activity. Notably, meta-analyses of transcriptomes suggest that Adc11 and Ahd1 are invariable. Overall, this work confirms the possible existence of a functional c-di-GMP network in Arthrospira, which will provide support for the revelation of the biological function of the c-di-GMP system in Arthrospira.
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Affiliation(s)
- Kang Wang
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (K.W.); (W.L.); (H.C.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenjun Li
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (K.W.); (W.L.); (H.C.)
| | - Hongli Cui
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (K.W.); (W.L.); (H.C.)
| | - Song Qin
- Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China; (K.W.); (W.L.); (H.C.)
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Yang W, Yan H, Dong G, Li Z, Jiang C, Gu D, Niu D, Zhou D, Luo Y. Comparative transcriptomics reveal different genetic adaptations of biofilm formation in Bacillus subtilis isolate 1JN2 in response to Cd2+ treatment. Front Microbiol 2022; 13:1002482. [PMID: 36267191 PMCID: PMC9577173 DOI: 10.3389/fmicb.2022.1002482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 09/05/2022] [Indexed: 12/01/2022] Open
Abstract
Biofilm plays important roles in the life cycle of Bacillus species, such as promoting host and object surface colonization and resisting heavy metal stress. This study utilized transcriptomics to evaluate the impacts of cadmium on the components, morphology, and function of biofilms of Bacillus subtilis strain 1JN2. Under cadmium ion stress, the morphology of the B. subtilis 1JN2 biofilm was flattened, and its mobility increased. Moreover, differential gene expression analysis showed that the main regulator of biofilm formation, Spo0A, decreased in expression under cadmium ion stress, thereby inhibiting extracellular polysaccharide synthesis through the SinI/SinR two-component regulatory system and the AbrB pathway. Cadmium ion treatment also increased the SigD content significantly, thereby increasing the expression of the flagella encoding and assembly genes in the strain. This promoted poly-γ-glutamic acid production via the DegS/DegU two-component regulatory system and the conversion of biofilm extracellular polysaccharide to poly-γ-glutamic acid. This conferred cadmium stress tolerance in the strain. Additionally, the cadmium ion-mediated changes in the biofilm composition affected the colonization of the strain on the host plant root surface. Cadmium ions also induced surfactin synthesis. These findings illustrate the potential of Bacillus species as biocontrol strains that can mitigate plant pathogenic infections and heavy metal stress. The results also provide a basis for the screening of multifunctional biocontrol strains.
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Affiliation(s)
- Wei Yang
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huai’an, China
| | - Haixia Yan
- Agro-Tech Extension and Service Center, Huai’an, China
| | - Guanghui Dong
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
| | - Zhengpeng Li
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huai’an, China
| | - Chunhao Jiang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Dalu Gu
- Huaiyin Institute of Agricultural Sciences of Xuhuai Region in Jiangsu, Huaian Academy of Agricultural Sciences, Huai’an, China
| | - Dongdong Niu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Danni Zhou
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
| | - Yuming Luo
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology Around Hongze Lake, School of Life Science, Huaiyin Normal University, Huai’an, China
- Jiangsu Collaborative Innovation Center of Regional Modern Agriculture & Environmental Protection, Huai’an, China
- *Correspondence: Yuming Luo,
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Wang J, Yu Q, Peng Q, Slamti L, Zhang R, Hou S, Lereclus D, Song F. Deletion of the novel gene mother cell lysis X results in Cry1Ac encapsulation in the Bacillus thuringiensis HD73. Front Microbiol 2022; 13:951830. [PMID: 36016772 PMCID: PMC9397120 DOI: 10.3389/fmicb.2022.951830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 07/14/2022] [Indexed: 11/13/2022] Open
Abstract
The novel protein MclX (mother cell lysis X) in Bacillus thuringiensis subsp. kurstaki strain HD73 (B. thuringiensis HD73) was characterized in this work. MclX has no known domain and its gene deletion in HD73 resulted in Cry1Ac encapsulation in the mother cell and did not influence Cry1Ac protein production or insecticidal activity. In vitro cell wall hydrolysis experiments showed that MclX cannot hydrolyze the cell wall. In mclX deletion mutants, the expression of cwlC (which encodes a key cell wall hydrolase) was significantly decreased, as shown by the β-galactosidase activity assay. MclX cannot directly bind to the cwlC promoter, based on the electrophoretic mobility shift assay (EMSA). The cwlC was reported to be regulated by σK and GerE. However, the transcriptional activities of sigK and gerE showed no difference between HD73 and the mclX deletion mutant. It is indicated that MclX influenced cwlC expression independently of σK or GerE, through a new pathway to regulate cwlC expression. mclX deletion could be a new approach for insecticidal protein encapsulation in Bacillus thuringiensis.
