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Li K, Liao J, Wei M, Qiu S, Wu W, Zhao Y, Wang H, Liu Q, Liu F, Chang C. The Xanthomonas citri Reverse Fitness Deficiency by Activating a Novel β-Glucosidase Under Low Osmostress. Front Microbiol 2022; 13:887967. [PMID: 35586864 PMCID: PMC9108719 DOI: 10.3389/fmicb.2022.887967] [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: 03/02/2022] [Accepted: 03/17/2022] [Indexed: 11/13/2022] Open
Abstract
Bacteria can withstand various types of environmental osmostress. A sudden rise in osmostress affects bacterial cell growth that is countered by activating special genes. The change of osmostress is generally a slow process under the natural environment. However, the collective response of bacteria to low osmostress remains unknown. This study revealed that the deletion of phoP (ΔphoP) from X. citri significantly compromised the growth and virulence as compared to the wild-type strain. Interestingly, low osmostress reversed physiological deficiencies of X. citri phoP mutant related to bacterial growth and virulence. The results also provided biochemical and genetic evidence that the physiological deficiency of phoP mutant can be reversed by low osmostress induced β-glucosidase (BglS) expression. Based on the data, this study proposes a novel regulatory mechanism of a novel β-glucosidase activation in X. citri through low osmostress to reverse the fitness deficiency.
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Affiliation(s)
- Kaihuai Li
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Jinxing Liao
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Ming Wei
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Shanxu Qiu
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Weiyin Wu
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Yancun Zhao
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Haihong Wang
- College of Life Sciences, South China Agricultural University, Guangzhou, China
| | - Qiongguang Liu
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
| | - Fengquan Liu
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, China
- *Correspondence: Fengquan Liu,
| | - Changqing Chang
- College of Plant Protection, Integrate Microbiology Research Center, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- Changqing Chang,
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Lu HF, Wu BK, Huang YW, Lee MZ, Li MF, Ho HJ, Yang HC, Yang TC. PhoPQ two-component regulatory system plays a global regulatory role in antibiotic susceptibility, physiology, stress adaptation, and virulence in Stenotrophomonas maltophilia. BMC Microbiol 2020; 20:312. [PMID: 33054754 PMCID: PMC7559202 DOI: 10.1186/s12866-020-01989-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/30/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Stenotrophomonas maltophilia, an opportunistic pathogen, is ubiquitously present in various environments, signifying its high capability of environmental adaptation. Two-component regulatory system (TCS) is a powerful implement to help organisms to survive in different environments. In clinic, treatment of S. maltophilia infection is difficult because it is naturally resistant to many antibiotics, highlighting the necessity to develop novel drugs or adjuvants. Given their critical and extensively regulatory role, TCS system has been proposed as a convincing target for novel drugs or adjuvants. PhoPQ TCS, a highly conserved TCS in several pathogens, plays crucial roles in low-magnesium adaption, polymyxin resistance, and virulence. In this study, we aimed to characterize the role of PhoPQ TCS of S. maltophilia in antibiotic susceptibility, physiology, stress adaptation, and virulence. RESULTS To characterize PhoPQ system, phoP single mutant as well as phoP and phoQ double mutant were constructed. Distinct from most phoPQ systems of other microorganisms, two features were observed during the construction of phoP and phoQ single deletion mutant. Firstly, the phoQ mutant was not successfully obtained. Secondly, the compromised phenotypes of phoP mutant were not reverted by complementing an intact phoP gene, but were partially restored by complementing a phoPQ operon. Thus, wild-type KJ, phoP mutant (KJΔPhoP), phoPQ mutant (KJΔPhoPQ), and complemented strain (KJΔPhoPQ (pPhoPQ)) were used for functional assays, including antibiotic susceptibility, physiology (swimming motility and secreted protease activity), stress adaptation (oxidative, envelope, and iron-depletion stresses), and virulence to Caenorhabditis elegans. KJΔPhoPQ totally lost swimming motility, had enhanced secreted protease activity, increased susceptibility to antibiotics (β-lactam, quinolone, aminoglycoside, macrolide, chloramphenicol, and sulfamethoxazole/ trimethoprim), menadione, H2O2, SDS, and 2,2'-dipyridyl, as well as attenuated virulence to C. elegans. Trans-complementation of KJΔPhoPQ with phoPQ reverted these altered phenotypes to the wild-type levels. CONCLUSIONS Given the critical and global roles of PhoPQ TCS in antibiotic susceptibility, physiology, stress adaptation, and virulence, PhoPQ is a potential target for the design of drugs or adjuvants.
