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Xia H, Xia X, Guo M, Liu W, Tang G. The MAP kinase FvHog1 regulates FB1 synthesis and Ca 2+ homeostasis in Fusarium verticillioides. JOURNAL OF HAZARDOUS MATERIALS 2024; 473:134682. [PMID: 38795487 DOI: 10.1016/j.jhazmat.2024.134682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/08/2024] [Accepted: 05/20/2024] [Indexed: 05/28/2024]
Abstract
The high osmolarity glycerol 1 mitogen-activated protein kinase (Hog1-MAPK) cascade genes are important for diverse biological processes. The activated Hog1 upon multiple environmental stress stimuli enters into the nucleus where it directly phosphorylates transcription factors to regulate various physiological processes in phytopathogenic fungi. However, their roles have not been well-characterized in Fusarium verticillioides. In this study, FvHog1 is identified and functionally analyzed. The findings reveal that the phosphorylation level and nuclear localization of FvHog1 are increased in Fumonisin B1 (FB1)-inducing condition to regulate the expression of FB1 biosynthesis FUM genes. More importantly, the deletion mutants of Hog1-MAPK pathway show increased sensitivity to Ca2+ stress and elevated intracellular Ca2+ content. The phosphorylation level and nuclear localization of FvHog1 are increased with Ca2+ treatment. Furthermore, our results show that FvHog1 can directly phosphorylate Ca2+-responsive zinc finger transcription factor 1 (FvCrz1) to regulate Ca2+ homeostasis. In conclusion, our findings indicate that FvHog1 is required for FB1 biosynthesis, pathogenicity and Ca2+ homeostasis in F. verticillioides. It provides a theoretical basis for effective prevention and control maize ear and stalk rot disease.
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Affiliation(s)
- Haoxue Xia
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, College of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Xinyao Xia
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Min Guo
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, College of Plant Protection, Anhui Agricultural University, Hefei 230036, China
| | - Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Guangfei Tang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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Li W, Li S, Tang C, Klosterman SJ, Wang Y. Kss1 of Verticillium dahliae regulates virulence, microsclerotia formation, and nitrogen metabolism. Microbiol Res 2024; 281:127608. [PMID: 38241914 DOI: 10.1016/j.micres.2024.127608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/05/2024] [Accepted: 01/09/2024] [Indexed: 01/21/2024]
Abstract
Verticillium dahliae causes destructive vascular wilt diseases on more than 200 plant species, including economically important crops and ornamental trees worldwide. The melanized microsclerotia (MS) enable V. dahliae to survive for years in soil, thus the fungus is especially difficult to control once it has become established. Previously, we found that the mitogen activated protein kinase VdSte11 (MAPKKK) plays key roles in MS formation, penetration, and virulence in V. dahliae. In this study, two MAPK homologs of the yeast Ste7p and Kss1p were identified and characterized in V. dahliae. Deletion of VdSte7 or VdKss1 reuslted in severe defects in melaninized MS formation and virulence. Furthermore, phosphorylation assays demonstrated that VdSte11 and VdSte7 can phosphorylate VdKss1 in V. dahliae. Proteomic analysis revealed a significant change in sterol biosynthesis with a fold change of ≥ 1.2 after the deletion of VdKss1. In addition, phosphoproteomic analysis showed that VdKss1 was involved in the regulation of nitrogen metabolism. Finally, we identified VdRlm1 as a potentially downstream target of VdKss1, which is involved in regulating ammonium nitrogen utilization. This study sheds light on the network of regulatory proteins in V. dahliae that affect MS formation and nitrogen metabolism.
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Affiliation(s)
- Wenwen Li
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Sa Li
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Chen Tang
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China
| | - Steven J Klosterman
- United States Department of Agriculture, Agricultural Research Service, Salinas, CA, USA
| | - Yonglin Wang
- State Key Laboratory of Efficient Production of Forest Resources, Beijing Key Laboratory for Forest Pest Control, College of Forestry, Beijing Forestry University, Beijing, China.
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Ding Y, Ma N, Haseeb HA, Dai Z, Zhang J, Guo W. Genome-wide transcriptome analysis of toxigenic Fusarium verticillioides in response to variation of temperature and water activity on maize kernels. Int J Food Microbiol 2024; 410:110494. [PMID: 38006847 DOI: 10.1016/j.ijfoodmicro.2023.110494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 11/08/2023] [Accepted: 11/13/2023] [Indexed: 11/27/2023]
Abstract
Fusarium verticillioides is one of the important mycotoxigenic pathogens of maize since it causes severe yield losses and produces fumonisins (FBs) to threaten human and animal health. Previous studies showed that temperature and water activity (aw) are two pivotal environmental factors affecting F. verticillioides growth and FBs production during maize storage. However, the genome-wide transcriptome analysis of differentially expressed genes (DEGs) in F. verticillioides under the stress combinations of temperature and aw has not been studied in detail. In this study, DEGs of F. verticillioides and their related regulatory pathways were analyzed in response to the stress of temperature and aw combinations using RNA-Seq. The results showed that the optimal growth conditions for F. verticillioides were 0.98 aw and 25 °C, whereas the highest per-unit yield of the fumonisin B1 (FB1) was observed at 0.98 aw and 15 °C. The RNA-seq analysis showed that 9648 DEGs were affected by temperature regardless of aw levels, whereas only 218 DEGs were affected by aw regardless of temperature variations. Gene Ontology (GO) analysis revealed that a decrease in temperature at both aw levels led to a significant upregulation of genes associated with 24 biological processes, while three biological processes were downregulated. Furthermore, when aw was decreased at both temperatures, seven biological processes were significantly upregulated and four were downregulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that the genes, whose expression was upregulated when the temperature decreased, were predominantly associated with the proteasome pathway, whereas the genes, whose expression was downregulated when the aw decreased, were mainly linked to amino acid metabolism. For the FB1, except for the FUM15 gene, the other 15 biosynthetic-related genes were highly expressed at 0.98 aw and 15 °C. In addition, the expression pattern analysis of other biosynthetic genes involved in secondary metabolite production and regulation of fumonisins production was conducted to explore how this fungus responds to the stress combinations of temperature and aw. Overall, this study primarily examines the impact of temperature and aw on the growth of F. verticillioides and its production of FB1 using transcriptome data. The findings presented here have the potential to contribute to the development of novel strategies for managing fungal diseases and offer valuable insights for preventing fumonisin contamination in food and feed storage.
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Affiliation(s)
- Yi Ding
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Beijing 100193, PR China
| | - Nini Ma
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Beijing 100193, PR China
| | - Hafiz Abdul Haseeb
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Beijing 100193, PR China; Directorate General of Pest Warning and Quality Control of Pesticides, Punjab, Lahore, Pakistan
| | - Zhaoji Dai
- Sanya Nanfan Research Institute, Key Laboratory of Green Prevention and Control of Tropical Plant Diseases and Pests (Ministry of Education), School of Plant Protection, Hainan University, Haikou, Hainan 570228, PR China
| | - Jun Zhang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Beijing 100193, PR China
| | - Wei Guo
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Beijing 100193, PR China.
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Mesterhazy A. Food Safety Aspects of Breeding Maize to Multi-Resistance against the Major (Fusarium graminearum, F. verticillioides, Aspergillus flavus) and Minor Toxigenic Fungi ( Fusarium spp.) as Well as to Toxin Accumulation, Trends, and Solutions-A Review. J Fungi (Basel) 2024; 10:40. [PMID: 38248949 PMCID: PMC10817526 DOI: 10.3390/jof10010040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/23/2023] [Accepted: 12/26/2023] [Indexed: 01/23/2024] Open
Abstract
Maize is the crop which is most commonly exposed to toxigenic fungi that produce many toxins that are harmful to humans and animals alike. Preharvest grain yield loss, preharvest toxin contamination (at harvest), and storage loss are estimated to be between 220 and 265 million metric tons. In the past ten years, the preharvest mycotoxin damage was stable or increased mainly in aflatoxin and fumonisins. The presence of multiple toxins is characteristic. The few breeding programs concentrate on one of the three main toxigenic fungi. About 90% of the experiments except AFB1 rarely test toxin contamination. As disease resistance and resistance to toxin contamination often differ in regard to F. graminearum, F. verticillioides, and A. flavus and their toxins, it is not possible to make a food safety evaluation according to symptom severity alone. The inheritance of the resistance is polygenic, often mixed with epistatic and additive effects, but only a minor part of their phenotypic variation can be explained. All tests are made by a single inoculum (pure isolate or mixture). Genotype ranking differs between isolates and according to aggressiveness level; therefore, the reliability of such resistance data is often problematic. Silk channel inoculation often causes lower ear rot severity than we find in kernel resistance tests. These explain the slow progress and raise skepticism towards resistance breeding. On the other hand, during genetic research, several effective putative resistance genes were identified, and some overlapped with known QTLs. QTLs were identified as securing specific or general resistance to different toxicogenic species. Hybrids were identified with good disease and toxin resistance to the three toxigenic species. Resistance and toxin differences were often tenfold or higher, allowing for the introduction of the resistance and resistance to toxin accumulation tests in the variety testing and the evaluation of the food safety risks of the hybrids within 2-3 years. Beyond this, resistance breeding programs and genetic investigations (QTL-analyses, GWAM tests, etc.) can be improved. All other research may use it with success, where artificial inoculation is necessary. The multi-toxin data reveal more toxins than we can treat now. Their control is not solved. As limits for nonregulated toxins can be introduced, or the existing regulations can be made to be stricter, the research should start. We should mention that a higher resistance to F. verticillioides and A. flavus can be very useful to balance the detrimental effect of hotter and dryer seasons on aflatoxin and fumonisin contamination. This is a new aspect to secure food and feed safety under otherwise damaging climatic conditions. The more resistant hybrids are to the three main agents, the more likely we are to reduce the toxin losses mentioned by about 50% or higher.
