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Lai Y, Zheng W, Zheng Y, Lu H, Qu S, Wang L, Li M, Wang S. Unveiling a novel entry gate: Insect foregut as an alternative infection route for fungal entomopathogens. Innovation (N Y) 2024; 5:100644. [PMID: 38933340 PMCID: PMC11201351 DOI: 10.1016/j.xinn.2024.100644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 05/19/2024] [Indexed: 06/28/2024] Open
Abstract
Insects and their natural microbial pathogens are intertwined in constant arms races, with pathogens continually seeking entry into susceptible hosts through distinct routes. Entomopathogenic fungi are primarily believed to infect host insects through external cuticle penetration. Here, we report a new variety, Beauveria bassiana var. majus (Bbm), that can infect insects through the previously unrecognized foregut. Dual routes of infection significantly accelerate insect mortality. The pH-responsive transcription factor PacC in Bbm exhibits rapid upregulation and efficient proteolytic processing via PalC for alkaline adaptation in the foregut. Expression of PalC is regulated by the adjacent downstream gene Aia. Compared to non-enteropathogenic strains such as ARSEF252, Aia in Bbm lacks a 249-bp fragment, resulting in its enhanced alkaline-induced expression. This induction promotes PalC upregulation and facilitates PacC activation. Expressing the active form of BbmPacC in ARSEF252 enables intestinal infection. This study uncovers the pH-responsive Aia-PalC-PacC cascade enhancing fungal alkaline tolerance for intestinal infection, laying the foundation for developing a new generation of fungal insecticides to control destructive insect pests.
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Affiliation(s)
- Yiling Lai
- New Cornerstone Science Laboratory, CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weilu Zheng
- New Cornerstone Science Laboratory, CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yitong Zheng
- New Cornerstone Science Laboratory, CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Haiquan Lu
- New Cornerstone Science Laboratory, CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, China
- Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212000, China
| | - Shuang Qu
- New Cornerstone Science Laboratory, CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, China
| | - Lili Wang
- New Cornerstone Science Laboratory, CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Muwang Li
- Sericultural Research Institute, Jiangsu University of Science and Technology, Zhenjiang 212000, China
| | - Sibao Wang
- New Cornerstone Science Laboratory, CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences (CAS), Shanghai 200032, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
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Luo XC, Yu L, Xu SY, Ying SH, Feng MG. Rad6, a ubiquitin conjugator required for insect-pathogenic lifestyle, UV damage repair, and genomic expression of Beauveria bassiana. Microbiol Res 2024; 281:127622. [PMID: 38246123 DOI: 10.1016/j.micres.2024.127622] [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: 10/30/2023] [Revised: 11/09/2023] [Accepted: 01/13/2024] [Indexed: 01/23/2024]
Abstract
The E2 ubiquitin conjugator Rad6 is required for DNA damage bypass in budding yeast but remain functionally unknown in filamentous fungi. Here, we report pleiotropic effect of Rad6 ortholog in Beauveria bassiana, a wide-spectrum fungal insecticide. Global ubiquitination signal was greatly attenuated in the absence of rad6. The blocked ubiquitination led to severe growth defect, blocked asexual development, and abolished infectivity/insect pathogenicity, which correlated with compromised conidial quality (including viability, hydrophobicity, adherence to insect cuticle, and thermotolerance) and blocked secretion of cuticle-degrading enzymes including Pr1 family proteases. Importantly, Rad6 played much greater role in photoreactivation of UVB-impaired conidia by a 3- or 5-h light plus 9- or 7-h dark incubation than in dark reactivation of those impaired conidia by a 12-h dark incubation. The high activity of Rad6 in photoreactivation in vivo was derived from its link to a protein complex cored by the photolyase regulators WC1 and WC2 via the strong interactions of Rad6 with the E3 partner Rad18 and Rad18 with WC2 revealed in yeast two-hybrid assays. Transcriptomic analysis resulted in identification of 2700 differentially regulated genes involved in various function categories and metabolism pathways, indicating a regulatory role of Rad6-mediated ubiquitination in gene expression networks and genomic stability. Conclusively, Rad6 is required for asexual and insect-pathogenic lifecycles, solar UV damage repair, and genomic expression of B. bassiana. The primary dependence of its strong anti-UV role on photoreactivation in vivo unveils a scenario distinct from the core role of its yeast ortholog in DNA damage bypass.
