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Gong X, Zhou Y, Qin Q, Wang B, Wang L, Jin C, Fang W. Nitrate assimilation compensates for cell wall biosynthesis in the absence of Aspergillus fumigatus phosphoglucose isomerase. Appl Environ Microbiol 2024:e0113824. [PMID: 39158312 DOI: 10.1128/aem.01138-24] [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: 06/11/2024] [Accepted: 07/20/2024] [Indexed: 08/20/2024] Open
Abstract
Phosphoglucose isomerase (PGI) links glycolysis, the pentose phosphate pathway (PPP), and the synthesis of cell wall precursors in fungi by facilitating the reversible conversion between glucose-6-phosphate (Glc6p) and fructose-6-phosphate (Fru6P). In a previous study, we established the essential role of PGI in cell wall biosynthesis in the opportunistic human fungal pathogen Aspergillus fumigatus, highlighting its potential as a therapeutic target. In this study, we conducted transcriptomic analysis and discovered that the Δpgi mutant exhibited enhanced glycolysis, reduced PPP, and an upregulation of cell wall precursor biosynthesis pathways. Phenotypic analysis revealed defective protein N-glycosylation in the mutant, notably the absence of glycosylated virulence factors DPP V and catalase 1. Interestingly, the cell wall defects in the mutant were not accompanied by activation of the MpkA-dependent cell wall integrity (CWI) signaling pathway. Instead, nitrate assimilation was activated in the Δpgi mutant, stimulating glutamine synthesis and providing amino donors for chitin precursor biosynthesis. Blocking the nitrate assimilation pathway severely impaired the growth of the Δpgi mutant, highlighting the crucial role of nitrate assimilation in rescuing cell wall defects. This study unveils the connection between nitrogen assimilation and cell wall compensation in A. fumigatus.IMPORTANCEAspergillus fumigatus is a common and serious human fungal pathogen that causes a variety of diseases. Given the limited availability of antifungal drugs and increasing drug resistance, it is imperative to understand the fungus' survival mechanisms for effective control of fungal infections. Our previous study highlighted the essential role of A. fumigatus PGI in maintaining cell wall integrity, phosphate sugar homeostasis, and virulence. The present study further illuminates the involvement of PGI in protein N-glycosylation. Furthermore, this research reveals that the nitrogen assimilation pathway, rather than the canonical MpkA-dependent CWI pathway, compensates for cell wall deficiencies in the mutant. These findings offer valuable insights into a novel adaptation mechanism of A. fumigatus to address cell wall defects, which could hold promise for the treatment of infections.
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Affiliation(s)
- Xiufang Gong
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yao Zhou
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Qijian Qin
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Bin Wang
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Cheng Jin
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wenxia Fang
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
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Zeng C, Sun Y, Lin H, Li Z, Zhang Q, Cai T, Xiang W, Tang J, Yasurin P. D-Limonene Inhibits Pichia kluyveri Y-11519 in Sichuan Pickles by Disrupting Metabolism. Molecules 2024; 29:3561. [PMID: 39124965 PMCID: PMC11314558 DOI: 10.3390/molecules29153561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/13/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024] Open
Abstract
The Pichia kluyveri, a proliferation commonly found in Sichuan pickles (SCPs), can accelerate the growth and reproduction of spoilage bacteria, causing off-odor development and decay. Although D-limonene, a common natural preservative, effectively restricts P. kluyveri, its inhibitory mechanism remains unclear. This study aimed to elucidate this molecular mechanism by investigating the impact on basic P. kluyveri metabolism. The findings revealed that D-limonene inhibited P. kluyveri growth and disrupted the transcription of the genes responsible for encoding the enzymes involved in cell wall and membrane synthesis, oxidative phosphorylation, glycolysis, and the tricarboxylic acid (TCA) cycle pathway. The results indicated that these events disrupted crucial metabolism such as cell wall and membrane integrity, adenosine triphosphate (ATP) synthesis, and reactive oxygen species (ROS) balance. These insights provided a comprehensive understanding of the inhibitory effect of D-limonene on the growth and reproduction of P. kluyveri while highlighting its potential application in the SCP industry.
