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Functional analyses of regulators of G protein signaling in Gibberella zeae. Fungal Genet Biol 2012; 49:511-20. [PMID: 22634273 DOI: 10.1016/j.fgb.2012.05.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 05/08/2012] [Accepted: 05/09/2012] [Indexed: 11/20/2022]
Abstract
Regulators of G protein signaling (RGS) proteins make up a highly diverse and multifunctional protein family that plays a critical role in controlling heterotrimeric G protein signaling. In this study, seven RGS genes (FgFlbA, FgFlbB, FgRgsA, FgRgsB, FgRgsB2, FgRgsC, and FgGprK) were functionally characterized in the plant pathogenic fungus, Gibberella zeae. Mutant phenotypes were observed for deletion mutants of FgRgsA and FgRgsB in vegetative growth, FgFlbB and FgRgsB in conidia morphology, FgFlbA in conidia production, FgFlbA, FgRgsB, and FgRgsC in sexual development, FgFlbA and FgRgsA in spore germination and mycotoxin production, and FgFlbA, FgRgsA, and FgRgsB in virulence. Furthermore, FgFlbA, FgRgsA, and FgRgsB acted pleiotropically, while FgFlbB and FgRgsC deletion mutants exhibited a specific defect in conidia morphology and sexual development, respectively. Amino acid substitutions in Gα subunits and overexpression of the FgFlbA gene revealed that deletion of FgFlbA and dominant active GzGPA2 mutant, gzgpa2(Q207L), had similar phenotypes in cell wall integrity, perithecia formation, mycotoxin production, and virulence, suggesting that FgFlbA may regulate asexual/sexual development, mycotoxin biosynthesis, and virulence through GzGPA2-dependent signaling in G. zeae.
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52
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Lin Y, Son H, Min K, Lee J, Choi GJ, Kim JC, Lee YW. A putative transcription factor MYT2 regulates perithecium size in the ascomycete Gibberella zeae. PLoS One 2012; 7:e37859. [PMID: 22649560 PMCID: PMC3359310 DOI: 10.1371/journal.pone.0037859] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 04/25/2012] [Indexed: 11/18/2022] Open
Abstract
The homothallic ascomycete fungus Gibberella zeae is a plant pathogen that is found worldwide, causing Fusarium head blight (FHB) in cereal crops and ear rot of maize. Ascospores formed in fruiting bodies (i.e., perithecia) are hypothesized to be the primary inocula for FHB disease. Perithecium development is a complex cellular differentiation process controlled by many developmentally regulated genes. In this study, we selected a previously reported putative transcription factor containing the Myb DNA-binding domain MYT2 for an in-depth study on sexual development. The deletion of MYT2 resulted in a larger perithecium, while its overexpression resulted in a smaller perithecium when compared to the wild-type strain. These data suggest that MYT2 regulates perithecium size differentiation. MYT2 overexpression affected pleiotropic phenotypes including vegetative growth, conidia production, virulence, and mycotoxin production. Nuclear localization of the MYT2 protein supports its role as a transcriptional regulator. Transcriptional analyses of trichothecene synthetic genes suggest that MYT2 additionally functions as a suppressor for trichothecene production. This is the first study characterizing a transcription factor required for perithecium size differentiation in G. zeae, and it provides a novel angle for understanding sexual development in filamentous fungi.