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Affiliation(s)
- Xin-Cheng Luo
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Lei Yu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Si-Yuan Xu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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Azizullah, Noman M, Gao Y, Wang H, Xiong X, Wang J, Li D, Song F. The SUMOylation pathway regulates the pathogenicity of Fusarium oxysporum f. sp. niveum in watermelon through stabilizing the pH regulator FonPalC via SUMOylation. Microbiol Res 2024; 281:127632. [PMID: 38310728 DOI: 10.1016/j.micres.2024.127632] [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: 10/21/2023] [Revised: 01/12/2024] [Accepted: 01/28/2024] [Indexed: 02/06/2024]
Abstract
SUMOylation is a key post-translational modification, where small ubiquitin-related modifier (SUMO) proteins regulate crucial biological processes, including pathogenesis, in phytopathogenic fungi. Here, we investigated the function and mechanism of the SUMOylation pathway in the pathogenicity of Fusarium oxysporum f. sp. niveum (Fon), the fungal pathogen that causes watermelon Fusarium wilt. Disruption of key SUMOylation pathway genes, FonSMT3, FonAOS1, FonUBC9, and FonMMS21, significantly reduced pathogenicity, impaired penetration ability, and attenuated invasive growth capacity of Fon. Transcription and proteomic analyses identified a diverse set of SUMOylation-regulated differentially expressed genes and putative FonSMT3-targeted proteins, which are predicted to be involved in infection, DNA damage repair, programmed cell death, reproduction, growth, and development. Among 155 putative FonSMT3-targeted proteins, FonPalC, a Pal/Rim-pH signaling regulator, was confirmed to be SUMOylated. The FonPalC protein accumulation was significantly decreased in SUMOylation-deficient mutant ∆Fonsmt3. Deletion of FonPalC resulted in impaired mycelial growth, decreased pathogenicity, enhanced osmosensitivity, and increased intracellular vacuolation in Fon. Importantly, mutations in conserved SUMOylation sites of FonPalC failed to restore the defects in ∆Fonpalc mutant, indicating the critical function of the SUMOylation in FonPalC stability and Fon pathogenicity. Identifying key SUMOylation-regulated pathogenicity-related proteins provides novel insights into the molecular mechanisms underlying Fon pathogenesis regulated by SUMOylation.
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Affiliation(s)
- Azizullah
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Muhammad Noman
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
| | - Yizhou Gao
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Hui Wang
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiaohui Xiong
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jiajing Wang
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Dayong Li
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Fengming Song
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China; State Key Laboratory of Rice Biology and Breeding, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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Wang Y, Liu F, Pei J, Yan H, Wang Y. The AwHog1 Transcription Factor Influences the Osmotic Stress Response, Mycelium Growth, OTA Production, and Pathogenicity in Aspergillus westerdijkiae fc-1. Toxins (Basel) 2023; 15:432. [PMID: 37505700 PMCID: PMC10467130 DOI: 10.3390/toxins15070432] [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: 05/22/2023] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/29/2023] Open
Abstract
Aspergillus westerdijkiae, known as the major ochratoxin A (OTA) producer, usually occurs on agricultural crops, fruits, and dry-cured meats. Microorganisms produce OTA to adapt to the high osmotic pressure environment that is generated during food processing and storage. To investigate the relationship between OTA biosynthesis and the high osmolarity glycerol (HOG) pathway, the transcription factor AwHog1 gene in A. westerdijkiae was functionally characterised by means of a loss-of-function mutant. Our findings demonstrated that the growth and OTA production of a mutant lacking AwHog1 decreased significantly and was more sensitive to high osmotic media. The ΔAwHog1 mutant displayed a lower growth rate and a 73.16% reduction in OTA production in the wheat medium compared to the wild type. After three days of culture, the growth rate of the ΔAwHog1 mutant in medium with 60 g/L NaCl and 150 g/L glucose was slowed down 19.57% and 13.21%, respectively. Additionally, the expression of OTA biosynthesis genes was significantly reduced by the deletion of the AwHog1 gene. The infection ability of the ΔAwHog1 mutant was decreased, and the scab diameter of the pear was 6% smaller than that of the wild type. These data revealed that transcription factor AwHog1 plays a key role in the osmotic response, growth, OTA production, and pathogenicity in A. westerdijkiae.
