751
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Arbelet D, Malfatti P, Simond-Côte E, Fontaine T, Desquilbet L, Expert D, Kunz C, Soulié MC. Disruption of the Bcchs3a chitin synthase gene in Botrytis cinerea is responsible for altered adhesion and overstimulation of host plant immunity. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1324-1334. [PMID: 20672878 DOI: 10.1094/mpmi-02-10-0046] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The fungal cell wall is a dynamic structure that protects the cell from different environmental stresses suggesting that wall synthesizing enzymes are of great importance for fungal virulence. Previously, we reported the isolation and characterization of a mutant in class III chitin synthase, Bcchs3a, in the phytopathogenic fungus Botrytis cinerea. We demonstrated that virulence of this mutant is severely impaired. Here, we describe the virulence phenotype of the cell-wall mutant Bcchs3a on the model plant Arabidopsis thaliana and analyze its virulence properties, using a variety of A. thaliana mutants. We found that mutant Bcchs3a is virulent on pad2 and pad3 mutant leaves defective in camalexin. Mutant Bcchs3a was not more susceptible towards camalexin than the wild-type strain but induced phytoalexin accumulation at the infection site on Col-0 plants. Moreover, this increase in camalexin was correlated with overexpression of the PAD3 gene observed as early as 18 h postinoculation. The infection process of the mutant mycelium was always delayed by 48 h, even on pad3 plants, probably because of lack of mycelium adhesion. No loss in virulence was found when Bcchs3a conidia were used as the inoculum source. Collectively, these data led us to assign a critical role to the BcCHS3a chitin synthase isoform, both in fungal virulence and plant defense response.
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752
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Han L, Li GJ, Yang KY, Mao G, Wang R, Liu Y, Zhang S. Mitogen-activated protein kinase 3 and 6 regulate Botrytis cinerea-induced ethylene production in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 64:114-27. [PMID: 20659280 DOI: 10.1111/j.1365-313x.2010.04318.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants challenged by pathogens, especially necrotrophic fungi such as Botrytis cinerea, produce high levels of ethylene. At present, the signaling pathways underlying the induction of ethylene after pathogen infection are largely unknown. MPK6, an Arabidopsis stress-responsive mitogen-activated protein kinase (MAPK) was previously shown to regulate the stability of ACS2 and ACS6, two type I ACS isozymes (1-amino-cyclopropane-1-carboxylic acid synthase). Phosphorylation of ACS2 and ACS6 by MPK6 prevents rapid degradation of ACS2/ACS6 by the 26S proteasome pathway, resulting in an increase in cellular ACS activity and ethylene biosynthesis. Here, we show that MPK3, which shares high homology and common upstream MAPK kinases with MPK6, is also capable of phosphorylating ACS2 and ACS6. In the mpk3 mutant background, ethylene production in gain-of-function GVG-NtMEK2(DD) transgenic plants was compromised, suggesting that MPK6 and MPK3 function together to stabilize ACS2 and ACS6. Using a liquid-cultured seedling system, we found that B. cinerea-induced ethylene biosynthesis was greatly compromised in mpk3/mpk6 double mutant seedlings. In contrast, ethylene production decreased only slightly in the mpk6 single mutant and not at all in the mpk3 single mutant, demonstrating overlapping roles for these two highly homologous MAPKs in pathogen-induced ethylene induction. Consistent with the role of MPK3/MPK6 in the process, mutation of ACS2 and ACS6, two genes encoding downstream substrates of MPK3/MPK6, also reduced B. cinerea-induced ethylene production. The residual levels of ethylene induction in the acs2/acs6 double mutant suggest the involvement of additional ACS isoforms, possibly regulated by MAPK-independent pathway(s).
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Affiliation(s)
- Ling Han
- Division of Biochemistry, Interdisciplinary Plant Group and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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753
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Wu M, Zhang L, Li G, Jiang D, Ghabrial SA. Genome characterization of a debilitation-associated mitovirus infecting the phytopathogenic fungus Botrytis cinerea. Virology 2010; 406:117-26. [DOI: 10.1016/j.virol.2010.07.010] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Revised: 05/06/2010] [Accepted: 07/02/2010] [Indexed: 11/24/2022]
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754
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Patel RM, Van Kan JAL, Bailey AM, Foster GD. Inadvertent gene silencing of argininosuccinate synthase (bcass1) in Botrytis cinerea by the pLOB1 vector system. MOLECULAR PLANT PATHOLOGY 2010; 11:613-24. [PMID: 20696000 PMCID: PMC6640230 DOI: 10.1111/j.1364-3703.2010.00632.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
For several years, researchers working on the plant pathogen Botrytis cinerea and a number of other related fungi have routinely used the pLOB1 vector system, based on hygromycin resistance, under the control of the Aspergillus nidulans oliC promoter and what was reported to be the beta-tubulin (tubA) terminator. Recently, it has been demonstrated that this vector contains a 446-bp portion of the B. cinerea argininosuccinate synthase gene (bcass1) rather than the tubA terminator. As argininosuccinate synthase is essential for the production of L-arginine, inadvertent gene silencing of bcass1 may result in partial L-arginine auxotrophy and, indeed, may lead to altered phenotypes in planta. In this article, we report our findings relating to possible problems arising from this incorrect plasmid construction. As an absolute baseline, gene disruption of bcass1 was carried out and generated a strict auxotroph, unable to grow without exogenous arginine supplementation. The knockout displayed an alteration in host range in planta, showing a reduction in pathogenicity on strawberries, French bean leaves and tomatoes, but maintained wild-type growth on grape, which is in accordance with the reported arginine availability in such tissues. Deliberate gene silencing of bcass1 mirrored these effects, with strongly silenced lines showing reduced virulence. The degree of silencing as seen by partial auxotrophy was correlated with an observed reduction in virulence. We also showed that inadvertent silencing of bcass1 is possible when using the pLOB1 vector or derivatives thereof. Partial arginine auxotrophy and concomitant reductions in virulence were triggered in approximately 6% of transformants obtained when expressing enhanced green fluorescent protein, luciferase, monomeric red fluorescent protein or beta-glucuronidase using the pLOB1-based expression system, which inadvertently contains 446 bp of the bcass1 coding sequence. We recommend the testing of transformants obtained using this vector system for arginine auxotrophy in order to provide assurance that any observed effects on the development or virulence are a result of the desired genetic alteration rather than accidental bcass1 silencing.