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Affiliation(s)
- Yang Lin
- Department of Agricultural Biotechnology and the Center for Fungal Pathogenesis, Seoul National University, Seoul, Republic of Korea
| | - Hokyoung Son
- Department of Agricultural Biotechnology and the Center for Fungal Pathogenesis, Seoul National University, Seoul, Republic of Korea
| | - Kyunghun Min
- Department of Agricultural Biotechnology and the Center for Fungal Pathogenesis, Seoul National University, Seoul, Republic of Korea
| | - Jungkwan Lee
- Department of Applied Biology, Dong-A University, Busan, Republic of Korea
| | - Gyung Ja Choi
- Eco-friendly New Materials Research Group, Research Center for Biobased Chemistry, Division of Convergence Chemistry, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
| | - Jin-Cheol Kim
- Eco-friendly New Materials Research Group, Research Center for Biobased Chemistry, Division of Convergence Chemistry, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
| | - Yin-Won Lee
- Department of Agricultural Biotechnology and the Center for Fungal Pathogenesis, Seoul National University, Seoul, Republic of Korea
- * E-mail:
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53
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Son H, Lee J, Lee YW. Mannitol induces the conversion of conidia to chlamydospore-like structures that confer enhanced tolerance to heat, drought, and UV in Gibberella zeae. Microbiol Res 2012; 167:608-15. [PMID: 22580127 DOI: 10.1016/j.micres.2012.04.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 03/29/2012] [Accepted: 04/16/2012] [Indexed: 01/16/2023]
Abstract
Fungi use mannitol to store carbon, balance redox, and mannitol serves as an antioxidant. Several fungi also increase stress tolerance by accumulating mannitol. The results of this study showed that conidia of the cereal head blight fungus Gibberella zeae were readily changed to chlamydospore-like structures (CLS) in cultures supplemented with high amounts of mannitol. CLS cellular features were atypical of chlamydospores, but accumulated high levels of glycogen, lipids, and chitin in the cytoplasm. In addition, CLS exhibited increased tolerance to environmental stresses, including UV, heat, and drought compared to normal conidia. Molecular approaches revealed that several genes associated with lipid metabolism, signal transduction, acetyl-CoA production, and chitin synthesis were involved in CLS formation. This is the first report to characterize conidia modifications similar to chlamydospores in G. zeae applying histological and molecular approaches. The results suggest CLS serve a role in G. zeae survival strategies under hot and dry field conditions.
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Affiliation(s)
- Hokyoung Son
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Republic of Korea
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54
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Lee J, Myong K, Kim JE, Kim HK, Yun SH, Lee YW. FgVelB globally regulates sexual reproduction, mycotoxin production and pathogenicity in the cereal pathogen Fusarium graminearum. MICROBIOLOGY-SGM 2012; 158:1723-1733. [PMID: 22516221 DOI: 10.1099/mic.0.059188-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The velvet genes are conserved in ascomycetous fungi and function as global regulators of differentiation and secondary metabolism. Here, we characterized one of the velvet genes, designated FgVelB, in the plant-pathogenic fungus Fusarium graminearum, which causes fusarium head blight in cereals and produces mycotoxins within plants. FgVelB-deleted (ΔFgVelB) strains produced fewer aerial mycelia with less pigmentation than those of the wild-type (WT) during vegetative growth. Under sexual development conditions, the ΔFgVelB strains produced no fruiting bodies but retained male fertility, and conidiation was threefold higher compared with the WT strain. Production of trichothecene and zearalenone was dramatically reduced compared with the WT strain. In addition, the ΔFgVelB strains were incapable of colonizing host plant tissues. Transcript analyses revealed that FgVelB was highly expressed during the sexual development stage, and may be regulated by a mitogen-activated protein kinase cascade. Microarray analysis showed that FgVelB affects regulatory pathways mediated by the mating-type loci and a G-protein alpha subunit, as well as primary and secondary metabolism. These results suggest that FgVelB has diverse biological functions, probably by acting as a member of a possible velvet protein complex, although identification of the FgVelB-FgVeA complex and the determination of its roles require further investigation.
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Affiliation(s)
- Jungkwan Lee
- Department of Applied Biology, Dong-A University, Busan 604-714, Republic of Korea
| | - Kilseon Myong
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Republic of Korea
| | - Jung-Eun Kim
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Republic of Korea
| | - Hee-Kyoung Kim
- Department of Medical Biotechnology, Soonchunhyang University, Asan 336-745, Republic of Korea
| | - Sung-Hwan Yun
- Department of Medical Biotechnology, Soonchunhyang University, Asan 336-745, Republic of Korea
| | - Yin-Won Lee
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Republic of Korea
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55
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Effect of salicylic acid on Fusarium graminearum, the major causal agent of fusarium head blight in wheat. Fungal Biol 2012; 116:413-26. [DOI: 10.1016/j.funbio.2012.01.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 11/14/2011] [Accepted: 01/03/2012] [Indexed: 11/19/2022]
