1
|
Xiang J, Cheng J, Wei L, Li M, Wu J. Functional analysis of the Nep1-like proteins from Plasmopara viticola. PLANT SIGNALING & BEHAVIOR 2022; 17:2000791. [PMID: 35152834 PMCID: PMC9176246 DOI: 10.1080/15592324.2021.2000791] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 06/14/2023]
Abstract
Necrosis and ethylene-inducing peptide 1 (Nep1) -like proteins (NLP) are secreted by multiple taxonomically unrelated plant pathogens (bacteria, fungi, and oomycete) and are best known for inducing cell death and immune responses in dicotyledonous plants. A group of putative NLP genes from obligate biotrophic oomycete Plasmopara viticola were predicted by RNA-Seq in our previous study, but their activity has not been established. Therefore, we analyzed the P. viticola NLP (PvNLP) family and identified seven PvNLP genes. They all belong to type 1 NLP genes and form a P. viticola-specific cluster when compared with other pathogen NLP genes. The expression of PvNLPs was induced during early infection process and the expression patterns could be categorized into two groups. Agrobacterium tumefaciens-mediated transient expression assays revealed that only PvNLP7 was cytotoxic and could induce Phytophthora capsici resistance in Nicotiana benthamiana. Functional analysis showed that PvNLP4, PvNLP5, PvNLP7, and PvNLP10 significantly improved disease resistance of Arabidopsis thaliana to Hyaloperonospora arabidopsidis. Moreover, the four genes caused an inhibition of plant growth which is typically associated with enhanced immunity when over-expressed in Arabidopsis. Further research found that PvNLP7 could activate the expression of defense-related genes and its conserved NPP1 domain was critical for cell death- and immunity-inducing activity. This record of NLP genes from P. viticola showed a functional diversification, laying a foundation for further study on pathogenic mechanism of the devastating pathogen.
Collapse
Affiliation(s)
- Jiang Xiang
- Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jianhui Cheng
- Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Lingzhu Wei
- Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Mingshan Li
- Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Jiang Wu
- Institute of Horticulture, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| |
Collapse
|
2
|
Structure-Functional Characteristics of the Svx Protein—The Virulence Factor of the Phytopathogenic Bacterium Pectobacterium atrosepticum. Int J Mol Sci 2022; 23:ijms23136914. [PMID: 35805920 PMCID: PMC9266454 DOI: 10.3390/ijms23136914] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 11/17/2022] Open
Abstract
The Svx proteins are virulence factors of phytopathogenic bacteria of the Pectobacterium genus. The specific functions of these proteins are unknown. Here we show that most of the phytopathogenic species of Pectobacterium, Dickeya, and Xanthomonas genera have genes encoding Svx proteins, as well as some plant-non-associated species of different bacterial genera. As such, the Svx-like proteins of phytopathogenic species form a distinct clade, pointing to the directed evolution of these proteins to provide effective interactions with plants. To get a better insight into the structure and functions of the Svx proteins, we analyzed the Svx of Pectobacterium atrosepticum (Pba)—an extracellular virulence factor secreted into the host plant cell wall (PCW). Using in silico analyses and by obtaining and analyzing the recombinant Pba Svx and its mutant forms, we showed that this protein was a gluzincin metallopeptidase. The 3D structure model of the Pba Svx was built and benchmarked against the experimental overall secondary structure content. Structure-based substrate specificity analysis using molecular docking revealed that the Pba Svx substrate-binding pocket might accept α-glycosylated proteins represented in the PCW by extensins—proteins that strengthen the PCW. Thus, these results elucidate the way in which the Pba Svx may contribute to the Pba virulence.
Collapse
|
3
|
Yang G, Yang J, Zhang Q, Wang W, Feng L, Zhao L, An B, Wang Q, He C, Luo H. The Effector Protein CgNLP1 of Colletotrichum gloeosporioides Affects Invasion and Disrupts Nuclear Localization of Necrosis-Induced Transcription Factor HbMYB8-Like to Suppress Plant Defense Signaling. Front Microbiol 2022; 13:911479. [PMID: 35770165 PMCID: PMC9234567 DOI: 10.3389/fmicb.2022.911479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 05/13/2022] [Indexed: 11/13/2022] Open
Abstract
Fungi secrete numerous effectors to modulate host defense systems. Understanding the molecular mechanisms by which fungal effectors regulate plant defense is of great importance for the development of novel strategies for disease control. In this study, we identified necrosis- and ethylene-inducing protein 1 (Nep1)-like protein (NLP) effector gene, CgNLP1, which contributed to conidial germination, appressorium formation, invasive growth, and virulence of Colletotrichum gloeosporioides to the rubber tree. Transient expression of CgNLP1 in the leaves of Nicotiana benthamiana induced ethylene production in plants. Ectopic expression of CgNLP1 in Arabidopsis significantly enhanced the resistance to Botrytis cinerea and Alternaria brassicicola. An R2R3 type transcription factor HbMYB8-like of rubber tree was identified as the target of CgNLP1.HbMYB8-like, localized on the nucleus, and induced cell death in N. benthamiana. CgNLP1 disrupted nuclear accumulation of HbMYB8-like and suppressed HbMYB8-like induced cell death, which is mediated by the salicylic acid (SA) signal pathway. This study suggested a new strategy whereby C. gloeosporioides exploited the CgNLP1 effector to affect invasion and suppress a host defense regulator HbMYB8-like to facilitate infection.
Collapse
Affiliation(s)
- Guangyong Yang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
| | - Jie Yang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
| | - Qiwei Zhang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
| | - Wenfeng Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
| | - Liping Feng
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
| | - Li Zhao
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
| | - Bang An
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
| | - Qiannan Wang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
| | - Chaozu He
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
| | - Hongli Luo
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, College of Tropical Corps, Hainan University, Haikou, China
- Hainan Yazhou Bay Seed Laboratory, Sanya Nanfan Research Institute of Hainan University, Sanya, China
- *Correspondence: Hongli Luo
| |
Collapse
|
4
|
SsNEP2 Contributes to the Virulence of Sclerotinia sclerotiorum. Pathogens 2022; 11:pathogens11040446. [PMID: 35456121 PMCID: PMC9026538 DOI: 10.3390/pathogens11040446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/01/2022] [Accepted: 04/05/2022] [Indexed: 01/06/2023] Open
Abstract
Sclerotinia sclerotiorum is a notorious soilborne fungal pathogen that causes serious economic losses globally. The necrosis and ethylene-inducible peptide 1 (NEP1)-like proteins (NLPs) were previously shown to play an important role in pathogenicity in fungal and oomycete pathogens. Here, we generated S. sclerotiorum necrosis and ethylene-inducible peptide 2 (SsNEP2) deletion mutant through homologous recombination and found that SsNEP2 contributes to the virulence of S. sclerotiorum without affecting the development of mycelia, the formation of appressoria, or the secretion of oxalic acid. Although knocking out SsNEP2 did not affect fungal sensitivity to oxidative stress, it did lead to decreased accumulation of reactive oxygen species (ROS) in S. sclerotiorum. Furthermore, Ssnlp24SsNEP2 peptide derived from SsNEP2 triggered host mitogen-activated protein kinase (MAPK) activation, increased defense marker gene expression, and enhanced resistance to Hyaloperonospora arabidopsidis Noco2. Taken together, our data suggest that SsNEP2 is involved in fungal virulence by affecting ROS levels in S. sclerotiorum. It can serve as a pathogen-associated molecular pattern (PAMP) and trigger host pattern triggered immunity to promote the necrotrophic lifestyle of S. sclerotiorum.
Collapse
|
5
|
Gorshkov V, Parfirova O, Petrova O, Gogoleva N, Kovtunov E, Vorob’ev V, Gogolev Y. The Knockout of Enterobactin-Related Gene in Pectobacterium atrosepticum Results in Reduced Stress Resistance and Virulence towards the Primed Plants. Int J Mol Sci 2021; 22:ijms22179594. [PMID: 34502502 PMCID: PMC8431002 DOI: 10.3390/ijms22179594] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 11/16/2022] Open
Abstract
Siderophores produced by microorganisms to scavenge iron from the environment have been shown to contribute to virulence and/or stress resistance of some plant pathogenic bacteria. Phytopathogenic bacteria of Pectobacterium genus possess genes for the synthesis of siderophore enterobactin, which role in plant-pathogen interactions has not been elucidated. In the present study we characterized the phenotype of the mutant strain of Pba deficient for the enterobactin-biosynthetic gene entA. We showed that enterobactin may be considered as a conditionally beneficial virulence factor of Pba. The entA knockout did not reduce Pba virulence on non-primed plants; however, salicylic acid-primed plants were more resistant to ΔentA mutant than to the wild type Pba. The reduced virulence of ΔentA mutant towards the primed plants is likely explained by its compromised resistance to oxidative stress.
Collapse
Affiliation(s)
- Vladimir Gorshkov
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (O.P.); (O.P.); (N.G.); (E.K.); (V.V.); (Y.G.)
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
- Correspondence:
| | - Olga Parfirova
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (O.P.); (O.P.); (N.G.); (E.K.); (V.V.); (Y.G.)
| | - Olga Petrova
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (O.P.); (O.P.); (N.G.); (E.K.); (V.V.); (Y.G.)
| | - Natalia Gogoleva
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (O.P.); (O.P.); (N.G.); (E.K.); (V.V.); (Y.G.)
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
| | - Evgeny Kovtunov
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (O.P.); (O.P.); (N.G.); (E.K.); (V.V.); (Y.G.)
| | - Vladimir Vorob’ev
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (O.P.); (O.P.); (N.G.); (E.K.); (V.V.); (Y.G.)
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
| | - Yuri Gogolev
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (O.P.); (O.P.); (N.G.); (E.K.); (V.V.); (Y.G.)
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia
| |
Collapse
|
6
|
Narváez-Barragán DA, Tovar-Herrera OE, Torres M, Rodríguez M, Humphris S, Toth IK, Segovia L, Serrano M, Martínez-Anaya C. Expansin-like Exl1 from Pectobacterium is a virulence factor required for host infection, and induces a defence plant response involving ROS, and jasmonate, ethylene and salicylic acid signalling pathways in Arabidopsis thaliana. Sci Rep 2020; 10:7747. [PMID: 32385404 PMCID: PMC7210985 DOI: 10.1038/s41598-020-64529-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 04/17/2020] [Indexed: 01/09/2023] Open
Abstract
Expansins are encoded by some phytopathogenic bacteria and evidence indicates that they act as virulence factors for host infection. Here we analysed the expression of exl1 by Pectobacterium brasiliense and Pectobacterium atrosepticum. In both, exl1 gene appears to be under quorum sensing control, and protein Exl1 can be observed in culture medium and during plant infection. Expression of exl1 correlates with pathogen virulence, where symptoms are reduced in a Δexl1 mutant strain of P. atrosepticum. As well as Δexl1 exhibiting less maceration of potato plants, fewer bacteria are observed at distance from the inoculation site. However, bacteria infiltrated into the plant tissue are as virulent as the wild type, suggesting that this is due to alterations in the initial invasion of the tissue. Additionally, swarming from colonies grown on MacConkey soft agar was delayed in the mutant in comparison to the wild type. We found that Exl1 acts on the plant tissue, probably by remodelling of a cell wall component or altering the barrier properties of the cell wall inducing a plant defence response, which results in the production of ROS and the induction of marker genes of the JA, ET and SA signalling pathways in Arabidopsis thaliana. Exl1 inactive mutants fail to trigger such responses. This defence response is protective against Pectobacterium brasiliense and Botrytis cinerea in more than one plant species.
