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Yang C, Zou Z, Fernando WGD. The Effect of Temperature on the Hypersensitive Response (HR) in the Brassica napus-Leptosphaeria maculans Pathosystem. PLANTS (BASEL, SWITZERLAND) 2021; 10:843. [PMID: 33922044 PMCID: PMC8143495 DOI: 10.3390/plants10050843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/07/2021] [Accepted: 04/19/2021] [Indexed: 11/16/2022]
Abstract
Temperature is considered one of the crucial environmental elements in plant pathological interactions, and previous studies have indicated that there is a relationship between temperature change and host-pathogen interactions. The objective of this research is to investigate the link between temperature and the incompatible interactions of the host and pathogen. In this study, two Leptosphaeria maculans isolates (HCRT75 8-1 and HCRT77 7-2) and two Brassica napus genotypes (Surpass400 and 01-23-2-1) were selected. The selected B. napus genotypes displayed intermediate and resistant phenotypes. The inoculated seedlings were tested under three temperature conditions: 16 °C/10 °C, 22 °C/16 °C and 28 °C/22 °C (day/night: 16 h/8 h). Lesion measurements demonstrated that the necrotic lesions from the 28 °C/22 °C treatment were enlarged compared with the other two temperature treatments (i.e., 16 °C/10 °C and 22 °C/16 °C). The results of expression analysis indicated that the three temperature treatments displayed distinct differences in two marker genes (PATHOGENESIS-RELATED (PR) 1 and 2) for plant defense and one temperature-sensitive gene BONZAI 1 (BON1). Additionally, seven dpi at 22 °C/16 °C appeared to be the optimal pre-condition for the induction of PR1 and 2. These findings suggest that B. napus responds to temperature changes when infected with L. maculans.
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Transcriptome analysis of early stages of sorghum grain mold disease reveals defense regulators and metabolic pathways associated with resistance. BMC Genomics 2021; 22:295. [PMID: 33888060 PMCID: PMC8063297 DOI: 10.1186/s12864-021-07609-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/22/2021] [Indexed: 12/26/2022] Open
Abstract
Background Sorghum grain mold is the most important disease of the crop. The disease results from simultaneous infection of the grain by multiple fungal species. Host responses to these fungi and the underlying molecular and cellular processes are poorly understood. To understand the genetic, molecular and biochemical components of grain mold resistance, transcriptome profiles of the developing grain of resistant and susceptible sorghum genotypes were studied. Results The developing kernels of grain mold resistant RTx2911 and susceptible RTx430 sorghum genotypes were inoculated with a mixture of fungal pathogens mimicking the species complexity of the disease under natural infestation. Global transcriptome changes corresponding to multiple molecular and cellular processes, and biological functions including defense, secondary metabolism, and flavonoid biosynthesis were observed with differential regulation in the two genotypes. Genes encoding pattern recognition receptors (PRRs), regulators of growth and defense homeostasis, antimicrobial peptides, pathogenesis-related proteins, zein seed storage proteins, and phytoalexins showed increased expression correlating with resistance. Notably, SbLYK5 gene encoding an orthologue of chitin PRR, defensin genes SbDFN7.1 and SbDFN7.2 exhibited higher expression in the resistant genotype. The SbDFN7.1 and SbDFN7.2 genes are tightly linked and transcribed in opposite orientation with a likely common bidirectional promoter. Interestingly, increased expression of JAZ and other transcriptional repressors were observed that suggested the tight regulation of plant defense and growth. The data suggest a pathogen inducible defense system in the developing grain of sorghum that involves the chitin PRR, MAPKs, key transcription factors, downstream components regulating immune gene expression and accumulation of defense molecules. We propose a model through which the biosynthesis of 3-deoxyanthocynidin phytoalexins, defensins, PR proteins, other antimicrobial peptides, and defense suppressing proteins are regulated by a pathogen inducible defense system in the developing grain. Conclusions The transcriptome data from a rarely studied tissue shed light into genetic, molecular, and biochemical components of disease resistance and suggested that the developing grain shares conserved immune response mechanisms but also components uniquely enriched in the grain. Resistance was associated with increased expression of genes encoding regulatory factors, novel grain specific antimicrobial peptides including defensins and storage proteins that are potential targets for crop improvement. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07609-y.
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Mwimba M, Karapetyan S, Liu L, Marqués J, McGinnis EM, Buchler NE, Dong X. Daily humidity oscillation regulates the circadian clock to influence plant physiology. Nat Commun 2018; 9:4290. [PMID: 30327472 PMCID: PMC6191426 DOI: 10.1038/s41467-018-06692-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 09/20/2018] [Indexed: 01/27/2023] Open
Abstract
Early circadian studies in plants by de Mairan and de Candolle alluded to a regulation of circadian clocks by humidity. However, this regulation has not been described in detail, nor has its influence on physiology been demonstrated. Here we report that, under constant light, circadian humidity oscillation can entrain the plant circadian clock to a period of 24 h probably through the induction of clock genes such as CIRCADIAN CLOCK ASSOCIATED 1. Under simulated natural light and humidity cycles, humidity oscillation increases the amplitude of the circadian clock and further improves plant fitness-related traits. In addition, humidity oscillation enhances effector-triggered immunity at night possibly to counter increased pathogen virulence under high humidity. These results indicate that the humidity oscillation regulates specific circadian outputs besides those co-regulated with the light-dark cycle.
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Affiliation(s)
- Musoki Mwimba
- Howard Hughes Medical Institute, Duke University, Durham, NC, 27708, USA.,Department of Biology, Duke University, PO Box 90338, Durham, NC, 27708, USA
| | - Sargis Karapetyan
- Department of Biology, Duke University, PO Box 90338, Durham, NC, 27708, USA.,Department of Physics, Duke University, Durham, NC, 27708, USA
| | - Lijing Liu
- Howard Hughes Medical Institute, Duke University, Durham, NC, 27708, USA.,Department of Biology, Duke University, PO Box 90338, Durham, NC, 27708, USA
| | - Jorge Marqués
- Howard Hughes Medical Institute, Duke University, Durham, NC, 27708, USA.,Department of Biology, Duke University, PO Box 90338, Durham, NC, 27708, USA
| | - Erin M McGinnis
- Howard Hughes Medical Institute, Duke University, Durham, NC, 27708, USA.,Department of Biology, Duke University, PO Box 90338, Durham, NC, 27708, USA
| | - Nicolas E Buchler
- Department of Biology, Duke University, PO Box 90338, Durham, NC, 27708, USA.,Department of Physics, Duke University, Durham, NC, 27708, USA.,Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC, 27606, USA
| | - Xinnian Dong
- Howard Hughes Medical Institute, Duke University, Durham, NC, 27708, USA. .,Department of Biology, Duke University, PO Box 90338, Durham, NC, 27708, USA.
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Badhan S, Kole P, Ball A, Mantri N. RNA sequencing of leaf tissues from two contrasting chickpea genotypes reveals mechanisms for drought tolerance. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 129:295-304. [PMID: 29913357 DOI: 10.1016/j.plaphy.2018.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/07/2018] [Accepted: 06/07/2018] [Indexed: 05/02/2023]
Abstract
Chickpea (Cicer arietinum L.) is the second most important winter crop which is consumed globally due to its high nutritional value. Chickpea as one of the leguminous crop is important in crop rotation with cereal crops like wheat and barley. The main constraints for chickpea production are abiotic stresses such as drought, salinity, and heat. Among these, drought is a major cause of the decline in chickpea production in worldwide. Studies conducted so far have provided a limited insight into different genetic pathways associated with drought tolerance/response. In this study, the leaf tissue from shoots apical meristem stage of drought tolerant (ICC8261) and drought sensitive (ICC283) genotypes were analysed using RNA sequencing to identify genes/pathways associated with drought tolerance/sensitivity in both genotypes. It was observed that genes related to ethylene response, MYB-related protein, xyloglucan endotransglycosylase, alkane hydroxylase MAH-like, BON-1 associated, peroxidase 3, cysteine-rich and transmembrane domain, vignain and mitochondrial uncoupling were specifically up-regulated in the tolerant genotype whereas, same genes were down-regulated in sensitive genotype. The crosstalk between the different hormones and transcriptional factors involved in drought tolerance and sensitivity in both genotypes make them great candidates for future research.
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Affiliation(s)
- Sapna Badhan
- The Pangenomics Group, School of Science, RMIT University, Melbourne, Victoria, 3000, Australia.
| | - Pravas Kole
- The Pangenomics Group, School of Science, RMIT University, Melbourne, Victoria, 3000, Australia.
| | - Andrew Ball
- The Pangenomics Group, School of Science, RMIT University, Melbourne, Victoria, 3000, Australia.
| | - Nitin Mantri
- The Pangenomics Group, School of Science, RMIT University, Melbourne, Victoria, 3000, Australia.
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Abstract
Most reviews of climate change are epidemiological, focusing on impact assessment and risk mapping. However, there are many reports of the effects of environmental stress factors on defense mechanisms in plants against pathogens. We review those representative of key climate change-related stresses to determine whether there are any patterns or trends in adaptation responses. We recognize the complexity of climate change itself and the multitrophic nature of the complex biological interactions of plants, microbes, soil, and the environment and, therefore, the difficulty of reductionist dissection approaches to resolving the problems. We review host defense genes, germplasm, and environmental interactions in different types of organisms but find no significant group-specific trends. Similarly, we review by host defense mechanism type and by host-pathogen trophic relationship but identify no dominating mechanism for stress response. However, we do identify core stress response mechanisms playing key roles in multiple response pathways whether to biotic or abiotic stress. We suggest that these should be central to mechanistic climate change plant defense research. We also recognize biodiversity, heterogeneity, and the need for understanding stress in a true systems biology approach as being essential components of progressing our understanding of and response to climate change.