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56
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Kong LA, Yang J, Li GT, Qi LL, Zhang YJ, Wang CF, Zhao WS, Xu JR, Peng YL. Different chitin synthase genes are required for various developmental and plant infection processes in the rice blast fungus Magnaporthe oryzae. PLoS Pathog 2012; 8:e1002526. [PMID: 22346755 PMCID: PMC3276572 DOI: 10.1371/journal.ppat.1002526] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 12/24/2011] [Indexed: 11/18/2022] Open
Abstract
Chitin is a major component of fungal cell wall and is synthesized by chitin synthases (Chs). Plant pathogenic fungi normally have multiple chitin synthase genes. To determine their roles in development and pathogenesis, we functionally characterized all seven CHS genes in Magnaporthe oryzae. Three of them, CHS1, CHS6, and CHS7, were found to be important for plant infection. While the chs6 mutant was non-pathogenic, the chs1 and chs7 mutants were significantly reduced in virulence. CHS1 plays a specific role in conidiogenesis, an essential step for natural infection cycle. Most of chs1 conidia had no septum and spore tip mucilage. The chs6 mutant was reduced in hyphal growth and conidiation. It failed to penetrate and grow invasively in plant cells. The two MMD-containing chitin synthase genes, CHS5 and CHS6, have a similar expression pattern. Although deletion of CHS5 had no detectable phenotype, the chs5 chs6 double mutant had more severe defects than the chs6 mutant, indicating that they may have overlapping functions in maintaining polarized growth in vegetative and invasive hyphae. Unlike the other CHS genes, CHS7 has a unique function in appressorium formation. Although it was blocked in appressorium formation by germ tubes on artificial hydrophobic surfaces, the chs7 mutant still produced melanized appressoria by hyphal tips or on plant surfaces, indicating that chitin synthase genes have distinct impacts on appressorium formation by hyphal tip and germ tube. The chs7 mutant also was defective in appressorium penetration and invasive growth. Overall, our results indicate that individual CHS genes play diverse roles in hyphal growth, conidiogenesis, appressorium development, and pathogenesis in M. oryzae, and provided potential new leads in the control of this devastating pathogen by targeting specific chitin synthases.
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Affiliation(s)
- Ling-An Kong
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
- Purdue-NWAFU Joint Research Center and State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Jun Yang
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
| | - Guo-Tian Li
- Purdue-NWAFU Joint Research Center and State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Lin-Lu Qi
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
| | - Yu-Jun Zhang
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
| | - Chen-Fang Wang
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Wen-Sheng Zhao
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
| | - Jin-Rong Xu
- Purdue-NWAFU Joint Research Center and State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - You-Liang Peng
- State Key Laboratory of Agrobiotechnology and MOA Key Laboratory of Plant Pathology, China Agricultural University, Beijing, China
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57
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SON H, LEE YW. Fusarium graminearum mycotoxins and their biosynthetic genes. ACTA ACUST UNITED AC 2012. [DOI: 10.2520/myco.62.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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58
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Cao JB, Zhou Y, Zhang L, Zhang J, Yang L, Qin LH, Jiang DH, Li GQ, Huang HC. DsRNA-free transmissible hypovirulence associated with formation of intra-hyphal hyphae in Botrytis cinerea. Fungal Biol 2011; 115:660-71. [DOI: 10.1016/j.funbio.2011.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 04/21/2011] [Indexed: 10/18/2022]
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59
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Functional analyses of two acetyl coenzyme A synthetases in the ascomycete Gibberella zeae. EUKARYOTIC CELL 2011; 10:1043-52. [PMID: 21666077 DOI: 10.1128/ec.05071-11] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Acetyl coenzyme A (acetyl-CoA) is a crucial metabolite for energy metabolism and biosynthetic pathways and is produced in various cellular compartments with spatial and temporal precision. Our previous study on ATP citrate lyase (ACL) in Gibberella zeae revealed that ACL-dependent acetyl-CoA production is important for histone acetylation, especially in sexual development, but is not involved in lipid synthesis. In this study, we deleted additional acetyl-CoA synthetic genes, the acetyl-CoA synthetases (ACS genes ACS1 and ACS2), to identify alternative acetyl-CoA production mechanisms for ACL. The ACS1 deletion resulted in a defect in sexual development that was mainly due to a reduction in 1-palmitoyl-2-oleoyl-3-linoleoyl-rac-glycerol production, which is required for perithecium development and maturation. Another ACS coding gene, ACS2, has accessorial functions for ACS1 and has compensatory functions for ACL as a nuclear acetyl-CoA producer. This study showed that acetate is readily generated during the entire life cycle of G. zeae and has a pivotal role in fungal metabolism. Because ACSs are components of the pyruvate-acetaldehyde-acetate pathway, this fermentation process might have crucial roles in various physiological processes for filamentous fungi.