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Affiliation(s)
- Akos Mesterhazy
- Cereal Research Non-Profit Ltd., Alsokikotosor 9, 6726 Szeged, Hungary
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5
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Si P, Wang G, Wu W, Hussain S, Guo L, Wu W, Yang Q, Xing F. SakA Regulates Morphological Development, Ochratoxin A Biosynthesis and Pathogenicity of Aspergillus westerdijkiae and the Response to Different Environmental Stresses. Toxins (Basel) 2023; 15:toxins15040292. [PMID: 37104230 PMCID: PMC10141874 DOI: 10.3390/toxins15040292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/05/2023] [Accepted: 04/14/2023] [Indexed: 04/28/2023] Open
Abstract
Ochratoxin A (OTA), as a common mycotoxin, has seriously harmful effects on agricultural products, livestock and humans. There are reports on the regulation of SakA in the MAPK pathway, which regulates the production of mycotoxins. However, the role of SakA in the regulation of Aspergillus westerdijkiae and OTA production is not clear. In this study, a SakA deletion mutant (ΔAwSakA) was constructed. The effects of different concentrations of D-sorbitol, NaCl, Congo red and H2O2 on the mycelia growth, conidia production and biosynthesis of OTA were investigated in A. westerdijkiae WT and ΔAwSakA. The results showed that 100 g/L NaCl and 3.6 M D-sorbitol significantly inhibited mycelium growth and that a concentration of 0.1% Congo red was sufficient to inhibit the mycelium growth. A reduction in mycelium development was observed in ΔAwSakA, especially in high concentrations of osmotic stress. A lack of AwSakA dramatically reduced OTA production by downregulating the expression of the biosynthetic genes otaA, otaY, otaB and otaD. However, otaC and the transcription factor otaR1 were slightly upregulated by 80 g/L NaCl and 2.4 M D-sorbitol, whereas they were downregulated by 0.1% Congo red and 2 mM H2O2. Furthermore, ΔAwSakA showed degenerative infection ability toward pears and grapes. These results suggest that AwSakA is involved in the regulation of fungal growth, OTA biosynthesis and the pathogenicity of A. westerdijkiae and could be influenced by specific environmental stresses.
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Affiliation(s)
- Peidong Si
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Gang Wang
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wenqing Wu
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Sarfaraz Hussain
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Ling Guo
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Wei Wu
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China
| | - Qingli Yang
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China
| | - Fuguo Xing
- Key Laboratory of Agro-Products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China
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6
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Abah F, Kuang Y, Biregeya J, Abubakar YS, Ye Z, Wang Z. Mitogen-Activated Protein Kinases SvPmk1 and SvMps1 Are Critical for Abiotic Stress Resistance, Development and Pathogenesis of Sclerotiophoma versabilis. J Fungi (Basel) 2023; 9:jof9040455. [PMID: 37108909 PMCID: PMC10142639 DOI: 10.3390/jof9040455] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
Mitogen-activated protein kinase (MAPK) signaling pathways are evolutionarily conserved in eukaryotes and modulate responses to both internal and external stimuli. Pmk1 and Mps MAPK pathways regulate stress tolerance, vegetative growth and cell wall integrity in Saccharomyces cerevisiae and Pyricularia oryzae. Here, we deployed genetic and cell biology strategies to investigate the roles of the orthologs of Pmk1 and Mps1 in Sclerotiophoma versabilis (herein referred to as SvPmk1 and SvMps1, respectively). Our results showed that SvPmk1 and SvMps1 are involved in hyphal development, asexual reproduction and pathogenesis in S. versabilis. We found that ∆Svpmk1 and ∆Svmps1 mutants have significantly reduced vegetative growths on PDA supplemented with osmotic stress-inducing agents, compared to the wild type, with ∆Svpmps1 being hypersensitive to hydrogen peroxide. The two mutants failed to produce pycnidia and have reduced pathogenicity on Pseudostellaria heterophylla. Unlike SvPmk1, SvMps1 was found to be indispensable for the fungal cell wall integrity. Confocal microscopic analyses revealed that SvPmk1 and SvMps1 are ubiquitously expressed in the cytosol and nucleus. Taken together, we demonstrate here that SvPmk1 and SvMps1 play critical roles in the stress resistance, development and pathogenesis of S. versabilis.
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Affiliation(s)
- Felix Abah
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yunbo Kuang
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- The Engineering Technology Research Center of Characteristic Medicinal Plants of Fujian, College of Life Sciences, Ningde Normal University, Ningde 352100, China
| | - Jules Biregeya
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Yakubu Saddeeq Abubakar
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zuyun Ye
- The Engineering Technology Research Center of Characteristic Medicinal Plants of Fujian, College of Life Sciences, Ningde Normal University, Ningde 352100, China
| | - Zonghua Wang
- Ministerial and Provincial Joint Innovation Centre for Safety Production of Cross-Strait Crops, College of Life Sciences & College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Fujian Provincial Key Laboratory on Conservation and Sustainable Utilization of Marine Biodiversity, Fuzhou Institute of Oceanography, Minjiang University, Fuzhou 350108, China
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7
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Yang Y, Huang P, Ma Y, Jiang R, Jiang C, Wang G. Insights into intracellular signaling network in Fusarium species. Int J Biol Macromol 2022; 222:1007-1014. [PMID: 36179869 DOI: 10.1016/j.ijbiomac.2022.09.211] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/23/2022] [Indexed: 11/27/2022]
Abstract
Fusarium is a large genus of filamentous fungi including numerous important plant pathogens. In addition to causing huge economic losses of crops, some Fusarium species produce a wide range of mycotoxins in cereal crops that affect human and animal health. The intracellular signaling in Fusarium plays an important role in growth, sexual and asexual developments, pathogenesis, and mycotoxin biosynthesis. In this review, we highlight the recent advances and provide insight into signal sensing and transduction in Fusarium species. G protein-coupled receptors and other conserved membrane receptors mediate recognition of environmental cues and activate complex intracellular signaling. Once activated, the cAMP-PKA and three well-conserved MAP kinase pathways activate downstream transcriptional regulatory networks. The functions of individual signaling pathways have been well characterized in a variety of Fusarium species, showing the conserved components with diverged functions. Furthermore, these signaling pathways crosstalk and coordinately regulate various fungal development and infection-related morphogenesis.
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Affiliation(s)
- Yang Yang
- State Key Laboratory of Crop Stress Biology for Arid areas, Northwestern A&F University, Yangling, Shaanxi 712100, China
| | - Panpan Huang
- State Key Laboratory of Crop Stress Biology for Arid areas, Northwestern A&F University, Yangling, Shaanxi 712100, China
| | - Yutong Ma
- State Key Laboratory of Crop Stress Biology for Arid areas, Northwestern A&F University, Yangling, Shaanxi 712100, China
| | - Ruoxuan Jiang
- State Key Laboratory of Crop Stress Biology for Arid areas, Northwestern A&F University, Yangling, Shaanxi 712100, China
| | - Cong Jiang
- State Key Laboratory of Crop Stress Biology for Arid areas, Northwestern A&F University, Yangling, Shaanxi 712100, China.
| | - Guanghui Wang
- State Key Laboratory of Crop Stress Biology for Arid areas, Northwestern A&F University, Yangling, Shaanxi 712100, China.
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8
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Yu L, Yang Y, Xiong D, Tian C. Phosphoproteomic and Metabolomic Profiling Uncovers the Roles of CcPmk1 in the Pathogenicity of Cytospora chrysosperma. Microbiol Spectr 2022; 10:e0017622. [PMID: 35735975 PMCID: PMC9430611 DOI: 10.1128/spectrum.00176-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 04/23/2022] [Indexed: 11/20/2022] Open
Abstract
Pmk1, a highly conserved pathogenicity-related mitogen-activated protein kinase (MAPK) in pathogenic fungi, is phosphorylated and activated by MAP2K and acts as a global regulator of fungal infection and invasive growth by modulating downstream targets. However, the hierarchical CcPmk1 regulatory network in Cytospora chrysosperma, the main causal agent of canker disease in many woody plant species, is still unclear. In this study, we analyzed and compared the phosphoproteomes and metabolomes of ΔCcPmk1 and wild-type strains and identified pathogenicity-related downstream targets of CcPmk1. We found that CcPmk1 could interact with the downstream homeobox transcription factor CcSte12 and affect its phosphorylation. In addition, the ΔCcSte12 displayed defective phenotypes that were similar to yet not identical to that of the ΔCcPmk1 and included significantly reduced fungal growth, conidiation, and virulence. Remarkably, CcPmk1 could phosphorylate proteins translated from a putative secondary metabolism-related gene cluster, which is specific to C. chrysosperma, and the phosphorylation of several peptides was completely abolished in the ΔCcPmk1. Functional analysis of the core gene (CcPpns1) in this gene cluster revealed its essential roles in fungal growth and virulence. Metabolomic analysis showed that amino acid metabolism and biosynthesis of secondary metabolites, lipids, and lipid-like molecules significantly differed between wild type and ΔCcPmk1. Importantly, most of the annotated lipids and lipid-like molecules were significantly downregulated in the ΔCcPmk1 compared to the wild type. Collectively, these findings suggest that CcPmk1 may regulate a small number of downstream master regulators to control fungal growth, conidiation, and virulence in C. chrysosperma. IMPORTANCE Understanding the pathogenic mechanisms of plant pathogens is a prerequisite to developing effective disease-control methods. The Pmk1 MAPK is highly conserved among phytopathogenic fungi and acts as a global regulator of fungal pathogenicity by modulating downstream transcription factors or other components. However, the regulatory network of CcPmk1 from C. chrysosperma remains enigmatic. The present data provide evidence that the core pathogenicity regulator CcPmk1 modulates a few downstream master regulators to control fungal virulence in C. chrysosperma through transcription or phosphorylation and that CcPmk1 may be a potential target for disease control.