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Affiliation(s)
- Risha M Patel
- School of Biological Sciences, University of Bristol, Bristol, UK
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755
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Sanchez-Vallet A, Ramos B, Bednarek P, López G, Piślewska-Bednarek M, Schulze-Lefert P, Molina A. Tryptophan-derived secondary metabolites in Arabidopsis thaliana confer non-host resistance to necrotrophic Plectosphaerella cucumerina fungi. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:115-27. [PMID: 20408997 DOI: 10.1111/j.1365-313x.2010.04224.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A defence pathway contributing to non-host resistance to biotrophic fungi in Arabidopsis involves the synthesis and targeted delivery of the tryptophan (trp)-derived metabolites indol glucosinolates (IGs) and camalexin at pathogen contact sites. We have examined whether these metabolites are also rate-limiting for colonization by necrotrophic fungi. Inoculation of Arabidopsis with adapted or non-adapted isolates of the ascomycete Plectosphaerella cucumerina triggers the accumulation of trp-derived metabolites. We found that their depletion in cyp79B2 cyp79B3 mutants renders Arabidopsis fully susceptible to each of three tested non-adapted P. cucumerina isolates, and super-susceptible to an adapted P. cucumerina isolate. This assigns a key role to trp-derived secondary metabolites in limiting the growth of both non-adapted and adapted necrotrophic fungi. However, 4-methoxy-indol-3-ylmethylglucosinolate, which is generated by the P450 monooxygenase CYP81F2, and hydrolyzed by PEN2 myrosinase, together with the antimicrobial camalexin play a minor role in restricting the growth of the non-adapted necrotrophs. This contrasts with a major role of these two trp-derived phytochemicals in limiting invasive growth of non-adapted biotrophic powdery mildew fungi, thereby implying the existence of other unknown trp-derived metabolites in resistance responses to non-adapted necrotrophic P. cucumerina. Impaired defence to non-adapted P. cucumerina, but not to the non-adapted biotrophic fungus Erysiphe pisi, on cyp79B2 cyp79B3 plants is largely restored in the irx1 background, which shows a constitutive accumulation of antimicrobial peptides. Our findings imply differential contributions of antimicrobials in non-host resistance to necrotrophic and biotrophic pathogens.
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Affiliation(s)
- Andrea Sanchez-Vallet
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Universidad Politécnica de Madrid, Campus Montegancedo, E-28223-Pozuelo de Alarcón, Madrid, Spain
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756
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Hayashi N, Yamamoto K, Minowa N, Mitomi M, Nakada M. Synthesis of NH006--a photostable fungicide effective against Botrytis cinerea--according to the asymmetric total synthesis of MK8383. Org Biomol Chem 2010; 8:1821-5. [PMID: 20449485 DOI: 10.1039/b924096a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
MK8383, isolated from Phoma sp. T2526 in 1993, exhibits potent antibiotic activities against a variety of phytopathogens and has been considered a promising fungicide against Botrytis cinerea. Unfortunately, MK8383 is a photosensitive compound and it undergoes irreversible decomposition. Although much effort has been devoted to improving the photostability of MK8383 by chemical modification of its structure by a research group organized by Meiji Seika Kaishya, Ltd. and Mitsubishi Chemical Corporation, a photostable MK8383 derivative has never been prepared. We have found that a C13-14 double bond of MK8383 and (+)-phomopsidin is responsible for the photosensitivity, and herein, we report the synthesis of NH006, an MK8383 derivative with a saturated C13-14 double bond and (S) configuration at C14, based on the asymmetric total synthesis of MK8383. NH006 exhibits good photostability and potent antifungal activity against B. cinerea.
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Affiliation(s)
- Nobuyuki Hayashi
- Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo 169-8555, Japan
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757
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Deficiencies in jasmonate-mediated plant defense reveal quantitative variation in Botrytis cinerea pathogenesis. PLoS Pathog 2010; 6:e1000861. [PMID: 20419157 PMCID: PMC2855333 DOI: 10.1371/journal.ppat.1000861] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Accepted: 03/16/2010] [Indexed: 11/26/2022] Open
Abstract
Despite the described central role of jasmonate signaling in plant defense against necrotrophic pathogens, the existence of intraspecific variation in pathogen capacity to activate or evade plant jasmonate-mediated defenses is rarely considered. Experimental infection of jasmonate-deficient and jasmonate-insensitive Arabidopsis thaliana with diverse isolates of the necrotrophic fungal pathogen Botrytis cinerea revealed pathogen variation for virulence inhibition by jasmonate-mediated plant defenses and induction of plant defense metabolites. Comparison of the transcriptional effects of infection by two distinct B. cinerea isolates showed only minor differences in transcriptional responses of wild-type plants, but notable isolate-specific transcript differences in jasmonate-insensitive plants. These transcriptional differences suggest B. cinerea activation of plant defenses that require plant jasmonate signaling for activity in response to only one of the two B. cinerea isolates tested. Thus, similar infection phenotypes observed in wild-type plants result from different signaling interactions with the plant that are likely integrated by jasmonate signaling. While many important elements of plant defense signaling have been identified, the function of these defense signaling pathways may mask additional variation in the plant–pathogen interaction, including both pathogen variation and variation in downstream plant defense responses. Jasmonate plant hormones contribute to both plant development and defense, including plant defense against necrotrophic fungal pathogens such as the grey mold Botrytis cinerea. Ten diverse B. cinerea isolates all showed increased virulence and decreased induction of a plant antimicrobial metabolite in experimental infections of Arabidopsis thaliana lacking functional jasmonate signaling. Yet within this consistent result, B. cinerea isolates varied considerably. Through comparing the transcript profiles of A. thaliana infected with the two most disparate B. cinerea isolates, we found that wild-type plants showed similar transcriptional responses to infection with these two isolates, but the absence of functional jasmonate signaling revealed dramatic differences in plant response, including groups of co-regulated genes that may participate in undescribed plant response networks. Jasmonate signaling appears to integrate plant responses to diverse pathogen inputs, and its absence may reveal novel aspects of plant–pathogen interaction.