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Affiliation(s)
- Chaoyi Zeng
- College of Food and Bioengineering, Xihua University, Chengdu 610039, China; (Y.S.); (H.L.); (Z.L.); (T.C.); (W.X.); (J.T.)
- Department of Food Biotechnology, Faculty of Biotechnology, Assumption University, Bangkok 10240, Thailand;
- Food Microbiology Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
| | - Yue Sun
- College of Food and Bioengineering, Xihua University, Chengdu 610039, China; (Y.S.); (H.L.); (Z.L.); (T.C.); (W.X.); (J.T.)
- Food Microbiology Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
| | - Haoran Lin
- College of Food and Bioengineering, Xihua University, Chengdu 610039, China; (Y.S.); (H.L.); (Z.L.); (T.C.); (W.X.); (J.T.)
- Food Microbiology Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
| | - Ziyu Li
- College of Food and Bioengineering, Xihua University, Chengdu 610039, China; (Y.S.); (H.L.); (Z.L.); (T.C.); (W.X.); (J.T.)
- Food Microbiology Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
| | - Qing Zhang
- College of Food and Bioengineering, Xihua University, Chengdu 610039, China; (Y.S.); (H.L.); (Z.L.); (T.C.); (W.X.); (J.T.)
- Food Microbiology Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
| | - Ting Cai
- College of Food and Bioengineering, Xihua University, Chengdu 610039, China; (Y.S.); (H.L.); (Z.L.); (T.C.); (W.X.); (J.T.)
- Food Microbiology Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
| | - Wenliang Xiang
- College of Food and Bioengineering, Xihua University, Chengdu 610039, China; (Y.S.); (H.L.); (Z.L.); (T.C.); (W.X.); (J.T.)
- Food Microbiology Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
| | - Jie Tang
- College of Food and Bioengineering, Xihua University, Chengdu 610039, China; (Y.S.); (H.L.); (Z.L.); (T.C.); (W.X.); (J.T.)
- Department of Food Biotechnology, Faculty of Biotechnology, Assumption University, Bangkok 10240, Thailand;
- Food Microbiology Key Laboratory of Sichuan Province, Xihua University, Chengdu 610039, China
| | - Patchanee Yasurin
- Department of Food Biotechnology, Faculty of Biotechnology, Assumption University, Bangkok 10240, Thailand;
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He R, Wei P, Odiba AS, Gao L, Usman S, Gong X, Wang B, Wang L, Jin C, Lu G, Fang W. Amino sugars influence Aspergillus fumigatus cell wall polysaccharide biosynthesis, and biofilm formation through interfering galactosaminogalactan deacetylation. Carbohydr Polym 2024; 324:121511. [PMID: 37985096 DOI: 10.1016/j.carbpol.2023.121511] [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: 08/21/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 11/22/2023]
Abstract
Aspergillus fumigatus is a ubiquitous fungal pathogen responsible for a significant number of deaths annually due to invasive aspergillosis infection. While the utilization of diverse carbon sources, including amino sugars, has been explored in other fungi, its impact on A. fumigatus remains uncharted territory. In this study, we investigated A. fumigatus responses to glucose (Glc), glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) as carbon sources. GlcN inhibited growth, reduced sporulation and delayed germination, while GlcNAc had no such effects. Both amino sugars induced alterations in cell wall composition, leading to a reduction in glucan and galactomannan levels while increasing chitin and mannan content, rendering A. fumigatus susceptible to cell wall stress and osmotic stress. GlcN repressed biofilm formation via downregulation of galactosaminogalactan (GAG) cluster genes, notably agd3, which encodes a GAG-specific deacetylase. Moreover, GlcN increased biofilm susceptibility to echinocandins, suggesting its potential for enhancing the effectiveness of antifungal treatments. This study sheds light on the multifaceted effects of amino sugars on A. fumigatus, encompassing growth, cell wall biosynthesis, and biofilm formation, offering promising avenues for innovative aspergillosis treatment strategies.
