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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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2
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Dye KJ, Salar S, Allen U, Smith W, Yang Z. Myxococcus xanthus PilB interacts with c-di-GMP and modulates motility and biofilm formation. J Bacteriol 2023; 205:e0022123. [PMID: 37695853 PMCID: PMC10521364 DOI: 10.1128/jb.00221-23] [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: 07/09/2023] [Accepted: 08/02/2023] [Indexed: 09/13/2023] Open
Abstract
The regulation of biofilm and motile states as alternate bacterial lifestyles has been studied extensively in flagellated bacteria, where the second messenger cyclic-di-GMP (cdG) plays a crucial role. However, much less is known about the mechanisms of such regulation in motile bacteria without flagella. The bacterial type IV pilus (T4P) serves as a motility apparatus that enables Myxococcus xanthus to move on solid surfaces. PilB, the T4P assembly ATPase, is, therefore, required for T4P-dependent motility in M. xanthus. Interestingly, T4P is also involved in the regulation of exopolysaccharide as the biofilm matrix material in this bacterium. A newly discovered cdG-binding domain, MshEN, is conserved in the N-terminus of PilB (PilBN) in M. xanthus and other bacteria. This suggests that cdG may bind to PilB to control the respective outputs that regulate biofilm development and T4P-powered motility. In this study, we aimed to validate M. xanthus PilB as a cdG effector protein. We performed a systematic mutational analysis of its cdG-binding domain to investigate its relationship with motility, piliation, and biofilm formation. Excluding those resulting in low levels of PilB protein, all other substitution mutations in PilBN resulted in pilB mutants with distinct and differential phenotypes in piliation and biofilm levels in M. xanthus. This suggests that the PilBN domain plays dual roles in modulating motility and biofilm levels, and these two functions of PilB can be dependent on and independent of each other in M. xanthus. IMPORTANCE The regulation of motility and biofilm by cyclic-di-GMP in flagellated bacteria has been extensively investigated. However, our knowledge regarding this regulation in motile bacteria without flagella remains limited. Here, we aimed to address this gap by investigating a non-flagellated bacterium with motility powered by bacterial type-IV pilus (T4P). Previous studies hinted at the possibility of Myxococcus xanthus PilB, the T4P assembly ATPase, serving as a cyclic-di-GMP effector involved in regulating both motility and biofilm. Our findings strongly support the hypothesis that PilB directly interacts with cyclic-di-GMP to act as a potential switch to promote biofilm formation or T4P-dependent motility. These results shed light on the bifurcation of PilB functions and its pivotal role in coordinating biofilm formation and T4P-mediated motility.
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Affiliation(s)
- Keane J. Dye
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Safoura Salar
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Uvina Allen
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Wraylyn Smith
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - Zhaomin Yang
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
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3
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Wang H, Chen F, Tang G, Ke W, Wang S, Zheng D, Ruan L. A transcriptional Regulator Gar Regulates the Growth and Virulence of Xanthomonas oryzae pv. oryzae. Curr Microbiol 2023; 80:279. [PMID: 37436661 DOI: 10.1007/s00284-023-03396-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/28/2023] [Indexed: 07/13/2023]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of bacterial blight, one of the most devastating diseases of rice. Pathogenic bacteria possess numerous transcriptional regulators to participate in the regulation of cellular processes. Here, we identified a transcriptional regulator Gar (PXO_RS11965) that is involved in regulating the growth and virulence of Xoo. Notably, the knockout of gar in Xoo enhanced bacterial virulence to the host rice. RNA-sequencing analysis and quantitative β-glucuronidase (GUS) assay indicated that Gar positively regulates the expression of a σ54 factor rpoN2. Further experiments confirmed that overexpression of rpoN2 restored the phenotypic changes caused by gar deletion. Our research revealed that Gar influences bacterial growth and virulence by positively regulating the expression of rpoN2.
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Affiliation(s)
- Huihui Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Fan Chen
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Guiyu Tang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Wenli Ke
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Shasha Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Dehong Zheng
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Key Laboratory of Agro-environment and Agro-product Safety, College of Agriculture, Guangxi University, Nanning, China
| | - Lifang Ruan
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
- College of Resources & Environment, Tibet Agriculture & Animal Husbandry University, Nyingchi, China.