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Affiliation(s)
- Yufei Wang
- College of Food Science and Technology, Zhejiang University of Technology, No. 18 Chaowang Road, Gongshu District, Hangzhou 310014, China; (Y.W.); (J.P.)
| | - Fei Liu
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China;
| | - Jingying Pei
- College of Food Science and Technology, Zhejiang University of Technology, No. 18 Chaowang Road, Gongshu District, Hangzhou 310014, China; (Y.W.); (J.P.)
| | - Hao Yan
- Zhejiang Provincial Center for Disease Control and Prevention, No. 3399 Binsheng Road, Binjiang District, Hangzhou 310051, China
| | - Yan Wang
- College of Food Science and Technology, Zhejiang University of Technology, No. 18 Chaowang Road, Gongshu District, Hangzhou 310014, China; (Y.W.); (J.P.)
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Luo Z, Chen Q, Su Y, Hu S, Keyhani NO, Wang J, Zhu C, Zhou T, Pan Y, Bidochka MJ, Zhang Y. The AreA Nitrogen Catabolite Repression Activator Balances Fungal Nutrient Utilization and Virulence in the Insect Fungal Pathogen Beauveria bassiana. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:646-659. [PMID: 36584226 DOI: 10.1021/acs.jafc.2c07047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
In many fungi, the AreA GATA-type transcription factor mediates nitrogen catabolite repression affecting fungal development and, where applicable, virulence. Here, we investigated the functions of AreA in the fungal entomopathogen and plant endophyte Beauveria bassiana using knockdown of gene expression. The antiAreA mutants were impaired in nitrogen utilization and showed increased sensitivities to osmotic stressors but increased tolerances to oxidative/hypoxia stresses. Repression of BbAreA caused overall minimal effects on fungal virulence. The minor effects on virulence appeared to be due in part to competing secondary effects where host defense phenoloxidase activity was significantly decreased, but production of the fungal metabolite oosporein was increased and hyphal body development was impaired. Knockdown of BbAreA expression also resulted in impairment in ability of the fungus to associate with host plants. These data implicate that BbAreA likely acts as a regulator to balance fungal nutrient utilization, pathogenicity, and mutualism, facilitating the fungal occupation of host niches.
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Affiliation(s)
- Zhibing Luo
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Qiyan Chen
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Yufeng Su
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Shasha Hu
- Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611, United States
| | - Junyao Wang
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Chenhua Zhu
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Teng Zhou
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Yunxia Pan
- College of Engineering and Technology, Southwest University, Chongqing 400715, P. R. China
| | - Michael J Bidochka
- Department of Biological Sciences, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - Yongjun Zhang
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, P. R. China
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Zhou L, Li M, Cui P, Tian M, Xu Y, Zheng X, Zhang K, Li G, Wang X. Arrestin-Coding Genes Regulate Endocytosis, Sporulation, Pathogenicity, and Stress Resistance in Arthrobotrys oligospora. Front Cell Infect Microbiol 2022; 12:754333. [PMID: 35252023 PMCID: PMC8890662 DOI: 10.3389/fcimb.2022.754333] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 01/20/2022] [Indexed: 12/12/2022] Open
Abstract
Arrestins are a family of scaffold proteins that play a crucial role in regulating numerous cellular processes, such as GPCR signaling. The Arthrobotrys oligospora arrestin family contains 12 members, which have highly conserved N-terminal and C-terminal domains. In the presence of ammonia, A. oligospora can change its lifestyle from saprotrophic to carnivorous. During this transition, the expression pattern of arrestin-coding (AoArc) genes was markedly upregulated. Therefore, we disrupted seven AoArc genes from A. oligospora to identify their functions. Although individual arrestin mutant strains display similar pathogenesis, phenotypes, and stress resistance, the fundamental data on the roles of AoArc genes in A. oligospora are obtained in this study. Membrane endocytosis in AoArc mutants was significantly reduced. Meanwhile, the capacity of trap device formation against nematodes and ammonia was impaired due to AoArc deletions. We also found that AoArc genes could regulate conidial phenotypes, cell nuclear distribution, pH response, and stress resistance. Results of qRT-PCR assays revealed that sporulation-regulated genes were affected after the deletion of AoArc genes. In particular, among the 12 arrestins, AoArc2 mediates pH signaling in the fungus A. oligospora. Notably, combined with the classical paradigm of arrestin–GPCR signal transduction, we suggest that arrestin-regulated trap formation in A. oligospora may be directly linked to the receptor endocytosis pathway.