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Affiliation(s)
- Lu Yu
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Yuchen Yang
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Dianguang Xiong
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
- Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing, China
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
- Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University, Beijing, China
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9
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FfCOX17 is Involved in Fumonisins Production, Growth, Asexual Reproduction, and Fungicide Sensitivity in Fusarium fujikuroi. Toxins (Basel) 2022; 14:toxins14070427. [PMID: 35878165 PMCID: PMC9319711 DOI: 10.3390/toxins14070427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/18/2022] [Accepted: 06/20/2022] [Indexed: 02/04/2023] Open
Abstract
Fusarium fujikuroi, a causal agent of Rice Bakanae Disease, produces secondary metabolites such as gibberellin, pigments bikaverin, and mycotoxins fumonisins. Fumonisins produced by F. fujikuroi pose a severe threat to human and animal health. The copper chaperone protein plays a critical role in different growth stages of plants, fungi, and yeasts, but their functions and regulation in fumonisin biosynthesis are still unclear. Here, a copper chaperone protein, FfCOX17, was identified in F. fujikuroi. The FfCOX17 deletion mutant (∆FfCOX17) exhibited decreased vegetative growth and asexual reproduction. The transcriptional level of the FfFUM2 gene was significantly induced in ∆FfCOX17, and the fumonisin production in ∆FfCOX17 mutants was significantly increased compared to wild-type F. fujikuroi, but the pathogenicity of ∆FfCOX17 mutants was unaffected, which may be caused by the no significantly changed gibberellin content. ∆FfCOX17 showed decreased sensitivity to oxidative stress, osmotic stress, and increased sensitivity to cell wall stress, heat shock stress, and high concentration glucose. In addition, ∆FfCOX17 also showed increased sensitivity to fungicide fluazinam and fludioxonil, and decreased sensitivity to phenamacril and prochloraz. Taken together, this study suggested that FfCOX17 is critical for fumonisin production, vegetative growth, asexual reproduction, and fungicide sensitivity, but is not required for the virulence function of F. fujikuroi on rice.
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10
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Fu T, Shin JH, Lee NH, Lee KH, Kim KS. Mitogen-Activated Protein Kinase CsPMK1 Is Essential for Pepper Fruit Anthracnose by Colletotrichum scovillei. Front Microbiol 2022; 13:770119. [PMID: 35283826 PMCID: PMC8907736 DOI: 10.3389/fmicb.2022.770119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 02/10/2022] [Indexed: 11/19/2022] Open
Abstract
The phytopathogenic fungus Colletotrichum scovillei, belonging to the Colletotrichum acutatum species complex, causes severe anthracnose disease on several fruits, including chili pepper (Capsicum annuum). However, the molecular mechanisms underlying the development and pathogenicity of Colletotrichum scovillei are unclear. The conserved Fus3/Kss1-related MAPK regulates fungal development and pathogenicity. Here, the role of CsPMK1, orthologous to Fus3/Kss1, was characterized by phenotypic comparison of a target deletion mutant (ΔCspmk1). The mycelial growth and conidiation of ΔCspmk1 were normal compared to that of the wild type. ΔCspmk1 produced morphologically abnormal conidia, which were delayed in conidial germination. Germinated conidia of ΔCspmk1 failed to develop appressoria on inductive surfaces of hydrophobic coverslips and host plants. ΔCspmk1 was completely defective in infectious growth, which may result from failure to suppress host immunity. Furthermore, ΔCspmk1 was impaired in nuclear division and lipid mobilization during appressorium formation, in response to a hydrophobic surface. CsPMK1 was found to interact with CsHOX7, a homeobox transcription factor essential for appressorium formation, via a yeast two-hybridization analysis. Taken together, these findings suggest that CsPMK1 is required for fungal development, stress adaptation, and pathogenicity of C. scovillei.
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Affiliation(s)
- Teng Fu
- Division of Bio-Resource Sciences, BioHerb Research Institute, and Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon, South Korea
| | - Jong-Hwan Shin
- Division of Bio-Resource Sciences, BioHerb Research Institute, and Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon, South Korea
| | - Noh-Hyun Lee
- Division of Bio-Resource Sciences, BioHerb Research Institute, and Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon, South Korea
| | - Kwang Ho Lee
- Division of Bio-Resource Sciences, BioHerb Research Institute, and Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon, South Korea
| | - Kyoung Su Kim
- Division of Bio-Resource Sciences, BioHerb Research Institute, and Interdisciplinary Program in Smart Agriculture, Kangwon National University, Chuncheon, South Korea
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11
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The CfMK1 Gene Regulates Reproduction, Appressorium Formation, and Pathogenesis in a Pear Anthracnose-Causing Fungus. J Fungi (Basel) 2022; 8:jof8010077. [PMID: 35050017 PMCID: PMC8779585 DOI: 10.3390/jof8010077] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/09/2022] [Accepted: 01/12/2022] [Indexed: 12/01/2022] Open
Abstract
Colletotrichum fructicola, the causal agent of pear anthracnose, causes significant annual economic losses. Mitogen-activated protein kinase (MAPK) cascades are highly conserved signal transduction pathways that play a crucial role in mediating cellular responses to environmental and host signals in plant pathogenic fungi. In this study, we identified an ortholog of the FUS3/KSS1-related MAPK gene, CfMK1, and characterized its function in C. fructicola. The Cfmk1 deletion mutants exhibited poorly developed aerial hyphae, autolysis, no conidial mass or perithecia on solid plates. However, the conidiation of the Cfmk1 mutant in PDB liquid medium was normal compared with that of the wild type (WT). Conidia of the Cfmk1 mutant exhibited a reduced germination rate on glass slides or plant surfaces. The Cfmk1 deletion mutants were unable to form appressoria and lost the capacity to penetrate plant epidermal cells. The ability of the Cfmk1 mutants to infect pear leaves and fruit was severely reduced. Moreover, RNA sequencing (RNA-seq) analysis of the WT and Cfmk1 mutant was performed, and the results revealed 1886 upregulated and 1554 downregulated differentially expressed genes (DEGs) in the mutant. The DEGs were significantly enriched in cell wall and pathogenesis terms, which was consistent with the defects of the Cfmk1 mutant in cell wall integrity and plant infection. Overall, our data demonstrate that CfMK1 plays critical roles in the regulation of aerial hyphal growth, asexual and sexual reproduction, autolysis, appressorium formation, and pathogenicity.
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12
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Deng Q, Wu H, Gu Q, Tang G, Liu W. Glycosyltransferase FvCpsA Regulates Fumonisin Biosynthesis and Virulence in Fusarium verticillioides. Toxins (Basel) 2021; 13:toxins13100718. [PMID: 34679011 PMCID: PMC8539240 DOI: 10.3390/toxins13100718] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 09/29/2021] [Indexed: 12/18/2022] Open
Abstract
Fusarium verticillioides is the major maize pathogen associated with ear rot and stalk rot worldwide. Fumonisin B1 (FB1) produced by F. verticillioides, poses a serious threat to human and animal health. However, our understanding of FB1 synthesis and virulence mechanism in this fungus is still very limited. Glycosylation catalyzed by glycosyltransferases (GTs) has been identified as contributing to fungal infection and secondary metabolism synthesis. In this study, a family 2 glycosyltransferase, FvCpsA, was identified and characterized in F. verticillioides. ΔFvcpsA exhibited significant defects in vegetative growth. Moreover, ΔFvcpsA also increased resistance to osmotic and cell wall stress agents. In addition, expression levels of FUM genes involved in FB1 production were greatly up-regulated in ΔFvcpsA. HPLC (high performance liquid chromatography) analysis revealed that ΔFvcpsA significantly increased FB1 production. Interestingly, we found that the deletion of FvCPSA showed penetration defects on cellophane membrane, and thus led to obvious defects in pathogenicity. Characterization of FvCpsA domain experiments showed that conserved DXD and QXXRW domains were vital for the biological functions of FvCpsA. Taken together, our results indicate that FvCpsA is critical for fungal growth, FB1 biosynthesis and virulence in F. verticillioides.
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Affiliation(s)
- Qi Deng
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (Q.D.); (H.W.)
| | - Hanxiang Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (Q.D.); (H.W.)
| | - Qin Gu
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Education, Nanjing 210095, China;
| | - Guangfei Tang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (Q.D.); (H.W.)
- Correspondence: (G.T.); (W.L.)
| | - Wende Liu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; (Q.D.); (H.W.)
- Correspondence: (G.T.); (W.L.)
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13
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Li T, Su X, Qu H, Duan X, Jiang Y. Biosynthesis, regulation, and biological significance of fumonisins in fungi: current status and prospects. Crit Rev Microbiol 2021; 48:450-462. [PMID: 34550845 DOI: 10.1080/1040841x.2021.1979465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Fumonisins are one of the most important mycotoxin classes due to their widespread occurrence and potential health threat to humans and animals. Currently, most of the research focuses on the control of fumonisin contamination in the food supply chain. In recent years, significant progress in biochemistry, enzymology, and genetic regulation of fumonisin biosynthesis has been achieved using molecular technology. Furthermore, new insights into the roles of fumonisins in the interaction between fungi and plant hosts have been reported. This review provides an overview of the current understanding of the biosynthesis and regulation of fumonisins. The ecological significance of fumonisins to Fusarium species that produce the toxins is discussed, and the complex regulatory networks of fumonisin synthesis is proposed.