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60
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Larson TM, Kendra DF, Busman M, Brown DW. Fusarium verticillioides chitin synthases CHS5 and CHS7 are required for normal growth and pathogenicity. Curr Genet 2011; 57:177-89. [PMID: 21246198 DOI: 10.1007/s00294-011-0334-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 12/21/2010] [Accepted: 01/03/2011] [Indexed: 12/11/2022]
Abstract
Fusarium verticillioides is both an endophyte and a pathogen of maize and is a health threat in many areas of the world because it can contaminate maize with fumonisins, a toxic secondary metabolite. We identified eight putative chitin synthase (CHS) genes in F. verticillioides genomic sequence, and phylogenetic evidence shows that they group into seven established CHS gene classes. We targeted two CHSs (CHS5 and CHS7) for deletion analysis and found that both are required for normal hyphal growth and maximal disease of maize seedlings and ears. CHS5 and CHS7 encode a putative class V and class VII fungal chitin synthase, respectively; they are located adjacent to each other and are divergently transcribed. Fluorescent microscopy found that both CHS deficient strains produce balloon-shaped hyphae, while growth assays indicated that they were more sensitive to cell wall stressing compounds (e.g., the antifungal compound Nikkomycin Z) than wild type. Pathogenicity assays on maize seedlings and ears indicated that both strains were significantly reduced in their ability to cause disease. Our results demonstrate that both CHS5 and CHS7 are necessary for proper hyphal growth and pathogenicity of F. verticillioides on maize.
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Affiliation(s)
- Troy M Larson
- Bacterial Foodborne Pathogens and Mycology Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Peoria, IL 61604-3999, USA.
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61
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Son H, Lee J, Park AR, Lee YW. ATP citrate lyase is required for normal sexual and asexual development in Gibberella zeae. Fungal Genet Biol 2011; 48:408-17. [PMID: 21237280 DOI: 10.1016/j.fgb.2011.01.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 12/13/2010] [Accepted: 01/03/2011] [Indexed: 01/08/2023]
Abstract
Adenosine triphosphate (ATP) citrate lyase (ACL) is a key enzyme in the production of cytosolic acetyl-CoA, which is crucial for de novo lipid synthesis and histone acetylation in mammalian cells. In this study, we characterized the mechanistic roles of ACL in the homothallic ascomycete fungus Gibberella zeae, which causes Fusarium head blight in major cereal crops. Deletion of ACL in the fungus resulted in a complete loss of self and female fertility as well as a reduction in asexual reproduction, virulence, and trichothecene production. When the wild-type strain was spermatized with the ACL deletion mutants, they produced viable ascospores, however ascospore delimitation was not properly regulated. Although lipid synthesis was not affected by ACL deletion, histone acetylation was dramatically reduced in the ACL deletion mutants during sexual development, suggesting that the defects in sexual reproduction were caused by the reduction in histone acetylation. This study is the first report demonstrating a link between sexual development and ACL-mediated histone acetylation in fungi.
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Affiliation(s)
- Hokyoung Son
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Republic of Korea
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62
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Wang Y, Liu W, Hou Z, Wang C, Zhou X, Jonkers W, Ding S, Kistler HC, Xu JR. A novel transcriptional factor important for pathogenesis and ascosporogenesis in Fusarium graminearum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:118-128. [PMID: 20795857 DOI: 10.1094/mpmi-06-10-0129] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Fusarium head blight or scab caused by Fusarium graminearum is an important disease of wheat and barley. The pathogen not only causes severe yield losses but also contaminates infested grains with mycotoxins. In a previous study, we identified several pathogenicity mutants by random insertional mutagenesis. One of these mutants was disrupted in the ZIF1 gene, which encodes a b-ZIP transcription factor unique to filamentous ascomycetes. The Δzif1 mutant generated by gene replacement was significantly reduced in deoxynivalenol (DON) production and virulence on flowering wheat heads. It was defective in spreading from inoculated florets to the rachis and other spikelets. Deletion of the ZIF1 ortholog MoZIF1 in the rice blast fungus also caused reductions in virulence and in invasive growth. In addition, the Δzif1 mutant is defective in sexual reproduction. Although it had normal male fertility, when selfed or mated as the female in outcrosess, the Δzif1 mutant produced small, pigmented perithecia that were sterile (lack of asci and ascospores), suggesting a female-specific role for ZIF1 during fertilization or ascus development. Similar female-specific defects in sexual reproduction were observed in the ΔMozif1 mutant. When mated as the female, the ΔMozif1 perithecia failed to develop long necks and asci or ascospores. The ZIF1 gene is well conserved in filamentous ascomycetes, particularly in the b-ZIP domain, which is essential for its function. Expression of ZIF1 in Magnaporthe oryzae complemented the defects of the ΔMozif1 mutant. These results indicate that this b-ZIP transcription factor is functionally conserved in these two fungal pathogens for plant infection and sexual reproduction.