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Affiliation(s)
- Liang Zhou
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Mengfei Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Peijie Cui
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Mengqing Tian
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Ya Xu
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Xi Zheng
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Keqin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
| | - Guohong Li
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- *Correspondence: Xin Wang, ; Guohong Li,
| | - Xin Wang
- State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, China
- Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, China
- *Correspondence: Xin Wang, ; Guohong Li,
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Improvement of laccase activity by silencing PacC in Ganoderma lucidum. World J Microbiol Biotechnol 2022; 38:32. [PMID: 34989903 DOI: 10.1007/s11274-021-03216-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 12/18/2021] [Indexed: 10/19/2022]
Abstract
Ganoderma lucidum is a representative white-rot fungus that has great potential to degrade lignocellulose biomass. Laccase is recognized as a class of the most important lignin-degrading enzymes in G. lucidum. However, the comprehensive regulatory mechanisms of laccase are still lacking. Based on the genome sequence of G. lucidum, 15 laccase genes were identified and their encoding proteins were analyzed in this study. All of the laccase proteins are predicted to be multicopper oxidases with conserved copper-binding domains. Most laccase proteins were secreted enzymes in addition to Lac14 in which the signal peptide could not be predicted. The activity of all laccases showed the highest level at pH 3.0 or pH 7.0, with total laccase activity of approximately 200 U/mg protein. Silencing PacC resulted in a 5.2 fold increase in laccase activity compared with WT. Five laccase genes (lac1, lac6, lac9, lac10 and lac14) showed an increased transcription levels (approximately 1.5-5.6 fold) in the PacC-silenced strains versus that in WT, while other laccase genes were downregulated or unchanged. The extracellular pH value was about 3.1, which was more acidic in the PacC-silenced strains than in the WT (pH 3.5). Moreover, maintaining the fermentation pH resulted in a downregulation of laccase activity which is induced by silencing PacC. Our findings indicate that in addition to its function in acidification of environmental pH, PacC plays an important role in regulating laccase activity in fungi.
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Wu M, Wei H, Ma K, Cui P, Zhu S, Lai D, Ren J, Wang W, Fan A, Lin W, Su H. ThpacC Acts as a Positive Regulator of Homodimericin A Biosynthesis and Antifungal Activities of Trichoderma harzianum 3.9236. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:12695-12704. [PMID: 34677054 DOI: 10.1021/acs.jafc.1c04330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The Pal/Rim pathway and its key transcription factor PacC play important roles in fungal adaptation to ambient pH regarding growth, secondary metabolism, and virulence. However, the effect of PacC on the secondary metabolism of the important biocontrol fungus Trichoderma harzianum remains elusive. To answer this question, ThpacC deletion (KO-ThpacC) and overexpression (OE-ThpacC) mutants of T. harzianum 3.9236 were constructed. Transcriptomic analysis of T. harzianum and KO-ThpacC suggested that ThpacC acted as both a positive and a negative regulator for secondary metabolite (SM) production. Further investigation revealed that deletion of ThpacC abolished homodimericin A and 8-epi-homodimericin A production. Moreover, ThpacC plays a role in the antagonism of T. harzianum against Sclerotinia sclerotiorum. 8-epi-Homodimericin A demonstrated moderate inhibitory activity against S. sclerotiorum. Our results contribute to a deeper understanding of the ThpacC function on SM production and the antifungal activity of T. harzianum.