Collapse
Affiliation(s)
- Delia A Narváez-Barragán
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico
| | - Omar E Tovar-Herrera
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico
- Department of Biomolecular Sciences, The Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Martha Torres
- Centro de Ciencias Genómicas. Universidad Nacional Autónoma de México, 62110, Cuernavaca, Morelos, Mexico
| | - Mabel Rodríguez
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico
| | - Sonia Humphris
- The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - Ian K Toth
- The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
| | - Lorenzo Segovia
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico
| | - Mario Serrano
- Centro de Ciencias Genómicas. Universidad Nacional Autónoma de México, 62110, Cuernavaca, Morelos, Mexico
| | - Claudia Martínez-Anaya
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico.
| |
Collapse
|
7
|
Narváez-Barragán DA, de Sandozequi A, Rodríguez M, Estrada K, Tovar-Herrera OE, Martínez-Anaya C. Analysis of two Mexican Pectobacterium brasiliense strains reveals an inverted relationship between c-di-GMP levels with exopolysaccharide production and swarming motility. Microbiol Res 2020; 235:126427. [PMID: 32109688 DOI: 10.1016/j.micres.2020.126427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 02/01/2020] [Accepted: 02/01/2020] [Indexed: 10/25/2022]
Abstract
Pectobacterium is a diverse genus of phytopathogenic species from soil and water that cause infection either to restricted or multiple plant hosts. Phylogenetic analysis and metabolic fingerprinting of large numbers of genomes have expanded classification of Pectobacterium members. Pectobacterium brasiliense sp. nov has been elevated to the species level having detached from P. carotovorum. Here we present two P. brasiliense strains BF20 and BF45 isolated in Mexico from Opuntia and tobacco, respectively, which cluster into two different groups in whole genome comparisons with other Pectobacterium. We found that BF20 and BF45 strains are phenotypically different as BF45 showed more severe and rapid symptoms in comparison to BF20 in the host models celery and broccoli. Both strains produced similar levels of the main autoinducers, but BF45 shows an additional low abundant autoinducer compared to strain BF20. The two strains had different levels of c-di-GMP, which regulates the transition from motile to sessile lifestyle. In contrast to BF45, BF20 had the highest levels of c-di-GMP, was more motile (swarming), non-flocculant and less proficient in biofilm formation and exopolysaccharide production. Genomic comparisons revealed that differences in c-di-GMP accumulation and perhaps the associated phenotypes might be due to unique c-di-GMP metabolic genes in these two strains. Our results improve our understanding of the associations between phenotype and genotype and how this has shaped the physiology of Pectobacterium strains.
Collapse
Affiliation(s)
- Delia A Narváez-Barragán
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, México
| | - Andrés de Sandozequi
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, México
| | - Mabel Rodríguez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, México
| | - Karel Estrada
- Unidad de Secuenciación Masiva y Bioinformática. Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, México
| | - Omar E Tovar-Herrera
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, México
| | - Claudia Martínez-Anaya
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Chamilpa, 62210 Cuernavaca, Morelos, México.
| |
Collapse
|
8
|
Nazar Pour F, Cobos R, Rubio Coque JJ, Serôdio J, Alves A, Félix C, Ferreira V, Esteves AC, Duarte AS. Toxicity of Recombinant Necrosis and Ethylene-Inducing Proteins (NLPs) from Neofusicoccum parvum. Toxins (Basel) 2020; 12:E235. [PMID: 32272814 PMCID: PMC7232490 DOI: 10.3390/toxins12040235] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/28/2020] [Accepted: 04/01/2020] [Indexed: 11/18/2022] Open
Abstract
Neofusicoccum parvum is a fungal pathogen associated with a wide range of plant hosts. Despite being widely studied, the molecular mechanism of infection of N. parvum is still far from being understood. Analysis of N. parvum genome lead to the identification of six putative genes encoding necrosis and ethylene-inducing proteins (NLPs). The sequence of NLPs genes (NprvNep 1-6) were analyzed and four of the six NLP genes were successfully cloned, expressed in E. coli and purified by affinity chromatography. Pure recombinant proteins were characterized according to their phytotoxic and cytotoxic effects to tomato leaves and to mammalian Vero cells, respectively. These assays revealed that all NprvNeps tested are cytotoxic to Vero cells and also induce cell death in tomato leaves. NprvNep2 was the most toxic to Vero cells, followed by NprvNep1 and 3. NprvNep4 induced weaker, but, nevertheless, still significant toxic effects to Vero cells. A similar trend of toxicity was observed in tomato leaves: the most toxic was NprvNep 2 and the least toxic NprvNep 4. This study describes for the first time an overview of the NLP gene family of N. parvum and provides additional insights into its pathogenicity mechanism.
Collapse
Affiliation(s)
- Forough Nazar Pour
- CESAM-Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; (F.N.P.); (J.S.); (A.A.); (C.F.); (V.F.)
| | - Rebeca Cobos
- Instituto de Investigación de la Viña y el Vino (IIVV), Escuela de Ingeniería Agraria, Universidad de León, Avda. Portugal, 41, 24009 León, Spain; (R.C.); (J.J.R.C.)
| | - Juan José Rubio Coque
- Instituto de Investigación de la Viña y el Vino (IIVV), Escuela de Ingeniería Agraria, Universidad de León, Avda. Portugal, 41, 24009 León, Spain; (R.C.); (J.J.R.C.)
| | - João Serôdio
- CESAM-Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; (F.N.P.); (J.S.); (A.A.); (C.F.); (V.F.)
| | - Artur Alves
- CESAM-Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; (F.N.P.); (J.S.); (A.A.); (C.F.); (V.F.)
| | - Carina Félix
- CESAM-Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; (F.N.P.); (J.S.); (A.A.); (C.F.); (V.F.)
| | - Vanessa Ferreira
- CESAM-Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; (F.N.P.); (J.S.); (A.A.); (C.F.); (V.F.)
| | - Ana Cristina Esteves
- Faculty of Dental Medicine, Center for Interdisciplinary Research in Health, Universidade Católica Portuguesa, Estrada da Circunvalação, 3504-505 Viseu, Spain;
| | - Ana Sofia Duarte
- Faculty of Dental Medicine, Center for Interdisciplinary Research in Health, Universidade Católica Portuguesa, Estrada da Circunvalação, 3504-505 Viseu, Spain;
| |
Collapse
|
9
|
Horizontally Acquired Quorum-Sensing Regulators Recruited by the PhoP Regulatory Network Expand the Host Adaptation Repertoire in the Phytopathogen Pectobacterium brasiliense. mSystems 2020; 5:5/1/e00650-19. [PMID: 31992632 PMCID: PMC6989131 DOI: 10.1128/msystems.00650-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In this study, we examine the impact of transcriptional network rearrangements driven by horizontal gene acquisition in PhoP and SlyA regulons using as a case study a phytopathosystem comprised of potato tubers and the soft-rot pathogen Pectobacterium brasiliense 1692 (Pb1692). Genome simulations and statistical analyses uncovered the tendency of PhoP and SlyA networks to mobilize lineage-specific traits predicted as horizontal gene transfer at late infection, highlighting the prominence of regulatory network rearrangements in this stage of infection. The evidence further supports the circumscription of two horizontally acquired quorum-sensing regulators (carR and expR1) by the PhoP network. By recruiting carR and expR1, the PhoP network also impacts certain host adaptation- and bacterial competition-related systems, seemingly in a quorum sensing-dependent manner, such as the type VI secretion system, carbapenem biosynthesis, and plant cell wall-degrading enzymes (PCWDE) like cellulases and pectate lyases. Conversely, polygalacturonases and the type III secretion system (T3SS) exhibit a transcriptional pattern that suggests quorum-sensing-independent regulation by the PhoP network. This includes an uncharacterized novel phage-related gene family within the T3SS gene cluster that has been recently acquired by two Pectobacterium species. The evidence further suggests a PhoP-dependent regulation of carbapenem- and PCWDE-encoding genes based on the synthesized products' optimum pH. The PhoP network also controls slyA expression in planta, which seems to impact carbohydrate metabolism regulation, especially at early infection, when 76.2% of the SlyA-regulated genes from that category also require PhoP to achieve normal expression levels.IMPORTANCE Exchanging genetic material through horizontal transfer is a critical mechanism that drives bacteria to efficiently adapt to host defenses. In this report, we demonstrate that a specific plant-pathogenic species (from the Pectobacterium genus) successfully integrated a population density-based behavior system (quorum sensing) acquired through horizontal transfer into a resident stress-response gene regulatory network controlled by the PhoP protein. Evidence found here underscores that subsets of bacterial weaponry critical for colonization, typically known to respond to quorum sensing, are also controlled by PhoP. Some of these traits include different types of enzymes that can efficiently break down plant cell walls depending on the environmental acidity level. Thus, we hypothesize that PhoP's ability to elicit regulatory responses based on acidity and nutrient availability fluctuations has strongly impacted the fixation of its regulatory connection with quorum sensing. In addition, another global gene regulator, known as SlyA, was found under the PhoP regulatory network. The SlyA regulator controls a series of carbohydrate metabolism-related traits, which also seem to be regulated by PhoP. By centralizing quorum sensing and slyA under PhoP scrutiny, Pectobacterium cells added an advantageous layer of control over those two networks that potentially enhances colonization efficiency.
Collapse
|
10
|
Genome-Wide Analyses Revealed Remarkable Heterogeneity in Pathogenicity Determinants, Antimicrobial Compounds, and CRISPR-Cas Systems of Complex Phytopathogenic Genus Pectobacterium. Pathogens 2019; 8:pathogens8040247. [PMID: 31756888 PMCID: PMC6963963 DOI: 10.3390/pathogens8040247] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/12/2019] [Accepted: 11/18/2019] [Indexed: 02/07/2023] Open
Abstract
The Pectobacterium genus comprises pectolytic enterobacteria defined as the causal agents of soft rot, blackleg, and aerial stem rot diseases of potato and economically important crops. In this study, we undertook extensive genome-wide comparative analyses of twelve species that conform the Pectobacterium genus. Bioinformatics approaches outlined a low nucleotide identity of P. parmentieri and P. wasabiae with other species, while P. carotovorum subsp. odoriferum was shown to harbor numerous pseudogenes, which suggests low coding capacity and genomic degradation. The genome atlases allowed for distinguishing distinct DNA structures and highlighted suspicious high transcription zones. The analyses unveiled a noteworthy heterogeneity in the pathogenicity determinants. Specifically, phytotoxins, polysaccharides, iron uptake systems, and the type secretion systems III-V were observed in just some species. Likewise, a comparison of gene clusters encoding antimicrobial compounds put in evidence for high conservation of carotovoricin, whereas a few species possessed the phenazine, carbapenem, and carocins. Moreover, three clustered regularly interspaced short palindromic repeats-Cas (CRISPR-Cas) systems: I-E, I-F, and III-A were identified. Surrounding some CRISPR-Cas regions, different toxin and antitoxin systems were found, which suggests bacterial suicide in the case of an immune system failure. Multiple whole-genome alignments shed light on to the presence of a novel cellobiose phosphotransferase system (PTS) exclusive to P. parmenteri, and an unreported T5SS conserved in almost all species. Several regions that were associated with virulence, microbe antagonism, and adaptive immune systems were predicted within genomic islands, which underscored the essential role that horizontal gene transfer has imparted in the dynamic evolution and speciation of Pectobacterium species. Overall, the results decipher the different strategies that each species has developed to infect their hosts, outcompete for food resources, and defend against bacteriophages. Our investigation provides novel genetic insights that will assist in understanding the pathogenic lifestyle of Pectobacterium, a genus that jeopardizes the agriculture sustainability of important crops worldwide.