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Affiliation(s)
- Taotao Li
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Xinguo Su
- Tropical Agriculture and Forestry Department, Guangdong AIB Polytechnic College, Guangzhou, China
| | - Hongxia Qu
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Xuewu Duan
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Yueming Jiang
- Key Laboratory of Plant Resource Conservation and Sustainable Utilization, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.,College of Life Sciences, Gannan Normal University, Ganzhou, China
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14
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Zhang X, Wang Z, Jiang C, Xu JR. Regulation of biotic interactions and responses to abiotic stresses by MAP kinase pathways in plant pathogenic fungi. STRESS BIOLOGY 2021; 1:5. [PMID: 37676417 PMCID: PMC10429497 DOI: 10.1007/s44154-021-00004-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/19/2021] [Indexed: 09/08/2023]
Abstract
Like other eukaryotes, fungi use MAP kinase (MAPK) pathways to mediate cellular changes responding to external stimuli. In the past two decades, three well-conserved MAP kinase pathways have been characterized in various plant pathogenic fungi for regulating responses and adaptations to a variety of biotic and abiotic stresses encountered during plant infection or survival in nature. The invasive growth (IG) pathway is homologous to the yeast pheromone response and filamentation pathways. In plant pathogens, the IG pathway often is essential for pathogenesis by regulating infection-related morphogenesis, such as appressorium formation, penetration, and invasive growth. The cell wall integrity (CWI) pathway also is important for plant infection although the infection processes it regulates vary among fungal pathogens. Besides its universal function in cell wall integrity, it often plays a minor role in responses to oxidative and cell wall stresses. Both the IG and CWI pathways are involved in regulating known virulence factors as well as effector genes during plant infection and mediating defenses against mycoviruses, bacteria, and other fungi. In contrast, the high osmolarity growth (HOG) pathway is dispensable for virulence in some fungi although it is essential for plant infection in others. It regulates osmoregulation in hyphae and is dispensable for appressorium turgor generation. The HOG pathway also plays a major role for responding to oxidative, heat, and other environmental stresses and is overstimulated by phenylpyrrole fungicides. Moreover, these three MAPK pathways crosstalk and coordinately regulate responses to various biotic and abiotic stresses. The IG and CWI pathways, particularly the latter, also are involved in responding to abiotic stresses to various degrees in different fungal pathogens, and the HOG pathway also plays a role in interactions with other microbes or fungi. Furthermore, some infection processes or stress responses are co-regulated by MAPK pathways with cAMP or Ca2+/CaM signaling. Overall, functions of individual MAP kinase pathways in pathogenesis and stress responses have been well characterized in a number of fungal pathogens, showing the conserved genetic elements with diverged functions, likely by rewiring transcriptional regulatory networks. In the near future, applications of genomics and proteomics approaches will likely lead to better understanding of crosstalk among the MAPKs and with other signaling pathways as well as roles of MAPKs in defense against other microbes (biotic interactions).
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Affiliation(s)
- Xue Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Zeyi Wang
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
| | - Cong Jiang
- State Key Laboratory of Crop Stress Biology for Arid Areas and NWAFU-Purdue Joint Research Center, College of Plant Protection, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Jin-Rong Xu
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
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15
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Xiong D, Yu L, Shan H, Tian C. CcPmk1 is a regulator of pathogenicity in Cytospora chrysosperma and can be used as a potential target for disease control. MOLECULAR PLANT PATHOLOGY 2021; 22:710-726. [PMID: 33835616 PMCID: PMC8126189 DOI: 10.1111/mpp.13059] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 05/13/2023]
Abstract
Fus3/Kss1, also known as Pmk1 in several pathogenic fungi, is a component of the mitogen-activated protein kinase (MAPK) signalling pathway that functions as a regulator in fungal development, stress response, mating, and pathogenicity. Cytospora chrysosperma, a notorious woody plant-pathogenic fungus, causes canker disease in many species, and its Pmk1 homolog, CcPmk1, is required for fungal development and pathogenicity. However, the global regulation network of CcPmk1 is still unclear. In this study, we compared transcriptional analysis between a CcPmk1 deletion mutant and the wild type during the simulated infection process. A subset of transcription factor genes and putative effector genes were significantly down-regulated in the CcPmk1 deletion mutant, which might be important for fungal pathogenicity. Additionally, many tandem genes were found to be regulated by CcPmk1. Eleven out of 68 core secondary metabolism biosynthesis genes and several gene clusters were significantly down-regulated in the CcPmk1 deletion mutant. GO annotation of down-regulated genes showed that the ribosome biosynthesis-related processes were over-represented in the CcPmk1 deletion mutant. Comparison of the CcPmk1-regulated genes with the Pmk1-regulated genes from Magnaporthe oryzae revealed only a few overlapping regulated genes in both CcPmk1 and Pmk1, while the enrichment GO terms in the ribosome biosynthesis-related processes were also found. Subsequently, we calculated that in vitro feeding artificial small interference RNAs of CcPmk1 could silence the target gene, resulting in inhibited fungal growth. Furthermore, silencing of BcPmk1 in Botrytis cinerea with conserved CcPmk1 and BcPmk1 fragments could significantly compromise fungal virulence using the virus-induced gene silencing system in Nicotiana benthamiana. These results suggest that CcPmk1 functions as a regulator of pathogenicity and can potentially be designed as a target for broad-spectrum disease control, but unintended effects on nonpathogenic fungi need to be avoided.
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Affiliation(s)
- Dianguang Xiong
- The Key Laboratory for Silviculture and Conservation of Ministry of EducationCollege of ForestryBeijing Forestry UniversityBeijingChina
- Beijing Key Laboratory for Forest Pest ControlBeijing Forestry UniversityBeijingChina
| | - Lu Yu
- The Key Laboratory for Silviculture and Conservation of Ministry of EducationCollege of ForestryBeijing Forestry UniversityBeijingChina
| | - Huimin Shan
- The Key Laboratory for Silviculture and Conservation of Ministry of EducationCollege of ForestryBeijing Forestry UniversityBeijingChina
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of EducationCollege of ForestryBeijing Forestry UniversityBeijingChina
- Beijing Key Laboratory for Forest Pest ControlBeijing Forestry UniversityBeijingChina
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16
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Wang X, Lu D, Tian C. Mitogen-activated protein kinase cascade CgSte50-Ste11-Ste7-Mk1 regulates infection-related morphogenesis in the poplar anthracnose fungus Colletotrichum gloeosporioides. Microbiol Res 2021; 248:126748. [PMID: 33752111 DOI: 10.1016/j.micres.2021.126748] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/09/2021] [Accepted: 03/11/2021] [Indexed: 11/28/2022]
Abstract
The hemibiotrophic pathogen Colletotrichum gloeosporioides is the causal agent of poplar anthracnose and causes considerable economic losses. This fungus infects its host through a specialized structure called an appressorium. In a previous study, we demonstrated that the mitogen-activated protein kinase (MAPK) CgMk1 plays a critical role in appressorium formation and pathogenicity. In this study, we identified three upstream components of CgMk1, the putative adaptor protein CgSte50, MAPKKK CgSte11, and MAPKK CgSte7, and showed that CgSte50, CgSte11, and CgSte7 positively regulate the phosphorylation of CgMk1. Deletion of CgSte50, CgSte11, and CgSte7 resulted in the loss of appressorium formation, penetration of the cellophane membrane, invasive growth and pathogenicity, similar to the defects observed in the CgMk1 mutant. CgSte50, CgSte11, CgSte7 and CgMk1 were also required for polarity during conidial germination. At the initial stage of appressorium formation, the accumulation of reactive oxygen species (ROS) was altered in the CgSte50, CgSte11, CgSte7 and CgMk1 deletion mutants compared with that in wild type (WT). Furthermore, the CgSte50, CgSte11, CgSte7 and CgMk1 deletion mutants manifested pleiotropic defects during vegetative growth; all mutants exhibited albino colonies, and the aerial hyphae had reduced hydrophobicity. In the mutants, autolysis was detected at the colony edge, and septum formation in the hyphae was elevated compared with that in the WT hyphae. Moreover, deletion of CgSte50, CgSte11, CgSte7 and CgMk1 affected vegetative growth under nitrogen-limiting and osmotic stress conditions. CgSte50, CgSte11, and CgSte7 but not CgMk1 were required for the oxidative stress response. Taken together, these results indicate that the CgMk1 MAPK cascade plays vital roles in various important functions in C. gloeosporioides.
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Affiliation(s)
- Xiaolian Wang
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Dongxiao Lu
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China
| | - Chengming Tian
- The Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, Beijing, China.
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17
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Ras2 is important for growth and pathogenicity in Fusarium circinatum. Fungal Genet Biol 2021; 150:103541. [PMID: 33639303 DOI: 10.1016/j.fgb.2021.103541] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 11/21/2022]
Abstract
In this study, we investigated to possible role of Ras2 in Fusarium circinatum- a fungus that causes pine pitch canker disease on many different pine species and has a wide geographic distribution. This protein is encoded by the RAS2 gene and has been shown to control growth and pathogenicity in a number of fungi in a mitogen-activated protein kinase- and/or cyclic adenosyl monophosphate pathway-dependent manner. The aim was therefore to characterize the phenotypes of RAS2 gene knockout and complementation mutants of F. circinatum. These mutants were generated by transforming protoplasts of the fungus with suitable split-marker constructs. The mutant strains, together with the wild type strain, were used in growth studies as well as pathogenicity assays on Pinus patula seedlings. Results showed that the knockout mutant strain produced significantly smaller lesions compared to the complementation mutant and wild type strains. Growth studies also showed significantly smaller colonies and delayed conidial germination in the knockout mutant strain compared to the complement mutant and wild type strains. Interestingly, the knockout mutant strain produced more macroconidia than the wild type strain. Collectively, these results showed that Ras2 plays an important role in both growth and pathogenicity of F. circinatum. Future studies will seek to determine the pathway(s) through which Ras2 controls these traits in F. circinatum.