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Affiliation(s)
- Hsu-Feng Lu
- Department of Clinical Pathology, Cheng Hsin General Hospital, Taipei, Taiwan
- Department of Restaurant, Hotel and Institutional Management, Fu-Jen Catholic University, New Taipei City, Taiwan
| | - Bo-Kuan Wu
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Wei Huang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Ming-Zhe Lee
- Department of Clinical Pathology, Cheng Hsin General Hospital, Taipei, Taiwan
| | - Ming-Fang Li
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Hsu-Jung Ho
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan
| | - Hung-Chi Yang
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University of Medical Technology, Hsinchu, Taiwan.
| | - Tsuey-Ching Yang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan.
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Wang FF, Qian W. The roles of histidine kinases in sensing host plant and cell-cell communication signal in a phytopathogenic bacterium. Philos Trans R Soc Lond B Biol Sci 2020; 374:20180311. [PMID: 30967026 DOI: 10.1098/rstb.2018.0311] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
It has long been known that phytopathogenic bacteria react to plant-specific stimuli or environmental factors. However, how bacterial cells sense these environmental cues remains incompletely studied. Recently, three kinds of histidine kinases (HKs) were identified as receptors to perceive plant-associated or quorum-sensing signals. Among these kinases, HK VgrS detects iron depletion by binding to ferric iron via an ExxE motif, RpfC binds diffusible signal factor (DSF) by its N-terminal peptide and activates its autokinase activity through relaxation of autoinhibition, and PcrK specifically senses plant hormone-cytokinin and elicits bacterial responses to oxidative stress. These HKs are critical sensors that regulate the virulence of a Gram-negative bacterium, Xanthomonas campestris pv. campestris. Research progress on the signal perception of phytopathogenic bacterial HKs suggests that inter-kingdom signalling between host plants and pathogens controls pathogenesis and can be used as a potential molecular target to protect plants from bacterial diseases. This article is part of the theme issue 'Biotic signalling sheds light on smart pest management'.
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Affiliation(s)
- Fang-Fang Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101 , People's Republic of China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101 , People's Republic of China
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Wei C, Ding T, Chang C, Yu C, Li X, Liu Q. Global Regulator PhoP is Necessary for Motility, Biofilm Formation, Exoenzyme Production and Virulence of Xanthomonas citri Subsp. citri on Citrus Plants. Genes (Basel) 2019; 10:genes10050340. [PMID: 31064142 PMCID: PMC6562643 DOI: 10.3390/genes10050340] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/28/2019] [Accepted: 05/02/2019] [Indexed: 01/27/2023] Open
Abstract
Citrus canker caused by Xanthomonas citri subsp. citri is one of the most important bacterial diseases of citrus, impacting both plant growth and fruit quality. Identifying and elucidating the roles of genes associated with pathogenesis has aided our understanding of the molecular basis of citrus-bacteria interactions. However, the complex virulence mechanisms of X. citri subsp. citri are still not well understood. In this study, we characterized the role of PhoP in X. citri subsp. citri using a phoP deletion mutant, ΔphoP. Compared with wild-type strain XHG3, ΔphoP showed reduced motility, biofilm formation, as well as decreased production of cellulase, amylase, and polygalacturonase. In addition, the virulence of ΔphoP on citrus leaves was significantly decreased. To further understand the virulence mechanisms of X. citri subsp. citri, high-throughput RNA sequencing technology (RNA-Seq) was used to compare the transcriptomes of the wild-type and mutant strains. Analysis revealed 1017 differentially-expressed genes (DEGs), of which 614 were up-regulated and 403 were down-regulated in ΔphoP. Gene ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggested that the DEGs were enriched in flagellar assembly, two-component systems, histidine metabolism, bacterial chemotaxis, ABC transporters, and bacterial secretion systems. Our results showed that PhoP activates the expression of a large set of virulence genes, including 22 type III secretion system genes and 15 type III secretion system effector genes, as well as several genes involved in chemotaxis, and flagellar and histidine biosynthesis. Two-step reverse-transcription polymerase chain reaction analysis targeting 17 genes was used to validate the RNA-seq data, and confirmed that the expression of all 17 genes, except for that of virB1, decreased significantly. Our results suggest that PhoP interacts with a global signaling network to co-ordinate the expression of multiple virulence factors involved in modification and adaption to the host environment during infection.