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758
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Fernández-Acero FJ, Colby T, Harzen A, Carbú M, Wieneke U, Cantoral JM, Schmidt J. 2-DE proteomic approach to the Botrytis cinerea secretome induced with different carbon sources and plant-based elicitors. Proteomics 2010; 10:2270-80. [DOI: 10.1002/pmic.200900408] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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759
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Rowe HC, Kliebenstein DJ. All mold is not alike: the importance of intraspecific diversity in necrotrophic plant pathogens. PLoS Pathog 2010; 6:e1000759. [PMID: 20361052 PMCID: PMC2845657 DOI: 10.1371/journal.ppat.1000759] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Affiliation(s)
- Heather C. Rowe
- Department of Plant Sciences, University of California, Davis, Davis, California, United States of America
| | - Daniel J. Kliebenstein
- Department of Plant Sciences, University of California, Davis, Davis, California, United States of America
- * E-mail:
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760
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Noda J, Brito N, González C. The Botrytis cinerea xylanase Xyn11A contributes to virulence with its necrotizing activity, not with its catalytic activity. BMC PLANT BIOLOGY 2010; 10:38. [PMID: 20184750 PMCID: PMC2844071 DOI: 10.1186/1471-2229-10-38] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 02/25/2010] [Indexed: 05/18/2023]
Abstract
BACKGROUND The Botrytis cinerea xylanase Xyn11A has been previously shown to be required for full virulence of this organism despite its poor contribution to the secreted xylanase activity and the low xylan content of B. cinerea hosts. Intriguingly, xylanases from other fungi have been shown to have the property, independent of the xylan degrading activity, to induce necrosis when applied to plant tissues, so we decided to test the hypothesis that secreted Xyn11A contributes to virulence by promoting the necrosis of the plant tissue surrounding the infection, therefore facilitating the growth of this necrotroph. RESULTS We show here that Xyn11A has necrotizing activity on plants and that this capacity is conserved in site-directed mutants of the protein lacking the catalytic activity. Besides, Xyn11A contributes to the infection process with the necrotizing and not with the xylan hydrolyzing activity, as the catalytically-impaired Xyn11A variants were able to complement the lower virulence of the xyn11A mutant. The necrotizing activity was mapped to a 30-amino acids peptide in the protein surface, and this region was also shown to mediate binding to tobacco spheroplasts by itself. CONCLUSIONS The main contribution of the xylanase Xyn11A to the infection process of B. cinerea is to induce necrosis of the infected plant tissue. A conserved 30-amino acids region on the enzyme surface, away from the xylanase active site, is responsible for this effect and mediates binding to plant cells.
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Affiliation(s)
- Judith Noda
- Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, E-38206 La Laguna (Tenerife), Spain
| | - Nélida Brito
- Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, E-38206 La Laguna (Tenerife), Spain
| | - Celedonio González
- Departamento de Bioquímica y Biología Molecular, Universidad de La Laguna, E-38206 La Laguna (Tenerife), Spain
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761
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Schamber A, Leroch M, Diwo J, Mendgen K, Hahn M. The role of mitogen-activated protein (MAP) kinase signalling components and the Ste12 transcription factor in germination and pathogenicity of Botrytis cinerea. MOLECULAR PLANT PATHOLOGY 2010; 11:105-19. [PMID: 20078780 PMCID: PMC6640347 DOI: 10.1111/j.1364-3703.2009.00579.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
In all fungi studied so far, mitogen-activated protein (MAP) kinase cascades serve as central signalling complexes that are involved in various aspects of growth, stress response and infection. In this work, putative components of the yeast Fus3/Kss1-type MAP kinase cascade and the putative downstream transcription factor Ste12 were analysed in the grey mould fungus Botrytis cinerea. Deletion mutants of the MAP triple kinase Ste11, the MAP kinase kinase Ste7 and the MAP kinase adaptor protein Ste50 all resulted in phenotypes similar to that of the previously described BMP1 MAP kinase mutant, namely defects in germination, delayed vegetative growth, reduced size of conidia, lack of sclerotia formation and loss of pathogenicity. Mutants lacking Ste12 showed normal germination, but delayed infection as a result of low penetration efficiency. Two differently spliced ste12 transcripts were detected, and both were able to complement the ste12 mutant, except for a defect in sclerotium formation, which was only corrected by the full-sized transcript. Overexpression of the smaller ste12 transcript resulted in delayed germination and strongly reduced infection. Bc-Gas2, a homologue of Magnaporthe grisea Gas2 that is required for appressorial function, was found to be non-essential for growth and infection, but its expression was under the control of both Bmp1 and Ste12. In summary, the role and regulatory connections of the Fus3/Kss1-type MAP kinase cascade in B. cinerea revealed both common and unique properties compared with those of other plant pathogenic fungi, and provide evidence for a regulatory link between the BMP1 MAP kinase cascade and Ste12.
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Affiliation(s)
- Astrid Schamber
- Department of Biology, University of Kaiserslautern, PO Box 3049, 67653 Kaiserslautern, Germany
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762
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Gardiner DM, Osborne S, Kazan K, Manners JM. Low pH regulates the production of deoxynivalenol by Fusarium graminearum. Microbiology (Reading) 2009; 155:3149-3156. [DOI: 10.1099/mic.0.029546-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fusarium graminearum, which causes the globally important head blight disease of wheat, is responsible for the production of the harmful mycotoxin deoxynivalenol (DON) in infected grain. The production of DON by F. graminearum occurs at much higher levels during infection than during axenic growth, and it is therefore important to understand how DON production is regulated in the fungus. Recently, we have identified amines as potent inducers of in vitro DON production in F. graminearum. Although amines strongly induced expression of the key DON biosynthesis gene TRI5 and DON production to levels equivalent to those observed during infection, the timing of this induction suggested that other factors are also likely to be important for the regulation of DON biosynthesis. Here we demonstrate that low extracellular pH both promotes and is required for DON production in F. graminearum. A combination of low pH and amines results in significantly enhanced expression of the TRI5 gene and increased DON production during axenic growth. A better understanding of DON production in F. graminearum would have implications in developing future toxin management strategies.