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18
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Yan H, Zhou Z, Shim WB. Two regulators of G-protein signaling (RGS) proteins FlbA1 and FlbA2 differentially regulate fumonisin B1 biosynthesis in Fusarium verticillioides. Curr Genet 2021; 67:305-315. [PMID: 33392742 DOI: 10.1007/s00294-020-01140-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/23/2020] [Accepted: 11/30/2020] [Indexed: 11/28/2022]
Abstract
Fumonisins are a group of mycotoxins produced by maize pathogen Fusarium verticillioides that pose health concerns to humans and animals. Yet we still lack a clear understanding of the mechanism of fumonisins regulation during pathogenesis. The heterotrimeric G protein complex, which consists of canonical subunits and various regulators of G-protein signaling (RGS) proteins, plays an important role in transducing signals under environmental stress. Earlier studies demonstrated that Gα and Gβ subunits are positive regulators of fumonisin B1 (FB1) biosynthesis and that two RGS genes, FvFlbA1 and FvFlbA2, were highly upregulated in Gβ deletion mutant ∆Fvgbb1. Notably, FvFlbA2 has a negative role in FB1 regulation. While many fungi contain a single copy of FlbA, F. verticillioides harbors two putative FvFlbA paralogs, FvFlbA1 and FvFlbA2. In this study, we further characterized functional roles of FvFlbA1 and FvFlbA2. While ∆FvflbA1 deletion mutant exhibited no significant defects, ∆FvflbA2 and ∆FvflbA2/A1 mutants showed thinner aerial hyphal growth while promoting FB1 production. FvFlbA2 is required for proper expression of key conidia regulation genes, including putative FvBRLA, FvWETA, and FvABAA, while suppressing FUM21, FUM1, and FUM8 expression. Split luciferase assays determined that FvFlbA paralogs interact with key heterotrimeric G protein components, which in turn will lead altered G-protein-mediated signaling pathways that regulate FB1 production and asexual development in F. verticillioides.
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Affiliation(s)
- Huijuan Yan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA
| | - Zehua Zhou
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA.,College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
| | - Won Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA.
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19
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Szabó Z, Pákozdi K, Murvai K, Pusztahelyi T, Kecskeméti Á, Gáspár A, Logrieco AF, Emri T, Ádám AL, Leiter É, Hornok L, Pócsi I. FvatfA regulates growth, stress tolerance as well as mycotoxin and pigment productions in Fusarium verticillioides. Appl Microbiol Biotechnol 2020; 104:7879-7899. [PMID: 32719911 PMCID: PMC7447684 DOI: 10.1007/s00253-020-10717-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/22/2020] [Accepted: 06/01/2020] [Indexed: 01/22/2023]
Abstract
FvatfA from the maize pathogen Fusarium verticillioides putatively encodes the Aspergillus nidulans AtfA and Schizasaccharomyces pombe Atf1 orthologous bZIP-type transcription factor, FvAtfA. In this study, a ΔFvatfA deletion mutant was constructed and then genetically complemented with the fully functional FvatfA gene. Comparing phenotypic features of the wild-type parental, the deletion mutant and the restored strains shed light on the versatile regulatory functions played by FvAtfA in (i) the maintenance of vegetative growth on Czapek-Dox and Potato Dextrose agars and invasive growth on unwounded tomato fruits, (ii) the preservation of conidiospore yield and size, (iii) the orchestration of oxidative (H2O2, menadione sodium bisulphite) and cell wall integrity (Congo Red) stress defences and (iv) the regulation of mycotoxin (fumonisins) and pigment (bikaverin, carotenoid) productions. Expression of selected biosynthetic genes both in the fumonisin (fum1, fum8) and the carotenoid (carRA, carB) pathways were down-regulated in the ΔFvatfA strain resulting in defected fumonisin production and considerably decreased carotenoid yields. The expression of bik1, encoding the polyketide synthase needed in bikaverin biosynthesis, was not up-regulated by the deletion of FvatfA meanwhile the ΔFvatfA strain produced approximately ten times more bikaverin than the wild-type or the genetically complemented strains. The abolishment of fumonisin production of the ΔFvatfA strain may lead to the development of new-type, biology-based mycotoxin control strategies. The novel information gained on the regulation of pigment production by this fungus can be interesting for experts working on new, Fusarium-based biomass and pigment production technologies.Key points • FvatfA regulates vegetative and invasive growths of F. verticillioides. • FvatfA also orchestrates oxidative and cell wall integrity stress defenses. • The ΔFvatfA mutant was deficient in fumonisin production. • FvatfA deletion resulted in decreased carotenoid and increased bikaverin yields. |
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Affiliation(s)
- Zsuzsa Szabó
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.,Doctoral School of Biological Sciences, Faculty of Agricultural and Environmental Sciences, Szent István University, Gödöllő, Hungary
| | - Klaudia Pákozdi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.,Doctoral School of Nutrition and Food Sciences, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Katalin Murvai
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Tünde Pusztahelyi
- Central Laboratory of Agricultural and Food Products, Faculty of Agricultural and Food Sciences and Environmental Management, University of Debrecen, Debrecen, Hungary
| | - Ádám Kecskeméti
- Department of Inorganic and Analytical Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Attila Gáspár
- Department of Inorganic and Analytical Chemistry, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | | | - Tamás Emri
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - Attila L Ádám
- Plant Protection Institute, Centre for Agricultural Research, Budapest, Hungary
| | - Éva Leiter
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary
| | - László Hornok
- Faculty of Agricultural and Environmental Sciences, Szent István University, Gödöllő, Hungary
| | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, Institute of Biotechnology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.
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20
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Delgado J, Núñez F, Asensio MA, Owens RA. Quantitative proteomic profiling of ochratoxin A repression in Penicillium nordicum by protective cultures. Int J Food Microbiol 2019; 305:108243. [DOI: 10.1016/j.ijfoodmicro.2019.108243] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/26/2019] [Accepted: 05/31/2019] [Indexed: 12/15/2022]
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21
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Ogawara H. Comparison of Strategies to Overcome Drug Resistance: Learning from Various Kingdoms. Molecules 2018; 23:E1476. [PMID: 29912169 PMCID: PMC6100412 DOI: 10.3390/molecules23061476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/13/2018] [Accepted: 06/15/2018] [Indexed: 11/16/2022] Open
Abstract
Drug resistance, especially antibiotic resistance, is a growing threat to human health. To overcome this problem, it is significant to know precisely the mechanisms of drug resistance and/or self-resistance in various kingdoms, from bacteria through plants to animals, once more. This review compares the molecular mechanisms of the resistance against phycotoxins, toxins from marine and terrestrial animals, plants and fungi, and antibiotics. The results reveal that each kingdom possesses the characteristic features. The main mechanisms in each kingdom are transporters/efflux pumps in phycotoxins, mutation and modification of targets and sequestration in marine and terrestrial animal toxins, ABC transporters and sequestration in plant toxins, transporters in fungal toxins, and various or mixed mechanisms in antibiotics. Antibiotic producers in particular make tremendous efforts for avoiding suicide, and are more flexible and adaptable to the changes of environments. With these features in mind, potential alternative strategies to overcome these resistance problems are discussed. This paper will provide clues for solving the issues of drug resistance.
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Affiliation(s)
- Hiroshi Ogawara
- HO Bio Institute, Yushima-2, Bunkyo-ku, Tokyo 113-0034, Japan.
- Department of Biochemistry, Meiji Pharmaceutical University, Noshio-2, Kiyose, Tokyo 204-8588, Japan.
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22
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Blacutt AA, Gold SE, Voss KA, Gao M, Glenn AE. Fusarium verticillioides: Advancements in Understanding the Toxicity, Virulence, and Niche Adaptations of a Model Mycotoxigenic Pathogen of Maize. PHYTOPATHOLOGY 2018; 108:312-326. [PMID: 28971734 DOI: 10.1094/phyto-06-17-0203-rvw] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The importance of understanding the biology of the mycotoxigenic fungus Fusarium verticillioides and its various microbial and plant host interactions is critical given its threat to maize, one of the world's most valuable food crops. Disease outbreaks and mycotoxin contamination of grain threaten economic returns and have grave implications for human and animal health and food security. Furthermore, F. verticillioides is a member of a genus of significant phytopathogens and, thus, data regarding its host association, biosynthesis of secondary metabolites, and other metabolic (degradative) capabilities are consequential to both basic and applied research efforts across multiple pathosystems. Notorious among its secondary metabolites are the fumonisin mycotoxins, which cause severe animal diseases and are implicated in human disease. Additionally, studies of these mycotoxins have led to new understandings of F. verticillioides plant pathogenicity and provide tools for research into cellular processes and host-pathogen interaction strategies. This review presents current knowledge regarding several significant lines of F. verticillioides research, including facets of toxin production, virulence, and novel fitness strategies exhibited by this fungus across rhizosphere and plant environments.