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Affiliation(s)
- Rui He
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China; Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Pingzhen Wei
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Arome Solomon Odiba
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Linlu Gao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Sayed Usman
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China; Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Xiufang Gong
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Bin Wang
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Cheng Jin
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guangtao Lu
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Wenxia Fang
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China; Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China.
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Hassan MG, Hawwa MT, Baraka DM, El-Shora HM, Hamed AA. Biogenic selenium nanoparticles and selenium/chitosan-Nanoconjugate biosynthesized by Streptomyces parvulus MAR4 with antimicrobial and anticancer potential. BMC Microbiol 2024; 24:21. [PMID: 38216871 PMCID: PMC10785380 DOI: 10.1186/s12866-023-03171-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 12/22/2023] [Indexed: 01/14/2024] Open
Abstract
BACKGROUND As antibiotics and chemotherapeutics are no longer as efficient as they once were, multidrug resistant (MDR) pathogens and cancer are presently considered as two of the most dangerous threats to human life. In this study, Selenium nanoparticles (SeNPs) biosynthesized by Streptomyces parvulus MAR4, nano-chitosan (NCh), and their nanoconjugate (Se/Ch-nanoconjugate) were suggested to be efficacious antimicrobial and anticancer agents. RESULTS SeNPs biosynthesized by Streptomyces parvulus MAR4 and NCh were successfully achieved and conjugated. The biosynthesized SeNPs were spherical with a mean diameter of 94.2 nm and high stability. Yet, Se/Ch-nanoconjugate was semispherical with a 74.9 nm mean diameter and much higher stability. The SeNPs, NCh, and Se/Ch-nanoconjugate showed significant antimicrobial activity against various microbial pathogens with strong inhibitory effect on their tested metabolic key enzymes [phosphoglucose isomerase (PGI), pyruvate dehydrogenase (PDH), glucose-6-phosphate dehydrogenase (G6PDH) and nitrate reductase (NR)]; Se/Ch-nanoconjugate was the most powerful agent. Furthermore, SeNPs revealed strong cytotoxicity against HepG2 (IC50 = 13.04 μg/ml) and moderate toxicity against Caki-1 (HTB-46) tumor cell lines (IC50 = 21.35 μg/ml) but low cytotoxicity against WI-38 normal cell line (IC50 = 85.69 μg/ml). Nevertheless, Se/Ch-nanoconjugate displayed substantial cytotoxicity against HepG2 and Caki-1 (HTB-46) with IC50 values of 11.82 and 7.83 μg/ml, respectively. Consequently, Se/Ch-nanoconjugate may be more easily absorbed by both tumor cell lines. However, it exhibited very low cytotoxicity on WI-38 with IC50 of 153.3 μg/ml. Therefore, Se/Ch-nanoconjugate presented the most anticancer activity. CONCLUSION The biosynthesized SeNPs and Se/Ch-nanoconjugate are convincingly recommended to be used in biomedical applications as versatile and potent antimicrobial and anticancer agents ensuring notable levels of biosafety, environmental compatibility, and efficacy.
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Affiliation(s)
- Mervat G Hassan
- Botany and Microbiology Department, Faculty of Science, Benha University, P. O. Box 13511, Banha, Qalyubia, Egypt
| | - Mariam T Hawwa
- Botany and Microbiology Department, Faculty of Science, Benha University, P. O. Box 13511, Banha, Qalyubia, Egypt
| | - Dina M Baraka
- Botany and Microbiology Department, Faculty of Science, Benha University, P. O. Box 13511, Banha, Qalyubia, Egypt
| | - Hamed M El-Shora
- Botany Department, Faculty of Science, Mansoura University, P. O. Box 35516, Mansoura, Dakahliaو, Egypt
| | - Ahmed A Hamed
- Microbial Chemistry Department, National Research Centre, 33 El-Buhouth Street, P. O. Box 12622, Giza, Dokki, Egypt.