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Affiliation(s)
- Jiaojiao Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qingyue Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qi Peng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Leyla Slamti
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Ruibin Zhang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Shuo Hou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Didier Lereclus
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Fuping Song
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Fuping Song,
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Kharadi RR, Sundin GW. CsrD regulates amylovoran biosynthesis and virulence in Erwinia amylovora in a novel cyclic-di-GMP dependent manner. MOLECULAR PLANT PATHOLOGY 2022; 23:1154-1169. [PMID: 35396793 PMCID: PMC9276943 DOI: 10.1111/mpp.13217] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Erwinia amylovora is an economically devastating plant pathogen that causes fire blight disease in members of the Rosaceae family, most notably in apple and pear. The exopolysaccharide amylovoran is a pathogenicity determinant in E. amylovora and a major component of the extracellular matrix of biofilms formed within the xylem vasculature of the host plant. The second messenger cyclic-di-GMP (c-di-GMP) has been reported to positively regulate the transcription of amsG (the first gene in the 12-gene amylovoran [ams] biosynthetic operon), thus impacting amylovoran production. However, the regulatory mechanism by which this interaction occurs is largely unknown. Here, we report that c-di-GMP can bind to specific residues in the EAL domain of the E. amylovora protein CsrD. CsrD and RNase E regulate the degradation of the sRNA CsrB in E. amylovora. When CsrD is bound to c-di-GMP, there is an enhancement in the level of RNase E-mediated degradation of CsrB, which then alters amsG transcription. Additionally, csrD was also found to positively contribute to virulence and biofilm formation. We thus present a pathway of conditional regulation of amylovoran production mediated by changing intracellular levels of c-di-GMP, which impacts disease progression.
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Affiliation(s)
- Roshni R. Kharadi
- Department of Plant, Soil and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
| | - George W. Sundin
- Department of Plant, Soil and Microbial SciencesMichigan State UniversityEast LansingMichiganUSA
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Römling U. The power of unbiased phenotypic screens - cellulose as a first receptor for the Schitoviridae phage S6 of Erwinia amylovora. Environ Microbiol 2022; 24:3316-3321. [PMID: 35415924 PMCID: PMC9544554 DOI: 10.1111/1462-2920.16010] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 04/09/2022] [Indexed: 11/30/2022]
Abstract
Bacteriophages, host‐dependent replicative non‐cellular entities which significantly shape the microbial genomes and consequently physiological and ecological properties of the microbial populations are exploited to restrict plant, animal and human pathogens. Unravelling of phage characteristics aids the understanding of the basic molecular mechanisms of phage infections which can subsequently lead to the development of rationalized strategies to combat microbial pathogens. In an unbiased screen to investigate the molecular basis of infectivity of the fire blight pathogen Erwinia amylovora by the lytic Schitoviridae phage S6, the biofilm extracellular matrix component cellulose has been identified as a cyclic di‐GMP dependent first receptor required for infection with the phage to possess beta‐1,4‐glucosidases to degrade the exopolysaccharide. This absolute receptor dependency allows maintenance of a phage‐microbe equilibrium with a low bacterial density.