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Affiliation(s)
- Alex A Blacutt
- First and fourth authors: Department of Plant Pathology, University of Georgia, Athens 30602; and second, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, U.S. National Poultry Research Center, Toxicology and Mycotoxin Research Unit, Athens, GA 30605-2720
| | - Scott E Gold
- First and fourth authors: Department of Plant Pathology, University of Georgia, Athens 30602; and second, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, U.S. National Poultry Research Center, Toxicology and Mycotoxin Research Unit, Athens, GA 30605-2720
| | - Kenneth A Voss
- First and fourth authors: Department of Plant Pathology, University of Georgia, Athens 30602; and second, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, U.S. National Poultry Research Center, Toxicology and Mycotoxin Research Unit, Athens, GA 30605-2720
| | - Minglu Gao
- First and fourth authors: Department of Plant Pathology, University of Georgia, Athens 30602; and second, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, U.S. National Poultry Research Center, Toxicology and Mycotoxin Research Unit, Athens, GA 30605-2720
| | - Anthony E Glenn
- First and fourth authors: Department of Plant Pathology, University of Georgia, Athens 30602; and second, third, and fifth authors: United States Department of Agriculture-Agricultural Research Service, U.S. National Poultry Research Center, Toxicology and Mycotoxin Research Unit, Athens, GA 30605-2720
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Valiante V. The Cell Wall Integrity Signaling Pathway and Its Involvement in Secondary Metabolite Production. J Fungi (Basel) 2017; 3:jof3040068. [PMID: 29371582 PMCID: PMC5753170 DOI: 10.3390/jof3040068] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/01/2017] [Accepted: 12/05/2017] [Indexed: 12/21/2022] Open
Abstract
The fungal cell wall is the external and first layer that fungi use to interact with the environment. Every stress signal, before being translated into an appropriate stress response, needs to overtake this layer. Many signaling pathways are involved in translating stress signals, but the cell wall integrity (CWI) signaling pathway is the one responsible for the maintenance and biosynthesis of the fungal cell wall. In fungi, the CWI signal is composed of a mitogen-activated protein kinase (MAPK) module. After the start of the phosphorylation cascade, the CWI signal induces the expression of cell-wall-related genes. However, the function of the CWI signal is not merely the activation of cell wall biosynthesis, but also the regulation of expression and production of specific molecules that are used by fungi to better compete in the environment. These molecules are normally defined as secondary metabolites or natural products. This review is focused on secondary metabolites affected by the CWI signal pathway with a special focus on relevant natural products such as melanins, mycotoxins, and antibacterial compounds.
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Affiliation(s)
- Vito Valiante
- Leibniz Research Group Biobricks of Microbial Natural Product Syntheses, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute (HKI), Beutenberg Strasse 11a, 07745 Jena, Germany.
- Department of General Microbiology and Microbial Genetics, Institute of Microbiology, Faculty of Biology and Pharmacy, Friedrich Schiller University Jena, Neugasse 24, 07743 Jena, Germany.
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24
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Ridenour JB, Bluhm BH. The novel fungal-specific gene FUG1 has a role in pathogenicity and fumonisin biosynthesis in Fusarium verticillioides. MOLECULAR PLANT PATHOLOGY 2017; 18:513-528. [PMID: 27071505 PMCID: PMC6638258 DOI: 10.1111/mpp.12414] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Revised: 04/06/2016] [Accepted: 04/07/2016] [Indexed: 05/05/2023]
Abstract
Fusarium verticillioides is a globally important pathogen of maize, capable of causing severe yield reductions and economic losses. In addition, F. verticillioides produces toxic secondary metabolites during kernel colonization that pose significant threats to human and animal health. Fusarium verticillioides and other plant-pathogenic fungi possess a large number of genes with no known or predicted function, some of which could encode novel virulence factors or antifungal targets. In this study, we identified and characterized the novel gene FUG1 (Fungal Unknown Gene 1) in F. verticillioides through functional genetics. Deletion of FUG1 impaired maize kernel colonization and fumonisin biosynthesis. In addition, deletion of FUG1 increased sensitivity to the antimicrobial compound 2-benzoxazolinone and to hydrogen peroxide, which indicates that FUG1 may play a role in mitigating stresses associated with host defence. Transcriptional profiling via RNA-sequencing (RNA-seq) identified numerous fungal genes that were differentially expressed in the kernel environment following the deletion of FUG1, including genes involved in secondary metabolism and mycelial development. Sequence analysis of the Fug1 protein provided evidence for nuclear localization, DNA binding and a domain of unknown function associated with previously characterized transcriptional regulators. This information, combined with the observed transcriptional reprogramming in the deletion mutant, suggests that FUG1 represents a novel class of fungal transcription factors or genes otherwise involved in signal transduction.
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Affiliation(s)
- John B. Ridenour
- Department of Plant PathologyUniversity of Arkansas Division of AgricultureFayettevilleAR 72701USA
| | - Burton H. Bluhm
- Department of Plant PathologyUniversity of Arkansas Division of AgricultureFayettevilleAR 72701USA
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25
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Vilanova L, Teixidó N, Torres R, Usall J, Viñas I, Sánchez-Torres P. Relevance of the transcription factor PdSte12 in Penicillium digitatum conidiation and virulence during citrus fruit infection. Int J Food Microbiol 2016; 235:93-102. [DOI: 10.1016/j.ijfoodmicro.2016.07.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 07/20/2016] [Accepted: 07/21/2016] [Indexed: 11/26/2022]
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26
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Ridenour JB, Smith JE, Bluhm BH. The HAP Complex Governs Fumonisin Biosynthesis and Maize Kernel Pathogenesis in Fusarium verticillioides. J Food Prot 2016; 79:1498-1507. [PMID: 28221941 DOI: 10.4315/0362-028x.jfp-15-596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Contamination of maize ( Zea mays ) with fumonisins produced by the fungus Fusarium verticillioides is a global concern for food safety. Fumonisins are a group of polyketide-derived secondary metabolites linked to esophageal cancer and neural tube birth defects in humans and numerous toxicoses in livestock. Despite the importance of fumonisins in global maize production, the regulation of fumonisin biosynthesis during kernel pathogenesis is poorly understood. The HAP complex is a conserved, heterotrimeric transcriptional regulator that binds the consensus sequence CCAAT to modulate gene expression. Recently, functional characterization of the Hap3 subunit linked the HAP complex to the regulation of secondary metabolism and stalk rot pathogenesis in F. verticillioides . Here, we determine the involvement of HAP3 in fumonisin biosynthesis and kernel pathogenesis. Deletion of HAP3 suppressed fumonisin biosynthesis on both nonviable and live maize kernels and impaired pathogenesis in living kernels. Transcriptional profiling via RNA sequencing indicated that the HAP complex regulates at least 1,223 genes in F. verticillioides , representing nearly 10% of all predicted genes. Disruption of the HAP complex caused the misregulation of biosynthetic gene clusters underlying the production of secondary metabolites, including fusarins. Taken together, these results reveal that the HAP complex is a central regulator of fumonisin biosynthesis and kernel pathogenesis and works as both a positive and negative regulator of secondary metabolism in F. verticillioides .
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Affiliation(s)
- John B Ridenour
- Department of Plant Pathology, Division of Agriculture, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Jonathon E Smith
- Department of Plant Pathology, Division of Agriculture, University of Arkansas, Fayetteville, Arkansas 72701, USA
| | - Burton H Bluhm
- Department of Plant Pathology, Division of Agriculture, University of Arkansas, Fayetteville, Arkansas 72701, USA
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27
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Chen W, Kastner C, Nowara D, Oliveira-Garcia E, Rutten T, Zhao Y, Deising HB, Kumlehn J, Schweizer P. Host-induced silencing of Fusarium culmorum genes protects wheat from infection. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:4979-91. [PMID: 27540093 PMCID: PMC5014151 DOI: 10.1093/jxb/erw263] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plants producing antisense or double-stranded RNA molecules that target specific genes of eukaryotic pests or pathogens can become protected from their attack. This beneficial effect was also reported for plant-fungus interactions and is believed to reflect uptake of the RNAs by the fungus via an as yet unknown mechanism, followed by target gene silencing. Here we report that wheat plants pre-infected with Barley stripe mosaic virus (BSMV) strains containing antisense sequences against target genes of the Fusarium head blight (FHB) fungus F. culmorum caused a reduction of corresponding transcript levels in the pathogen and reduced disease symptoms. Stable transgenic wheat plants carrying an RNAi hairpin construct against the β-1, 3-glucan synthase gene FcGls1 of F. culmorum or a triple combination of FcGls1 with two additional, pre-tested target genes also showed enhanced FHB resistance in leaf and spike inoculation assays under greenhouse and near-field conditions, respectively. Microscopic evaluation of F. culmorum development in plants transiently or stably expressing FcGls1 silencing constructs revealed aberrant, swollen fungal hyphae, indicating severe hyphal cell wall defects. The results lead us to propose host-induced gene silencing (HIGS) as a plant protection approach that may also be applicable to highly FHB-susceptible wheat genotypes.
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Affiliation(s)
- Wanxin Chen
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Christine Kastner
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Daniela Nowara
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Ely Oliveira-Garcia
- Martin-Luther Universität Halle-Wittenberg, Phytopathologie und Pflanzenschutz, Betty Heimann Straße 3, D-06120 Halle, Germany
| | - Twan Rutten
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Yusheng Zhao
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Holger B Deising
- Martin-Luther Universität Halle-Wittenberg, Phytopathologie und Pflanzenschutz, Betty Heimann Straße 3, D-06120 Halle, Germany
| | - Jochen Kumlehn
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
| | - Patrick Schweizer
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK) Gatersleben, Corrensstrasse 3, D-06466 Stadt Seeland, Germany
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28
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Bashi ZD, Gyawali S, Bekkaoui D, Coutu C, Lee L, Poon J, Rimmer SR, Khachatourians GG, Hegedus DD. The Sclerotinia sclerotiorum Slt2 mitogen-activated protein kinase ortholog, SMK3, is required for infection initiation but not lesion expansion. Can J Microbiol 2016; 62:836-850. [PMID: 27503454 DOI: 10.1139/cjm-2016-0091] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) play a central role in transferring signals and regulating gene expression in response to extracellular stimuli. An ortholog of the Saccharomyces cerevisiae cell wall integrity MAPK was identified in the phytopathogenic fungus Sclerotinia sclerotiorum. Disruption of the S. sclerotiorum Smk3 gene severely reduced virulence on intact host plant leaves but not on leaves stripped of cuticle wax. This was attributed to alterations in hyphal apical dominance leading to the inability to aggregate and form infection cushions. The mutation also caused loss of the ability to produce sclerotia, increased aerial hyphae formation, and altered hyphal hydrophobicity and cell wall integrity. Mutants had slower radial expansion rates on solid media but more tolerance to elevated temperatures. Loss of the SMK3 cell wall integrity MAPK appears to have impaired the ability of S. sclerotiorum to sense its surrounding environment, leading to misregulation of a variety of functions. Many of the phenotypes were similar to those observed in S. sclerotiorum adenylate cyclase and SMK1 MAPK mutants, suggesting that these signaling pathways co-regulate aspects of fungal growth, physiology, and pathogenicity.