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Chen L, Ma X, Sun T, Zhu QH, Feng H, Li Y, Liu F, Zhang X, Sun J, Li Y. VdPT1 Encoding a Neutral Trehalase of Verticillium dahliae Is Required for Growth and Virulence of the Pathogen. Int J Mol Sci 2023; 25:294. [PMID: 38203466 PMCID: PMC10778863 DOI: 10.3390/ijms25010294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/12/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024] Open
Abstract
Verticillum dahliae is a soil-borne phytopathogenic fungus causing destructive Verticillium wilt disease. We previously found a trehalase-encoding gene (VdPT1) in V. dahliae being significantly up-regulated after sensing root exudates from a susceptible cotton variety. In this study, we characterized the function of VdPT1 in the growth and virulence of V. dahliae using its deletion-mutant strains. The VdPT1 deletion mutants (ΔVdPT1) displayed slow colony expansion and mycelial growth, reduced conidial production and germination rate, and decreased mycelial penetration ability and virulence on cotton, but exhibited enhanced stress resistance, suggesting that VdPT1 is involved in the growth, pathogenesis, and stress resistance of V. dahliae. Host-induced silencing of VdPT1 in cotton reduced fungal biomass and enhanced cotton resistance against V. dahliae. Comparative transcriptome analysis between wild-type and mutant identified 1480 up-regulated and 1650 down-regulated genes in the ΔVdPT1 strain. Several down-regulated genes encode plant cell wall-degrading enzymes required for full virulence of V. dahliae to cotton, and down-regulated genes related to carbon metabolism, DNA replication, and amino acid biosynthesis seemed to be responsible for the decreased growth of the ΔVdPT1 strain. In contrast, up-regulation of several genes related to glycerophospholipid metabolism in the ΔVdPT1 strain enhanced the stress resistance of the mutated strain.
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Affiliation(s)
- Lihua Chen
- The Key Laboratory of Oasis Eco-Agriculture, Agriculture College, Shihezi University, Shihezi 832000, China; (L.C.); (X.M.); (T.S.); (Y.L.); (F.L.); (X.Z.)
| | - Xiaohu Ma
- The Key Laboratory of Oasis Eco-Agriculture, Agriculture College, Shihezi University, Shihezi 832000, China; (L.C.); (X.M.); (T.S.); (Y.L.); (F.L.); (X.Z.)
| | - Tiange Sun
- The Key Laboratory of Oasis Eco-Agriculture, Agriculture College, Shihezi University, Shihezi 832000, China; (L.C.); (X.M.); (T.S.); (Y.L.); (F.L.); (X.Z.)
| | - Qian-Hao Zhu
- CSIRO Agriculture and Food, GPO Box 1700, Canberra 2601, Australia;
| | - Hongjie Feng
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Sciences, Anyang 455000, China;
| | - Yongtai Li
- The Key Laboratory of Oasis Eco-Agriculture, Agriculture College, Shihezi University, Shihezi 832000, China; (L.C.); (X.M.); (T.S.); (Y.L.); (F.L.); (X.Z.)
| | - Feng Liu
- The Key Laboratory of Oasis Eco-Agriculture, Agriculture College, Shihezi University, Shihezi 832000, China; (L.C.); (X.M.); (T.S.); (Y.L.); (F.L.); (X.Z.)
| | - Xinyu Zhang
- The Key Laboratory of Oasis Eco-Agriculture, Agriculture College, Shihezi University, Shihezi 832000, China; (L.C.); (X.M.); (T.S.); (Y.L.); (F.L.); (X.Z.)
| | - Jie Sun
- The Key Laboratory of Oasis Eco-Agriculture, Agriculture College, Shihezi University, Shihezi 832000, China; (L.C.); (X.M.); (T.S.); (Y.L.); (F.L.); (X.Z.)
| | - Yanjun Li
- The Key Laboratory of Oasis Eco-Agriculture, Agriculture College, Shihezi University, Shihezi 832000, China; (L.C.); (X.M.); (T.S.); (Y.L.); (F.L.); (X.Z.)