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Affiliation(s)
- Donald M. Gardiner
- CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, Brisbane, Queensland 4067, Australia
| | - Sheree Osborne
- CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, Brisbane, Queensland 4067, Australia
| | - Kemal Kazan
- CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, Brisbane, Queensland 4067, Australia
| | - John M. Manners
- CSIRO Plant Industry, Queensland Bioscience Precinct, 306 Carmody Road, Brisbane, Queensland 4067, Australia
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763
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Wang CM, Hopson R, Lin X, Cane DE. Biosynthesis of the sesquiterpene botrydial in Botrytis cinerea. Mechanism and stereochemistry of the enzymatic formation of presilphiperfolan-8beta-ol. J Am Chem Soc 2009; 131:8360-1. [PMID: 19476353 DOI: 10.1021/ja9021649] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Presilphiperfolan-8beta-ol synthase, encoded by the BcBOT2 gene from the necrotrophic plant pathogen Botrytis cinerea, catalyzes the multistep cyclization of farnesyl diphosphate (2) to the tricyclic sesquiterpene alcohol presilphiperfolan-8beta-ol (3), the preursor of the phytotoxin botrydial, a strain-dependent fungal virulence factor. Incubation of (1R)-[1-(2)H]farnesyl diphosphate (2b) with recombinant presilphiperfolan-8beta-ol synthase gave exclusively (5R)-[5alpha-(2)H]-3b, while complementary incubation of (1S)-[1-(2)H]FPP (2c) gave (5S)-[5beta-(2)H]-3c. These results established that cyclization of farnesyl diphosphate involves displacement of the diphosphate group from C-1 with net inversion of configuration and ruled out the proposed intermediacy of the cisoid conformer of nerolidyl diphosphate (9) in the cyclization. While not a mandatory intermediate, (3R)-nerolidyl diphosphate was shown to act as a substrate surrogate. Cyclization of [13,13,13-(2)H(3)] farnesyl diphosphate (2d) gave [14,14,14-(2)H(3)]-3d, thereby establishing that electrophilic attack takes place exclusively on the si face of the 12,13-double bond of 2. The combined results provide a detailed picture of the conformation of enzyme-bound farnesyl diphosphate at the active site of presilphiperfolan-8beta-ol synthase.
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Affiliation(s)
- Chieh-Mei Wang
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912-9108, USA
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764
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Temme N, Tudzynski P. Does botrytis cinerea Ignore H(2)O(2)-induced oxidative stress during infection? Characterization of botrytis activator protein 1. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:987-98. [PMID: 19589074 DOI: 10.1094/mpmi-22-8-0987] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Botrytis cinerea is a phytopathogen infecting a broad range of plants including strawberries and grapevine. During infection, the necrotrophic fungus is exposed to reactive oxygen species (ROS) released by the oxidative burst, an early plant defense reaction. B. cinerea even produces ROS itself in planta. This raises questions about how the pathogen senses and responds to the host defense reaction and which role the pathogen's oxidative stress response systems play. Functional analysis of the AP-1 transcription factor Bap1 confirmed its role as a pivotal regulator of ROS detoxification in vitro. Macroarray analysis revealed 99 H(2)O(2)-induced Bap1 target genes, of which several genes encoded ROS-degrading enzymes as well as other central components of the cellular redox status. However, Bap1 is not essential for pathogenesis. In planta analyses revealed that the Bap1 target genes were not expressed 2 days postinoculation although H(2)O(2) was detectable, proving that the normal virulence of the Deltabap1 mutant is not due to alternative regulation of the major oxidative stress response system in planta. The fungus obviously does not suffer H(2)O(2)-induced oxidative stress in planta, questioning classical ideas about the role of the oxidative burst in the infection process.
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Affiliation(s)
- Nora Temme
- Institut für Botanik, Westf. Wilhelms-Universitaet Muenster, Schlossgarten 3, D-48149-Muenster, Germany
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765
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Barrett LG, Kniskern JM, Bodenhausen N, Zhang W, Bergelson J. Continua of specificity and virulence in plant host-pathogen interactions: causes and consequences. THE NEW PHYTOLOGIST 2009; 183:513-529. [PMID: 19563451 DOI: 10.1111/j.1469-8137.2009.02927.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Ecological, evolutionary and molecular models of interactions between plant hosts and microbial pathogens are largely based around a concept of tightly coupled interactions between species pairs. However, highly pathogenic and obligate associations between host and pathogen species represent only a fraction of the diversity encountered in natural and managed systems. Instead, many pathogens can infect a wide range of hosts, and most hosts are exposed to more than one pathogen species, often simultaneously. Furthermore, outcomes of pathogen infection vary widely because host plants vary in resistance and tolerance to infection, while pathogens are also variable in their ability to grow on or within hosts. Environmental heterogeneity further increases the potential for variation in plant host-pathogen interactions by influencing the degree and fitness consequences of infection. Here, we describe these continua of specificity and virulence inherent within plant host-pathogen interactions. Using this framework, we describe and contrast the genetic and environmental mechanisms that underlie this variation, outline consequences for epidemiology and community structure, explore likely ecological and evolutionary drivers, and highlight several key areas for future research.
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Affiliation(s)
- Luke G Barrett
- Department of Ecology and Evolution, University of Chicago, 1101 E. 57th Street, Chicago, IL 60637, USA
| | - Joel M Kniskern
- Department of Ecology and Evolution, University of Chicago, 1101 E. 57th Street, Chicago, IL 60637, USA
| | - Natacha Bodenhausen
- Department of Ecology and Evolution, University of Chicago, 1101 E. 57th Street, Chicago, IL 60637, USA
| | - Wen Zhang
- Department of Ecology and Evolution, University of Chicago, 1101 E. 57th Street, Chicago, IL 60637, USA
| | - Joy Bergelson
- Department of Ecology and Evolution, University of Chicago, 1101 E. 57th Street, Chicago, IL 60637, USA
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766
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Muñoz C, Gómez Talquenca S, Volpe ML. Tetra primer ARMS-PCR for identification of SNP in beta-tubulin of Botrytis cinerea, responsible of resistance to benzimidazole. J Microbiol Methods 2009; 78:245-6. [PMID: 19539666 DOI: 10.1016/j.mimet.2009.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Revised: 06/09/2009] [Accepted: 06/10/2009] [Indexed: 11/27/2022]
Abstract
A competitive polymerase chain reaction (PCR) technique called Tetra primer amplification refractory mutation system (ARMS) PCR was adapted to identify a single nucleotide polymorphism (SNP) in beta-tubulin gene of Botrytis cinerea. Over the 35 isolates analyzed, six of them showed a SNP in that gene, which was readily identified by the technique and in the six cases correspond to the resistant strain.