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Affiliation(s)
- Zafer Dallal Bashi
- a Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N OX2, Canada.,b Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada
| | - Sanjaya Gyawali
- a Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N OX2, Canada
| | - Diana Bekkaoui
- a Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N OX2, Canada
| | - Cathy Coutu
- a Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N OX2, Canada
| | - Leora Lee
- a Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N OX2, Canada
| | - Jenny Poon
- a Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N OX2, Canada
| | - S Roger Rimmer
- a Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N OX2, Canada
| | - George G Khachatourians
- b Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada
| | - Dwayne D Hegedus
- a Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N OX2, Canada.,b Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada
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29
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Hegedus DD, Gerbrandt K, Coutu C. The eukaryotic protein kinase superfamily of the necrotrophic fungal plant pathogen, Sclerotinia sclerotiorum. MOLECULAR PLANT PATHOLOGY 2016; 17:634-647. [PMID: 26395470 PMCID: PMC6638376 DOI: 10.1111/mpp.12321] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Protein kinases have been implicated in the regulation of many processes that guide pathogen development throughout the course of infection. A survey of the Sclerotinia sclerotiorum genome for genes encoding proteins containing the highly conserved eukaryotic protein kinase (ePK) domain, the largest protein kinase superfamily, revealed 92 S. sclerotiorum ePKs. This review examines the composition of the S. sclerotiorum ePKs based on conserved motifs within the ePK domain family, and relates this to orthologues found in other filamentous fungi and yeasts. The ePKs are also discussed in terms of their proposed role(s) in aspects of host pathogenesis, including the coordination of mycelial growth/development and deployment of pathogenicity determinants in response to environmental stimuli, nutrients and stress.
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Affiliation(s)
- Dwayne D Hegedus
- Agriculture and Agri-Food Canada, Saskatoon, SK, Canada, S7N 0X2
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada, S7N 5A9
| | - Kelsey Gerbrandt
- Agriculture and Agri-Food Canada, Saskatoon, SK, Canada, S7N 0X2
| | - Cathy Coutu
- Agriculture and Agri-Food Canada, Saskatoon, SK, Canada, S7N 0X2
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30
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Zhang C, Wang J, Tao H, Dang X, Wang Y, Chen M, Zhai Z, Yu W, Xu L, Shim WB, Lu G, Wang Z. FvBck1, a component of cell wall integrity MAP kinase pathway, is required for virulence and oxidative stress response in sugarcane Pokkah Boeng pathogen. Front Microbiol 2015; 6:1096. [PMID: 26500635 PMCID: PMC4597114 DOI: 10.3389/fmicb.2015.01096] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 09/22/2015] [Indexed: 11/13/2022] Open
Abstract
Fusarium verticillioides (formerly F. moniliforme) is suggested as one of the causal agents of Pokkah Boeng, a serious disease of sugarcane worldwide. Currently, detailed molecular and physiological mechanism of pathogenesis is unknown. In this study, we focused on cell wall integrity MAPK pathway as one of the potential signaling mechanisms associated with Pokkah Boeng pathogenesis. We identified FvBCK1 gene that encodes a MAP kinase kinase kinase homolog and determined that it is not only required for growth, micro- and macro-conidia production, and cell wall integrity but also for response to osmotic and oxidative stresses. The deletion of FvBCK1 caused a significant reduction in virulence and FB1 production, a possibly carcinogenic mycotoxin produced by the fungus. Moreover, we found the expression levels of three genes, which are known to be involved in superoxide scavenging, were down regulated in the mutant. We hypothesized that the loss of superoxide scavenging capacity was one of the reasons for reduced virulence, but overexpression of catalase or peroxidase gene failed to restore the virulence defect in the deletion mutant. When we introduced Magnaporthe oryzae MCK1 into the FvBck1 deletion mutant, while certain phenotypes were restored, the complemented strain failed to gain full virulence. In summary, FvBck1 plays a diverse role in F. verticillioides, and detailed investigation of downstream signaling pathways will lead to a better understanding of how this MAPK pathway regulates Pokkah Boeng on sugarcane.
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Affiliation(s)
- Chengkang Zhang
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Jianqiang Wang
- Fujian University Key Laboratory for Functional Genomics of Plant Fungal Pathogens, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Hong Tao
- Fujian University Key Laboratory for Functional Genomics of Plant Fungal Pathogens, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Xie Dang
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Yang Wang
- Fujian University Key Laboratory for Functional Genomics of Plant Fungal Pathogens, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Miaoping Chen
- Fujian University Key Laboratory for Functional Genomics of Plant Fungal Pathogens, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Zhenzhen Zhai
- Fujian University Key Laboratory for Functional Genomics of Plant Fungal Pathogens, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Wenying Yu
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Liping Xu
- Key Laboratory of Sugarcane Biology and Genetic Breeding, Ministry of Agriculture, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Won-Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M UniversityCollege Station, TX, USA
| | - Guodong Lu
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry UniversityFuzhou, China
- Fujian University Key Laboratory for Functional Genomics of Plant Fungal Pathogens, Fujian Agriculture and Forestry UniversityFuzhou, China
| | - Zonghua Wang
- Fujian Province Key Laboratory of Pathogenic Fungi and Mycotoxins, College of Life Sciences, Fujian Agriculture and Forestry UniversityFuzhou, China
- Fujian University Key Laboratory for Functional Genomics of Plant Fungal Pathogens, Fujian Agriculture and Forestry UniversityFuzhou, China
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31
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Guo L, Wenner N, Kuldau GA. FvSO regulates vegetative hyphal fusion, asexual growth, fumonisin B1 production, and virulence in Fusarium verticillioides. Fungal Biol 2015; 119:1158-1169. [PMID: 26615739 DOI: 10.1016/j.funbio.2015.08.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 07/24/2015] [Accepted: 08/20/2015] [Indexed: 12/26/2022]
Abstract
Hyphal anastomosis is a hallmark of filamentous fungi and plays vital roles including cellular homoeostasis, interhyphal communication and nutrient translocation. Here we identify a gene, FvSO, in Fusarium verticillioides, a filamentous ascomycete causing maize ear and stalk rot and producing fumonisin mycotoxins. FvSO, like its Neurospora crassa homologue SO, is required for vegetative hyphal fusion. It is also essential for normal vegetative growth, sporulation, and pathogenesis. FvSO encodes a predicted WW domain protein and shares 70 % protein sequence identity with N. crassa SO. FvSO deletion mutants (ΔFvSO) had abnormal distribution of conidia size, and conidia of ΔFvSO germinated much later and slower than wild type. ΔFvSO was deficient in hyphal anastomosis, had slower radial growth and produced less fungal biomass than wild type. ΔFvSO were unable to perform anastomosis, a key feature of filamentous fungi. Interestingly, production of fumonisin B1 by ΔFvSO was significantly reduced compared to wild type. Additionally, ΔFvSO was nonpathogenic to corn ears, stalks and seedlings, likely due to defective growth and development. In conclusion, FvSO is essential for vegetative hyphal fusion and is required for normal vegetative growth and sporulation, normal levels of fumonisin production and pathogenicity in F. verticillioides. The pleiotropic nature of ΔFvSO phenotypes suggests that FvSO is likely involved in certain signalling pathways that regulate multiple cellular functions.
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Affiliation(s)
- Li Guo
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Nancy Wenner
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Gretchen A Kuldau
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, USA.
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32
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Ridenour JB, Bluhm BH. The HAP complex in Fusarium verticillioides is a key regulator of growth, morphogenesis, secondary metabolism, and pathogenesis. Fungal Genet Biol 2014; 69:52-64. [PMID: 24875423 DOI: 10.1016/j.fgb.2014.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 11/28/2022]
Abstract
Among eukaryotic organisms, the HAP complex is a conserved, multimeric transcription factor that regulates gene expression by binding to the consensus sequence CCAAT. In filamentous fungi, the HAP complex has been linked to primary and secondary metabolism, but its role in pathogenesis has not been investigated extensively. The overarching goal of this study was to elucidate the role of the HAP complex in Fusariumverticillioides, a ubiquitous and damaging pathogen of maize. To this end, orthologs of core HAP complex genes (FvHAP2, FvHAP3, and FvHAP5) were identified and deleted in F. verticillioides via a reverse genetics approach. Deletion of FvHAP2, FvHAP3, or FvHAP5 resulted in an indistinguishable phenotype among the deletion strains, including reduced radial growth and conidiation, altered colony morphology, and derepression of pigmentation. Additionally, disruption of the HAP complex impaired infection and colonization of maize stalks. Deletion strains were hypersensitive to osmotic and oxidative stress, which suggests the HAP complex of F. verticillioides may mediate responses to environmental stress during pathogenesis. This study directly implicates the HAP complex in primary and secondary metabolism in F. verticillioides and provides one of the first links between the HAP complex and virulence in a plant pathogenic fungus.
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Affiliation(s)
- John B Ridenour
- Department of Plant Pathology, University of Arkansas, Division of Agriculture, Fayetteville, AR 72701, USA
| | - Burton H Bluhm
- Department of Plant Pathology, University of Arkansas, Division of Agriculture, Fayetteville, AR 72701, USA.