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Perestenko P, Watanabe M, Beusnard-Bee T, Guna P, McIlhinney J. The second C2-domain of copine-2, copine-6 and copine-7 is responsible for their calcium-dependent membrane association. FEBS J 2015; 282:3722-36. [DOI: 10.1111/febs.13370] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 06/13/2015] [Accepted: 07/07/2015] [Indexed: 11/26/2022]
Affiliation(s)
- Pavel Perestenko
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford; UK
| | - Masanori Watanabe
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford; UK
| | - Tobias Beusnard-Bee
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford; UK
| | - Prakash Guna
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford; UK
| | - Jeffrey McIlhinney
- Medical Research Council Brain Network Dynamics Unit at the University of Oxford; UK
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Bruggeman Q, Raynaud C, Benhamed M, Delarue M. To die or not to die? Lessons from lesion mimic mutants. FRONTIERS IN PLANT SCIENCE 2015; 6:24. [PMID: 25688254 PMCID: PMC4311611 DOI: 10.3389/fpls.2015.00024] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/12/2015] [Indexed: 05/19/2023]
Abstract
Programmed cell death (PCD) is a ubiquitous genetically regulated process consisting in an activation of finely controlled signaling pathways that lead to cellular suicide. Although some aspects of PCD control appear evolutionary conserved between plants, animals and fungi, the extent of conservation remains controversial. Over the last decades, identification and characterization of several lesion mimic mutants (LMM) has been a powerful tool in the quest to unravel PCD pathways in plants. Thanks to progress in molecular genetics, mutations causing the phenotype of a large number of LMM and their related suppressors were mapped, and the identification of the mutated genes shed light on major pathways in the onset of plant PCD such as (i) the involvements of chloroplasts and light energy, (ii) the roles of sphingolipids and fatty acids, (iii) a signal perception at the plasma membrane that requires efficient membrane trafficking, (iv) secondary messengers such as ion fluxes and ROS and (v) the control of gene expression as the last integrator of the signaling pathways.
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Affiliation(s)
- Quentin Bruggeman
- Institut de Biologie des Plantes, UMR CNRS 8618, Université Paris-Sud, Saclay Plant SciencesOrsay, France
| | - Cécile Raynaud
- Institut de Biologie des Plantes, UMR CNRS 8618, Université Paris-Sud, Saclay Plant SciencesOrsay, France
| | - Moussa Benhamed
- Institut de Biologie des Plantes, UMR CNRS 8618, Université Paris-Sud, Saclay Plant SciencesOrsay, France
- Division of Biological and Environmental Sciences and Engineering, Center for Desert Agriculture, King Abdullah University of Science and TechnologyThuwal, Saudi Arabia
| | - Marianne Delarue
- Institut de Biologie des Plantes, UMR CNRS 8618, Université Paris-Sud, Saclay Plant SciencesOrsay, France
- *Correspondence: Marianne Delarue, Institut de Biologie des Plantes, UMR CNRS 8618, Université Paris-Sud, Saclay Plant Sciences, Bâtiment 630, Route de Noetzlin, 91405 Orsay Cedex, France e-mail:
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Influence of the plant defense response to Escherichia coli O157:H7 cell surface structures on survival of that enteric pathogen on plant surfaces. Appl Environ Microbiol 2012; 78:5882-9. [PMID: 22706044 DOI: 10.1128/aem.01095-12] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Consumption of fresh and fresh-cut fruits and vegetables contaminated with Escherichia coli O157:H7 has resulted in hundreds of cases of illness and, in some instances, death. In this study, the influence of cell surface structures of E. coli O157:H7, such as flagella, curli fimbriae, lipopolysaccharides, or exopolysaccharides, on plant defense responses and on survival or colonization on the plant was investigated. The population of the E. coli O157:H7 ATCC 43895 wild-type strain was significantly lower on wild-type Arabidopsis plants than that of the 43895 flagellum-deficient mutant. The population of the E. coli O157:H7 43895 flagellum mutant was greater on both wild-type and npr1-1 mutant (nonexpressor of pathogenesis-related [PR] genes) plants and resulted in less PR gene induction, estimated based on a weak β-glucuronidase (GUS) signal, than did the 43895 wild-type strain. These results suggest that the flagella, among the other pathogen-associated molecular patterns (PAMPs), made a substantial contribution to the induction of plant defense response and contributed to the decreased numbers of the E. coli O157:H7 ATCC 43895 wild-type strain on the wild-type Arabidopsis plant. A curli-deficient E. coli O157:H7 86-24 strain survived better on wild-type Arabidopsis plants than the curli-producing wild-type 86-24 strain did. The curli-deficient E. coli O157:H7 86-24 strain exhibited a GUS signal at a level substantially lower than that of the curli-producing wild-type strain. Curli were recognized by plant defense systems, consequently affecting bacterial survival. The cell surface structures of E. coli O157:H7 have a significant impact on the induction of differential plant defense responses, thereby impacting persistence or survival of the pathogen on plants.
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Liu F, Guo J, Bai P, Duan Y, Wang X, Cheng Y, Feng H, Huang L, Kang Z. Wheat TaRab7 GTPase is part of the signaling pathway in responses to stripe rust and abiotic stimuli. PLoS One 2012; 7:e37146. [PMID: 22629358 PMCID: PMC3358313 DOI: 10.1371/journal.pone.0037146] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/17/2012] [Indexed: 11/22/2022] Open
Abstract
Small GTP-binding proteins function as regulators of specific intercellular fundamental biological processes. In this study, a small GTP-binding protein Rab7 gene, designated as TaRab7, was identified and characterized from a cDNA library of wheat leaves infected with Puccinia striiformis f. sp. tritici (Pst) the wheat stripe rust pathogen. The gene was predicted to encode a protein of 206 amino acids, with a molecular mass of 23.13 KDa and an isoeletric point (pI) of 5.13. Further analysis revealed the presence of a conserved signature that is characteristic of Rab7, and phylogenetic analysis demonstrated that TaRab7 has the highest similarity to a small GTP binding protein gene (BdRab7-like) from Brachypodium distachyon. Quantitative real-time PCR assays revealed that the expression of TaRab7 was higher in the early stage of the incompatible interactions between wheat and Pst than in the compatible interaction, and the transcription level of TaRab7 was also highly induced by environmental stress stimuli. Furthermore, knocking down TaRab7 expression by virus induced gene silencing enhanced the susceptibility of wheat cv. Suwon 11 to an avirulent race CYR23. These results imply that TaRab7 plays an important role in the early stage of wheat-stripe rust fungus interaction and in stress tolerance.
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Affiliation(s)
- Furong Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Jun Guo
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Pengfei Bai
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Yinhui Duan
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Xiaodong Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Yulin Cheng
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Hao Feng
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Lili Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, People's Republic of China
- * E-mail:
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Gou M, Shi Z, Zhu Y, Bao Z, Wang G, Hua J. The F-box protein CPR1/CPR30 negatively regulates R protein SNC1 accumulation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:411-20. [PMID: 21967323 DOI: 10.1111/j.1365-313x.2011.04799.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Disease resistance (R) proteins, as central regulators of plant immunity, are tightly regulated for effective defense responses and to prevent constitutive defense activation under non-pathogenic conditions. Here we report the identification of an F-box protein CPR1/CPR30 as a negative regulator of an R protein SNC1 likely through SCF (Skp1-cullin-F-box) mediated protein degradation. The cpr1-2 (cpr30-1) loss-of-function mutant has constitutive defense responses, and it interacts synergistically with a gain-of function mutant snc1-1 and a bon1-1 mutant where SNC1 is upregulated. The loss of SNC1 function suppresses the mutant phenotypes of cpr1-2 and cpr1-2 bon1-1, while overexpression of CPR1 rescues mutant phenotypes of both bon1-1 and snc1-1. Furthermore, the amount of SNC1 protein is upregulated in the cpr1-2 mutant and down-regulated when CPR1 is overexpressed. The regulation of SNC1 by CPR1 is dependent on the 26S proteosome as a protease inhibitor MG132 stabilizes SNC1 and reverses the effect of CPR1 on SNC1. Interestingly, CPR1 is induced after infection of both virulent and avirulent pathogens similarly to the other negative defense regulator BON1. Thus, this study reveals a new mechanism in R protein regulation likely through protein degradation and suggests negative regulation as a critical component in fine control of plant immunity.