Collapse
|
11
|
Cloning, characterization, in vitro and in planta expression of a necrosis-inducing Phytophthora protein 1 gene npp1 from Phytophthora cinnamomi. Mol Biol Rep 2019; 46:6453-6462. [PMID: 31571106 DOI: 10.1007/s11033-019-05091-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/22/2019] [Indexed: 10/25/2022]
Abstract
The soil-borne oomycete Phytophthora cinnamomi is a highly destructive Phytophthora species associated with the decline of forest. This pathogen secretes a novel class of necrosis-inducing proteins known as Nep1-like proteins (NLPs). In this work, we report the sequencing and molecular characterization of one of these proteins, more specifically the necrosis-inducing Phytophthora protein 1 (NPP1). The ORF of the npp1 gene (EMBL database AM403130) has 768 bp encoding a putative peptide of 256 amino acids with a molecular weight of approximately 25 kD. In order to understand its function, in vitro gene expression was studied during growth in different carbon sources (glucose, cellulose, and sawdust), and at different times of infection, in vivo by RT-qPCR. The highest expression of the npp1 gene occurred in glucose medium followed by sawdust. In vivo infection of Castanea sativa roots with P. cinnamomi revealed a decrease in npp1 expression from 12 to 24 h; at 36 h its expression increased suggesting the existence of a complex mechanism of defense/attack interaction between the pathogen and the host. Expression of recombinant npp1 gene was achieved in Pichia pastoris and assessed by SDS-PAGE analysis of the protein secreted into the culture supernatant, revealing the presence of the NPP1 protein.
Collapse
|
12
|
Seidl MF, Van den Ackerveken G. Activity and Phylogenetics of the Broadly Occurring Family of Microbial Nep1-Like Proteins. ANNUAL REVIEW OF PHYTOPATHOLOGY 2019; 57:367-386. [PMID: 31283435 DOI: 10.1146/annurev-phyto-082718-100054] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Necrosis- and ethylene-inducing peptide 1 (Nep1)-like proteins (NLP) have an extremely broad taxonomic distribution; they occur in bacteria, fungi, and oomycetes. NLPs come in two forms, those that are cytotoxic to eudicot plants and those that are noncytotoxic. Cytotoxic NLPs bind to glycosyl inositol phosphoryl ceramide (GIPC) sphingolipids that are abundant in the outer leaflet of plant plasma membranes. Binding allows the NLP to become cytolytic in eudicots but not monocots. The function of noncytotoxic NLPs remains enigmatic, but the expansion of NLP genes in oomycete genomes suggests they are important. Several plant species have evolved the capacity to recognize NLPs as molecular patterns and trigger plant immunity, e.g., Arabidopsis thaliana detects nlp peptides via the receptor-like protein RLP23. In this review, we provide a historical perspective from discovery to understanding of molecular mechanisms and describe the latest developments in the NLP field to shed light on these fascinating microbial proteins.
Collapse
Affiliation(s)
- Michael F Seidl
- Laboratory of Phytopathology, Wageningen University & Research, 6708 PB Wageningen, The Netherlands
- Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Guido Van den Ackerveken
- Plant-Microbe Interactions, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands;
| |
Collapse
|
13
|
Draft Genome Sequence of Pectobacterium carotovorum subsp. carotovorum ATCC 39048, a Carbapenem-Producing Phytopathogen. Microbiol Resour Announc 2018; 7:MRA00825-18. [PMID: 30533884 PMCID: PMC6256451 DOI: 10.1128/mra.00825-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/01/2018] [Indexed: 11/20/2022] Open
Abstract
Pectobacterium carotovorum subsp. carotovorum ATCC 39048 was originally isolated in the 1980s and studied because it produced the β-lactam antibiotic 1-carbapen-2-em-3-carboxylic acid. Pectobacterium carotovorum subsp. carotovorum ATCC 39048 was originally isolated in the 1980s and studied because it produced the β-lactam antibiotic 1-carbapen-2-em-3-carboxylic acid. The draft genome for this strain was 4,637,928 bp with a G+C content of 51.98%. The genome contained the carbapenem biosynthetic cluster, genes encoding plant virulence determinants, and a single metallo-β-lactamase.
Collapse
|
14
|
Chen XR, Huang SX, Zhang Y, Sheng GL, Li YP, Zhu F. Identification and functional analysis of the NLP-encoding genes from the phytopathogenic oomycete Phytophthora capsici. Mol Genet Genomics 2018; 293:931-943. [PMID: 29572661 DOI: 10.1007/s00438-018-1432-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/21/2018] [Indexed: 10/17/2022]
Abstract
Phytophthora capsici is a hemibiotrophic, phytopathogenic oomycete that infects a wide range of crops, resulting in significant economic losses worldwide. By means of a diverse arsenal of secreted effector proteins, hemibiotrophic pathogens may manipulate plant cell death to establish a successful infection and colonization. In this study, we described the analysis of the gene family encoding necrosis- and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) in P. capsici, and identified 39 real NLP genes and 26 NLP pseudogenes. Out of the 65 predicted NLP genes, 48 occur in groups with two or more genes, whereas the remainder appears to be singletons distributed randomly among the genome. Phylogenetic analysis of the 39 real NLPs delineated three groups. Key residues/motif important for the effector activities are degenerated in most NLPs, including the nlp24 peptide consisting of the conserved region I (11-aa immunogenic part) and conserved region II (the heptapeptide GHRHDWE motif) that is important for phytotoxic activity. Transcriptional profiling of eight selected NLP genes indicated that they were differentially expressed during the developmental and plant infection phases of P. capsici. Functional analysis of ten cloned NLPs demonstrated that Pc11951, Pc107869, Pc109174 and Pc118548 were capable of inducing cell death in the Solanaceae, including Nicotiana benthamiana and hot pepper. This study provides an overview of the P. capsici NLP gene family, laying a foundation for further elucidating the pathogenicity mechanism of this devastating pathogen.
Collapse
Affiliation(s)
- Xiao-Ren Chen
- College of Horticulture and Plant Protection, Yangzhou University, No. 48 Wenhui Eastern Road, Yangzhou, 225009, Jiangsu, China.
| | - Shen-Xin Huang
- College of Horticulture and Plant Protection, Yangzhou University, No. 48 Wenhui Eastern Road, Yangzhou, 225009, Jiangsu, China
| | - Ye Zhang
- College of Horticulture and Plant Protection, Yangzhou University, No. 48 Wenhui Eastern Road, Yangzhou, 225009, Jiangsu, China
| | - Gui-Lin Sheng
- College of Horticulture and Plant Protection, Yangzhou University, No. 48 Wenhui Eastern Road, Yangzhou, 225009, Jiangsu, China
| | - Yan-Peng Li
- College of Horticulture and Plant Protection, Yangzhou University, No. 48 Wenhui Eastern Road, Yangzhou, 225009, Jiangsu, China
| | - Feng Zhu
- College of Horticulture and Plant Protection, Yangzhou University, No. 48 Wenhui Eastern Road, Yangzhou, 225009, Jiangsu, China
| |
Collapse
|
15
|
Garge SS, Nerurkar AS. Evaluation of quorum quenching Bacillus spp. for their biocontrol traits against Pectobacterium carotovorum subsp. carotovorum causing soft rot. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2017. [DOI: 10.1016/j.bcab.2016.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
16
|
Monson R, Smith DS, Matilla MA, Roberts K, Richardson E, Drew A, Williamson N, Ramsay J, Welch M, Salmond GPC. A Plasmid-Transposon Hybrid Mutagenesis System Effective in a Broad Range of Enterobacteria. Front Microbiol 2015; 6:1442. [PMID: 26733980 PMCID: PMC4686594 DOI: 10.3389/fmicb.2015.01442] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 12/03/2015] [Indexed: 11/13/2022] Open
Abstract
Random transposon mutagenesis is a powerful technique used to generate libraries of genetic insertions in many different bacterial strains. Here we develop a system facilitating random transposon mutagenesis in a range of different Gram-negative bacterial strains, including Pectobacterium atrosepticum, Citrobacter rodentium, Serratia sp. ATCC39006, Serratia plymuthica, Dickeya dadantii, and many more. Transposon mutagenesis was optimized in each of these strains and three studies are presented to show the efficacy of this system. Firstly, the important agricultural pathogen D. dadantii was mutagenized. Two mutants that showed reduced protease production and one mutant producing the previously cryptic pigment, indigoidine, were identified and characterized. Secondly, the enterobacterium, Serratia sp. ATCC39006 was mutagenized and mutants incapable of producing gas vesicles, proteinaceous intracellular organelles, were identified. One of these contained a β-galactosidase transcriptional fusion within the gene gvpA1, essential for gas vesicle production. Finally, the system was used to mutate the biosynthetic gene clusters of the antifungal, anti-oomycete and anticancer polyketide, oocydin A, in the plant-associated enterobacterium, Dickeya solani MK10. The mutagenesis system was developed to allow easy identification of transposon insertion sites by sequencing, after facile generation of a replicon encompassing the transposon and adjacent DNA, post-excision. Furthermore, the system can also create transcriptional fusions with either β-galactosidase or β-glucuronidase as reporters, and exploits a variety of drug resistance markers so that multiple selectable fusions can be generated in a single strain. This system of various transposons has wide utility and can be combined in many different ways.
Collapse
Affiliation(s)
- Rita Monson
- Department of Biochemistry, University of Cambridge Cambridge, UK
| | - Debra S Smith
- Department of Biochemistry, University of Cambridge Cambridge, UK
| | - Miguel A Matilla
- Department of Biochemistry, University of Cambridge Cambridge, UK
| | - Kevin Roberts
- Department of Biochemistry, University of Cambridge Cambridge, UK
| | | | - Alison Drew
- Department of Biochemistry, University of Cambridge Cambridge, UK
| | - Neil Williamson
- Department of Biochemistry, University of Cambridge Cambridge, UK
| | - Josh Ramsay
- Department of Biochemistry, University of Cambridge Cambridge, UK
| | - Martin Welch
- Department of Biochemistry, University of Cambridge Cambridge, UK
| | | |
Collapse
|
17
|
Oome S, Van den Ackerveken G. Comparative and functional analysis of the widely occurring family of Nep1-like proteins. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:1081-94. [PMID: 25025781 DOI: 10.1094/mpmi-04-14-0118-r] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Nep1-like proteins (NLP) are best known for their cytotoxic activity in dicot plants. NLP are taxonomically widespread among microbes with very different lifestyles. To learn more about this enigmatic protein family, we analyzed more than 500 available NLP protein sequences from fungi, oomycetes, and bacteria. Phylogenetic clustering showed that, besides the previously documented two types, an additional, more divergent, third NLP type could be distinguished. By closely examining the three NLP types, we identified a noncytotoxic subgroup of type 1 NLP (designated type 1a), which have substitutions in amino acids making up a cation-binding pocket that is required for cytotoxicity. Type 2 NLP were found to contain a putative calcium-binding motif, which was shown to be required for cytotoxicity. Members of both type 1 and type 2 NLP were found to possess additional cysteine residues that, based on their predicted proximity, make up potential disulfide bridges that could provide additional stability to these secreted proteins. Type 1 and type 2 NLP, although both cytotoxic to plant cells, differ in their ability to induce necrosis when artificially targeted to different cellular compartments in planta, suggesting they have different mechanisms of cytotoxicity.