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4
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Differential Genetic Strategies of Burkholderia vietnamiensis and Paraburkholderia kururiensis for Root Colonization of Oryza sativa subsp.
japonica
and O. sativa subsp.
indica
, as Revealed by Transposon Mutagenesis Sequencing. Appl Environ Microbiol 2022; 88:e0064222. [DOI: 10.1128/aem.00642-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Burkholderiaceae
are frequent and abundant colonizers of the rice rhizosphere and interesting candidates to investigate for growth promotion. Species of
Paraburkholderia
have repeatedly been described to stimulate plant growth.
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5
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Abram F, Arcari T, Guerreiro D, O'Byrne CP. Evolutionary trade-offs between growth and survival: The delicate balance between reproductive success and longevity in bacteria. Adv Microb Physiol 2021; 79:133-162. [PMID: 34836610 DOI: 10.1016/bs.ampbs.2021.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
All living cells strive to allocate cellular resources in a way that promotes maximal evolutionary fitness. While there are many competing demands for resources the main decision making process centres on whether to proceed with growth and reproduction or to "hunker down" and invest in protection and survival (or to strike an optimal balance between these two processes). The transcriptional programme active at any given time largely determines which of these competing processes is dominant. At the top of the regulatory hierarchy are the sigma factors that commandeer the transcriptional machinery and determine which set of promoters are active at any given time. The regulatory inputs controlling their activity are therefore often highly complex, with multiple layers of regulation, allowing relevant environmental information to produce the most beneficial response. The tension between growth and survival is also evident in the developmental programme necessary to promote biofilm formation, which is typically associated with low growth rates and enhanced long-term survival. Nucleotide second messengers and energy pools (ATP/ADP levels) play critical roles in determining the fate of individual cells. Regulatory small RNAs frequently play important roles in the decision making processes too. In this review we discuss the trade-off that exists between reproduction and persistence in bacteria and discuss some of the recent advances in this fascinating field.
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Affiliation(s)
- Florence Abram
- Microbiology & Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Talia Arcari
- Microbiology & Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Duarte Guerreiro
- Microbiology & Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Conor P O'Byrne
- Microbiology & Ryan Institute, School of Natural Sciences, National University of Ireland, Galway, Ireland.
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6
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Fu Y, Yu Z, Zhu L, Li Z, Yin W, Shang X, Chou SH, Tan Q, He J. The Multiple Regulatory Relationship Between RNA-Chaperone Hfq and the Second Messenger c-di-GMP. Front Microbiol 2021; 12:689619. [PMID: 34335515 PMCID: PMC8323549 DOI: 10.3389/fmicb.2021.689619] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/18/2021] [Indexed: 11/25/2022] Open
Abstract
RNA chaperone protein Hfq is an important post-transcriptional regulator in bacteria, while c-di-GMP is a second messenger signaling molecule widely distributed in bacteria. Both factors have been found to play key roles in post-transcriptional regulation and signal transduction pathways, respectively. Intriguingly, the two factors show some common aspects in the regulation of certain physiological functions such as bacterial motility, biofilm formation, pathogenicity and so on. Therefore, there may be regulatory relationship between Hfq and c-di-GMP. For example, Hfq can directly regulate the activity of c-di-GMP metabolic enzymes or alter the c-di-GMP level through other systems, while c-di-GMP can indirectly enhance or inhibit the hfq gene expression through intermediate factors. In this article, after briefly introducing the Hfq and c-di-GMP regulatory systems, we will focus on the direct and indirect regulation reported between Hfq and c-di-GMP, aiming to compare and link the two regulatory systems to further study the complicated physiological and metabolic systems of bacteria, and to lay a solid foundation for drawing a more complete global regulatory network.