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Affiliation(s)
- Mingyue Gou
- Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA
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Bouwmeester K, de Sain M, Weide R, Gouget A, Klamer S, Canut H, Govers F. The lectin receptor kinase LecRK-I.9 is a novel Phytophthora resistance component and a potential host target for a RXLR effector. PLoS Pathog 2011; 7:e1001327. [PMID: 21483488 PMCID: PMC3068997 DOI: 10.1371/journal.ppat.1001327] [Citation(s) in RCA: 166] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 02/28/2011] [Indexed: 12/03/2022] Open
Abstract
In plants, an active defense against biotrophic pathogens is dependent on a functional continuum between the cell wall (CW) and the plasma membrane (PM). It is thus anticipated that proteins maintaining this continuum also function in defense. The legume-like lectin receptor kinase LecRK-I.9 is a putative mediator of CW-PM adhesions in Arabidopsis and is known to bind in vitro to the Phytophthora infestans RXLR-dEER effector IPI-O via a RGD cell attachment motif present in IPI-O. Here we show that LecRK-I.9 is associated with the plasma membrane, and that two T-DNA insertions lines deficient in LecRK-I.9 (lecrk-I.9) have a ‘gain-of-susceptibility’ phenotype specifically towards the oomycete Phytophthora brassicae. Accordingly, overexpression of LecRK-I.9 leads to enhanced resistance to P. brassicae. A similar ‘gain-of-susceptibility’ phenotype was observed in transgenic Arabidopsis lines expressing ipiO (35S-ipiO1). This phenocopy behavior was also observed with respect to other defense-related functions; lecrk-I.9 and 35S-ipiO1 were both disturbed in pathogen- and MAMP-triggered callose deposition. By site-directed mutagenesis, we demonstrated that the RGD cell attachment motif in IPI-O is not only essential for disrupting the CW-PM adhesions, but also for disease suppression. These results suggest that destabilizing the CW-PM continuum is one of the tactics used by Phytophthora to promote infection. As countermeasure the host may want to strengthen CW-PM adhesions and the novel Phytophthora resistance component LecRK-I.9 seems to function in this process. Phytophthora species are notorious plant pathogens which cause a variety of devastating crop diseases. Phytophthora pathogens secrete a plethora of effector proteins, several of which are known to interact with receptors in the host cell thereby either activating or suppressing defense responses. Unlike animals, plants lack an adaptive immune system; however, they are not defenseless and have acquired other mechanisms to withstand pathogens. Receptor proteins play important roles in sensing alterations at the plant cell wall and in mediating responses upon pathogen attack. This paper focuses on the Arabidopsis lectin receptor kinase LecRK-I.9, a mediator of cell wall – plasma membrane (CW-PM) adhesions that is known to bind in vitro to the Phytophthora infestans effector IPI-O via the cell attachment motif RGD. T-DNA mutants deficient in LecRK-I.9 and transgenic Arabidopsis lines expressing ipiO1 were found to behave as phenocopies. Both show a ‘gain-of-susceptibility’ phenotype towards the Arabidopsis pathogen Phytophthora brassicae and are disturbed in callose deposition. Overall, the results suggest that destabilizing the CW-PM continuum is a strategy for Phytophthora to promote infection. As countermeasure, the host may want to strengthen CW-PM adhesions, and the novel resistance component LecRK-I.9 apparently functions in this process.
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Affiliation(s)
- Klaas Bouwmeester
- Laboratory of Phytopathology, Plant Sciences Group, Wageningen University, Wageningen, The Netherlands
- Centre for BioSystems Genomics (CBSG), Wageningen, The Netherlands
| | - Mara de Sain
- Laboratory of Phytopathology, Plant Sciences Group, Wageningen University, Wageningen, The Netherlands
- Centre for BioSystems Genomics (CBSG), Wageningen, The Netherlands
| | - Rob Weide
- Laboratory of Phytopathology, Plant Sciences Group, Wageningen University, Wageningen, The Netherlands
| | - Anne Gouget
- UMR 5546 CNRS-Université Paul Sabatier-Toulouse III, Castanet-Tolosan, France
| | - Sofieke Klamer
- Laboratory of Phytopathology, Plant Sciences Group, Wageningen University, Wageningen, The Netherlands
| | - Herve Canut
- UMR 5546 CNRS-Université Paul Sabatier-Toulouse III, Castanet-Tolosan, France
| | - Francine Govers
- Laboratory of Phytopathology, Plant Sciences Group, Wageningen University, Wageningen, The Netherlands
- Centre for BioSystems Genomics (CBSG), Wageningen, The Netherlands
- * E-mail:
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Cloning and characterization of a calcium binding EF-hand protein gene TaCab1 from wheat and its expression in response to Puccinia striiformis f. sp. tritici and abiotic stresses. Mol Biol Rep 2010; 38:3857-66. [PMID: 21110112 DOI: 10.1007/s11033-010-0501-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2010] [Accepted: 11/13/2010] [Indexed: 10/18/2022]
Abstract
Calcium is a ubiquitous and essential secondary messenger in eukaryotic signal transduction pathways. Calcium binding protein, as a component of pathways, plays various roles in response to biotic and abiotic stresses, as well as in developmental processes in plants. In this study, a calcium binding protein gene, designated as TaCab1 (Triticum aestivum calcium binding EF-hand protein 1), was isolated and characterized from wheat leaves (cv. Suwon 11) infected by Puccinia striiformis f. sp. tritici by in silico cloning and reverse transcription PCR (RT-PCR). TaCab1 did not have an intron and was predicted to encode a 216 amino acid protein which possesses an N-terminal region with a signal peptide, a transmembrane domain, an EF-hand motif and a caleosin domain. The results of transient assays with constructs of TaCab1 with green fluorescent protein (GFP) gene indicated that TaCab1 encodes a transmembrane protein. Quantitative real-time PCR (qRT-PCR) analyses revealed that TaCab1 was highly expressed in leaves than roots and stems. Although up-regulated expression profiles of TaCab1 were quite similar in both incompatible and compatible interactions, its transcript accumulation in the compatible interaction was much higher than in the incompatible interaction. The transcription of TaCab1 was also up-regulated at different degrees after treated by phytohormones [abscisic acid, benzyl adenine, ethylene, methyl jasmonate and salicylic acid (SA)] and stress stimuli [wounding, low temperature, polyethylene glycol and high salinity]. These results suggest that TaCab1 is involved in the plant-pathogen recognition, symptom development, and the basal tolerance to biotic and abiotic stresses through the SA signaling pathway.
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Perestenko PV, Pooler AM, Noorbakhshnia M, Gray A, Bauccio C, Jeffrey McIlhinney RA. Copines-1, -2, -3, -6 and -7 show different calcium-dependent intracellular membrane translocation and targeting. FEBS J 2010; 277:5174-89. [DOI: 10.1111/j.1742-4658.2010.07935.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Silencing of SlFTR-c, the catalytic subunit of ferredoxin:thioredoxin reductase, induces pathogenesis-related genes and pathogen resistance in tomato plants. Biochem Biophys Res Commun 2010; 399:750-4. [DOI: 10.1016/j.bbrc.2010.08.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 08/04/2010] [Indexed: 11/29/2022]
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15
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Smith TS, Pineda JM, Donaghy AC, Damer CK. Copine A plays a role in the differentiation of stalk cells and the initiation of culmination in Dictyostelium development. BMC DEVELOPMENTAL BIOLOGY 2010; 10:59. [PMID: 20525180 PMCID: PMC2890595 DOI: 10.1186/1471-213x-10-59] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 06/02/2010] [Indexed: 12/23/2022]
Abstract
Background Copines are calcium-dependent phospholipid-binding proteins found in diverse eukaryotic organisms. We are studying the function of copines in Dictyostelium discoideum, a single-celled amoeba that undergoes cell differentiation and morphogenesis to form multicellular fruiting bodies when placed in starvation conditions. Previously, we showed that Dictyostelium cells lacking the copine A (cpnA) gene are not able to complete the developmental cycle, arresting at the slug stage. The aim of this study is to further characterize the developmental defect of the cpnA- cells. Results Time-lapse imaging revealed that cpnA- cells exhibited delayed aggregation and made large mounds that formed one large slug as compared to the smaller slugs of the wild-type cells. While the prespore cell patterning appeared to be normal within the cpnA- slugs, the prestalk cell patterning was different from wild-type. When cpnA- cells were mixed with a small percentage of wild-type cells, chimeric fruiting bodies with short stalks formed. When a small percentage of cpnA- cells was mixed with wild-type cells, the cpnA- cells labeled with GFP were found located throughout the chimeric slug and in both the stalk and sporehead of the fruiting bodies. However, there appeared to be a small bias towards cpnA- cells becoming spore cells. When cpnA- cells were developed in buffer containing EGTA, they were also able to differentiate into either stalk or spore cells to form fruiting bodies with short stalks. Conclusions Our results indicate that CpnA is involved in the regulation of aggregation, slug size, and culmination during Dictyostelium development. More specifically, CpnA appears to be involved in the function and differentiation of prestalk cells and plays a role in a calcium-regulated signaling pathway critical to triggering the initiation of culmination.