Collapse
|
18
|
Teng W, Zhang H, Wang W, Li D, Wang M, Liu J, Zhang H, Zheng X, Zhang Z. ALY proteins participate in multifaceted Nep1Mo-triggered responses in Nicotiana benthamiana and Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2483-94. [PMID: 24723400 PMCID: PMC4036512 DOI: 10.1093/jxb/eru136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Previously, it was found that Nep1Mo (a Nep1-like protein from Magnaporthe oryzae) could trigger a variety of plant responses, including stomatal closure, hypersensitive cell death (HCD), and defence-related gene expression, in Nicotiana benthamiana. In this study, it was found that Nep1Mo-induced cell death could be inhibited by the virus-induced gene silencing of NbALY916 in N. benthamiana. NbALY916-silenced plants showed impaired Nep1Mo-induced stomatal closure, decreased Nep1Mo-induced production of hydrogen peroxide (H2O2) and nitric oxide (NO) in guard cells, and reduced Nep1Mo-induced resistance against Phytophthora nicotianae. It also found that the deletion of AtALY4, an orthologue of NbALY916 in Arabidopsis thaliana, impaired Nep1Mo-triggered stomatal closure, HCD, and defence-related gene expression. The compromised stomatal closure observed in the NbALY916-silenced plants and AtALY4 mutants was inhibited by the application of H2O2 and sodium nitroprusside (an NO donor), and both Nep1Mo and H2O2 stimulated guard cell NO synthesis. Conversely, NO-induced stomatal closure was found not to require H2O2 synthesis; and NO treatment did not induce H2O2 production in guard cells. Taken together, these results demonstrate that the NbAlY916/AtAlY4-H2O2-NO pathway mediates multiple Nep1Mo-triggered responses, including stomatal closure, HCD, and defence-related gene expression.
Collapse
Affiliation(s)
- Wenjun Teng
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Huajian Zhang
- Department of Plant Pathology, College of Plant Protection, Anhui Agricultural University, Hefei, 230036, China
| | - Wei Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Deqing Li
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Meifang Wang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Jiewen Liu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Haifeng Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Xiaobo Zheng
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, 210095, China
| |
Collapse
|
19
|
Feng BZ, Zhu XP, Fu L, Lv RF, Storey D, Tooley P, Zhang XG. Characterization of necrosis-inducing NLP proteins in Phytophthora capsici. BMC PLANT BIOLOGY 2014; 14:126. [PMID: 24886309 PMCID: PMC4023171 DOI: 10.1186/1471-2229-14-126] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 05/02/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND Effector proteins function not only as toxins to induce plant cell death, but also enable pathogens to suppress or evade plant defense responses. NLP-like proteins are considered to be effector proteins, and they have been isolated from bacteria, fungi, and oomycete plant pathogens. There is increasing evidence that NLPs have the ability to induce cell death and ethylene accumulation in plants. RESULTS We evaluated the expression patterns of 11 targeted PcNLP genes by qRT-PCR at different time points after infection by P. capsici. Several PcNLP genes were strongly expressed at the early stages in the infection process, but the expression of other PcNLP genes gradually increased to a maximum at late stages of infection. The genes PcNLP2, PcNLP6 and PcNLP14 showed the highest expression levels during infection by P. capsici. The necrosis-inducing activity of all targeted PcNLP genes was evaluated using heterologous expression by PVX agroinfection of Capsicum annuum and Nicotiana benthamiana and by Western blot analysis. The members of the PcNLP family can induce chlorosis or necrosis during infection of pepper and tobacco leaves, but the chlorotic or necrotic response caused by PcNLP genes was stronger in pepper leaves than in tobacco leaves. Moreover, PcNLP2, PcNLP6, and PcNLP14 caused the largest chlorotic or necrotic areas in both host plants, indicating that these three genes contribute to strong virulence during infection by P. capsici. This was confirmed through functional evaluation of their silenced transformants. In addition, we further verified that four conserved residues are putatively active sites in PcNLP1 by site-directed mutagenesis. CONCLUSIONS Each targeted PcNLP gene affects cells or tissues differently depending upon the stage of infection. Most PcNLP genes could trigger necrotic or chlorotic responses when expressed in the host C. annuum and the non-host N. benthamiana. Individual PcNLP genes have different phytotoxic effects, and PcNLP2, PcNLP6, and PcNLP14 may play important roles in symptom development and may be crucial for virulence, necrosis-inducing activity, or cell death during infection by P. capsici.
Collapse
Affiliation(s)
- Bao-Zhen Feng
- Department of Plant Pathology, Shandong Agricultural University, 61, Daizong Street, Tai’an, Shandong 271018, China
| | - Xiao-Ping Zhu
- Department of Plant Pathology, Shandong Agricultural University, 61, Daizong Street, Tai’an, Shandong 271018, China
| | - Li Fu
- Department of Plant Pathology, Shandong Agricultural University, 61, Daizong Street, Tai’an, Shandong 271018, China
| | - Rong-Fei Lv
- Department of Plant Pathology, Shandong Agricultural University, 61, Daizong Street, Tai’an, Shandong 271018, China
| | - Dylan Storey
- University of Tennessee, Genome Sciences and Technology, Knoxville, TN, USA
| | - Paul Tooley
- Foreign Disease-Weed Science Research Unit, USDA, ARS, 1301 Ditto Ave., Ft. Detrick, MD 21702-5023, USA
| | - Xiu-Guo Zhang
- Department of Plant Pathology, Shandong Agricultural University, 61, Daizong Street, Tai’an, Shandong 271018, China
| |
Collapse
|
20
|
Zaitseva YV, Popova AA, Khmel IA. Quorum sensing regulation in bacteria of the family enterobacteriaceae. RUSS J GENET+ 2014. [DOI: 10.1134/s1022795414030120] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
|
21
|
Kulkarni PR, Jia T, Kuehne SA, Kerkering TM, Morris ER, Searle MS, Heeb S, Rao J, Kulkarni RV. A sequence-based approach for prediction of CsrA/RsmA targets in bacteria with experimental validation in Pseudomonas aeruginosa. Nucleic Acids Res 2014; 42:6811-25. [PMID: 24782516 PMCID: PMC4066749 DOI: 10.1093/nar/gku309] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
CsrA/RsmA homologs are an extensive family of ribonucleic acid (RNA)-binding proteins that function as global post-transcriptional regulators controlling important cellular processes such as secondary metabolism, motility, biofilm formation and the production and secretion of virulence factors in diverse bacterial species. While direct messenger RNA binding by CsrA/RsmA has been studied in detail for some genes, it is anticipated that there are numerous additional, as yet undiscovered, direct targets that mediate its global regulation. To assist in the discovery of these targets, we propose a sequence-based approach to predict genes directly regulated by these regulators. In this work, we develop a computer code (CSRA_TARGET) implementing this approach, which leads to predictions for several novel targets in Escherichia coli and Pseudomonas aeruginosa. The predicted targets in other bacteria, specifically Salmonella enterica serovar Typhimurium, Pectobacterium carotovorum and Legionella pneumophila, also include global regulators that control virulence in these pathogens, unraveling intricate indirect regulatory roles for CsrA/RsmA. We have experimentally validated four predicted RsmA targets in P. aeruginosa. The sequence-based approach developed in this work can thus lead to several testable predictions for direct targets of CsrA homologs, thereby complementing and accelerating efforts to unravel global regulation by this important family of proteins.
Collapse
Affiliation(s)
- Prajna R Kulkarni
- Department of Physics, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Tao Jia
- Social Cognitive Networks Academic Research Center, and Department of Computer Science, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Sarah A Kuehne
- School of Life Sciences, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Thomas M Kerkering
- Section of Infectious Diseases, Carilion Clinic/Virginia Tech Carilion School of Medicine/Jefferson College of Health Sciences, Roanoke, VA 24013, USA
| | - Elizabeth R Morris
- School of Chemistry, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Mark S Searle
- School of Chemistry, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Stephan Heeb
- School of Life Sciences, Centre for Biomolecular Sciences, University Park, University of Nottingham, Nottingham NG7 2RD, UK
| | - Jayasimha Rao
- Section of Infectious Diseases, Carilion Clinic/Virginia Tech Carilion School of Medicine/Jefferson College of Health Sciences, Roanoke, VA 24013, USA
| | - Rahul V Kulkarni
- Department of Physics, University of Massachusetts Boston, Boston, MA 02125, USA
| |
Collapse
|
22
|
Laasik E, Põllumaa L, Pasanen M, Mattinen L, Pirhonen M, Mäe A. Expression of nipP.w of Pectobacterium wasabiae is dependent on functional flgKL flagellar genes. MICROBIOLOGY (READING, ENGLAND) 2014; 160:179-186. [PMID: 24173527 DOI: 10.1099/mic.0.071092-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
While flagellum-driven motility is hypothesized to play a role in the virulence of Pectobacterium species, there is no direct evidence that genes involved in flagellum assembly regulate the synthesis of virulence factors. The purpose of this study was to identify genes that affect the production or secretion of necrosis-inducing protein (Nip) in the strain SCC3193. Transposon mutagenesis of an RpoS strain overexpressing NipP.w was performed, and a mutant associated with decreased necrosis of tobacco leaves was detected. The mutant contained a transposon in the regulatory region upstream of the flagellar genes flgK and flgL. Additional mutants were generated related to the flagellar genes fliC and fliA. The mutation in flgKL, but not those in fliC and fliA, inhibited nipP.w transcription. Moreover, the regulatory effect of the flgKL mutation on nipP.w transcription was partially dependent on the Rcs phosphorelay. Secretion of NipP.w was also dependent on a type II secretion mechanism. Overall, the results of this study indicate that the flgKL mutation is responsible for reduced motility and lower levels of nipP.w expression.