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Affiliation(s)
- Claudio Muñoz
- Plant Virology Laboratory, EEA Mendoza INTA, San Martín 3853, Luján de Cuyo (5507), Mendoza, Argentina
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767
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Shah P, Gutierrez-Sanchez G, Orlando R, Bergmann C. A proteomic study of pectin-degrading enzymes secreted by Botrytis cinerea grown in liquid culture. Proteomics 2009; 9:3126-35. [PMID: 19526562 PMCID: PMC2761233 DOI: 10.1002/pmic.200800933] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 02/25/2009] [Indexed: 11/10/2022]
Abstract
Botrytis cinerea is a pathogenic filamentous fungus, which infects more than 200 plant species. The enzymes secreted by B. cinerea play an important role in the successful colonization of a host plant. Some of the secreted enzymes are involved in the degradation of pectin, a major component of the plant cell wall. A total of 126 proteins secreted by B. cinerea were identified by growing the fungus on highly or partially esterified pectin, or on sucrose in liquid culture. Sixty-seven common proteins were identified in each of the growth conditions, of which 50 proteins exhibited a SignalP motif. Thirteen B. cinerea proteins with functions related to pectin degradation were identified in both pectin growth conditions, while only four were identified in sucrose. Our results indicate it is unlikely that the activation of B. cinerea from the dormant state to active infection is solely dependent on changes in the degree of esterification of the pectin component of the plant cell wall. Further, these results suggest that future studies of the B. cinerea secretome in infections of ripe and unripe fruits will provide important information that will describe the mechanisms that the fungus employs to access nutrients and decompose tissues.
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Affiliation(s)
- Punit Shah
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602-4712, USA
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768
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Fernández-Acero FJ, Colby T, Harzen A, Cantoral JM, Schmidt J. Proteomic analysis of the phytopathogenic fungus Botrytis cinerea
during cellulose degradation. Proteomics 2009; 9:2892-902. [DOI: 10.1002/pmic.200800540] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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769
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Stefanato FL, Abou-Mansour E, Buchala A, Kretschmer M, Mosbach A, Hahn M, Bochet CG, Métraux JP, Schoonbeek HJ. The ABC transporter BcatrB from Botrytis cinerea exports camalexin and is a virulence factor on Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 58:499-510. [PMID: 19154205 DOI: 10.1111/j.1365-313x.2009.03794.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflux of fungitoxic compounds. B. cinerea inoculated on wild-type A. thaliana plants yields smaller lesions than on camalexin-deficient A. thaliana mutants. A B. cinerea strain lacking functional BcatrB is more sensitive to camalexin in vitro and less virulent on wild-type plants, but is still fully virulent on camalexin-deficient mutants. Pre-treatment of A. thaliana with UV-C leads to increased camalexin accumulation and substantial resistance to B. cinerea. UV-C-induced resistance was not seen in the camalexin-deficient mutants cyp79B2/B3, cyp71A13, pad3 or pad2, and was strongly reduced in ups1. Here we demonstrate that an ABC transporter is a virulence factor that increases tolerance of the pathogen towards a phytoalexin, and the complete restoration of virulence on host plants lacking this phytoalexin.
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Affiliation(s)
- Francesca L Stefanato
- Department of Biology, University of Fribourg, Chemin du Musée 8, CH-1700 Fribourg, Switzerland
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770
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Isolation and characterization of Bacillus subtilis EB-28, an endophytic bacterium strain displaying biocontrol activity against Botrytis cinerea Pers. ACTA ACUST UNITED AC 2009. [DOI: 10.1007/s11703-009-0042-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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771
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Decognet V, Bardin M, Trottin-Caudal Y, Nicot PC. Rapid change in the genetic diversity of Botrytis cinerea populations after the introduction of strains in a tomato glasshouse. PHYTOPATHOLOGY 2009; 99:185-193. [PMID: 19159311 DOI: 10.1094/phyto-99-2-0185] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In tomato glasshouses, the population structure of airborne inoculum of Botrytis cinerea depends on the production of endogenous inoculum on diseased plants as well as on incoming exogenous inoculum. Both types of inocula may contribute differently to the development of epidemics. Two strains of B. cinerea were introduced in each of four separate compartments of an experimental tomato glasshouse. We monitored their impact on disease development and on the genetic diversity of B. cinerea populations using microsatellite markers. The naturally occurring airborne inoculum of B. cinerea displayed a high level of genetic diversity and was rapidly displaced in the glasshouse, as isolates with microsatellite profiles identical to the introduced strains amounted to 66% of the inoculum sampled from the air 14 days after inoculation and 91% of those collected from stem lesions 60 days after inoculation. This suggested an important role of secondary inoculum in disease development, which is compatible with the hypothesis of a polycyclic development of gray mold epidemics in tomato glasshouses. In controlled-environment tests on tomatoes, a wide range of aggressiveness levels was observed, both for isolates sampled from the air and from lesions on plants. Hypotheses are proposed to explain the negligible impact of naturally incoming isolates on the epidemics observed inside the four glasshouse compartments.
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Affiliation(s)
- V Decognet
- INRA, UR0407, Plant Pathology Unit, Domaine St. Maurice, F-84140 Montfavet, France.
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772
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Pinedo C, Wang CM, Pradier JM, Dalmais B, Choquer M, Le Pêcheur P, Morgant G, Collado IG, Cane DE, Viaud M. Sesquiterpene synthase from the botrydial biosynthetic gene cluster of the phytopathogen Botrytis cinerea. ACS Chem Biol 2008; 3:791-801. [PMID: 19035644 DOI: 10.1021/cb800225v] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The fungus Botrytis cinerea is the causal agent of the economically important gray mold disease that affects more than 200 ornamental and agriculturally important plant species. B. cinerea is a necrotrophic plant pathogen that secretes nonspecific phytotoxins, including the sesquiterpene botrydial and the polyketide botcinic acid. The region surrounding the previously characterized BcBOT1 gene has now been identified as the botrydial biosynthetic gene cluster.Five genes including BcBOT1 and BcBOT2 were shown by quantitative reverse transcription-PCR to be co-regulated through the calcineurin signaling pathway. Inactivation of the BcBOT2 gene, encoding a putative sesquiterpene cyclase, abolished botrydial biosynthesis, which could be restored by in trans complementation.Inactivation of BcBOT2 also resulted in overproduction of botcinic acid that was observed to be strain-dependent. Recombinant BcBOT2 protein converted farnesyl diphosphate to the parent sesquiterpene of the botrydial biosynthetic pathway, the tricyclic alcohol presilphiperfolan-8beta-ol.