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Affiliation(s)
- Tasha S Smith
- Department of Biology, Central Michigan University, Mount Pleasant, Michigan 48859, USA
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Mosher S, Moeder W, Nishimura N, Jikumaru Y, Joo SH, Urquhart W, Klessig DF, Kim SK, Nambara E, Yoshioka K. The lesion-mimic mutant cpr22 shows alterations in abscisic acid signaling and abscisic acid insensitivity in a salicylic acid-dependent manner. PLANT PHYSIOLOGY 2010; 152:1901-13. [PMID: 20164209 PMCID: PMC2850030 DOI: 10.1104/pp.109.152603] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 02/15/2010] [Indexed: 05/19/2023]
Abstract
A number of Arabidopsis (Arabidopsis thaliana) lesion-mimic mutants exhibit alterations in both abiotic stress responses and pathogen resistance. One of these mutants, constitutive expresser of PR genes22 (cpr22), which has a mutation in two cyclic nucleotide-gated ion channels, is a typical lesion-mimic mutant exhibiting elevated levels of salicylic acid (SA), spontaneous cell death, constitutive expression of defense-related genes, and enhanced resistance to various pathogens; the majority of its phenotypes are SA dependent. These defense responses in cpr22 are suppressed under high-humidity conditions and enhanced by low humidity. After shifting plants from high to low humidity, the cpr22 mutant, but not the wild type, showed a rapid increase in SA levels followed by an increase in abscisic acid (ABA) levels. Concomitantly, genes for ABA metabolism were up-regulated in the mutant. The expression of a subset of ABA-inducible genes, such as RD29A and KIN1/2, was down-regulated, but that of other genes, like ABI1 and HAB1, was up-regulated in cpr22 after the humidity shift. cpr22 showed reduced responsiveness to ABA not only in abiotic stress responses but also in germination and stomatal closure. Double mutant analysis with nahG plants that degrade SA indicated that these alterations in ABA signaling were attributable to elevated SA levels. Furthermore, cpr22 displayed suppressed drought responses by long-term drought stress. Taken together, these results suggest an effect of SA on ABA signaling/abiotic stress responses during the activation of defense responses in cpr22.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Keiko Yoshioka
- Department of Cell and Systems Biology (S.M., W.M., W.U., E.N., K.Y.) and Center for the Analysis of Genome Evolution and Function (W.M., E.N., K.Y.), University of Toronto, Toronto, Ontario M5S 3B2, Canada; Division of Biological Sciences, Cell and Developmental Biology Section, and Center for Molecular Genetics, University of California, San Diego, La Jolla, California 92093–0116 (N.N.); Growth Regulation Research Group, RIKEN Plant Science Center, Suehiro-cho, Tsurumi-ku, Yokohama 230–0045, Japan (Y.J., E.N.); Department of Life Science, Chung-Ang University, Seoul 156–756, South Korea (S.-H.J., S.-K.K.); and Boyce Thompson Institute for Plant Research, Ithaca, New York 14850 (D.F.K.)
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Lee TF, McNellis TW. Evidence that the BONZAI1/COPINE1 protein is a calcium- and pathogen-responsive defense suppressor. PLANT MOLECULAR BIOLOGY 2009; 69:155-166. [PMID: 18855102 DOI: 10.1007/s11103-008-9413-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 09/29/2008] [Indexed: 05/26/2023]
Abstract
Copines are calcium-responsive, phospholipid-binding proteins involved in cellular signaling. The Arabidopsis BONZAI1/COPINE1 (BON1/CPN1) gene is a suppressor of defense responses controlled by the disease resistance (R) gene homolog SNC1. The BON1/CPN1 null mutant cpn1-1 has a recessive, temperature- and humidity-dependent, lesion mimic phenotype that includes activation of Pathogenesis-Related (PR) gene expression. Here, we demonstrated that the accumulation of BON1/CPN1 protein in wild-type plants was up-regulated by bacterial pathogen inoculation and by the activation of defense signaling responses controlled by two R genes, SNC1 and RPS2. Interestingly, however, over-accumulation of BON1/CPN1 in two BON1/CPN1 promoter T-DNA insertion mutants did not affect resistance to a bacterial pathogen. Promoter deletion analysis identified a 280 bp segment of the BON1/CPN1 promoter as being required for pathogen-induced gene expression; the same promoter region was also required for calcium ionophore-induced gene expression. Leaf infiltration with calcium ionophore triggered high-level PR gene expression specifically in cpn1-1 plants grown under permissive conditions, while co-infiltration of the calcium chelator EGTA attenuated this effect. These results explain the conditional nature of the cpn1-1 phenotype and are consistent with BON1/CPN1 being a calcium- and pathogen-responsive plant defense suppressor.
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Affiliation(s)
- Tzuu-Fen Lee
- 211 Buckhout Laboratory, Plant Pathology Department, Pennsylvania State University, University Park, PA 16802, USA
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18
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Wang X, Li Q, Niu X, Chen H, Xu L, Qi C. Characterization of a canola C2 domain gene that interacts with PG, an effector of the necrotrophic fungus Sclerotinia sclerotiorum. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:2613-20. [PMID: 19436047 PMCID: PMC2692008 DOI: 10.1093/jxb/erp104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Sspg1d, one of endopolygalacturonases, is an important fungal effector secreted by the necrotrophic fungus Sclerotinia sclerotiorum during early infection. Using sspg1d as bait, a small C2 domain protein (designated as IPG-1) was identified by yeast two-hybrid screening of a canola cDNA library. Deletion analysis confirmed that the C-terminus of IPG-1 is responsible for its interaction with sspg1d in the yeast two-hybrid assay. The sspg1d/IPG-1 interaction was further confirmed in plant cells by a biomolecular fluorescence complementation (BiFC) assay. A transient expression assay showed that the IPG-1-GFP fusion protein was targeted to the plasma membrane and nucleus in onion epidermal cells. Following treatment with a Ca(2+) ionophore, it was distributed throughout the cytosol. Real-time PCR assay demonstrated that IPG-1 was highly induced by Sclerotinia sclerotiorum in canola leaves and stems. Southern blot analysis indicated the presence of about five homologues of IPG-1 in the canola genome. Two additional members of the IPG-1gene family were isolated by RT-PCR. Their sequence similarity with IPG-1 is as high as 95%. However, they did not interact with sspg1d in the yeast two-hybrid assay. Possible roles of IPG-1 and its association with sspg1d in the defence signalling pathway were discussed.
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Affiliation(s)
- Xinyu Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
- The State Key Laboratory of Crop Genetics & Germplasm enhancement, Nanjing Agricultural University, Nanjing 210095, China
- Academy of Jiangsu Agricultural Sciences, Nanjing 210014, China
- To whom correspondence should be addressed. E-mail: ,
| | - Qian Li
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaowei Niu
- The State Key Laboratory of Crop Genetics & Germplasm enhancement, Nanjing Agricultural University, Nanjing 210095, China
| | - Haiyan Chen
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Langlai Xu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Cunkou Qi
- Academy of Jiangsu Agricultural Sciences, Nanjing 210014, China
- To whom correspondence should be addressed. E-mail: ,
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Biomphalaria glabrata transcriptome: cDNA microarray profiling identifies resistant- and susceptible-specific gene expression in haemocytes from snail strains exposed to Schistosoma mansoni. BMC Genomics 2008; 9:634. [PMID: 19114004 PMCID: PMC2631019 DOI: 10.1186/1471-2164-9-634] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2008] [Accepted: 12/29/2008] [Indexed: 01/18/2023] Open
Abstract
Background Biomphalaria glabrata is an intermediate snail host for Schistosoma mansoni, one of the important schistosomes infecting man. B. glabrata/S. mansoni provides a useful model system for investigating the intimate interactions between host and parasite. Examining differential gene expression between S. mansoni-exposed schistosome-resistant and susceptible snail lines will identify genes and pathways that may be involved in snail defences. Results We have developed a 2053 element cDNA microarray for B. glabrata containing clones from ORESTES (Open Reading frame ESTs) libraries, suppression subtractive hybridization (SSH) libraries and clones identified in previous expression studies. Snail haemocyte RNA, extracted from parasite-challenged resistant and susceptible snails, 2 to 24 h post-exposure to S. mansoni, was hybridized to the custom made cDNA microarray and 98 differentially expressed genes or gene clusters were identified, 94 resistant-associated and 4 susceptible-associated. Quantitative PCR analysis verified the cDNA microarray results for representative transcripts. Differentially expressed genes were annotated and clustered using gene ontology (GO) terminology and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis. 61% of the identified differentially expressed genes have no known function including the 4 susceptible strain-specific transcripts. Resistant strain-specific expression of genes implicated in innate immunity of invertebrates was identified, including hydrolytic enzymes such as cathepsin L, a cysteine proteinase involved in lysis of phagocytosed particles; metabolic enzymes such as ornithine decarboxylase, the rate-limiting enzyme in the production of polyamines, important in inflammation and infection processes, as well as scavenging damaging free radicals produced during production of reactive oxygen species; stress response genes such as HSP70; proteins involved in signalling, such as importin 7 and copine 1, cytoplasmic intermediate filament (IF) protein and transcription enzymes such as elongation factor 1α and EF-2. Conclusion Production of the first cDNA microarray for profiling gene expression in B. glabrata provides a foundation for expanding our understanding of pathways and genes involved in the snail internal defence system (IDS). We demonstrate resistant strain-specific expression of genes potentially associated with the snail IDS, ranging from signalling and inflammation responses through to lysis of proteinacous products (encapsulated sporocysts or phagocytosed parasite components) and processing/degradation of these targeted products by ubiquitination.