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Affiliation(s)
- Yang Fu
- National Engineering Research Center of Edible Fungi, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, China.,State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhaoqing Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Li Zhu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Zhou Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Xiaodong Shang
- National Engineering Research Center of Edible Fungi, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Qi Tan
- National Engineering Research Center of Edible Fungi, Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai, China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China
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7
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Kakkar A, Verma RK, Samal B, Chatterjee S. Interplay between the cyclic di-GMP network and the cell-cell signalling components coordinates virulence-associated functions in Xanthomonas oryzae pv. oryzae. Environ Microbiol 2021; 23:5433-5462. [PMID: 34240791 DOI: 10.1111/1462-2920.15664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 07/06/2021] [Indexed: 11/29/2022]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) causes a serious disease of rice known as bacterial leaf blight. Several virulence-associated functions have been characterized in Xoo. However, the role of important second messenger c-di-GMP signalling in the regulation of virulence-associated functions still remains elusive in this phytopathogen. In this study we have performed an investigation of 13 c-di-GMP modulating deletion mutants to understand their contribution in Xoo virulence and lifestyle transition. We show that four Xoo proteins, Xoo2331, Xoo2563, Xoo2860 and Xoo2616, are involved in fine-tuning the in vivo c-di-GMP abundance and also play a role in the regulation of virulence-associated functions. We have further established the importance of the GGDEF domain of Xoo2563, a previously characterized c-di-GMP phosphodiesterase, in the virulence-associated functions of Xoo. Interestingly the strain harbouring the GGDEF domain deletion (ΔXoo2563GGDEF ) exhibited EPS deficiency and hypersensitivity to streptonigrin, indicative of altered iron metabolism. This is in contrast to the phenotype exhibited by an EAL overexpression strain wherein, the ΔXoo2563GGDEF exhibited other phenotypes, similar to the strain overexpressing the EAL domain. Taken together, our results indicate a complex interplay of c-di-GMP signalling with the cell-cell signalling to coordinate virulence-associated function in Xoo.
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Affiliation(s)
- Akanksha Kakkar
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
| | - Raj Kumar Verma
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
| | - Biswajit Samal
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
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8
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Yu C, Nguyen DP, Yang F, Shi J, Wei Y, Tian F, Zhao X, Chen H. Transcriptome Analysis Revealed Overlapping and Special Regulatory Roles of RpoN1 and RpoN2 in Motility, Virulence, and Growth of Xanthomonas oryzae pv. oryzae. Front Microbiol 2021; 12:653354. [PMID: 33746934 PMCID: PMC7970052 DOI: 10.3389/fmicb.2021.653354] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
σ54 factor (RpoN) plays a crucial role in bacterial motility, virulence, growth, and other biological functions. In our previous study, two homologous σ54 factors, RpoN1 and RpoN2, were identified in Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial leaf blight in rice. However, their functional roles, i.e., whether they exert combined or independent effects, remain unknown. In the current study, rpoN1 or rpoN2 deletion in Xoo significantly disrupted bacterial swimming motility, flagellar assembly, and virulence. Transcriptome analysis led to the identification of 127 overlapping differentially expressed genes (DEGs) regulated by both RpoN1 and RpoN2. Furthermore, GO and KEGG classification demonstrated that these DEGs were highly enriched in flagellar assembly, chemotaxis, and c-di-GMP pathways. Interestingly, ropN1 deletion decreased ropN2 transcription, while rpoN2 deletion did not affect ropN1 transcription. No interaction between the rpoN2 promoter and RpoN1 was detected, suggesting that RpoN1 indirectly regulates rpoN2 transcription. In addition, RpoN1-regulated DEGs were specially enriched in ribosome, carbon, and nitrogen metabolism pathways. Besides, bacterial growth was remarkably repressed in ΔrpoN1 but not in ΔrpoN2. Taken together, this study demonstrates the overlapping and unique regulatory roles of RpoN1 and RpoN2 in motility, virulence, growth and provides new insights into the regulatory mechanism of σ54 factors in Xoo.