Collapse
Affiliation(s)
- Eve Laasik
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia Street, Tartu 51010, Estonia
| | - Lee Põllumaa
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia Street, Tartu 51010, Estonia
| | - Miia Pasanen
- Department of Agricultural Sciences, PO Box 27, 00014 University of Helsinki, Finland
| | - Laura Mattinen
- Department of Agricultural Sciences, PO Box 27, 00014 University of Helsinki, Finland
| | - Minna Pirhonen
- Department of Agricultural Sciences, PO Box 27, 00014 University of Helsinki, Finland
| | - Andres Mäe
- Department of Genetics, Institute of Molecular and Cell Biology, University of Tartu, 23 Riia Street, Tartu 51010, Estonia
| |
Collapse
|
23
|
Bowden SD, Eyres A, Chung JCS, Monson RE, Thompson A, Salmond GPC, Spring DR, Welch M. Virulence in Pectobacterium atrosepticum is regulated by a coincidence circuit involving quorum sensing and the stress alarmone, (p)ppGpp. Mol Microbiol 2013; 90:457-71. [PMID: 23957692 DOI: 10.1111/mmi.12369] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2013] [Indexed: 12/19/2022]
Abstract
Pectobacterium atrosepticum (Pca) is a Gram-negative phytopathogen which causes disease by secreting plant cell wall degrading exoenzymes (PCWDEs). Previous studies have shown that PCWDE production is regulated by (i) the intercellular quorum sensing (QS) signal molecule, 3-oxo-hexanoyl-l-homoserine lactone (OHHL), and (ii) the intracellular 'alarmone', (p)ppGpp, which reports on nutrient limitation. Here we show that these two signals form an integrated coincidence circuit which ensures that metabolically costly PCWDE synthesis does not occur unless the population is simultaneously quorate and nutrient limited. A (p)ppGpp null ΔrelAΔspoT mutant was defective in both OHHL and PCWDE production, and nutritional supplementation of wild type cultures (which suppresses (p)ppGpp production) also suppressed OHHL and PCWDE production. There was a substantial overlap in the transcriptome of a (p)ppGpp deficient relA mutant and of a QS defective expI (OHHL synthase) mutant, especially with regards to virulence-associated genes. Random transposon mutagenesis revealed that disruption of rsmA was sufficient to restore PCWDE production in the (p)ppGpp null strain. We found that the ratio of RsmA protein to its RNA antagonist, rsmB, was modulated independently by (p)ppGpp and QS. While QS predominantly controlled virulence by modulating RsmA levels, (p)ppGpp exerted regulation through the modulation of the RsmA antagonist, rsmB.
Collapse
Affiliation(s)
- Steven D Bowden
- Department of Biochemistry, University of Cambridge, Building O, Downing Site, Cambridge, CB2 1QW, UK
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Varani AM, Monteiro-Vitorello CB, Nakaya HI, Van Sluys MA. The role of prophage in plant-pathogenic bacteria. ANNUAL REVIEW OF PHYTOPATHOLOGY 2013; 51:429-451. [PMID: 23725471 DOI: 10.1146/annurev-phyto-081211-173010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A diverse set of phage lineages is associated with the bacterial plant-pathogen genomes sequenced to date. Analysis of 37 genomes revealed 5,169 potential genes (approximately 4.3 Mbp) of phage origin, and at least 50% had no function assigned or are nonessential to phage biology. Some phytopathogens have transcriptionally active prophage genes under conditions that mimic plant infection, suggesting an association between plant disease and prophage transcriptional modulation. The role of prophages within genomes for cell biology varies. For pathogens such as Pectobacterium, Pseudomonas, Ralstonia, and Streptomyces, involvement of prophage in disease symptoms has been demonstrated. In Xylella and Xanthomonas, prophage activity is associated with genome rearrangements and strain differentiation. For other pathogens, prophage roles are yet to be established. This review integrates available information in a unique interface ( http://propnav.esalq.usp.br ) that may be assessed to improve research in prophage biology and its association with genome evolution and pathogenicity.
Collapse
Affiliation(s)
- Alessandro M Varani
- Departamento de Genética (LGN), Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, 13418-900 Piracicaba/SP, Brazil
| | | | | | | |
Collapse
|
25
|
Santhanam P, van Esse HP, Albert I, Faino L, Nürnberger T, Thomma BPHJ. Evidence for functional diversification within a fungal NEP1-like protein family. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:278-86. [PMID: 23051172 DOI: 10.1094/mpmi-09-12-0222-r] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this study, we functionally analyzed the gene family encoding necrosis- and ethylene-inducing-like proteins (NLP) of the vascular wilt pathogen Verticillium dahliae. We show that the composition of the NLP gene family varies little among V. dahliae isolates. The cytotoxic activity of NLP family members of a tomato-pathogenic V. dahliae strain was determined, demonstrating that only two of the seven NLP induced plant cell death. The genes encoding these cytotoxic NLP were found to be induced in V. dahliae upon colonization of tomato. Interestingly, targeted deletion of either of the two genes in V. dahliae significantly compromised virulence on tomato as well as on Arabidopsis plants, whereas deletion of only one of the two genes affected virulence on Nicotiana benthamiana. This could be attributed to differential induction of the two NLP genes in V. dahliae upon N. benthamiana colonization, revealing that the in planta induction of NLP genes varies between plant hosts. Intriguingly, one of the NLP genes appears to also affect vegetative growth and conidiospore production, because the corresponding deletion strain produced significantly fewer conidiospores and developed extensive aerial mycelium. In conclusion, we demonstrate that the expanded V. dahliae NLP family shows functional diversification, revealing not only differential cytotoxicity between family members but also that the cytotoxic NLP play a role in vegetative growth and asexual reproduction in addition to their contribution to virulence.
Collapse
|
26
|
Kwan G, Charkowski AO, Barak JD. Salmonella enterica suppresses Pectobacterium carotovorum subsp. carotovorum population and soft rot progression by acidifying the microaerophilic environment. mBio 2013; 4:e00557-12. [PMID: 23404399 PMCID: PMC3573663 DOI: 10.1128/mbio.00557-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/11/2013] [Indexed: 12/02/2022] Open
Abstract
UNLABELLED Although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. Plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. To characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between Pectobacterium carotovorum subsp. carotovorum and Salmonella enterica or Escherichia coli O157:H7 with regard to bacterial populations, soft rot progression, and changes in local pH. The presence of P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7 on leaves. However, in a microaerophilic environment, S. enterica reduced P. carotovorum subsp. carotovorum populations and soft rot progression by moderating local environmental pH. Reduced soft rot was not due to S. enterica proteolytic activity. Limitations on P. carotovorum subsp. carotovorum growth, disease progression, and pH elevation were not observed on leaves coinoculated with E. coli O157:H7 or when leaves were coinoculated with S. enterica in an aerobic environment. S. enterica also severely undermined the relationship between the phytobacterial population and disease progression of a P. carotovorum subsp. carotovorum budB mutant defective in the 2,3-butanediol pathway for acid neutralization. Our results show that S. enterica and E. coli O157:H7 interact differently with the enteric phytobacterial pathogen P. carotovorum subsp. carotovorum. S. enterica inhibition of soft rot progression may conceal a rapidly growing human pathogen population. Whereas soft rotted produce can alert consumers to the possibility of food-borne pathogens, healthy-looking produce may entice consumption of contaminated vegetables. IMPORTANCE Salmonella enterica and Escherichia coli O157:H7 may use plants to move between animal and human hosts. Their populations are higher on plants cocolonized with the common bacterial soft rot pathogen Pectobacterium carotovorum subsp. carotovorum, turning edible plants into a risk factor for human disease. We inoculated leaves with P. carotovorum subsp. carotovorum and S. enterica or E. coli O157:H7 to study the interactions between these bacteria. While P. carotovorum subsp. carotovorum enhanced the growth of both S. enterica and E. coli O157:H7, these human pathogens affected P. carotovorum subsp. carotovorum fundamentally differently. S. enterica reduced P. carotovorum subsp. carotovorum growth and acidified the environment, leading to less soft rot on leaves; E. coli O157:H7 had no such effects. As soft rot signals a food safety risk, the reduction of soft rot symptoms in the presence of S. enterica may lead consumers to eat healthy-looking but S. enterica-contaminated produce.
Collapse
Affiliation(s)
- Grace Kwan
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | | | | |
Collapse
|
27
|
Zhang H, Li D, Wang M, Liu J, Teng W, Cheng B, Huang Q, Wang M, Song W, Dong S, Zheng X, Zhang Z. The Nicotiana benthamiana mitogen-activated protein kinase cascade and WRKY transcription factor participate in Nep1(Mo)-triggered plant responses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:1639-53. [PMID: 22835275 DOI: 10.1094/mpmi-11-11-0293] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Many bacterial, fungal, and oomycete species secrete necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLP) that trigger programmed cell death (PCD) and innate immune responses in dicotyledonous plants. However, how NLP induce such immune responses is not understood. Here, we show that silencing of the MAPKKKα-MEK2-WIPK mitogen-activated protein kinase (MAPK) cascade through virus-induced gene silencing compromises hydrogen peroxide accumulation and PCD induced by Nep1(Mo) from Magnaporthe oryzae. WIPK interacts with NbWRKY2, a transcription factor in Nicotiana benthamiana, in vitro and in vivo, suggesting an effector pathway that mediates Nep1(Mo)-induced cell death. Unexpectedly, salicylic acid-induced protein kinase (SIPK)- and NbWRKY2-silenced plants showed impaired Nep1(Mo)-induced stomatal closure, decreased Nep1(Mo)-promoted nitric oxide (NO) production in guard cells, and a reduction in Nep1(Mo)-induced resistance against Phytophthora nicotianae. Expression studies by real-time polymerase chain reaction suggested that the MEK2-WIPK-NbWRKY2 pathway regulated Nep1(Mo)triggered NO accumulation could be partly dependent on nitrate reductase, which was implicated in NO synthesis. Taken together, these studies demonstrate that the MAPK cascade is involved in Nep1(Mo)-triggered plant responses and MAPK signaling associated with PCD exhibits shared and distinct components with that for stomatal closure.
Collapse
Affiliation(s)
- Huajian Zhang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Nykyri J, Niemi O, Koskinen P, Nokso-Koivisto J, Pasanen M, Broberg M, Plyusnin I, Törönen P, Holm L, Pirhonen M, Palva ET. Revised phylogeny and novel horizontally acquired virulence determinants of the model soft rot phytopathogen Pectobacterium wasabiae SCC3193. PLoS Pathog 2012; 8:e1003013. [PMID: 23133391 PMCID: PMC3486870 DOI: 10.1371/journal.ppat.1003013] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 09/18/2012] [Indexed: 11/19/2022] Open
Abstract
Soft rot disease is economically one of the most devastating bacterial diseases affecting plants worldwide. In this study, we present novel insights into the phylogeny and virulence of the soft rot model Pectobacterium sp. SCC3193, which was isolated from a diseased potato stem in Finland in the early 1980s. Genomic approaches, including proteome and genome comparisons of all sequenced soft rot bacteria, revealed that SCC3193, previously included in the species Pectobacterium carotovorum, can now be more accurately classified as Pectobacterium wasabiae. Together with the recently revised phylogeny of a few P. carotovorum strains and an increasing number of studies on P. wasabiae, our work indicates that P. wasabiae has been unnoticed but present in potato fields worldwide. A combination of genomic approaches and in planta experiments identified features that separate SCC3193 and other P. wasabiae strains from the rest of soft rot bacteria, such as the absence of a type III secretion system that contributes to virulence of other soft rot species. Experimentally established virulence determinants include the putative transcriptional regulator SirB, two partially redundant type VI secretion systems and two horizontally acquired clusters (Vic1 and Vic2), which contain predicted virulence genes. Genome comparison also revealed other interesting traits that may be related to life in planta or other specific environmental conditions. These traits include a predicted benzoic acid/salicylic acid carboxyl methyltransferase of eukaryotic origin. The novelties found in this work indicate that soft rot bacteria have a reservoir of unknown traits that may be utilized in the poorly understood latent stage in planta. The genomic approaches and the comparison of the model strain SCC3193 to other sequenced Pectobacterium strains, including the type strain of P. wasabiae, provides a solid basis for further investigation of the virulence, distribution and phylogeny of soft rot bacteria and, potentially, other bacteria as well.