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Yang W, Ng P, Zhao M, Wong TKF, Yiu SM, Lau YL. Promoter-sharing by different genes in human genome--CPNE1 and RBM12 gene pair as an example. BMC Genomics 2008; 9:456. [PMID: 18831769 PMCID: PMC2568002 DOI: 10.1186/1471-2164-9-456] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Accepted: 10/03/2008] [Indexed: 11/27/2022] Open
Abstract
Background Regulation of gene expression plays important role in cellular functions. Co-regulation of different genes may indicate functional connection or even physical interaction between gene products. Thus analysis on genomic structures that may affect gene expression regulation could shed light on the functions of genes. Results In a whole genome analysis of alternative splicing events, we found that two distinct genes, copine I (CPNE1) and RNA binding motif protein 12 (RBM12), share the most 5' exons and therefore the promoter region in human. Further analysis identified many gene pairs in human genome that share the same promoters and 5' exons but have totally different coding sequences. Analysis of genomic and expressed sequences, either cDNAs or expressed sequence tags (ESTs) for CPNE1 and RBM12, confirmed the conservation of this phenomenon during evolutionary courses. The co-expression of the two genes initiated from the same promoter is confirmed by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) in different tissues in both human and mouse. High degrees of sequence conservation among multiple species in the 5'UTR region common to CPNE1 and RBM12 were also identified. Conclusion Promoter and 5'UTR sharing between CPNE1 and RBM12 is observed in human, mouse and zebrafish. Conservation of this genomic structure in evolutionary courses indicates potential functional interaction between the two genes. More than 20 other gene pairs in human genome were found to have the similar genomic structure in a genome-wide analysis, and it may represent a unique pattern of genomic arrangement that may affect expression regulation of the corresponding genes.
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Affiliation(s)
- Wanling Yang
- Department of Paediatrics & Adolescent Medicine, LKS Faculty of Medicine, University of Hong Kong, Hong Kong, PR China.
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21
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Cheung MY, Zeng NY, Tong SW, Li WYF, Xue Y, Zhao KJ, Wang C, Zhang Q, Fu Y, Sun Z, Sun SSM, Lam HM. Constitutive expression of a rice GTPase-activating protein induces defense responses. THE NEW PHYTOLOGIST 2008; 179:530-545. [PMID: 19086295 DOI: 10.1111/j.1469-8137.2008.02473.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
G-proteins (guanine nucleotide-binding proteins that usually exhibit GTPase activities) and related signal transduction processes play important roles in mediating plant defense responses; here, a rice (Oryza sativa) cDNA clone, OsGAP1, encoding a GTPase-activating protein (GAP) that also contains a protein kinase C conserved region 2 (C2) domain is reported. An interacting G-protein partner for the OsGAP1 protein was identified by yeast two-hybrid library screening and confirmed by co-immunoprecipitation; the GTPase-activation activity of OsGAP1 on this interacting G-protein was demonstrated using in vitro assays. OsGAP1 was induced by wounding in rice and the presence of the R locus Xa14 enhances such induction. Gain-of-function tests in transgenic rice and Arabidopsis thaliana showed that constitutive expression of OsGAP1 led to increased resistance to bacterial pathogens in both monocots and dicots.
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Affiliation(s)
- Ming-Yan Cheung
- Department of Biology and
- State (China) Key Laboratory for Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | | | - Suk-Wah Tong
- Department of Biology and
- State (China) Key Laboratory for Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | - Wing-Yen Francisca Li
- Department of Biology and
- State (China) Key Laboratory for Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | - Yan Xue
- State (China) Key Laboratory for Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | - Kai-Jun Zhao
- Institute of Crop Sciences, The Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chunlian Wang
- Institute of Crop Sciences, The Chinese Academy of Agricultural Sciences, Beijing, China
| | - Qi Zhang
- Institute of Crop Sciences, The Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yaping Fu
- China National Rice Research Institute, Hangzhou, China
| | - Zongxiu Sun
- China National Rice Research Institute, Hangzhou, China
| | - Samuel Sai-Ming Sun
- Department of Biology and
- State (China) Key Laboratory for Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
| | - Hon-Ming Lam
- Department of Biology and
- State (China) Key Laboratory for Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong Special Administrative Region
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Zhang Y, Gao Q, Duan S, He Y, Sun X, Jiang R, Duan Y, Zhong X, Ge J. Upregulation of Copine1 in trabecular meshwork cells of POAG patients: a membrane proteomics approach. Mol Vis 2008; 14:1028-36. [PMID: 18523666 PMCID: PMC2408776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 05/22/2008] [Indexed: 11/16/2022] Open
Abstract
PURPOSE Primary open-angle glaucoma (POAG) is a leading cause of irreversible blindness worldwide, and its pathogenesis is still unknown. The purpose of this study was to determine molecular changes in membrane proteins in trabecular meshwork (TM) cells from POAG patients compared to those of age-matched normal controls. METHODS Two-dimensional (2-D) gel electrophoresis profiles of membrane extracts from normal and glaucomatous TM cells were compared. The desired spots were identified after trypsin digestion and mass spectrometric analysis. Based on the results, a calcium-dependant membrane-binding protein, copine1, was further approached for a possible role in glaucomatous TM cells. The intracellular calcium concentration ([Ca(2+)]i) of TM cells was increased by incubating with calcium ionophore, A23187. Relative quantification real-time polymerase chain reaction (PCR) and western blot analysis measured copine1 expression and localization both in untreated and A23187-treated TM cells. RESULTS Real-time PCR and western blot analysis confirmed that copine1 mRNA and protein expression were upregulated in glaucomatous TM cells when compared to normal ones. The cell distribution studies further showed that copine1 existed both in the membrane and cytoplasm fractions of glaucomatous TM cells but existed exclusively in cytoplasm fractions of their normal counterparts. More importantly, an influx of Ca(2+) markedly promoted the translocation of copine1 from the cytoplasm to membranes in glaucomatous TM cells. CONCLUSIONS Copine1 is upregulated in plasma membranes of TM cells in individuals with POAG, which may be partly explained by its Ca(2+)-dependent translocation from the cytoplasm to the membranes. Investigation of the role and functions of copine1 in TM cells should offer new insight into the abnormal intracellular Ca(2+)-signaling pathway in glaucomatous TM and help to clarify the molecular mechanism of POAG.
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Ding X, Jin Y, Wu Y, Wu Y, Wu H, Xiong L, Song X, Liu S, Fan W, Fan M. Localization and cellular distribution of CPNE5 in embryonic mouse brain. Brain Res 2008; 1224:20-8. [PMID: 18614158 DOI: 10.1016/j.brainres.2008.05.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2007] [Revised: 05/07/2008] [Accepted: 05/19/2008] [Indexed: 10/22/2022]
Abstract
CPNE5 is one of the ubiquitous Ca(2+)-dependent, phospholipid-binding proteins that are highly conserved in animals. It was cloned in the fetal human brain with no exact functions identified yet. We have examined the distribution pattern of CPNE5 mRNA and protein in the developing murine brain by using in situ hybridization, western blotting and immunocytochemistry. Expression of CPNE5 mRNA remains high from embryonic day 9.5 (E9.5) to E15.5 in the developing murine brain. Whole-mount in situ hybridization with the E11.5 and E12.5 embryos showed the strong positive signals in the central nervous system. Western-blot analysis showed that CPNE5 protein is expressed in the developing but not in the adult murine brain. In situ hybridization and immunohistochemistry analysis on the embryonic brain sections indicated that both at RNA and protein levels CPNE5 is mainly expressed in frontal cortex, medial nasal prominence, ganglionic eminence and medulla, particularly in the ventricular zones. Further investigation revealed the co-localization of CPNE5 with Tuj1 and Nestin on embryonic brain sections. In addition to the slight expression in primary cultured neural progenitor cells, CPNE5 is found in soma and neurite projections of primary cultured neurons where Tuj1 is co-localized. Our results demonstrate that CPNE5 is expressed in both neural progenitor cells and the differentiated neurons during the neural development, which suggests that CPNE5 might play an important role in the development of murine central nervous system.
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Affiliation(s)
- Xuefeng Ding
- Department of Brain Protection and Plasticity Research, Beijing Institute of Basic Medical Sciences, Taiping Road 27, Beijing 100850, P.R. China
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Bove J, Kim CY, Gibson CA, Assmann SM. Characterization of wound-responsive RNA-binding proteins and their splice variants in Arabidopsis. PLANT MOLECULAR BIOLOGY 2008; 67:71-88. [PMID: 18278441 DOI: 10.1007/s11103-008-9302-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Accepted: 01/25/2008] [Indexed: 05/24/2023]
Abstract
We report the characterization of three UBA2 genes (UBA2a, -b, and -c; corresponding to At3g56860, At2g41060, and At3g15010) encoding Arabidopsis thaliana proteins with high homology to Vicia faba AKIP1 and other heterogeneous nuclear ribonucleoprotein (hnRNP)-type RNA-binding proteins. In vitro RNA binding assays revealed that the three UBA2 proteins interact efficiently with homoribopolymers. Biolistic transient expression of UBA2-GFPs demonstrated that the three UBA2 proteins localize to the nucleus. Expression analysis by RNA gel blot, RT-PCR, and promoter::GUS assays showed that UBA2 transcripts are present in all organs. UBA2 genes are subject to alternative splicing affecting only the 3'-untranslated regions (UTRs): six different splice variants were detected for UBA2a, and two each were found for UBA2b and UBA2c. RT-PCR and quantitative real-time RT-PCR analysis showed that the levels of UBA2 transcripts are regulated by wounding in a splice variant-specific manner: splice variants UBA2a.1 and UBA2c.1 increased following mechanical wounding. Wounding effects on gene expression are transduced by methyl jasmonate (MeJA)-dependent and oligogalacturonide (OGA)-dependent pathways. However, neither MeJA nor OGA treatment altered levels of any of the UBA2 transcripts, and other plant hormones implicated in wound responses, ethylene and abscisic acid (ABA), also had no effect on accumulation of UBA2 transcripts. Taken together, these results imply that the three UBA2 genes encode hnRNP-type nuclear RNA-binding proteins that function in a novel wound signal transduction pathway.