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Affiliation(s)
- Cristina Pinedo
- Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Spain
| | - Chieh-Mei Wang
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912-9108
| | | | | | - Mathias Choquer
- UMR BIOGER, INRA, Route de Saint-Cyr, 78086 Versailles, France
| | | | | | - Isidro G. Collado
- Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Spain
| | - David E. Cane
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912-9108
| | - Muriel Viaud
- UMR BIOGER, INRA, Route de Saint-Cyr, 78086 Versailles, France
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773
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Meléndez HG, Billon-Grand G, Fèvre M, Mey G. Role of the Botrytis cinerea FKBP12 ortholog in pathogenic development and in sulfur regulation. Fungal Genet Biol 2008; 46:308-20. [PMID: 19116175 DOI: 10.1016/j.fgb.2008.11.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 11/12/2008] [Accepted: 11/14/2008] [Indexed: 01/06/2023]
Abstract
The functional characterization of the FKBP12 encoding gene from the phytopathogenic fungus Botrytis cinerea was carried out. B. cinerea genome sequence owns a single ortholog, named BcFKBP12, encoding a FK506-binding protein of 12kDa. BcFKBP12 mediates rapamycin sensitivity both in B. cinerea and in Saccharomyces cerevisiae, a property unique to FKBP12 proteins, probably via the inhibition of the protein kinase TOR (target of rapamycin). The relative abundance of the prolyl isomerase appeared to be regulated and increased in response to the presence of extracellular nutrients. Surprisingly, the BcFKBP12 deletion did not affect the pathogenic development of the strain B05.10, while it was reported to cause a reduction of the virulence of the strain T4. We report for the first time the BcFKBP12 involvement in the sulfur repression of the synthesis of a secreted serine protease. Rapamycin treatment did not relieve the sulfur repression of the reporter system in the wild-type strain. Thus BcFKBP12 may participate in sulfur regulation and its contribution seems to be independent of TOR.
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Affiliation(s)
- Heber Gamboa Meléndez
- Laboratoire de Génomique Fonctionnelle des Champignons Pathogènes des Plantes, UMR 5240 CNRS-UCB-INSA-Bayer CropScience, Domaine Scientifique de la Doua, Université Lyon I, Bât Lwoff, RDC, Villeurbanne, France
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774
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Patel RM, van Kan JAL, Bailey AM, Foster GD. RNA-mediated gene silencing of superoxide dismutase (bcsod1) in Botrytis cinerea. PHYTOPATHOLOGY 2008; 98:1334-9. [PMID: 19000009 DOI: 10.1094/phyto-98-12-1334] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Gene silencing is a powerful tool utilized for identification of gene function and analysis in plants, animals, and fungi. Here, we report the silencing of superoxide dismutase (bcsod1) in Botrytis cinerea through sense and antisense-mediated silencing mechanisms. Because superoxide dismutase (SOD) is a virulence factor, transformants were tested for phenotypic silencing in vitro and reduction in pathogenicity in planta. Plate-based assays with and without paraquat were performed to screen initial silencing efficiency, and a subset of transformants was used for in planta studies of virulence. Transformants exhibiting strongly decreased transcripts levels were recovered with both constructs but none of those exhibited a reduction in virulence in planta. Our investigations may help optimize a high-throughput gene silencing system useful for identifying potential gene targets for future fungal control.
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Affiliation(s)
- R M Patel
- School of Biological Sciences, University of Bristol, UK
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775
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Rowe HC, Kliebenstein DJ. Complex genetics control natural variation in Arabidopsis thaliana resistance to Botrytis cinerea. Genetics 2008; 180:2237-50. [PMID: 18845849 PMCID: PMC2600955 DOI: 10.1534/genetics.108.091439] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2008] [Accepted: 10/07/2008] [Indexed: 12/20/2022] Open
Abstract
The genetic architecture of plant defense against microbial pathogens may be influenced by pathogen lifestyle. While plant interactions with biotrophic pathogens are frequently controlled by the action of large-effect resistance genes that follow classic Mendelian inheritance, our study suggests that plant defense against the necrotrophic pathogen Botrytis cinerea is primarily quantitative and genetically complex. Few studies of quantitative resistance to necrotrophic pathogens have used large plant mapping populations to dissect the genetic structure of resistance. Using a large structured mapping population of Arabidopsis thaliana, we identified quantitative trait loci influencing plant response to B. cinerea, measured as expansion of necrotic lesions on leaves and accumulation of the antimicrobial compound camalexin. Testing multiple B. cinerea isolates, we identified 23 separate QTL in this population, ranging in isolate-specificity from being identified with a single isolate to controlling resistance against all isolates tested. We identified a set of QTL controlling accumulation of camalexin in response to pathogen infection that largely colocalized with lesion QTL. The identified resistance QTL appear to function in epistatic networks involving three or more loci. Detection of multilocus connections suggests that natural variation in specific signaling or response networks may control A. thaliana-B. cinerea interaction in this population.
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Affiliation(s)
- Heather C Rowe
- Department of Plant Sciences, University of California, Davis, California 95616, USA
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776
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Patel RM, Heneghan MN, van Kan JAL, Bailey AM, Foster GD. The pOT and pLOB vector systems: improving ease of transgene expression in Botrytis cinerea. J GEN APPL MICROBIOL 2008; 54:367-76. [PMID: 19164879 DOI: 10.2323/jgam.54.367] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This paper outlines the construction of a novel vector system comprising interchangeable terminators, as well as a multiple cloning site (MCS), to facilitate the transformation of the fungal plant pathogen Botrytis cinerea. Previous molecular studies on B. cinerea have relied upon the pLOB1 based vector system (controlled by the Aspergillus nidulans oliC promoter and a region reported to be the B. cinerea tubA terminator). Investigations, however, have revealed that, rather than the genuine B. cinerea tubA terminator, the pLOB1 terminator fragment is from another gene locus within the genome. Because previous studies have found that terminators aide in transcript stability, the main aims of this study were to develop and evaluate both vector systems, pOT (controlled by the A. nidulans oliC promoter and A. nidulans trpC terminator) and pLOB, with a range of exogenous genes, including enhanced green fluorescent protein (eGFP), monomeric red fluorescent protein (mRFP), luciferase (LUC) and beta-glucuronidase (GUS). Our investigations demonstrate that pLOB and pOT based vectors are capable of expressing all four reporter genes and may be applied to future molecular studies on B. cinerea and other related ascomycetes. Additionally, this is the first reported expression of mRFP and LUC in B. cinerea.