Collapse
Affiliation(s)
- Johanna Nykyri
- Department of Agricultural Sciences, Plant Pathology, University of Helsinki, Helsinki, Finland
| | - Outi Niemi
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | - Patrik Koskinen
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | | | - Miia Pasanen
- Department of Agricultural Sciences, Plant Pathology, University of Helsinki, Helsinki, Finland
| | - Martin Broberg
- Department of Agricultural Sciences, Plant Pathology, University of Helsinki, Helsinki, Finland
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | - Ilja Plyusnin
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Petri Törönen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Liisa Holm
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Minna Pirhonen
- Department of Agricultural Sciences, Plant Pathology, University of Helsinki, Helsinki, Finland
| | - E. Tapio Palva
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| |
Collapse
|
29
|
de Oliveira GAP, Pereira EG, Dias CV, Souza TLF, Ferretti GDS, Cordeiro Y, Camillo LR, Cascardo J, Almeida FC, Valente AP, Silva JL. Moniliophthora perniciosa necrosis- and ethylene-inducing protein 2 (MpNep2) as a metastable dimer in solution: structural and functional implications. PLoS One 2012; 7:e45620. [PMID: 23029140 PMCID: PMC3454426 DOI: 10.1371/journal.pone.0045620] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/21/2012] [Indexed: 11/18/2022] Open
Abstract
Understanding how Nep-like proteins (NLPs) behave during the cell cycle and disease progression of plant pathogenic oomycetes, fungi and bacteria is crucial in light of compelling evidence that these proteins play a role in Witches` Broom Disease (WBD) of Theobroma cacao, one of the most important phytopathological problems to afflict the Southern Hemisphere. The crystal structure of MpNep2, a member of the NLP family and the causal agent of WBD, revealed the key elements for its activity. This protein has the ability to refold after heating and was believed to act as a monomer in solution, in contrast to the related homologs MpNep1 and NPP from the oomyceteous fungus Phytophthora parasitica. Here, we identify and characterize a metastable MpNep2 dimer upon over-expression in Escherichia coli using different biochemical and structural approaches. We found using ultra-fast liquid chromatography that the MpNep2 dimer can be dissociated by heating but not by dilution, oxidation or high ionic strength. Small-angle X-ray scattering revealed a possible tail-to-tail interaction between monomers, and nuclear magnetic resonance measurements identified perturbed residues involved in the putative interface of interaction. We also explored the ability of the MpNep2 monomer to refold after heating or chemical denaturation. We observed that MpNep2 has a low stability and cooperative fold that could be an explanation for its structure and activity recovery after stress. These results can provide new insights into the mechanism for MpNep2's action in dicot plants during the progression of WBD and may open new avenues for the involvement of NLP- oligomeric species in phytopathological disorders.
Collapse
Affiliation(s)
- Guilherme A. P. de Oliveira
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Instituto Nacional de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Elen G. Pereira
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Instituto Nacional de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Cristiano V. Dias
- Laboratório de Proteômica, Centro de Biotecnologia e Genética, Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil
- Mars Center For Cocoa Science, Itajuípe, Bahia, Brazil
| | - Theo L. F. Souza
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Giulia D. S. Ferretti
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Instituto Nacional de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Yraima Cordeiro
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luciana R. Camillo
- Laboratório de Proteômica, Centro de Biotecnologia e Genética, Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil
| | - Júlio Cascardo
- Laboratório de Proteômica, Centro de Biotecnologia e Genética, Universidade Estadual de Santa Cruz, Ilhéus, Bahia, Brazil
| | - Fabio C. Almeida
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Instituto Nacional de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Paula Valente
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Instituto Nacional de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jerson L. Silva
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica, Instituto Nacional de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| |
Collapse
|
30
|
Monson R, Burr T, Carlton T, Liu H, Hedley P, Toth I, Salmond GP. Identification of genes in the VirR regulon ofPectobacterium atrosepticumand characterization of their roles in quorum sensing-dependent virulence. Environ Microbiol 2012; 15:687-701. [DOI: 10.1111/j.1462-2920.2012.02822.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
31
|
Zhou BJ, Jia PS, Gao F, Guo HS. Molecular characterization and functional analysis of a necrosis- and ethylene-inducing, protein-encoding gene family from Verticillium dahliae. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:964-75. [PMID: 22414440 DOI: 10.1094/mpmi-12-11-0319] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Verticillium dahliae Kleb. is a hemibiotrophic, phytopathogenic fungus that causes wilt disease in a wide range of crops, including cotton. Successful host colonization by hemibiotrophic pathogens requires the induction of plant cell death to provide the saprophytic nutrition for the transition from the biotrophic to the necrotrophic stage. In this study, we identified a necrosis-inducing Phytophthora protein (NPP1) domain-containing protein family containing nine genes in a virulent, defoliating isolate of V. dahliae (V592), named the VdNLP genes. Functional analysis demonstrated that only two of these VdNLP genes, VdNLP1 and VdNLP2, encoded proteins that were capable of inducing necrotic lesions and triggering defense responses in Nicotiana benthamiana, Arabidopsis, and cotton plants. Both VdNLP1 and VdNLP2 induced the wilting of cotton seedling cotyledons. However, gene-deletion mutants targeted by VdNLP1, VdNLP2, or both did not affect the pathogenicity of V. dahliae V592 in cotton infection. Similar expression and induction patterns were found for seven of the nine VdNLP transcripts. Through a comparison of the conserved amino acid residues of VdNLP with different necrosis-inducing activities, combined with mutagenesis-based analyses, we identified several novel conserved amino acid residues, in addition to the known conserved heptapeptide GHRHDWE motif and the cysteine residues of the NPP domain-containing protein, that are indispensable for the necrosis-inducing activity of the VdNLP2 protein.
Collapse
Affiliation(s)
- Bang-Jun Zhou
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | | | | | | |
Collapse
|
32
|
Dong S, Kong G, Qutob D, Yu X, Tang J, Kang J, Dai T, Wang H, Gijzen M, Wang Y. The NLP toxin family in Phytophthora sojae includes rapidly evolving groups that lack necrosis-inducing activity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:896-909. [PMID: 22397404 DOI: 10.1094/mpmi-01-12-0023-r] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Necrosis- and ethylene-inducing-like proteins (NLP) are widely distributed in eukaryotic and prokaryotic plant pathogens and are considered to be important virulence factors. We identified, in total, 70 potential Phytophthora sojae NLP genes but 37 were designated as pseudogenes. Sequence alignment of the remaining 33 NLP delineated six groups. Three of these groups include proteins with an intact heptapeptide (Gly-His-Arg-His-Asp-Trp-Glu) motif, which is important for necrosis-inducing activity, whereas the motif is not conserved in the other groups. In total, 19 representative NLP genes were assessed for necrosis-inducing activity by heterologous expression in Nicotiana benthamiana. Surprisingly, only eight genes triggered cell death. The expression of the NLP genes in P. sojae was examined, distinguishing 20 expressed and 13 nonexpressed NLP genes. Real-time reverse-transcriptase polymerase chain reaction results indicate that most NLP are highly expressed during cyst germination and infection stages. Amino acid substitution ratios (Ka/Ks) of 33 NLP sequences from four different P. sojae strains resulted in identification of positive selection sites in a distinct NLP group. Overall, our study indicates that expansion and pseudogenization of the P. sojae NLP family results from an ongoing birth-and-death process, and that varying patterns of expression, necrosis-inducing activity, and positive selection suggest that NLP have diversified in function.
Collapse
Affiliation(s)
- Suomeng Dong
- College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Quorum sensing and expression of virulence in pectobacteria. SENSORS 2012; 12:3327-49. [PMID: 22737011 PMCID: PMC3376562 DOI: 10.3390/s120303327] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 02/21/2012] [Accepted: 03/02/2012] [Indexed: 01/23/2023]
Abstract
Quorum sensing (QS) is a population density-dependent regulatory mechanism in which gene expression is coupled to the accumulation of a chemical signaling molecule. QS systems are widespread among the plant soft-rotting bacteria. In Pectobacterium carotovorum, at least two QS systems exist being specified by the nature of chemical signals involved. QS in Pectobacterium carotovorum uses N-acylhomoserine lactone (AHL) based, as well as autoinducer-2 (AI-2) dependent signaling systems. This review will address the importance of the QS in production of virulence factors and interaction of QS with other regulatory systems in Pectobacterium carotovorum.
Collapse
|
34
|
Charkowski A, Blanco C, Condemine G, Expert D, Franza T, Hayes C, Hugouvieux-Cotte-Pattat N, López Solanilla E, Low D, Moleleki L, Pirhonen M, Pitman A, Perna N, Reverchon S, Rodríguez Palenzuela P, San Francisco M, Toth I, Tsuyumu S, van der Waals J, van der Wolf J, Van Gijsegem F, Yang CH, Yedidia I. The role of secretion systems and small molecules in soft-rot Enterobacteriaceae pathogenicity. ANNUAL REVIEW OF PHYTOPATHOLOGY 2012; 50:425-49. [PMID: 22702350 DOI: 10.1146/annurev-phyto-081211-173013] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Soft-rot Enterobacteriaceae (SRE), which belong to the genera Pectobacterium and Dickeya, consist mainly of broad host-range pathogens that cause wilt, rot, and blackleg diseases on a wide range of plants. They are found in plants, insects, soil, and water in agricultural regions worldwide. SRE encode all six known protein secretion systems present in gram-negative bacteria, and these systems are involved in attacking host plants and competing bacteria. They also produce and detect multiple types of small molecules to coordinate pathogenesis, modify the plant environment, attack competing microbes, and perhaps to attract insect vectors. This review integrates new information about the role protein secretion and detection and production of ions and small molecules play in soft-rot pathogenicity.
Collapse
Affiliation(s)
- Amy Charkowski
- Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin 53706, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Silent mischief: bacteriophage Mu insertions contaminate products of Escherichia coli random mutagenesis performed using suicidal transposon delivery plasmids mobilized by broad-host-range RP4 conjugative machinery. J Bacteriol 2010; 192:6418-27. [PMID: 20935093 DOI: 10.1128/jb.00621-10] [Citation(s) in RCA: 198] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Random transposon mutagenesis is the strategy of choice for associating a phenotype with its unknown genetic determinants. It is generally performed by mobilization of a conditionally replicating vector delivering transposons to recipient cells using broad-host-range RP4 conjugative machinery carried by the donor strain. In the present study, we demonstrate that bacteriophage Mu, which was deliberately introduced during the original construction of the widely used donor strains SM10 λpir and S17-1 λpir, is silently transferred to Escherichia coli recipient cells at high frequency, both by hfr and by release of Mu particles by the donor strain. Our findings suggest that bacteriophage Mu could have contaminated many random-mutagenesis experiments performed on Mu-sensitive species with these popular donor strains, leading to potential misinterpretation of the transposon mutant phenotype and therefore perturbing analysis of mutant screens. To circumvent this problem, we precisely mapped Mu insertions in SM10 λpir and S17-1 λpir and constructed a new Mu-free donor strain, MFDpir, harboring stable hfr-deficient RP4 conjugative functions and sustaining replication of Π-dependent suicide vectors. This strain can therefore be used with most of the available transposon-delivering plasmids and should enable more efficient and easy-to-analyze mutant hunts in E. coli and other Mu-sensitive RP4 host bacteria.