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Affiliation(s)
- Jérôme Bove
- Biology Department, Penn State University, 208 Mueller Laboratory, University Park, PA 16802, USA
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Király L, Hafez YM, Fodor J, Király Z. Suppression of tobacco mosaic virus-induced hypersensitive-type necrotization in tobacco at high temperature is associated with downregulation of NADPH oxidase and superoxide and stimulation of dehydroascorbate reductase. J Gen Virol 2008; 89:799-808. [PMID: 18272772 DOI: 10.1099/vir.0.83328-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tissue necroses and resistance during the hypersensitive response (HR) of tobacco to tobacco mosaic virus (TMV) are overcome at temperatures above 28 degrees C and the virus multiplies to high levels in the originally resistant N-gene expressing plants. We have demonstrated that chemical compounds that generate reactive oxygen species (ROS) or directly applied hydrogen peroxide (H(2)O(2)) are able to induce HR-type necroses in TMV-inoculated Xanthi-nc tobacco even at high temperatures (e.g. 30 degrees C). The amount of superoxide (O(2)(*-)) decreased, while H(2)O(2) slightly increased in TMV- and mock-inoculated leaves at 30 degrees C, as compared with 20 degrees C. Activity of NADPH oxidase and mRNA levels of genes that encode NADPH oxidase and an alternative oxidase, respectively, were significantly lower, while activity of dehydroascorbate reductase was significantly higher at 30 degrees C, as compared with 20 degrees C. It was possible to reverse or suppress the chemically induced HR-type necrotization at 30 degrees C by the application of antioxidants, such as superoxide dismutase and catalase, demonstrating that the development of HR-type necroses indeed depends on a certain level of superoxide and other ROS. Importantly, high TMV levels at 30 degrees C were similar in infected plants, whether the HR-type necrotization developed or not. Suppression of virus multiplication in resistant, HR-producing tobacco at lower temperatures seems to be independent of the appearance of necroses but is associated with temperatures below 28 degrees C.
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Affiliation(s)
- L Király
- Plant Protection Institute, Hungarian Academy of Sciences, PO Box 102, H-1525 Budapest, Hungary
| | - Y M Hafez
- Department of Botany, Plant Pathology Branch, Faculty of Agriculture, Kafr-El-Sheikh University, Kafr-El-Sheikh, Egypt
| | - J Fodor
- Plant Protection Institute, Hungarian Academy of Sciences, PO Box 102, H-1525 Budapest, Hungary
| | - Z Király
- Plant Protection Institute, Hungarian Academy of Sciences, PO Box 102, H-1525 Budapest, Hungary
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Zhou F, Mosher S, Tian M, Sassi G, Parker J, Klessig DF. The Arabidopsis gain-of-function mutant ssi4 requires RAR1 and SGT1b differentially for defense activation and morphological alterations. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:40-49. [PMID: 18052881 DOI: 10.1094/mpmi-21-1-0040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A gain-of-function mutation in resistance (R) gene SSI4 causes constitutive activation of defense responses, spontaneous necrotic lesion formation, enhanced resistance against virulent pathogens, and a severe dwarf phenotype. Genetic analysis revealed that ssi4-induced H(2)O(2) accumulation and spontaneous cell death require RAR1, whereas ssi4-mediated stunting is dependent on SGT1b. By contrast, both RAR1 and SGT1b are required in a genetically additive manner for ssi4-induced disease resistance, SA accumulation, and lesion formation after pathogen infection. These data point to cooperative yet distinct functions of RAR1 and SGT1b in responses conditioned by a deregulated nucleotide-binding leucine-rich repeat protein. We also found that RAR1 and SGT1b together contribute to basal resistance because an ssi4 rar1 sgt1b triple mutant exhibited enhanced susceptibility to virulent pathogen infection compared with wild-type SSI4 plants. All ssi4-induced phenotypes were suppressed when plants were grown at 22 degrees C under high relative humidity. However, low temperature (16 degrees C) triggered ssi4-mediated cell death via an RAR1-dependent pathway even in the presence of high humidity. Thus, multiple environmental factors impact on ssi4 signaling, as has been observed for other constitutive defense mutants and R gene-triggered pathways.
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Affiliation(s)
- Fasong Zhou
- Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY 14853, USA
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Ahn IP, Suh SC. Calcium Restores Prepenetration Morphogenesis Abolished by Methylglyoxal-Bis-Guanyl Hydrazone in Cochliobolus miyabeanus Infecting Rice. PHYTOPATHOLOGY 2007; 97:331-337. [PMID: 18943653 DOI: 10.1094/phyto-97-3-0331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
ABSTRACT Cochliobolus miyabeanus forms a specialized infection structure, an appressorium, to infect its host rice plants. Curtailment of prepenetration development by spermidine and spermine was more evident in appressorium development and germination remained unaffected, whereas putrescine and methylglyoxal-bis-guanyl hydrazone (MGBG) impaired both morphogenetic events. Exogenous calcium nullified the inhibitory effect of MGBG on the prepenetration development in vitro and in vivo and the disease progression. High levels of polyamines were detected in freshly collected conidia, but the amounts were reduced during germination and appressorium formation. MGBG fortified the decrease of polyamines within conidia under development and calcium amendment did not affect the reduction. Hard-surface contact augmented messenger RNA synthesis of calmodulin gene (CmCaM) and protein kinase C (PKC) activity in germinating or appressorium-forming conidia. Calcium restored transcription of CmCaM and upregulation of PKC activity suppressed by MGBG. Taken together, fine-tuning of intracellular polyamine transition is indispensable for the conidial germination and appressorium formation in C. miyabeanus. Biochemical and molecular analyses revealed that the MGBG-acting site or sites are upstream of Ca(2+)-dependent signaling pathways regulating prepenetration morphogenesis of C. miyabeanus causing rice brown leaf spot.
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Hong JK, Choi HW, Hwang IS, Hwang BK. Role of a novel pathogen-induced pepper C3-H-C4 type RING-finger protein gene, CaRFPI, in disease susceptibility and osmotic stress tolerance. PLANT MOLECULAR BIOLOGY 2007; 63:571-88. [PMID: 17149652 DOI: 10.1007/s11103-006-9110-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 11/01/2006] [Indexed: 05/12/2023]
Abstract
Limited information is available about the roles of RING-finger proteins in plant defense. A pepper CaRFP1 encoding the C3-H-C4 type RING-finger protein that physically interacted with the basic PR-1 protein CABPR1 was isolated from pepper leaves infected by Xanthomonas campestris pv. vesicatoria. The CaRFP1 protein has VWFA domain, and N-terminal serine-rich and C-terminal cysteine-rich regions. The CaRFP1 transcripts accumulated earlier than did those of the basic PR-1 gene CABPR1 during the incompatible interaction of pepper leaves with X. campestris pv. vesicatoria, as well as in the systemic, uninoculated pepper leaf tissues. The CaRFP1 gene also was induced in pepper leaf tissues infected by Colletotrichum coccodes. The CaRFP1 gene was strongly induced much earlier by salicylic acid, ethylene and methyl jasmonate treatments, as well as environmental stresses including methyl viologen, mannitol and NaCl treatments. Overexpression of the CaRFP1 gene in the transgenic Arabidopsis plants conferred disease susceptibility to Pseudomonas syringae pv. tomato infection, accompanied by reduced PR-2 and PR-5 gene expression, suggesting that the CaRFP1 acts as an E3 ligase for polyubiquitination of target PR proteins. Exogenous salicylic acid treatment also abolished PR-2 and PR-5 gene expression in the transgenic plants. Differential osmotic stress tolerance was induced by high salt and drought in the CaRFPI-overexpressing plants during germination and seedling development, which was closely correlated with abscisic acid sensitivity of Arabidopsis plants. These results suggest that the CaRFP1 gene functions as an early defense regulator controlling bacterial disease susceptibility and osmotic stress tolerance.
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Affiliation(s)
- Jeum Kyu Hong
- Laboratory of Molecular Plant Pathology, College of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-ku, Seoul 136-713, Republic of Korea
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Suarez-Rodriguez MC, Adams-Phillips L, Liu Y, Wang H, Su SH, Jester PJ, Zhang S, Bent AF, Krysan PJ. MEKK1 is required for flg22-induced MPK4 activation in Arabidopsis plants. PLANT PHYSIOLOGY 2007; 143:661-9. [PMID: 17142480 PMCID: PMC1803745 DOI: 10.1104/pp.106.091389] [Citation(s) in RCA: 236] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The Arabidopsis (Arabidopsis thaliana) gene MEKK1 encodes a mitogen-activated protein kinase kinase kinase that has been implicated in the activation of the map kinases MPK3 and MPK6 in response to the flagellin elicitor peptide flg22. In this study, analysis of plants carrying T-DNA knockout alleles indicated that MEKK1 is required for flg22-induced activation of MPK4 but not MPK3 or MPK6. Experiments performed using a kinase-impaired version of MEKK1 (K361M) showed that the kinase activity of MEKK1 may not be required for flg22-induced MPK4 activation or for other macroscopic FLS2-mediated responses. MEKK1 may play a structural role in signaling, independent of its protein kinase activity. mekk1 knockout mutants display a severe dwarf phenotype, constitutive callose deposition, and constitutive expression of pathogen response genes. This dwarf phenotype was largely rescued by introduction into mekk1 knockout plants of either the MEKK1 (K361M) construct or a nahG transgene that degrades salicylic acid. When treated with pathogenic bacteria, the K361M plants were slightly more susceptible to an avirulent strain of Pseudomonas syringae and showed a delayed hypersensitive response, suggesting a role for MEKK1 kinase activity in this aspect of plant disease resistance. Our results indicate that MEKK1 acts upstream of MPK4 as a negative regulator of pathogen response pathways, a function that may not require MEKK1's full kinase activity.