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Affiliation(s)
- Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Doan-Phuong Nguyen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jia Shi
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yiming Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiuxiang Zhao
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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9
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Yan W, Wei Y, Fan S, Yu C, Tian F, Wang Q, Yang F, Chen H. Diguanylate Cyclase GdpX6 with c-di-GMP Binding Activity Involved in the Regulation of Virulence Expression in Xanthomonas oryzae pv. oryzae. Microorganisms 2021; 9:microorganisms9030495. [PMID: 33652966 PMCID: PMC7996900 DOI: 10.3390/microorganisms9030495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 11/16/2022] Open
Abstract
Cyclic diguanylate monophosphate (c-di-GMP) is a secondary messenger present in bacteria. The GGDEF-domain proteins can participate in the synthesis of c-di-GMP as diguanylate cyclase (DGC) or bind with c-di-GMP to function as a c-di-GMP receptor. In the genome of Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial blight of rice, there are 11 genes that encode single GGDEF domain proteins. The GGDEF domain protein, PXO_02019 (here GdpX6 [GGDEF-domain protein of Xoo6]) was characterized in the present study. Firstly, the DGC and c-di-GMP binding activity of GdpX6 was confirmed in vitro. Mutation of the crucial residues D403 residue of the I site in GGDEF motif and E411 residue of A site in GGDEF motif of GdpX6 abolished c-di-GMP binding activity and DGC activity of GdpX6, respectively. Additionally, deletion of gdpX6 significantly increased the virulence, swimming motility, and decreased sliding motility and biofilm formation. In contrast, overexpression of GdpX6 in wild-type PXO99A strain decreased the virulence and swimming motility, and increased sliding motility and biofilm formation. Mutation of the E411 residue but not D403 residue of the GGDEF domain in GdpX6 abolished its biological functions, indicating the DGC activity to be imperative for its biological functions. Furthermore, GdpX6 exhibited multiple subcellular localization in bacterial cells, and D403 or E411 did not contribute to the localization of GdpX6. Thus, we concluded that GdpX6 exhibits DGC activity to control the virulence, swimming and sliding motility, and biofilm formation in Xoo.
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Affiliation(s)
- Weiwei Yan
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (W.Y.); (Y.W.); (C.Y.); (F.T.); (H.C.)
- The MOA Key Laboratory of Plant Pathology, Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China;
| | - Yiming Wei
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (W.Y.); (Y.W.); (C.Y.); (F.T.); (H.C.)
| | - Susu Fan
- Shandong Provincial Key Laboratory of Applied Microbiology, Ecology Institute, Shandong Academy of Sciences, Jinan 250014, China;
| | - Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (W.Y.); (Y.W.); (C.Y.); (F.T.); (H.C.)
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (W.Y.); (Y.W.); (C.Y.); (F.T.); (H.C.)
| | - Qi Wang
- The MOA Key Laboratory of Plant Pathology, Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China;
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (W.Y.); (Y.W.); (C.Y.); (F.T.); (H.C.)
- Correspondence: ; Tel.: +86-010-62896063
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (W.Y.); (Y.W.); (C.Y.); (F.T.); (H.C.)
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10
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Shahbaz MU, Qian S, Yun F, Zhang J, Yu C, Tian F, Yang F, Chen H. Identification of the Regulatory Components Mediated by the Cyclic di-GMP Receptor Filp and Its Interactor PilZX3 and Functioning in Virulence of Xanthomonas oryzae pv. oryzae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:1196-1208. [PMID: 32720873 DOI: 10.1094/mpmi-04-20-0088-r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The degenerate GGDEF/EAL domain protein Filp was previously shown to function as a cyclic di-GMP (c-di-GMP) signal receptor through its specific interaction with an atypical PilZ domain protein PilZX3 (formerly PXO_02715) and that this interaction is involved in regulating virulence in Xanthomonas oryzae pv. oryzae. As a step toward understanding the regulatory role of Filp/PilZX3-mediated c-di-GMP signaling in the virulence of X. oryzae pv. oryzae, differentially expressed proteins (DEPs) downstream of Filp/PilZX3 were identified by isobaric tagging for relative and absolute quantitation (iTRAQ). A total of 2,346 proteins were identified, of which 157 displayed significant differential expression in different strains. Western blot and quantitative reverse transcription-PCR analyses showed that the expression of HrrP (histidine kinase-response regulator hybrid protein), PhrP (PhoPQ-regulated protein), ProP (prophage Lp2 protein 6) were increased in the ∆filp, ∆pilZX3, and ∆filp∆pilZX3 mutant strains, while expression of CheW1 (chemotaxis protein CheW1), EdpX2 (the second EAL domain protein identified in X. oryzae pv. oryzae), HGdpX2 (the second HD-GYP domain protein identified in X. oryzae pv. oryzae) was decreased in all mutant strains compared with that in the wild type, which was consistent with the iTRAQ data. Deletion of the hrrP and proP genes resulted in significant increases in virulence, whereas deletion of the cheW1, hGdpX2, or tdrX2 genes resulted in decreased virulence. Enzyme assays indicated that EdpX2 and HGdpX2 were active phosphodiesterases (PDEs). This study provides a proteomic description of putative regulatory pathway of Filp and PilZX3 and characterized novel factors that contributed to the virulence of X. oryzae pv. oryzae regulated by c-di-GMP signaling.