Collapse
|
36
|
Terta M, Kettani-Halabi M, Ibenyassine K, Tran D, Meimoun P, M'hand RA, El-Maarouf-Bouteau H, Val F, Ennaji MM, Bouteau F. Arabidopsis thaliana cells: a model to evaluate the virulence of Pectobacterium carotovorum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:139-43. [PMID: 20064057 DOI: 10.1094/mpmi-23-2-0139] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Pectobacterium carotovorum are economically important plant pathogens that cause plant soft rot. These enterobacteria display high diversity world-wide. Their pathogenesis depends on production and secretion of virulence factors such as plant cell wall-degrading enzymes, type III effectors, a necrosis-inducing protein, and a secreted virulence factor from Xanthomonas spp., which are tightly regulated by quorum sensing. Pectobacterium carotovorum also present pathogen-associated molecular patterns that could participate in their pathogenicity. In this study, by using suspension cells of Arabidopsis thaliana, we correlate plant cell death and pectate lyase activities during coinfection with different P. carotovorum strains. When comparing soft rot symptoms induced on potato slices with pectate lyase activities and plant cell death observed during coculture with Arabidopsis thaliana cells, the order of strain virulence was found to be the same. Therefore, Arabidopsis thaliana cells could be an alternative tool to evaluate rapidly and efficiently the virulence of different P. carotovorum strains.
Collapse
Affiliation(s)
- Meriam Terta
- LEM-EA3514-Universite Paris Diderot-Paris 7, 2 place Jussieu, 75251 Paris cedex 05, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Evans TJ, Coulthurst SJ, Komitopoulou E, Salmond GPC. Two mobile Pectobacterium atrosepticum prophages modulate virulence. FEMS Microbiol Lett 2010; 304:195-202. [PMID: 20146746 DOI: 10.1111/j.1574-6968.2010.01901.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The Pectobacterium atrosepticum strain SCRI1043 genome contains two complete prophage sequences. One, ECA41, is Mu-like and is able to integrate into, and excise from, various genomic locations. The other, ECA29, is a P2 family prophage, and is also able to excise from the genome. Excision of both prophages is rare and we were unable to induce lysis of cultures. Deletion of the entire prophages, both separately and in combination, did not affect the growth rate or the secretion of plant cell wall-degrading enzymes, but swimming motility was decreased. The virulence of prophage deletion strains in the potato host was decreased.
Collapse
Affiliation(s)
- Terry J Evans
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | | | | |
Collapse
|
38
|
Hein I, Gilroy EM, Armstrong MR, Birch PRJ. The zig-zag-zig in oomycete-plant interactions. MOLECULAR PLANT PATHOLOGY 2009; 10:547-62. [PMID: 19523107 PMCID: PMC6640229 DOI: 10.1111/j.1364-3703.2009.00547.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
In addition to a range of preformed barriers, plants defend themselves against microbial invasion by detecting conserved, secreted molecules, called pathogen-associated molecular patterns (PAMPs). PAMP-triggered immunity (PTI) is the first inducible layer of plant defence that microbial pathogens must navigate by the delivery of effector proteins that act to suppress or otherwise manipulate key components of resistance. Effectors may themselves be targeted by a further layer of defence, effector-triggered immunity (ETI), as their presence inside or outside host cells may be detected by resistance proteins. This 'zig-zag-zig' of tightly co-evolving molecular interactions determines the outcome of attempted infection. In this article, we consider the complex molecular interplay between plants and plant pathogenic oomycetes, drawing on recent literature to illustrate what is known about oomycete PAMPs and elicitors of defence responses, the effectors they utilize to suppress PTI, and the phenomenal molecular 'battle' between effector and resistance (R) genes that dictates the establishment or evasion of ETI.
Collapse
Affiliation(s)
- Ingo Hein
- Scottish Crop Research Institute, Invergowrie, Dundee, UK
| | | | | | | |
Collapse
|
39
|
Motteram J, Küfner I, Deller S, Brunner F, Hammond-Kosack KE, Nürnberger T, Rudd JJ. Molecular characterization and functional analysis of MgNLP, the sole NPP1 domain-containing protein, from the fungal wheat leaf pathogen Mycosphaerella graminicola. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:790-9. [PMID: 19522561 DOI: 10.1094/mpmi-22-7-0790] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Analysis of the fully sequenced genome of the wheat leaf-specific fungal pathogen Mycosphaerella graminicola identified only a single gene encoding a member of the necrosis- and ethylene-inducing peptide 1 (Nep1)-like protein family (NLP). NLP proteins have frequently been shown to trigger cell death and the activation of defense signaling reactions in dicotyledonous plants. However, complete loss-of-function reverse genetics analyses for their importance in the virulence of eukaryotic plant pathogens are generally lacking. Real-time quantitative polymerase chain reaction on MgNLP demonstrated the gene to be specifically expressed in planta. Peak expression was observed during the immediate presymptomatic phase of colonization of a susceptible host genotype. This was followed by a dramatic decrease during disease lesion formation which, in this system, exhibits characteristics of host programmed cell death (PCD). No comparable peak in transcript levels was seen during an incompatible interaction with a host genotype exhibiting gene-for-gene-based disease resistance. Heterologously expressed MgNLP protein induced necrotic cell death and the activation of defense-related genes when infiltrated into Arabidopsis leaves but not in leaves of a susceptible wheat genotype. MgNLP infiltration also failed to stimulate wheat mitogen-activated protein kinase activities. Finally, targeted deletion of M. graminicola MgNLP caused no detectable reduction in plant pathogenicity or virulence, suggesting that this protein is not a major virulence determinant during fungal infection of its host plant. To our knowledge, this represents the first complete loss-of-function analysis of NLP in a eukaryotic plant pathogen and we discuss our findings in the context of possible functions for NLP in pathogens which only infect monocotyledonous plants.
Collapse
Affiliation(s)
- Juliet Motteram
- Centre for Sustainable Pest and Disease Management, Department of Plant Pathology and Microbiology, Rothamsted Research, Harpenden, Herts, UK
| | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
Many plant pathogens secrete toxins that enhance microbial virulence by killing host cells. Usually, these toxins are produced by particular microbial taxa, such as bacteria or fungi. In contrast, many bacterial, fungal and oomycete species produce necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLPs) that trigger leaf necrosis and immunity-associated responses in various plants. We have determined the crystal structure of an NLP from the phytopathogenic oomycete Pythium aphanidermatum to 1.35A resolution. The protein fold exhibits structural similarities to cytolytic toxins produced by marine organisms (actinoporins). Computational modeling of the 3-dimensional structure of NLPs from another oomycete, Phytophthora parasitica, and from the phytopathogenic bacterium, Pectobacterium carotovorum, revealed a high extent of fold conservation. Expression of the 2 oomycete NLPs in an nlp-deficient P. carotovorum strain restored bacterial virulence, suggesting that NLPs of prokaryotic and eukaryotic origins are orthologous proteins. NLP mutant protein analyses revealed that identical structural properties were required to cause plasma membrane permeabilization and cytolysis in plant cells, as well as to restore bacterial virulence. In sum, NLPs are conserved virulence factors whose taxonomic distribution is exceptional for microbial phytotoxins, and that contribute to host infection by plasma membrane destruction and cytolysis. We further show that NLP-mediated phytotoxicity and plant defense gene expression share identical fold requirements, suggesting that toxin-mediated interference with host integrity triggers plant immunity-associated responses. Phytotoxin-induced cellular damage-associated activation of plant defenses is reminiscent of microbial toxin-induced inflammasome activation in vertebrates and may thus constitute another conserved element in animal and plant innate immunity.
Collapse
|
41
|
Fungal LysM effectors: extinguishers of host immunity? Trends Microbiol 2009; 17:151-7. [PMID: 19299132 DOI: 10.1016/j.tim.2009.01.002] [Citation(s) in RCA: 158] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 12/20/2008] [Accepted: 01/15/2009] [Indexed: 01/19/2023]
Abstract
Lysin motifs (LysMs) have been recognized in prokaryotes and plants as carbohydrate-binding protein modules. Recently, a novel virulence factor with LysMs was characterized from the plant pathogenic fungus Cladosporium fulvum. Here, we present a survey of public sequence data of 70 fungal species to demonstrate that putatively secreted LysM-containing proteins are widespread in the fungal kingdom, as they are found in mammalian and plant pathogenic species, in addition to saprophytes. We propose that these putative LysM effectors might have a role in sequestration of chitin oligosaccharides - breakdown products of fungal cell walls that are released during invasion and act as triggers of host immunity - to dampen host defence.
Collapse
|
42
|
McClean AE, Kluepfel DA. Genetic loci involved in rubrifacine production in the walnut pathogen Brenneria rubrifaciens. PHYTOPATHOLOGY 2009; 99:145-151. [PMID: 19159306 DOI: 10.1094/phyto-99-2-0145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Brenneria rubrifaciens produces a unique red pigment known as rubrifacine that has been hypothesized to play a role in pathogenesis on walnut. Analysis of DNA flanking the Tn5 insertion site in 20 rubrifacine minus (pig(-)) mutants identified three regions required for rubrifacine production. The first region was homologous to nonribosomal peptide synthetases (NRPS), the second was homologous to autoinducer synthase genes (expI homologs), and the third region was homologous to the slyA gene of Candidatus blochmania and Escherichia coli. Pigment production was not necessary for elicitation of the hypersensitive response (HR) in tobacco and had little impact on virulence in tissue-cultured walnut plants. The expI-interrupted mutants exhibited reduced virulence on walnut and were HR negative on tobacco. Pigment production was restored in Br-212 when grown in the presence of wild-type B. rubrifaciens, E. coli carrying the cloned expI-like gene, or introduction of the cloned wild-type copy of the expI-like gene. Two Brenneria spp., B. nigrifluens and B. salicis, also restored pigment production in Br-212. These results demonstrate that rubrifacine production and virulence of B. rubrifaciens on walnut are under the control of a quorum-sensing system and are sensitive to signal molecules from other Brenneria spp.
Collapse
Affiliation(s)
- Ali E McClean
- Crops Pathology and Genetics Research Unit, United States Department of Agriculture-Agricultural Research Service, 259 Hutchison Hall, USA
| | | |
Collapse
|
43
|
Valverde C, Haas D. Small RNAs Controlled by Two-Component Systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 631:54-79. [DOI: 10.1007/978-0-387-78885-2_5] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
44
|
PecS is a global regulator of the symptomatic phase in the phytopathogenic bacterium Erwinia chrysanthemi 3937. J Bacteriol 2008; 190:7508-22. [PMID: 18790868 DOI: 10.1128/jb.00553-08] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Pathogenicity of the enterobacterium Erwinia chrysanthemi (Dickeya dadantii), the causative agent of soft-rot disease in many plants, is a complex process involving several factors whose production is subject to temporal regulation during infection. PecS is a transcriptional regulator that controls production of various virulence factors. Here, we used microarray analysis to define the PecS regulon and demonstrated that PecS notably regulates a wide range of genes that could be linked to pathogenicity and to a group of genes concerned with evading host defenses. Among the targets are the genes encoding plant cell wall-degrading enzymes and secretion systems and the genes involved in flagellar biosynthesis, biosurfactant production, and the oxidative stress response, as well as genes encoding toxin-like factors such as NipE and hemolysin-coregulated proteins. In vitro experiments demonstrated that PecS interacts with the regulatory regions of five new targets: an oxidative stress response gene (ahpC), a biosurfactant synthesis gene (rhlA), and genes encoding exported proteins related to other plant-associated bacterial proteins (nipE, virK, and avrL). The pecS mutant provokes symptoms more rapidly and with more efficiency than the wild-type strain, indicating that PecS plays a critical role in the switch from the asymptomatic phase to the symptomatic phase. Based on this, we propose that the temporal regulation of the different groups of genes required for the asymptomatic phase and the symptomatic phase is, in part, the result of a gradual modulation of PecS activity triggered during infection in response to changes in environmental conditions emerging from the interaction between both partners.