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Affiliation(s)
- Risha M Patel
- School of Biological Sciences, University of Bristol, UK
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777
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Schumacher J, Kokkelink L, Huesmann C, Jimenez-Teja D, Collado IG, Barakat R, Tudzynski P, Tudzynski B. The cAMP-dependent signaling pathway and its role in conidial germination, growth, and virulence of the gray mold Botrytis cinerea. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:1443-1459. [PMID: 18842094 DOI: 10.1094/mpmi-21-11-1443] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In Botrytis cinerea, some components of the cAMP-dependent pathway, such as alpha subunits of heterotrimeric G proteins and the adenylate cyclase BAC, have been characterized and their impact on growth, conidiation, germination, and virulence has been demonstrated. Here, we describe the functions of more components of the cAMP cascade: the catalytic subunits BcPKA1 and BcPKA2 and the regulatory subunit BcPKAR of the cAMP-dependent protein kinase (PKA). Although Deltabcpka2 mutants showed no obvious phenotypes, growth and virulence were severely affected by deletion of both bcpka1 and bcpkaR. Similar to Deltabac, lesion development of Deltabcpka1 and DeltabcpkaR was slower than in controls and soft rot of leaves never occurred. In contrast to Deltabac, Deltabcpka1 and DeltabcpkaR mutants sporulated in planta, and growth rate, conidiation, and conidial germination were not impaired, indicating PKA-independent functions of cAMP. Unexpectedly, Deltabcpka1 and DeltabcpkaR showed identical phenotypes, suggesting the total loss of PKA activity in both mutants. The deletion of bcras2 encoding the fungal-specific Ras GTPase resulted in significantly delayed germination and decreased growth rates. Both effects could be partially restored by exogenous cAMP, suggesting that BcRAS2 activates the adenylate cyclase in addition to the Galpha subunits BCG1 and BCG3, thus influencing cAMP-dependent signal transduction.
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Affiliation(s)
- Julia Schumacher
- Institut für Botanik der Westfälischen Wilhelms-Universität Münster, Schlossgarten 3, D-48149 Münster, Germany
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778
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Cettul E, Rekab D, Locci R, Firrao G. Evolutionary analysis of endopolygalacturonase-encoding genes of Botrytis cinerea. MOLECULAR PLANT PATHOLOGY 2008; 9:675-685. [PMID: 19018996 PMCID: PMC6640430 DOI: 10.1111/j.1364-3703.2008.00492.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Sequence analysis of five of the six endopolygalacturonase-encoding genes (Bcpg1, Bcpg2, Bcpg3, Bcpg4, Bcpg5) from 32 strains of Botrytis cinerea showed marked gene to gene differences in the amount of among-strains diversity. Bcpg4 was almost invariable in all strains; Bcpg3 and Bcpg5 showed a moderate variability, similar to that of non-pathogenicity-associated genes examined in other studies. Conversely, Bcpg1 and Bcpg2 were highly variable and were shown to be under positive selection based on the McDonald-Kreitman test and likelihood ratio test. The evolution of the five endopolygalacturonase genes is explained by their different ecophysiological role. Diversification and balancing selection, as detected in Bcpg1 and Bcpg2, can be used by the pathogen to escape recognition by the host and delay plant reaction in the early phases of infection. The analysis of the polymorphisms and the location of the sites with high probability of being positively selected highlighted the relevance of variability of the BcPG1 and BcPG2 proteins at their C-terminal end. By contrast, the absence of variability in Bcpg4 suggests that the efficiency of the product of this gene is critical for B. cinerea growth in late phases of infection or during intraspecific competition, thus markedly affecting strain fitness.
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Affiliation(s)
- Emanuele Cettul
- Dipartimento di Biologia e Protezione delle Piante, Università di Udine, via Scienze 208, 33100 Udine, Italy
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779
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Liu W, Leroux P, Fillinger S. The HOG1-like MAP kinase Sak1 of Botrytis cinerea is negatively regulated by the upstream histidine kinase Bos1 and is not involved in dicarboximide- and phenylpyrrole-resistance. Fungal Genet Biol 2008; 45:1062-74. [DOI: 10.1016/j.fgb.2008.04.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 03/31/2008] [Accepted: 04/02/2008] [Indexed: 11/16/2022]
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780
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Segmüller N, Kokkelink L, Giesbert S, Odinius D, van Kan J, Tudzynski P. NADPH oxidases are involved in differentiation and pathogenicity in Botrytis cinerea. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:808-819. [PMID: 18624644 DOI: 10.1094/mpmi-21-6-0808] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nicotinamide adenine dinucleotide (NADPH) oxidases have been shown to be involved in various differentiation processes in fungi. We investigated the role of two NADPH oxidases in the necrotrophic phytopathogenic fungus, Botrytis cinerea. The genes bcnoxA and bcnoxB were cloned and characterized; their deduced amino acid sequences show high homology to fungal NADPH oxidases. Analyses of single and double knock-out mutants of both NADPH oxidase genes showed that both bcnoxA and bcnoxB are involved in formation of sclerotia. Both genes have a great impact on pathogenicity: whereas bcnoxB mutants showed a retarded formation of primary lesions, probably due to an impaired formation of penetration structures, bcnoxA mutants were able to penetrate host tissue in the same way as the wild type but were much slower in colonizing the host tissue. Double mutants showed an additive effect: they were aberrant in penetration and colonization of plant tissue and, therefore, almost nonpathogenic. To study the structure of the fungal Nox complex in more detail, bcnoxR (encoding a homolog of the mammalian p67(phox), a regulatory subunit of the Nox complex) was functionally characterized. The phenotype of DeltabcnoxR mutants is identical to that of DeltabcnoxAB double mutants, providing evidence that BcnoxR is involved in activation of both Bcnox enzymes.