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Affiliation(s)
- Chudan Wei
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Tian Ding
- Guangzhou Airport Entry-Exit Inspection and Quarantine Bureau, Guangzhou 510800, China.
| | - Changqing Chang
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Guangzhou 510642, China.
| | - Chengpeng Yu
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Xingwei Li
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Qiongguang Liu
- College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
- State Key Laboratory of Conservation and Utilization of Subtropical Agro-bioresources, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Guangzhou 510642, China.
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Yang RL, Deng CY, Wei JW, He W, Li AN, Qian W. A Large-Scale Mutational Analysis of Two-Component Signaling Systems of Lonsdalea quercina Revealed that KdpD-KdpE Regulates Bacterial Virulence Against Host Poplar Trees. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:724-736. [PMID: 29424663 DOI: 10.1094/mpmi-10-17-0248-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Poplar, which is a dominant species in plant communities distributed in the northern hemisphere, is commonly used as a model plant in forestry studies. Poplar production can be inhibited by infections caused by bacteria, including Lonsdalea quercina subsp. populi, which is a gram-negative bacterium responsible for bark canker disease. However, the molecular basis of the pathogenesis remains uncharacterized. In this study, we annotated the two-component signal transduction systems (TCSs) encoded by the L. quercina subsp. populi N-5-1 genome and identified 18 putative histidine kinases and 24 response regulators. A large-scale mutational analysis revealed that 19 TCS genes regulated bacterial virulence against poplar trees. Additionally, the deletion of kdpE or overexpression of kdpD resulted in almost complete loss of bacterial virulence. We observed that kdpE and kdpD formed a bi-cistronic operon. KdpD exhibited autokinase activity and could bind to KdpE (Kd = 5.73 ± 0.64 μM). Furthermore, KdpE is an OmpR family response regulator. A chromatin immunoprecipitation sequencing analysis revealed that KdpE binds to an imperfect palindromic sequence within the promoters of 44 genes, including stress response genes Lqp0434, Lqp3037, and Lqp3270. A comprehensive analysis of TCS functions may help to characterize the regulation of poplar bark canker disease.
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Affiliation(s)
- Ruo-Lan Yang
- 1 The College of Forestry, Beijing Forestry University, Beijing 100083, China
- 2 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and
| | - Chao-Ying Deng
- 2 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and
| | - Jin-Wei Wei
- 2 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and
- 3 School of Biological Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei He
- 1 The College of Forestry, Beijing Forestry University, Beijing 100083, China
| | - Ai-Ning Li
- 1 The College of Forestry, Beijing Forestry University, Beijing 100083, China
| | - Wei Qian
- 2 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; and
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Pan Y, Liang F, Li RJ, Qian W. MarR-Family Transcription Factor HpaR Controls Expression of the vgrR-vgrS Operon of Xanthomonas campestris pv. campestris. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:299-310. [PMID: 29077520 DOI: 10.1094/mpmi-07-17-0187-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
MarR (multiple antibiotic resistance regulator)-family transcription factors (TFs), which regulate the expression of virulence factors and other physiological pathways in pathogenic bacteria, are regarded as ideal molecular targets for the development of novel antimicrobial strategies. In the plant bacterial pathogen Xanthomonas campestris pv. campestris, HpaR, a typical MarR-family TF, is associated with bacterial virulence, but its mechanism of virulence regulation remains unclear. Here, we dissected the HpaR regulon using high-throughput RNA sequencing and chromatin immunoprecipitation sequencing. HpaR directly or indirectly controls the expression of approximately 448 genes; it acts both as a transcriptional activator and a repressor to control the expression of downstream genes by directly binding to their promoter regions. The consensus HpaR-binding DNA motifs contain imperfect palindromic sequences similar to [G/T]CAACAATT[C/T]TTG. In-depth analysis revealed that HpaR positively modulates transcription level of the vgrR-vgrS operon that encodes an important two-component signal transduction system to sense iron depletion and regulate bacterial virulence. Epistasis analysis demonstrated that vgrR-vgrS is a core downstream component of HpaR regulation, as overexpression of vgrR restored the phenotypic deficiencies caused by a hpaR mutation. This dissection of the HpaR regulon should facilitate future studies focused on the activating mechanism of HpaR during bacterial infection.
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Affiliation(s)
- Yue Pan
- 1 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- 2 School of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; and
| | - Fang Liang
- 3 Beijing Institute of Genomics, Chinese Academy of Sciences
| | - Ru-Jiao Li
- 3 Beijing Institute of Genomics, Chinese Academy of Sciences
| | - Wei Qian
- 1 State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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