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Heo L, Han Y, Cho Y, Choi J, Lee J, Han SW. A putative glucose 6-phosphate isomerase has pleiotropic functions on virulence and other mechanisms in Acidovorax citrulli. FRONTIERS IN PLANT SCIENCE 2023; 14:1275438. [PMID: 38023913 PMCID: PMC10664246 DOI: 10.3389/fpls.2023.1275438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023]
Abstract
Acidovorax citrulli (Ac) is a causal agent of watermelon bacterial fruit blotch (BFB) disease. Because resistance cultivars/lines have not yet been developed, it is imperative to elucidate Ac's virulence factors and their mechanisms to develop resistant cultivars/lines in different crops, including watermelon. The glucose-6-phosphate isomerase (GPI) is a reversible enzyme in both glycolysis and gluconeogenesis pathways in living organisms. However, the functions of GPI are not characterized in Ac. In this study, we determined the roles of GpiAc (GPI in Ac) by proteomic and phenotypic analyses of the mutant lacking GPI. The mutant displayed significantly reduced virulence to watermelon in two different virulence assays. The mutant's growth patterns were comparable to the wild-type strain in rich medium and M9 with glucose but not with fructose. The comparative proteome analysis markedly identified proteins related to virulence, motility, and cell wall/membrane/envelope. In the mutant, biofilm formation and twitching halo production were reduced. We further demonstrated that the mutant was less tolerant to osmotic stress and lysozyme treatment than the wild-type strain. Interestingly, the tolerance to alkali conditions was remarkably enhanced in the mutant. These results reveal that GpiAc is involved not only in virulence and glycolysis/gluconeogenesis but also in biofilm formation, twitching motility, and tolerance to diverse external stresses suggesting the pleiotropic roles of GpiAc in Ac. Our study provides fundamental and valuable information on the functions of previously uncharacterized glucose 6-phosphate isomerase and its virulence mechanism in Ac.
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Affiliation(s)
| | | | | | | | | | - Sang-Wook Han
- Department of Plant Science and Technology, Chung-Ang University, Anseong, Republic of Korea
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Keller MR, Dörr T. Bacterial metabolism and susceptibility to cell wall-active antibiotics. Adv Microb Physiol 2023; 83:181-219. [PMID: 37507159 PMCID: PMC11024984 DOI: 10.1016/bs.ampbs.2023.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Bacterial infections are increasingly resistant to antimicrobial therapy. Intense research focus has thus been placed on identifying the mechanisms that bacteria use to resist killing or growth inhibition by antibiotics and the ways in which bacteria share these traits with one another. This work has led to the advancement of new drugs, combination therapy regimens, and a deeper appreciation for the adaptability seen in microorganisms. However, while the primary mechanisms of action of most antibiotics are well understood, the more subtle contributions of bacterial metabolic state to repairing or preventing damage caused by antimicrobials (thereby promoting survival) are still understudied. Here, we review a modern viewpoint on a classical system: examining bacterial metabolism's connection to antibiotic susceptibility. We dive into the relationship between metabolism and antibiotic efficacy through the lens of growth rate, energy state, resource allocation, and the infection environment, focusing on cell wall-active antibiotics.
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Affiliation(s)
- Megan Renee Keller
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States; Department of Microbiology, Cornell University, Ithaca, NY, United States; Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States.
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Usman S, Ge X, Xu Y, Qin Q, Xie J, Wang B, Jin C, Fang W. Loss of Phosphomannose Isomerase Impairs Growth, Perturbs Cell Wall Integrity, and Reduces Virulence of Fusarium oxysporum f. sp. cubense on Banana Plants. J Fungi (Basel) 2023; 9:jof9040478. [PMID: 37108932 PMCID: PMC10145770 DOI: 10.3390/jof9040478] [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: 03/04/2023] [Revised: 04/08/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4) causes Fusarium wilt of banana, necessitating urgent measures to control this disease. However, the molecular mechanisms underlying Foc TR4 virulence remain elusive. Phosphomannose isomerase is a key enzyme involved in the biosynthesis of GDP mannose, an important precursor of fungal cell walls. In this study, two phosphomannose isomerases were identified in the Foc TR4 genome, of which only Focpmi1 was highly expressed throughout all developmental stages. Generated null mutants in Foc TR4 showed that only the ΔFocpmi1 mutant required exogenous mannose for growth, indicating that Focpmi1 is the key enzyme involved in GDP mannose biosynthesis. The Focpmi1 deficient strain was unable to grow without exogenous mannose and exhibited impaired growth under stress conditions. The mutant had reduced chitin content in its cell wall, rendering it vulnerable to cell wall stresses. Transcriptomic analysis revealed up- and down-regulation of several genes involved in host cell wall degradation and physiological processes due to the loss of Focpmi1. Furthermore, Focpmi1 was also found to be crucial for Foc TR4 infection and virulence, making it a potential antifungal target to address the threats posed by Foc TR4.