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Damer CK, Bayeva M, Kim PS, Ho LK, Eberhardt ES, Socec CI, Lee JS, Bruce EA, Goldman-Yassen AE, Naliboff LC. Copine A is required for cytokinesis, contractile vacuole function, and development in Dictyostelium. EUKARYOTIC CELL 2007; 6:430-42. [PMID: 17259548 PMCID: PMC1828924 DOI: 10.1128/ec.00322-06] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Copines make up a family of soluble, calcium-dependent, membrane binding proteins found in a variety of eukaryotic organisms. In an earlier study, we identified six copine genes in the Dictyostelium discoideum genome and focused our studies on cpnA. Our previous localization studies of green fluorescent protein-tagged CpnA in Dictyostelium suggested that CpnA may have roles in contractile vacuole function, endolysosomal trafficking, and development. To test these hypotheses, we created a cpnA- knockout strain, and here we report the initial characterization of the mutant phenotype. The cpnA- cells exhibited normal growth rates and a slight cytokinesis defect. When placed in starvation conditions, cpnA- cells appeared to aggregate into mounds and form fingers with normal timing; however, they were delayed or arrested in the finger stage. When placed in water, cpnA- cells formed unusually large contractile vacuoles, indicating a defect in contractile vacuole function, while endocytosis and phagocytosis rates for the cpnA- cells were similar to those seen for wild-type cells. These studies indicate that CpnA plays a role in cytokinesis and contractile vacuole function and is required for normal development, specifically in the later stages prior to culmination. We also used real-time reverse transcription-PCR to determine the expression patterns of all six copine genes during development. The six copine genes were expressed in vegetative cells, with each gene exhibiting a distinct pattern of expression throughout development. All of the copine genes except cpnF showed an upregulation of mRNA expression at one or two developmental transitions, suggesting that copines may be important regulators of Dictyostelium development.
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Affiliation(s)
- Cynthia K Damer
- Biology Department, Vassar College, Box 566, 124 Raymond Ave., Poughkeepsie, NY 12604, USA.
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Yang H, Li Y, Hua J. The C2 domain protein BAP1 negatively regulates defense responses in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 48:238-48. [PMID: 17018034 DOI: 10.1111/j.1365-313x.2006.02869.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The Arabidopsis BAP1 gene encodes a small protein with a C2-like domain. Here we show that the BAP1 protein is capable of binding to phospholipids in a calcium-dependent manner and is associated with membranes in vivo. We identify multiple roles of BAP1 in negatively regulating defense responses and cell death in Arabidopsis thaliana. The loss of BAP1 function confers an enhanced disease resistance to virulent bacterial and oomycete pathogens. The enhanced resistance is mediated by salicylic acid, PAD4 and a disease resistance gene SNC1. BAP1 is also involved in the control of cell death, which is suggested by an altered hypersensitive response to an avirulent bacterial pathogen in the bap1 loss-of-function mutant. BAP1 overexpression leads to an enhanced susceptibility to a virulent oomycete, suggesting a role for BAP1 in basal defense response. Furthermore, the BAP1 protein probably functions together with an evolutionarily conserved C2 domain protein BON1/CPN1 to negatively regulate defense responses in plants.
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Affiliation(s)
- Huijun Yang
- Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA
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Garcia-Brugger A, Lamotte O, Vandelle E, Bourque S, Lecourieux D, Poinssot B, Wendehenne D, Pugin A. Early signaling events induced by elicitors of plant defenses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2006; 19:711-24. [PMID: 16838784 DOI: 10.1094/mpmi-19-0711] [Citation(s) in RCA: 339] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Plant pathogen attacks are perceived through pathogen-issued compounds or plant-derived molecules that elicit defense reactions. Despite the large variety of elicitors, general schemes for cellular elicitor signaling leading to plant resistance can be drawn. In this article, we review early signaling events that happen after elicitor perception, including reversible protein phosphorylations, changes in the activities of plasma membrane proteins, variations in free calcium concentrations in cytosol and nucleus, and production of nitric oxide and active oxygen species. These events occur within the first minutes to a few hours after elicitor perception. One specific elicitor transduction pathway can use a combination or a partial combination of such events which can differ in kinetics and intensity depending on the stimulus. The links between the signaling events allow amplification of the signal transduction and ensure specificity to get appropriate plant defense reactions. This review first describes the early events induced by cryptogein, an elicitor of tobacco defense reactions, in order to give a general scheme for signal transduction that will be use as a thread to review signaling events monitored in different elicitor or plant models.
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Affiliation(s)
- Angela Garcia-Brugger
- UMR 1088 INRA/CNRS 5184/Université de Bourgogne Plante Microbe Environnement, INRA, Dijon, France.
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Jambunathan N, Mahalingam R. Analysis of Arabidopsis growth factor gene 1 (GFG1) encoding a nudix hydrolase during oxidative signaling. PLANTA 2006; 224:1-11. [PMID: 16328543 DOI: 10.1007/s00425-005-0183-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Accepted: 11/08/2005] [Indexed: 05/05/2023]
Abstract
Maintenance of pyridine nucleotide homeostasis is vital for normal growth and development of plants and animals. We demonstrate that Arabidopsis Growth Factor Gene 1 (GFG1; At4g12720) encoding a nudix hydrolase, is an NADH pyrophosphatase and ADP-ribose pyrophosphatase. The affinity for NADH and ADP-ribose indicates that this enzyme could serve as a connection between sensing cellular redox changes and downstream signaling. GFG1 transcript levels were rapidly and transiently induced during both biotic stresses imposed by avirulent pathogens and abiotic stresses like ozone and osmoticum. T-DNA knock out plants of GFG1 gene, gfg1-1, exhibit pleiotropic phenotypes such as reduced size, increased levels of reactive oxygen species and NADH, microscopic cell death, constitutive expression of pathogenesis-related genes and enhanced resistance to bacterial pathogens. The recombinant protein failed to complement the mutator deficiency in SBMutT- strain of Escherichia coli, suggesting this protein may not play a role in sanitizing the nucleotide pool. Based on rapid transcriptional changes in response to various stresses, substrate specificity of the enzyme, and analysis of the knock out mutant, we propose that GFG1 is a key gene linking cellular metabolism and oxidative signaling.
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Affiliation(s)
- Niranjani Jambunathan
- Department of Biochemistry and Molecular Biology, 246 Noble Research center, Oklahoma State University, Stillwater, OK 74078, USA
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Abstract
In plant cells, the calcium ion is a ubiquitous intracellular second messenger involved in numerous signalling pathways. Variations in the cytosolic concentration of Ca2+ ([Ca2+]cyt) couple a large array of signals and responses. Here we concentrate on calcium signalling in plant defence responses, particularly on the generation of the calcium signal and downstream calcium-dependent events participating in the establishment of defence responses with special reference to calcium-binding proteins.
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Affiliation(s)
- David Lecourieux
- UMR CNRS 5546 Université Paul Sabatier, Signaux et Messages Cellulaires chez les Végétaux, Pôle de Biotechnologies Végétales, 24 chemin de Borde Rouge, BP 17, Auzeville, 31326 Castanet-Tolosan, France
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Damer CK, Bayeva M, Hahn ES, Rivera J, Socec CI. Copine A, a calcium-dependent membrane-binding protein, transiently localizes to the plasma membrane and intracellular vacuoles in Dictyostelium. BMC Cell Biol 2005; 6:46. [PMID: 16343335 PMCID: PMC1327671 DOI: 10.1186/1471-2121-6-46] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Accepted: 12/12/2005] [Indexed: 01/18/2023] Open
Abstract
Background Copines are soluble, calcium-dependent membrane binding proteins found in a variety of organisms. Copines are characterized as having two C2 domains at the N-terminal region followed by an "A domain" at the C-terminal region. The "A domain" is similar in sequence to the von Willebrand A (VWA) domain found in integrins. The presence of C2 domains suggests that copines may be involved in cell signaling and/or membrane trafficking pathways. Results We have identified six copines genes in the Dictyostelium discoideum genome, cpnA-cpnF, and have focused our studies on cpnA. CpnA is expressed throughout development and was shown to be capable of binding to membranes in a calcium-dependent manner in vitro. A GFP-tagged CpnA was also capable of binding to membranes in a calcium-dependent manner in vitro. In live wildtype Dictyostelium cells expressing GFP-CpnA, GFP-CpnA was typically found in the cytoplasm without any specific localization to membranes. However, in a small subset of starved cells, GFP-CpnA was observed to bind transiently (typically ~1–10 s) to the plasma membrane and intracellular vacuoles. In some cells, the transient membrane localization of GFP-CpnA was observed to occur multiple times in an oscillatory manner over several minutes. In plasma membrane disrupted cells, GFP-CpnA was observed to associate with the plasma membrane and intracellular vacuoles in a calcium-dependent manner. In fixed cells, GFP-CpnA labeled the plasma membrane and intracellular vacuoles, including contractile vacuoles, organelles of the endolysosomal pathway, and phagosomes. Conclusion Our results show that Dictyostelium has multiple copine homologs and provides an excellent system in which to study copine function. The localization of a GFP-tagged CpnA to the plasma membrane, contractile vacuoles, organelles of the endolysosomal pathway, and phagosomes suggests that CpnA may have a role in the function of these organelles or the trafficking to and from them. In addition, we hypothesize that the observed transient oscillatory membrane localization of GFP-CpnA in a small subset of starved cells is caused by fast calcium waves and speculate that CpnA may have a role in development, particularly in the differentiation of stalk cells.