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MESH Headings
- Blotting, Northern
- Blotting, Southern
- Botrytis/enzymology
- Botrytis/pathogenicity
- Botrytis/physiology
- Fabaceae/microbiology
- Fabaceae/ultrastructure
- Fungal Proteins/genetics
- Fungal Proteins/metabolism
- Gene Expression Regulation, Fungal/drug effects
- Hydrogen Peroxide/pharmacology
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Microscopy, Electron, Transmission
- Models, Biological
- Mutation
- NAD/pharmacology
- NADPH Oxidases/classification
- NADPH Oxidases/genetics
- NADPH Oxidases/metabolism
- Onium Compounds/pharmacology
- Phylogeny
- Plant Leaves/microbiology
- Plant Leaves/ultrastructure
- Reactive Oxygen Species/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
- Spores, Fungal/cytology
- Spores, Fungal/drug effects
- Spores, Fungal/growth & development
- Virulence/genetics
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Affiliation(s)
- Nadja Segmüller
- Institut für Botanik, Westf. Wilhelms-Universität, Schlossgarten 3, D-48149 Münster, Germany
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781
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A fungal-responsive MAPK cascade regulates phytoalexin biosynthesis in Arabidopsis. Proc Natl Acad Sci U S A 2008; 105:5638-43. [PMID: 18378893 DOI: 10.1073/pnas.0711301105] [Citation(s) in RCA: 248] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Plant recognition of pathogens leads to rapid activation of MPK3 and MPK6, two Arabidopsis mitogen-activated protein kinases (MAPKs), and their orthologs in other species. Here, we report that synthesis of camalexin, the major phytoalexin in Arabidopsis, is regulated by the MPK3/MPK6 cascade. Activation of MPK3/MPK6 by expression of active upstream MAPK kinase (MAPKK) or MAPKK kinase (MAPKKK) was sufficient to induce camalexin synthesis in the absence of pathogen attack. Induction of camalexin by Botrytis cinerea was preceded by MPK3/MPK6 activation, and compromised in mpk3 and mpk6 mutants. Genetic analysis placed the MPK3/MPK6 cascade upstream of PHYTOALEXIN DEFICIENT 2 (PAD2) and PAD3, but independent or downstream of PAD1 and PAD4. Camalexin induction after MPK3/MPK6 activation was preceded by rapid and coordinated up-regulation of multiple genes encoding enzymes in the tryptophan (Trp) biosynthetic pathway, in the conversion of Trp to indole-3-acetaldoxime (IAOx, a branch point between primary and secondary metabolism), and in the camalexin biosynthetic pathway downstream of IAOx. These results indicate that the MPK3/MPK6 cascade regulates camalexin synthesis through transcriptional regulation of the biosynthetic genes after pathogen infection.
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782
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Schumacher J, Viaud M, Simon A, Tudzynski B. The Gα subunit BCG1, the phospholipase C (BcPLC1) and the calcineurin phosphatase co-ordinately regulate gene expression in the grey mould fungus Botrytis cinerea. Mol Microbiol 2008; 67:1027-50. [DOI: 10.1111/j.1365-2958.2008.06105.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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783
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Calcineurin-responsive zinc finger transcription factor CRZ1 of Botrytis cinerea is required for growth, development, and full virulence on bean plants. EUKARYOTIC CELL 2008; 7:584-601. [PMID: 18263765 DOI: 10.1128/ec.00426-07] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Recently, we showed that the alpha subunit BCG1 of a heterotrimeric G protein is an upstream activator of the Ca(2+)/calmodulin-dependent phosphatase calcineurin in the gray mold fungus Botrytis cinerea. To identify the transcription factor acting downstream of BCG1 and calcineurin, we cloned the gene encoding the B. cinerea homologue of CRZ1 ("CRaZy," calcineurin-responsive zinc finger transcription factor), the mediator of calcineurin function in yeast. BcCRZ1 is able to partially complement the corresponding Saccharomyces cerevisiae mutant, and the subcellular localization of the green fluorescent protein-BcCRZ1 fusion product in yeast cells depends on the calcium level and calcineurin activity. Bccrz1 deletion mutants are not able to grow on minimal media and grow slowly on media containing plant extracts. Hyphal morphology, conidiation, and sclerotium formation are impaired. The cell wall and membrane integrity, stress response (extreme pH, H(2)O(2), Ca(2+), Li(+)), and ability of the hyphae to penetrate the intact plant surface are affected in the mutants. However, BcCRZ1 is almost dispensable for the conidium-derived infection of bean plants. The addition of Mg(2+) restores the growth rate, conidiation, and penetration and improves the cell wall integrity but has no impact on sclerotium formation or hypersensitivity to Ca(2+) and H(2)O(2). The expression of a set of recently identified BCG1- and calcineurin-dependent genes is also affected in DeltaBccrz1 mutants, confirming that this transcription factor acts downstream of calcineurin in B. cinerea. Since the Bccrz1 mutants still respond to calcineurin inhibitors, we conclude that BcCRZ1 is not the only target of calcineurin.
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784
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Schouten A, Van Baarlen P, Van Kan JAL. Phytotoxic Nep1-like proteins from the necrotrophic fungus Botrytis cinerea associate with membranes and the nucleus of plant cells. THE NEW PHYTOLOGIST 2008; 177:493-505. [PMID: 18028294 DOI: 10.1111/j.1469-8137.2007.02274.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Nep1-like proteins (NLPs), produced by an array of unrelated microorganisms, are phytotoxic for dicotyledonous plant cells but their mode of action has not yet been established. Two paralogous NLPs from the necrotrophic plant pathogenic fungus Botrytis cinerea were characterized, designated BcNEP1 and BcNEP2. Both proteins were produced in the heterologous host Pichia pastoris and purified to homogeneity. The localization of fluorescently labelled proteins was studied and mechanisms of cell death were investigated in protoplasts and suspension cells. Purified BcNEP1 and BcNEP2 caused necrosis in all dicotyledonous plant species tested, but not in monocotyledons. A synthetic heptapeptide comprising a sequence (GHRHDWE) that is conserved in all NLPs did not cause symptoms and was unable to interfere with necrosis induction by BcNEP1 and BcNEP2 proteins. Fluorescently labelled BcNEP1 and BcNEP2 proteins were associated with plasma membranes and the nuclear envelope, as well as in the nucleolus of responding plant cells. A strong hydrogen peroxide (H(2)O(2)) accumulation was observed in chloroplasts. The death process was characterized by TUNEL assays as apoptosis, necrosis or intermediate forms of both. BcNEP1- and BcNEP2-induced cell death execution could not be abolished by specific inhibitors. These results provide further information on mechanisms of NLP-inflicted cell death.
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Affiliation(s)
- Alexander Schouten
- Laboratory of Phytopathology, Wageningen University, PO Box 8025, NL-6700 EE Wageningen, the Netherlands
| | - Peter Van Baarlen
- Laboratory of Phytopathology, Wageningen University, PO Box 8025, NL-6700 EE Wageningen, the Netherlands
| | - Jan A L Van Kan
- Laboratory of Phytopathology, Wageningen University, PO Box 8025, NL-6700 EE Wageningen, the Netherlands
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