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Affiliation(s)
- Sayed Usman
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning 530007, China
| | - Xinwei Ge
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning 530007, China
| | - Yueqiang Xu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qijian Qin
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning 530007, China
| | - Jin Xie
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning 530007, China
| | - Bin Wang
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning 530007, China
| | - Cheng Jin
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning 530007, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenxia Fang
- College of Life Science and Technology, Guangxi University, Nanning 530004, China
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning 530007, China
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9
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Keller M, Han X, Dörr T. Disrupting Central Carbon Metabolism Increases β-Lactam Antibiotic Susceptibility in Vibrio cholerae. J Bacteriol 2023; 205:e0047622. [PMID: 36840595 PMCID: PMC10029711 DOI: 10.1128/jb.00476-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 01/31/2023] [Indexed: 02/24/2023] Open
Abstract
Antibiotic tolerance, the ability of bacteria to sustain viability in the presence of typically bactericidal antibiotics for extended time periods, is an understudied contributor to treatment failure. The Gram-negative pathogen Vibrio cholerae, the causative agent of cholera, becomes highly tolerant to β-lactam antibiotics (penicillin and related compounds) in a process requiring the two-component system VxrAB. VxrAB is induced by exposure to cell wall damaging conditions, which results in the differential regulation of >100 genes. While the effectors of VxrAB are relatively well known, VxrAB environment-sensing and activation mechanisms remain a mystery. Here, we used transposon mutagenesis to screen for mutants that spontaneously upregulate VxrAB signaling. This screen was answered by genes known to be required for proper cell envelope homeostasis, validating the approach. Unexpectedly, we also uncovered a new connection between central carbon metabolism and antibiotic tolerance in Vibrio cholerae. Inactivation of pgi (vc0374, coding for glucose-6-phosphate isomerase) resulted in an intracellular accumulation of glucose-6-phosphate and fructose-6-phosphate, concomitant with a marked cell envelope defect, resulting in VxrAB induction. Deletion of pgi also increased sensitivity to β-lactams and conferred a growth defect on salt-free LB, phenotypes that could be suppressed by deleting sugar uptake systems and by supplementing cell wall precursors in the growth medium. Our data suggest an important connection between central metabolism and cell envelope integrity and highlight a potential new target for developing novel antimicrobial agents. IMPORTANCE Antibiotic tolerance (the ability to survive exposure to antibiotics) is a stepping stone toward antibiotic resistance (the ability to grow in the presence of antibiotics), an increasingly common cause of antibiotic treatment failure. The mechanisms promoting tolerance are poorly understood. Here, we identified central carbon metabolism as a key contributor to antibiotic tolerance and resistance. A strain with a mutation in a sugar utilization pathway accumulates metabolites that likely shut down the synthesis of cell wall precursors, which weakens the cell wall and thus increases susceptibility to cell wall-active drugs. Our results illuminate the connection between central carbon metabolism and cell wall homeostasis in V. cholerae and suggest that interfering with metabolism may be a fruitful future strategy for the development of antibiotic adjuvants.