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33
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Rocha LO, Tralamazza SM, Reis GM, Rabinovitch L, Barbosa CB, Corrêa B. Multi-method approach for characterizing the interaction between Fusarium verticillioides and Bacillus thuringiensis subsp. Kurstaki. PLoS One 2014; 9:e92189. [PMID: 24739804 PMCID: PMC3989188 DOI: 10.1371/journal.pone.0092189] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 02/20/2014] [Indexed: 12/15/2022] Open
Abstract
Bacterial antagonists used as biocontrol agents represent part of an integrated management program to reduce pesticides in the environment. Bacillus thuringiensis is considered a good alternative as a biocontrol agent for suppressing plant pathogens such as Fusarium. In this study, we used microscopy, flow cytometry, indirect immunofluorescence, and high performance liquid chromatography to determine the interaction between B. thuringiensis subsp. kurstaki LFB-FIOCRUZ (CCGB) 257 and F. verticillioides MRC 826, an important plant pathogen frequently associated with maize. B. thuringiensis showed a strong in vitro suppressive effect on F. verticillioides growth and inhibited fumonisin production. Flow cytometry analysis was found to be adequate for characterizing the fungal cell oscillations and death during these interactions. Further studies of the antagonistic effect of this isolate against other fungi and in vivo testing are necessary to determine the efficacy of B. thuringiensis subsp. kurstaki in controlling plant pathogens. This is the first report on the use of flow cytometry for quantifying living and apoptotic F. verticillioides cells and the B. thuringiensis Cry 1Ab toxin.
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Affiliation(s)
- Liliana O. Rocha
- Department of Microbiology, Laboratory of Mycotoxins and Toxigenic Fungi, University of São Paulo, São Paulo, São Paulo, Brazil
- * E-mail:
| | - Sabina Moser. Tralamazza
- Department of Microbiology, Laboratory of Mycotoxins and Toxigenic Fungi, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Gabriela M. Reis
- Department of Microbiology, Laboratory of Mycotoxins and Toxigenic Fungi, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Leon Rabinovitch
- Department of Bacteriology, Laboratory of Bacterial Physiology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Cynara B. Barbosa
- Department of Microbiology, Laboratory of Mycotoxins and Toxigenic Fungi, University of São Paulo, São Paulo, São Paulo, Brazil
| | - Benedito Corrêa
- Department of Microbiology, Laboratory of Mycotoxins and Toxigenic Fungi, University of São Paulo, São Paulo, São Paulo, Brazil
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Foroud NA, Chatterton S, Reid LM, Turkington TK, Tittlemier SA, Gräfenhan T. Fusarium Diseases of Canadian Grain Crops: Impact and Disease Management Strategies. Fungal Biol 2014. [DOI: 10.1007/978-1-4939-1188-2_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Ridenour JB, Smith JE, Hirsch RL, Horevaj P, Kim H, Sharma S, Bluhm BH. UBL1 of Fusarium verticillioides links the N-end rule pathway to extracellular sensing and plant pathogenesis. Environ Microbiol 2013; 16:2004-22. [PMID: 24237664 DOI: 10.1111/1462-2920.12333] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 11/07/2013] [Indexed: 01/06/2023]
Abstract
Fusarium verticillioides produces fumonisin mycotoxins during colonization of maize. Currently, molecular mechanisms underlying responsiveness of F.verticillioides to extracellular cues during pathogenesis are poorly understood. In this study, insertional mutants were created and screened to identify genes involved in responses to extracellular starch. In one mutant, the restriction enzyme-mediated integration cassette disrupted a gene (UBL1) encoding a UBR-Box/RING domain E3 ubiquitin ligase involved in the N-end rule pathway. Disruption of UBL1 in F.verticillioides (Δubl1) influenced conidiation, hyphal morphology, pigmentation and amylolysis. Disruption of UBL1 also impaired kernel colonization, but the ratio of fumonisin B1 per unit growth was not significantly reduced. The inability of a Δubl1 mutant to recognize an N-end rule degron confirmed involvement of UBL1 in the N-end rule pathway. Additionally, Ubl1 physically interacted with two G protein α subunits of F.verticillioides, thus implicating UBL1 in G protein-mediated sensing of the external environment. Furthermore, deletion of the UBL1 orthologue in F.graminearum reduced virulence on wheat and maize, thus indicating that UBL1 has a broader role in virulence among Fusarium species. This study provides the first linkage between the N-end rule pathway and fungal pathogenesis, and illustrates a new mechanism through which fungi respond to the external environment.
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Affiliation(s)
- John B Ridenour
- Department of Plant Pathology, Division of Agriculture, University of Arkansas, Fayetteville, AR, 72701, USA
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Wu L, Wang X, Xu R, Li H. Difference between resistant and susceptible maize to systematic colonization as revealed by DsRed-labeled Fusarium verticillioides. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.cj.2013.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Schmidt-Heydt M, Stoll DA, Mrohs J, Geisen R. Intraspecific variability of HOG1 phosphorylation in Penicillium verrucosum reflects different adaptation levels to salt rich habitats. Int J Food Microbiol 2013; 165:246-50. [DOI: 10.1016/j.ijfoodmicro.2013.05.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/02/2013] [Accepted: 05/13/2013] [Indexed: 10/26/2022]
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Graf E, Schmidt-Heydt M, Geisen R. HOG MAP kinase regulation of alternariol biosynthesis in Alternaria alternata is important for substrate colonization. Int J Food Microbiol 2012; 157:353-9. [DOI: 10.1016/j.ijfoodmicro.2012.06.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 05/29/2012] [Accepted: 06/05/2012] [Indexed: 02/04/2023]
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Kazan K, Gardiner DM, Manners JM. On the trail of a cereal killer: recent advances in Fusarium graminearum pathogenomics and host resistance. MOLECULAR PLANT PATHOLOGY 2012; 13:399-413. [PMID: 22098555 PMCID: PMC6638652 DOI: 10.1111/j.1364-3703.2011.00762.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The ascomycete fungal pathogen Fusarium graminearum (sexual stage: Gibberella zeae) causes the devastating head blight or scab disease on wheat and barley, and cob or ear rot disease on maize. Fusarium graminearum infection causes significant crop and quality losses. In addition to roles as virulence factors during pathogenesis, trichothecene mycotoxins (e.g. deoxynivalenol) produced by this pathogen constitute a significant threat to human and animal health if consumed in respective food or feed products. In the last few years, significant progress has been made towards a better understanding of the processes involved in F. graminearum pathogenesis, toxin biosynthesis and host resistance mechanisms through the use of high-throughput genomic and phenomic technologies. In this article, we briefly review these new advances and also discuss how future research can contribute to the development of sustainable plant protection strategies against this important plant pathogen.
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Affiliation(s)
- Kemal Kazan
- CSIRO Plant Industry, Queensland Bioscience Precinct, St Lucia, Brisbane, Qld 4067, Australia.
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Transcription of genes in the biosynthetic pathway for fumonisin mycotoxins is epigenetically and differentially regulated in the fungal maize pathogen Fusarium verticillioides. EUKARYOTIC CELL 2012; 11:252-9. [PMID: 22117026 PMCID: PMC3294439 DOI: 10.1128/ec.05159-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
When the fungal pathogen Gibberella moniliformis (anamorph, Fusarium verticillioides) colonizes maize and maize-based products, it produces class B fumonisin (FB) mycotoxins, which are a significant threat to human and animal health. FB biosynthetic enzymes and accessory proteins are encoded by a set of clustered and cotranscribed genes collectively named FUM, whose molecular regulation is beginning to be unraveled by researchers. FB accumulation correlates with the amount of transcripts from the key FUM genes, FUM1, FUM21, and FUM8. In fungi in general, gene expression is often partially controlled at the chromatin level in secondary metabolism; when this is the case, the deacetylation and acetylation (and other posttranslational modifications) of histones are usually crucial in the regulation of transcription. To assess whether epigenetic factors regulate the FB pathway, we monitored FB production and FUM1, FUM21, and FUM8 expression in the presence of a histone deacetylase inhibitor and verified by chromatin immunoprecipitation the relative degree of histone acetylation in the promoter regions of FUM1, FUM21, and FUM8 under FB-inducing and noninducing conditions. Moreover, we generated transgenic F. verticillioides strains expressing GFP under the control of the FUM1 promoter to determine whether its strength under FB-inducing and noninducing conditions was influenced by its location in the genome. Our results indicate a clear and differential role for chromatin remodeling in the regulation of FUM genes. This epigenetic regulation can be attained through the modulation of histone acetylation at the level of the promoter regions of the key biosynthetic genes FUM1 and FUM21, but less so for FUM8.
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A Pmk1-interacting gene is involved in appressorium differentiation and plant infection in Magnaporthe oryzae. EUKARYOTIC CELL 2011; 10:1062-70. [PMID: 21642506 DOI: 10.1128/ec.00007-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the rice blast fungus Magnaporthe oryzae, the PMK1 mitogen-activated protein (MAP) kinase gene regulates appressorium formation and infectious growth. Its homologs in many other fungi also play critical roles in fungal development and pathogenicity. However, the targets of this important MAP kinase and its interacting genes are not well characterized. In this study, we constructed two yeast two-hybrid libraries of M. oryzae and screened for Pmk1-interacting proteins. Among the nine Pmk1-interacting clones (PICs) identified, two of them, PIC1 and PIC5, were selected for further characterization. Pic1 has one putative nuclear localization signal and one putative MAP kinase phosphorylation site. Pic5 contains one transmembrane domain and two functionally unknown CTNS (cystinosin/ERS1p repeat) motifs. The interaction of Pmk1 with Pic1 or Pic5 was confirmed by coimmunoprecipitation assays. Targeted gene deletion of PIC1 had no apparent effects on vegetative growth and pathogenicity but resulted in a significant reduction in conidiation and abnormal germ tube differentiation on onion epidermal cells. Deletion of PIC5 led to a reduction in conidiation and hyphal growth. Autolysis of aerial hyphae became visible in cultures older than 4 days. The pic5 mutant was defective in germ tube growth and appressorium differentiation. It was reduced in appressorial penetration and virulence on the plant. Both PIC1 and PIC5 are conserved in filamentous ascomycetes, but none of their orthologs have been functionally characterized. Our data indicate that PIC5 is a novel virulence factor involved in appressorium differentiation and pathogenesis in M. oryzae.
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