Collapse
|
45
|
Sjöblom S, Harjunpää H, Brader G, Palva ET. A novel plant ferredoxin-like protein and the regulator Hor are quorum-sensing targets in the plant pathogen Erwinia carotovora. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:967-978. [PMID: 18533837 DOI: 10.1094/mpmi-21-7-0967] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Quorum sensing (QS), a population-density-sensing mechanism, controls the production of the main virulence determinants, the plant cell-wall-degrading enzymes (PCWDEs) of the soft-rot phytopathogen Erwinia carotovora subsp. carotovora. In this study, we used random transposon mutagenesis with a gusA reporter construct to identify two new QS-controlled genes encoding the regulator Hor and a plant ferredoxin-like protein, FerE. The QS control of the identified genes was executed by the QS regulators ExpR1 and ExpR2 and mediated by the global repressor RsmA. Hor was shown to contribute to bacterial virulence at least partly through its control of PCWDE production. Our results showed that FerE contributes to oxidative stress tolerance and in planta fitness of the bacteria and suggest that QS could be central to control of oxidative stress tolerance. The presence of the FerE protein appears to be rather unique in heterotrophic bacteria and suggests an acquisition of the corresponding gene from plant host by horizontal gene transfer.
Collapse
Affiliation(s)
- Solveig Sjöblom
- Viikki Biocenter, Faculty of Biosciences, Department of Biological and Environmental Sciences, Division of Genetics, University of Helsinki, P.O.Box 56, FIN-00014, Helsinki, Finland
| | | | | | | |
Collapse
|
46
|
Liu H, Coulthurst SJ, Pritchard L, Hedley PE, Ravensdale M, Humphris S, Burr T, Takle G, Brurberg MB, Birch PRJ, Salmond GPC, Toth IK. Quorum sensing coordinates brute force and stealth modes of infection in the plant pathogen Pectobacterium atrosepticum. PLoS Pathog 2008; 4:e1000093. [PMID: 18566662 PMCID: PMC2413422 DOI: 10.1371/journal.ppat.1000093] [Citation(s) in RCA: 168] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Accepted: 05/20/2008] [Indexed: 01/11/2023] Open
Abstract
Quorum sensing (QS) in vitro controls production of plant cell wall degrading enzymes (PCWDEs) and other virulence factors in the soft rotting enterobacterial plant pathogen Pectobacterium atrosepticum (Pba). Here, we demonstrate the genome-wide regulatory role of QS in vivo during the Pba-potato interaction, using a Pba-specific microarray. We show that 26% of the Pba genome exhibited differential transcription in a QS (expI-) mutant, compared to the wild-type, suggesting that QS may make a greater contribution to pathogenesis than previously thought. We identify novel components of the QS regulon, including the Type I and II secretion systems, which are involved in the secretion of PCWDEs; a novel Type VI secretion system (T6SS) and its predicted substrates Hcp and VgrG; more than 70 known or putative regulators, some of which have been demonstrated to control pathogenesis and, remarkably, the Type III secretion system and associated effector proteins, and coronafacoyl-amide conjugates, both of which play roles in the manipulation of plant defences. We show that the T6SS and a novel potential regulator, VirS, are required for full virulence in Pba, and propose a model placing QS at the apex of a regulatory hierarchy controlling the later stages of disease progression in Pba. Our findings indicate that QS is a master regulator of phytopathogenesis, controlling multiple other regulators that, in turn, co-ordinately regulate genes associated with manipulation of host defences in concert with the destructive arsenal of PCWDEs that manifest the soft rot disease phenotype.
Collapse
Affiliation(s)
- Hui Liu
- Plant Pathology Programme, SCRI, Invergowrie, Dundee, United Kingdom
| | - Sarah J. Coulthurst
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | | | - Peter E. Hedley
- Plant Pathology Programme, SCRI, Invergowrie, Dundee, United Kingdom
| | | | - Sonia Humphris
- Plant Pathology Programme, SCRI, Invergowrie, Dundee, United Kingdom
| | - Tom Burr
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Gunnhild Takle
- Bioforsk, Norwegian Institute for Agricultural and Environmental Research, Ås, Norway
| | - May-Bente Brurberg
- Bioforsk, Norwegian Institute for Agricultural and Environmental Research, Ås, Norway
| | - Paul R. J. Birch
- Plant Pathology Programme, SCRI, Invergowrie, Dundee, United Kingdom
| | | | - Ian K. Toth
- Plant Pathology Programme, SCRI, Invergowrie, Dundee, United Kingdom
| |
Collapse
|
47
|
Coulthurst SJ, Lilley KS, Hedley PE, Liu H, Toth IK, Salmond GPC. DsbA plays a critical and multifaceted role in the production of secreted virulence factors by the phytopathogen Erwinia carotovora subsp. atroseptica. J Biol Chem 2008; 283:23739-53. [PMID: 18562317 DOI: 10.1074/jbc.m801829200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Erwinia carotovora subsp. atroseptica is an enterobacterial phytopathogen causing economically significant soft rot disease. Pathogenesis is mediated by multiple secreted virulence factors, many of which are secreted by the type II (Out) secretion system. DsbA catalyzes the introduction of disulfide bonds into periplasmic and secreted proteins. In this study, the extracellular proteome (secretome) of wild type E. carotovora subsp. atroseptica SCRI1043, and dsbA and out mutants, was analyzed by spectral counting mass spectrometry. This revealed that dsbA inactivation had a huge impact on the secretome and identified diverse DsbA- and Out-dependent secreted proteins, representing known, predicted, and novel candidate virulence factors. Further characterization of the dsbA mutant showed that secreted enzyme activities, motility, production of the quorum-sensing signal, and virulence were absent or substantially reduced. The impact of DsbA on secreted virulence factor production was mediated at multiple levels, including impacting on the Out secretion system and the virulence gene regulatory network. Transcriptome analyses revealed that the abundance of a broad, but defined, set of transcripts, including many virulence factors, was altered in the dsbA mutant, identifying a new virulence regulon responsive to extracytoplasmic conditions. In conclusion, DsbA plays a crucial, multifaceted role in the pathogenesis of E. carotovora subsp. atroseptica.
Collapse
Affiliation(s)
- Sarah J Coulthurst
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, United Kingdom
| | | | | | | | | | | |
Collapse
|
48
|
Cechin AL, Sinigaglia M, Lemke N, Echeverrigaray S, Cabrera OG, Pereira GAG, Mombach JCM. Cupin: a candidate molecular structure for the Nep1-like protein family. BMC PLANT BIOLOGY 2008; 8:50. [PMID: 18447914 PMCID: PMC2396628 DOI: 10.1186/1471-2229-8-50] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Accepted: 04/30/2008] [Indexed: 05/10/2023]
Abstract
BACKGROUND NEP1-like proteins (NLPs) are a novel family of microbial elicitors of plant necrosis. Some NLPs induce a hypersensitive-like response in dicot plants though the basis for this response remains unclear. In addition, the spatial structure and the role of these highly conserved proteins are not known. RESULTS We predict a 3d-structure for the beta-rich section of the NLPs based on alignments, prediction tools and molecular dynamics. We calculated a consensus sequence from 42 NLPs proteins, predicted its secondary structure and obtained a high quality alignment of this structure and conserved residues with the two Cupin superfamily motifs. The conserved sequence GHRHDWE and several common residues, especially some conserved histidines, in NLPs match closely the two cupin motifs. Besides other common residues shared by dicot Auxin-Binding Proteins (ABPs) and NLPs, an additional conserved histidine found in all dicot ABPs was also found in all NLPs at the same position. CONCLUSION We propose that the necrosis inducing protein class belongs to the Cupin superfamily. Based on the 3d-structure, we are proposing some possible functions for the NLPs.
Collapse
Affiliation(s)
- Adelmo L Cechin
- Programa de Pós-Graduação em Computação Aplicada, Unisinos, Av. Unisinos – 950, São Leopoldo, Brasil
| | - Marialva Sinigaglia
- Programa de Pós-Graduação em Computação Aplicada, Unisinos, Av. Unisinos – 950, São Leopoldo, Brasil
| | - Ney Lemke
- Departamento de Física e Biofísica, UNESP, Dist. Rubião Jr. sn, Botucatu, Brasil
| | - Sérgio Echeverrigaray
- Instituto de Biotecnologia, UCS, R. Francisco Getúlio Vargas 1130, Caxias do Sul, Brasil
| | - Odalys G Cabrera
- Departamento de Genética e Evolução, IB/UNICAMP, Campinas, Brasil
| | | | - José CM Mombach
- Centro de Ciências Rurais, UFPampa/UFSM, São Gabriel, Brasil
| |
Collapse
|
49
|
|
50
|
Wang J, Gardiol N, Burr T, Salmond GPC, Welch M. RelA-dependent (p)ppGpp production controls exoenzyme synthesis in Erwinia carotovora subsp. atroseptica. J Bacteriol 2007; 189:7643-52. [PMID: 17766416 PMCID: PMC2168740 DOI: 10.1128/jb.00920-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Accepted: 08/22/2007] [Indexed: 11/20/2022] Open
Abstract
In this report, we investigate the link between nutrient limitation, RelA-mediated (p)ppGpp production, and virulence in the phytopathogen Erwinia carotovora subsp. atroseptica. A relA null mutant (JWC7) was constructed by allelic exchange, and we confirmed that, unlike the wild-type progenitor, this mutant did not produce elevated levels of (p)ppGpp upon nutrient downshift. However, (p)ppGpp production could be restored in strain JWC7 during nutrient limitation by supplying relA in trans. During growth on exoenzyme-inducing minimal medium, the relA mutant showed a diminution in secreted pectate lyase and protease activities and a severe defect in motility. The relA mutant was also impaired in its ability to cause rot in potato tubers. In the presence of serine hydroxamate (a competitive inhibitor of seryl tRNA synthase and a potent inducer of the stringent response in wild-type E. carotovora subsp. atroseptica), exoenzyme production was essentially abolished in JWC7 but could be restored in the presence of plasmid-borne relA. The inhibition of exoenzyme production in JWC7 caused by serine hydroxamate could not be overcome by addition of the quorum-sensing signal molecule, N-3-oxohexanoyl-l-homoserine lactone. Quantitative reverse transcription-PCR analysis of selected RNA species confirmed that the effects of relA on secreted pectate lyase activity and motility could be attributed to a reduction in transcription of the corresponding genes. We conclude that nutrient limitation is a potent environmental cue that triggers (p)ppGpp-dependent exoenzyme production in E. carotovora subsp. atroseptica. Furthermore, our data suggest that nutrient limitation [or rather, (p)ppGpp accumulation] is a prerequisite for effective quorum-sensing-dependent activation of exoenzyme production.
Collapse
Affiliation(s)
- Jinhong Wang
- Department of Biochemistry, Tennis Court Road, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | | | | | | | | |
Collapse
|