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Affiliation(s)
- Megan Keller
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
| | - Xiang Han
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
- Department of Microbiology, Cornell University, Ithaca, New York, USA
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York, USA
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Juxtaposing Caenorhabditis elegans-Pathogenic Mould Model with Other Models; How Reliable Is This Nematode Model? A Mini Review. Curr Microbiol 2023; 80:105. [PMID: 36790616 DOI: 10.1007/s00284-023-03209-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 02/01/2023] [Indexed: 02/16/2023]
Abstract
The application of Caenorhabditis elegans as a pathogenic model has spanned decades. Its use for pathogenic mould modeling has been attracting some attention lately, though not without some reservations. Several studies have shown C. elegans to be a reliable model for evaluating moulds' virulence factors and patterns as well as for screening the pathogenicity of mutant strains alongside their parental/wild type and revertant/complementary strains. There is a very high degree of reported similarities between the virulence patterns demonstrated in C. elegans and those of other invertebrate and vertebrate models. We have here presented several works in which this nematode model was adopted for virulence evaluation, and other comparative research in which virulence in C. elegans model were juxtaposed with other models. We have further presented possible reasons why there might have been variations of virulence in a few cases, thereby validating C. elegans to be an effective and reliable tool in the study of pathogenic moulds.
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Phosphomannose Isomerase Is Involved in Development, Stress Responses, and Pathogenicity of Aspergillus flavus. Microbiol Spectr 2022; 10:e0202722. [PMID: 35980200 PMCID: PMC9603912 DOI: 10.1128/spectrum.02027-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Aspergillus flavus causes invasive aspergillosis in immunocompromised patients and severe contamination of agriculturally important crops by producing aflatoxins. The fungal cell wall is absent in animals and is structurally different from that of plants, which makes it a potential antifungal drug target due to its essentiality for fungal survival. Mannose is one of the important components in the fungal cell wall, which requires GDP-mannose (GDP-Man) as the primary donor. Three consecutive enzymes, namely, phosphomannose isomerase (PMI), phosphomannose mutase (PMM), and GDP-mannose phosphorylase (GMPP), are required for GDP-Man biosynthesis. Thus, PMI is of prime importance in cell wall biosynthesis and also has an active role in sugar metabolism. Here, we investigated the functional role of PMI in A. flavus by generating a pmiA-deficient strain. The mutant required exogenous mannose to survive and exhibited reduced growth rate, impaired conidiation, early germination, disturbance in stress responses, and defects in colonization of crop seeds. Furthermore, attenuated virulence of the mutant was documented in both Caenorhabditis elegans and Galleria mellonella infection models. Our results suggested that PMI plays an important role in the development, stress responses, and pathogenicity of A. flavus and therefore could serve as a potential target for battling against infection and controlling aflatoxin contamination caused by A. flavus. IMPORTANCE Aspergillus flavus is a common fungal pathogen of humans, animals, and agriculturally important crops. It causes invasive aspergillosis in humans and also produces highly carcinogenic mycotoxins in postharvest crops that threaten food safety worldwide. To alleviate or eliminate the threats posed by A. flavus, it is necessary to identify genes involved in pathogenicity and mycotoxin contamination. However, little progress has been made in this regard. Here, we focused on PMI, which is the first enzyme involved in the biosynthesis pathway of GDP-Man and thus is important for cell wall synthesis and protein glycosylation. Our study revealed that PMI is important for growth of A. flavus. It is also involved in conidiation, germination, morphogenesis, stress responses, and pathogenicity of A. flavus. Thus, PMI is a potent antifungal target to curb the threats posed by A. flavus.
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Central Sugar Metabolism and the Cell Wall. mBio 2022; 13:e0210422. [PMID: 36094091 PMCID: PMC9600152 DOI: 10.1128/mbio.02104-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The human opportunistic pathogen Aspergillus fumigatus is recognized for its versatile cell wall when it comes to remodeling its components in adaptation to external threats, and this remodeling renders it refractory to antifungals targeting cell wall biosynthesis. A specific role for general sugar metabolism in the regulation of the synthesis of cell wall polymers has been previously demonstrated. Delving deeper into central sugar metabolism may reveal unexpected fundamental aspects in cell wall construction, as shown by the work of Zhou and coworkers (Y. Zhou, K. Yan, Q. Qin, O.G. Raimi, et al., mBio 13:e01426-22, 2022, https://doi.org/10.1128/mbio.01426-22) on the roles of the phosphoglucose isomerase of A. fumigatus in cell wall biosynthesis.
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