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Affiliation(s)
- Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Biomedicum, Karolinska Institutet, Stockholm, Sweden
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Cui Z, Huntley RB, Schultes NP, Kakar KU, Yang CH, Zeng Q. Expression of the Type III Secretion System Genes in Epiphytic Erwinia amylovora Cells on Apple Stigmas Benefits Endophytic Infection at the Hypanthium. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1119-1127. [PMID: 34698527 DOI: 10.1094/mpmi-06-21-0152-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Erwinia amylovora causes fire blight on rosaceous plants. One of the major entry points of E. amylovora into hosts is flowers, where E. amylovora proliferates epiphytically on stigmatic and hypanthium surfaces and, subsequently, causes endophytic infection at the hypanthium. The type III secretion system (T3SS) is an important virulence factor in E. amylovora. Although the role of T3SS during endophytic infection is well characterized, its expression during epiphytic colonization and role in the subsequent infection is less understood. Here, we investigated T3SS gene expression in epiphytic E. amylovora on stigma and hypanthium of apple flowers under different relative humidities (RH). On stigma surfaces, T3SS was expressed in a high percentage of E. amylovora cells, and its expression promoted epiphytic growth. On hypanthium surfaces, however, T3SS was expressed in fewer E. amylovora cells than on the stigma, and displayed no correlation with epiphytic growth, even though T3SS expression is essential for infection. E. amylovora cells grown on stigmatic surfaces and then flushed down to the hypanthium displayed a higher level of T3SS expression than cells grown on the hypanthium surface alone. Furthermore, E. amylovora cells precultured on stigma had a higher potential to infect flowers than E. amylovora cells precultured in a T3SS-repressive medium. This suggests that T3SS induction during the stigmatic epiphytic colonization may be beneficial for subsequent infection. Finally, epiphytic expression of T3SS was influenced by RH. Higher percentage of stigmatic E. amylovora cells expressed T3SS under high RH than under low RH.[Formula: see text] Copyright © 2021 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)
- Zhouqi Cui
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, U.S.A
| | - Regan B Huntley
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, U.S.A
| | - Neil P Schultes
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, U.S.A
| | - Kaleem U Kakar
- Department of Microbiology, Faculty of Life Sciences and Informatics, Balochistan University of Information Technology, Engineering and Management Sciences (BUITEMS), Quetta, 87300, Pakistan
| | - Ching-Hong Yang
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A
| | - Quan Zeng
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, U.S.A
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Kharadi RR, Schachterle JK, Yuan X, Castiblanco LF, Peng J, Slack SM, Zeng Q, Sundin GW. Genetic Dissection of the Erwinia amylovora Disease Cycle. ANNUAL REVIEW OF PHYTOPATHOLOGY 2021; 59:191-212. [PMID: 33945696 DOI: 10.1146/annurev-phyto-020620-095540] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Fire blight, caused by the bacterial phytopathogen Erwinia amylovora, is an economically important and mechanistically complex disease that affects apple and pear production in most geographic production hubs worldwide. We compile, assess, and present a genetic outlook on the progression of an E. amylovora infection in the host. We discuss the key aspects of type III secretion-mediated infection and systemic movement, biofilm formation in xylem, and pathogen dispersal via ooze droplets, a concentrated suspension of bacteria and exopolysaccharide components. We present an overall outlook on the genetic elements contributing to E. amylovora pathogenesis, including an exploration of the impact of floral microbiomes on E. amylovora colonization, and summarize the current knowledge of host responses to an incursion and how this response stimulates further infection and systemic spread. We hope to facilitate the identification of new, unexplored areas of research in this pathosystem that can help identify evolutionarily susceptible genetic targets to ultimately aid in the design of sustainable strategies for fire blight disease mitigation.
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Affiliation(s)
- Roshni R Kharadi
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Jeffrey K Schachterle
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
- Floral and Nursery Plants Research Unit, US National Arboretum, USDA-ARS, Beltsville, Maryland 20705, USA
| | - Xiaochen Yuan
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Luisa F Castiblanco
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Jingyu Peng
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Suzanne M Slack
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
| | - Quan Zeng
- Department of Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, USA
| | - George W Sundin
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, Michigan 48824, USA;
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