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Affiliation(s)
- Muhammad Umar Shahbaz
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Plant Pathology Section, Plant Pathology Research Institute, AARI, Faisalabad 38850, Pakistan
| | - Shanshan Qian
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fei Yun
- National Tobacco Cultivation and Physiology and Biochemistry Research Centre/Key Laboratory for Tobacco Cultivation of Tobacco Industry, Henan Agricultural University, Zhengzhou 450002, China
| | - Jie Zhang
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Chao Yu
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fang Tian
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Fenghuan Yang
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huamin Chen
- State Key Laboratory for Biology Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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11
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Kwak GY, Choi O, Goo E, Kang Y, Kim J, Hwang I. Quorum Sensing-Independent Cellulase-Sensitive Pellicle Formation Is Critical for Colonization of Burkholderia glumae in Rice Plants. Front Microbiol 2020; 10:3090. [PMID: 32010117 PMCID: PMC6978641 DOI: 10.3389/fmicb.2019.03090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/20/2019] [Indexed: 01/19/2023] Open
Abstract
Bacteria form biofilms as a means to adapt to environmental changes for survival. Pellicle is a floating biofilm formed at the air-liquid interface in static culture conditions; however, its functional roles have received relatively little attention compared to solid surface-associated biofilms in gram-negative bacteria. Here we show that the rice pathogen Burkholderia glumae BGR1 forms cellulase-sensitive pellicles in a bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP)- and flagellum-dependent, but quorum sensing (QS)-independent, manner. Pellicle formation was more favorable at 28°C than at the optimum growth temperature (37°C), and was facilitated by constitutive expression of pelI, a diguanylate cyclase gene from B. glumae, or pleD, the GGDEF response regulator from Agrobacterium tumefaciens. Constitutive expression of pelI or pleD raised the levels of c-di-GMP, facilitated pellicle formation, and suppressed swarming motility in B. glumae. QS-defective mutants of B. glumae formed pellicles, while flagellum-defective mutants did not. Pellicles of B. glumae were sensitive to cellulase but not to proteinase K or DNase I. A gene cluster containing seven genes involved in bacterial cellulose biosynthesis, bcsD, bcsR, bcsQ, bcsA, bcsB, bcsZ, and bcsC, homologous to known genes involved in cellulose biosynthesis in other bacteria, was identified in B. glumae. Mutations in each gene abolished pellicle formation. These results revealed a positive correlation between cellulase-sensitive pellicles and putative cellulose biosynthetic genes. Pellicle-defective mutants did not colonize as successfully as the wild-type strain BGR1 in rice plants, which resulted in a significant reduction in virulence. Our findings show that cellulase-sensitive pellicles produced in a QS-independent manner play important roles in the interactions between rice plants and B. glumae.
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Affiliation(s)
- Gi-Young Kwak
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Okhee Choi
- Division of Applied Life Science, Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju, South Korea
| | - Eunhye Goo
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Yongsung Kang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Jinwoo Kim
- Division of Applied Life Science, Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju, South Korea
| | - Ingyu Hwang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
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