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Affiliation(s)
- Yang Wang
- College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
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63
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Lee J, Park C, Kim JC, Kim JE, Lee YW. Identification and functional characterization of genes involved in the sexual reproduction of the ascomycete fungus Gibberella zeae. Biochem Biophys Res Commun 2010; 401:48-52. [PMID: 20836989 DOI: 10.1016/j.bbrc.2010.09.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 09/03/2010] [Indexed: 11/17/2022]
Abstract
We previously reported that G protein alpha subunit 1 (GPA1) is essential for sexual reproduction in the homothallic ascomycete fungus Gibberella zeae. In this study we performed microarray analyses on a GPA1 deletion mutant of G. zeae (Δgpa1) to identify genes involved in the sexual reproduction of this fungus. In the Δgpa1 strain, 645 genes were down-regulated and 550 genes were up-regulated during sexual reproduction when compared to the wild-type strain. One hundred of the down-regulated genes were selected for further investigation based on orthologous group clusters and differences in transcript levels. Quantitative real time-PCR was used to determine transcriptional profiles of these genes at various sexual and vegetative stages. We observed that transcript levels of 78 of these genes were dramatically increased in the wild-type strain during sexual reproduction compared to levels observed during vegetative growth, and were down-regulated in Δgpa1 compared to the wild-type strain. We deleted 57 of these genes and found that four of the deletion mutants lost self-fertility and five produced fewer perithecia compared to the wild-type strain. Two mutants produced wild-type numbers of perithecia, but maturation of perithecia and ascospores was delayed. In all we identified 11 genes that are involved in sexual reproduction of G. zeae and present evidence that some of these genes function at distinct stages during sexual reproduction in the fungus.
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Affiliation(s)
- Jungkwan Lee
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, Seoul National University, Seoul 151-921, Republic of Korea
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64
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Treitschke S, Doehlemann G, Schuster M, Steinberg G. The myosin motor domain of fungal chitin synthase V is dispensable for vesicle motility but required for virulence of the maize pathogen Ustilago maydis. THE PLANT CELL 2010; 22:2476-94. [PMID: 20663961 PMCID: PMC2929105 DOI: 10.1105/tpc.110.075028] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 06/26/2010] [Accepted: 07/08/2010] [Indexed: 05/23/2023]
Abstract
Class V chitin synthases are fungal virulence factors required for plant infection. They consist of a myosin motor domain fused to a membrane-spanning chitin synthase region that participates in fungal cell wall formation. The function of the motor domain is unknown, but it might deliver the myosin chitin synthase-attached vesicles to the growth region. Here, we analyze the importance of both domains in Mcs1, the chitin synthase V of the maize smut fungus Ustilago maydis. By quantitative analysis of disease symptoms, tissue colonization, and single-cell morphogenic parameters, we demonstrate that both domains are required for fungal virulence. Fungi carrying mutations in the chitin synthase domain are rapidly recognized and killed by the plant, whereas fungi carrying a deletion of the motor domain show alterations in cell wall composition but can invade host tissue and cause a moderate plant response. We also show that Mcs1-bound vesicles exhibit long-range movement for up to 20 microm at a velocity of approximately 1.75 microm/s. Apical Mcs1 localization depends on F-actin and the motor domain, whereas Mcs1 motility requires microtubules and persists when the Mcs1 motor domain is deleted. Our results suggest that the myosin motor domain of ChsV supports exocytosis but not long-range delivery of transport vesicles.
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Affiliation(s)
- Steffi Treitschke
- School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
- Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
| | - Gunther Doehlemann
- Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany
| | - Martin Schuster
- School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - Gero Steinberg
- School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
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65
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Disruption of the chitin synthase gene CHS1 from Fusarium asiaticum results in an altered structure of cell walls and reduced virulence. Fungal Genet Biol 2010; 47:205-15. [DOI: 10.1016/j.fgb.2009.11.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 11/22/2022]
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