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Affiliation(s)
- Cynthia K Damer
- Biology Department, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604
| | - Marina Bayeva
- Biology Department, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604
| | - Emily S Hahn
- Biology Department, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604
| | - Javier Rivera
- Biology Department, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604
| | - Catherine I Socec
- Biology Department, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604
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Racapé J, Belbahri L, Engelhardt S, Lacombe B, Lee J, Lochman J, Marais A, Nicole M, Nürnberger T, Parlange F, Puverel S, Keller H. Ca2+-dependent lipid binding and membrane integration of PopA, a harpin-like elicitor of the hypersensitive response in tobacco. Mol Microbiol 2005; 58:1406-20. [PMID: 16313625 DOI: 10.1111/j.1365-2958.2004.04910.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PopA is released by type III secretion from the bacterial plant pathogen Ralstonia solanacearum and triggers the hypersensitive response (HR) in tobacco. The function of PopA remains obscure, mainly because mutants lacking this protein are not altered in their ability to interact with plants. In an attempt to identify the site of PopA activity in plant cells, we generated transgenic tobacco plants expressing the popA gene under the control of an inducible promoter. Immunocytologic analysis revealed that the HR phenotype of these plants correlated with the presence of PopA at the plant plasma membrane. Membrane localization was observed irrespective of whether the protein was designed to accumulate in the cytoplasm or to be secreted by the plant cell, suggesting a general lipid-binding ability. We found that the protein had a high affinity for sterols and sphingolipids in vitro and that it required Ca2+ for both lipid binding and oligomerization. In addition, the protein was integrated into liposomes and membranes from Xenopus laevis oocytes where it formed ion-conducting pores. These characteristics suggest that PopA is part of a system that aims to attach the host cell plasma membrane and to allow molecules cross this barrier.
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Affiliation(s)
- Judith Racapé
- Unité Mixte de Recherches Interactions Plantes-Microorganismes et Santé Végétale, INRA-CNRS-UNSA, 400 Route des Chappes, 06903 Sophia Antipolis, France
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Wang C, Cai X, Zheng Z. High humidity represses Cf-4/Avr4- and Cf-9/Avr9-dependent hypersensitive cell death and defense gene expression. PLANTA 2005; 222:947-56. [PMID: 16059720 DOI: 10.1007/s00425-005-0036-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Accepted: 06/06/2005] [Indexed: 05/03/2023]
Abstract
Gene-for-gene resistance is a well-known type of plant disease resistance. It is governed by plant resistance (R) genes and their matching pathogen avirulence (Avr) genes. This resistance is characterized by a hypersensitive response (HR) resulting from the interaction between products of a complementary R and Avr gene pair. The pathosystem of tomato (Lycopersicon esculentum Mill.) and its leaf mold fungal pathogen Cladosporium fulvum is a model system to study gene-for-gene resistance. HR occurs in tomato seedlings carrying a tomato Cf resistance gene and a matching C. fulvum Avr gene, including, for example, Cf-4/Avr4 and Cf-9/Avr9. Employing Cf/Avr tomato seedlings that both express a Cf gene and the matching Avr gene, here we report that both Cf-4/Avr4- and Cf-9/Avr9-dependent HR is delayed and reduced under high humidity (95%), and that Cf-9/Avr9-dependent HR is more sensitive to high humidity when compared to Cf-4/Avr4-dependent HR. Furthermore, high humidity acts synergistically with high temperature on HR suppression, resulting in complete blocking of the HR. The transcript profile of over 60 genes, related to HR, signaling and defense, in Cf/Avr seedlings grown under high humidity and thus showing no HR, significantly differed from that of the same seedlings grown under normal humidity and thus showing HR. These results demonstrate that high humidity probably acts at a very early point of the Cf downstream signaling pathway, or alternatively influences the interaction between the Cf and the Avr proteins.
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Affiliation(s)
- Changchun Wang
- Institute of Biotechnology and Department of Plant Protection, Zhejiang University, 258 Kai Xuan Road, Hangzhou, 310029, People's Republic of China
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Liu J, Jambunathan N, McNellis TW. Transgenic expression of the von Willebrand A domain of the BONZAI 1/COPINE 1 protein triggers a lesion-mimic phenotype in Arabidopsis. PLANTA 2005; 221:85-94. [PMID: 15843967 DOI: 10.1007/s00425-004-1413-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Accepted: 09/18/2004] [Indexed: 05/23/2023]
Abstract
The copines are a newly identified, widely distributed class of Ca(2+)-dependent, phospholipid-binding proteins that may be involved in cellular signaling. The copines have a characteristic domain structure: two C2 domains in the N-terminal region and a von Willebrand A (VWA) domain in the C-terminal region. Studies suggest that copines interact with target protein(s) via their VWA domain and recruit the proteins to a membrane location through the activity of the C2 domains. Arabidopsis thaliana (L.) Heynh. plants with loss-of-function mutations in the BONZAI 1/COPINE 1 (BON1/CPN1) gene display aberrant regulation of defense responses, including development of a lesion-mimic phenotype, an accelerated hypersensitive response, and increased resistance to a bacterial and an oomycetous pathogen. The phenotype of mutants in BON1/CPN1 is both humidity- and temperature-sensitive. In this study, we generated transgenic plants expressing either the VWA or the C2 portions of BON1/CPN1 in the wild-type Columbia-0 (Col-0) genetic background. Transgenic plants expressing the BON1/CPN1 C2 domain portion appeared like wild-type plants. However, transgenic plants expressing the BON1/CPN1 VWA domain exhibited a lesion-mimic phenotype that partially phenocopied bon1/cpn1 mutant plants. Our data suggest that BON1/CPN1 VWA domain fragments may interfere with the function of the full-length endogenous BON1/CPN1 protein, possibly by competing with the full-length BON1/CPN1 protein for association with target proteins normally bound to the full-length BON1/CPN1 protein.
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Affiliation(s)
- Jianxin Liu
- Plant Pathology Department, 211 Buckhout Laboratory, Pennsylvania State University, University Park, PA 16802, USA
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Podell S, Gribskov M. Predicting N-terminal myristoylation sites in plant proteins. BMC Genomics 2004; 5:37. [PMID: 15202951 PMCID: PMC449705 DOI: 10.1186/1471-2164-5-37] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2004] [Accepted: 06/17/2004] [Indexed: 01/09/2023] Open
Abstract
Background N-terminal myristoylation plays a vital role in membrane targeting and signal transduction in plant responses to environmental stress. Although N-myristoyltransferase enzymatic function is conserved across plant, animal, and fungal kingdoms, exact substrate specificities vary, making it difficult to predict protein myristoylation accurately within specific taxonomic groups. Results A new method for predicting N-terminal myristoylation sites specifically in plants has been developed and statistically tested for sensitivity, specificity, and robustness. Compared to previously available methods, the new model is both more sensitive in detecting known positives, and more selective in avoiding false positives. Scores of myristoylated and non-myristoylated proteins are more widely separated than with other methods, greatly reducing ambiguity and the number of sequences giving intermediate, uninformative results. The prediction model is available at . Conclusion Superior performance of the new model is due to the selection of a plant-specific training set, covering 266 unique sequence examples from 40 different species, the use of a probability-based hidden Markov model to obtain predictive scores, and a threshold cutoff value chosen to provide maximum positive-negative discrimination. The new model has been used to predict 589 plant proteins likely to contain N-terminal myristoylation signals, and to analyze the functional families in which these proteins occur.
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Affiliation(s)
- Sheila Podell
- San Diego Supercomputer Center, University of California San Diego, La Jolla CA 92093-0537, USA
- Department of Biology, University of California San Diego, La Jolla CA 92093-0537, USA
| | - Michael Gribskov
- San Diego Supercomputer Center, University of California San Diego, La Jolla CA 92093-0537, USA
- Department of Biology, University of California San Diego, La Jolla CA 92093-0537, USA
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Yang S, Hua J. A haplotype-specific Resistance gene regulated by BONZAI1 mediates temperature-dependent growth control in Arabidopsis. THE PLANT CELL 2004; 16:1060-71. [PMID: 15031411 PMCID: PMC412877 DOI: 10.1105/tpc.020479] [Citation(s) in RCA: 239] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2003] [Accepted: 02/11/2004] [Indexed: 05/17/2023]
Abstract
Plant growth homeostasis and defense responses are regulated by BONZAI1 (BON1), an evolutionarily conserved gene. Here, we show that growth regulation by BON1 is mediated through defense responses. BON1 is a negative regulator of a haplotype-specific Resistance (R) gene SNC1. The bon1-1 loss-of-function mutation activates SNC1, leading to constitutive defense responses and, consequently, reduced cell growth. In addition, a feedback amplification of the SNC1 gene involving salicylic acid is subject to temperature control, accounting for the regulation of growth and defense by temperature in bon1-1 and many other mutants. Thus, plant growth homeostasis involves the regulation of an R gene by BON1 and the intricate interplay between defense responses and temperature responses.
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Affiliation(s)
- Shuhua Yang
- Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA
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