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Affiliation(s)
- Mengyue Wu
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, 15 North Third Ring Road, Chaoyang District, Beijing 100029, P. R. China
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191, P. R. China
| | - Huiling Wei
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, 15 North Third Ring Road, Chaoyang District, Beijing 100029, P. R. China
| | - Ke Ma
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191, P. R. China
| | - Peiqi Cui
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, 15 North Third Ring Road, Chaoyang District, Beijing 100029, P. R. China
| | - Shaozhou Zhu
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, 15 North Third Ring Road, Chaoyang District, Beijing 100029, P. R. China
| | - Daowan Lai
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing 100193, P. R. China
| | - Jinwei Ren
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Wenzhao Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Aili Fan
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, 15 North Third Ring Road, Chaoyang District, Beijing 100029, P. R. China
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191, P. R. China
| | - Wenhan Lin
- State Key Laboratory of Natural and Biomimetic Drugs, Peking University, 38 Xueyuan Road, Haidian District, Beijing 100191, P. R. China
| | - Haijia Su
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, 15 North Third Ring Road, Chaoyang District, Beijing 100029, P. R. China
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9
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Mou YN, Gao BJ, Ren K, Tong SM, Ying SH, Feng MG. P-type Na +/K + ATPases essential and nonessential for cellular homeostasis and insect pathogenicity of Beauveria bassiana. Virulence 2020; 11:1415-1431. [PMID: 33103596 PMCID: PMC7588218 DOI: 10.1080/21505594.2020.1836903] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 08/11/2020] [Accepted: 10/11/2020] [Indexed: 02/06/2023] Open
Abstract
ENA1 and ENA2 are P-type IID/ENA Na+/K+-ATPases required for cellular homeostasis in yeasts but remain poorly understood in filamentous fungal insect pathogens. Here, we characterized seven genes encoding five ENA1/2 homologues (ENA1a-c and ENA2a/b) and two P-type IIC/NK Na+/K+-ATPases (NK1/2) in Beauveria bassiana, an insect-pathogenic fungus serving as a main source of fungal insecticides worldwide. Most of these genes were highly responsive to alkaline pH and Na+/K+ cues at transcription level. Cellular Na+, K+ and H+ homeostasis was disturbed only in the absence of ena1a or ena2b. The disturbed homeostasis featured acceleration of vacuolar acidification, elevation of cytosolic Na+/K+ level at pH 5.0 to 9.0, and stabilization of extracellular H+ level to initial pH 7.5 during a 5-day period of submerged incubation. Despite little defect in hyphal growth and asexual development, the Δena1a and Δena2b mutants were less tolerant to metal cations (Na+, K+, Li+, Zn2+, Mn2+ and Fe3+), cell wall perturbation, oxidation, non-cation hyperosmolarity and UVB irradiation, severely compromised in insect pathogenicity via normal cuticle infection, and attenuated in virulence via hemocoel injection. The deletion mutants of five other ENA and NK genes showed little change in vacuolar pH and all examined phenotypes. Therefore, only ENA1a and ENA2b evidently involved in both transmembrane and vacuolar activities are essential for cellular cation homeostasis, insect pathogenicity and multiple stress tolerance in B. bassiana. These findings provide a novel insight into ENA1a- and ENA2b-dependent vacuolar pH stability, cation-homeostatic process and fungal fitness to host insect and environment.
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Affiliation(s)
- Ya-Ni Mou
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ben-Jie Gao
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Kang Ren
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Sen-Miao Tong
- College of Agricultural and Food Science, Zhejiang A&F University, Lin’an, Zhejiang, China
| | - Sheng-Hua Ying
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ming-Guang Feng
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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Wang J, Chen J, Hu Y, Ying SH, Feng MG. Roles of six Hsp70 genes in virulence, cell wall integrity, antioxidant activity and multiple stress tolerance of Beauveria bassiana. Fungal Genet Biol 2020; 144:103437. [DOI: 10.1016/j.fgb.2020.103437] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/25/2020] [Accepted: 07/19/2020] [Indexed: 12/31/2022]
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11
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Castrejón-Antonio JE, Tamez-Guerra P, Montesinos-Matías R, Ek-Ramos MJ, Garza-López PM, Arredondo-Bernal HC. Selection of Beauveria bassiana (Hypocreales: Cordycipitaceae) strains to control Xyleborus affinis (Curculionidae: Scolytinae) females. PeerJ 2020; 8:e9472. [PMID: 32685289 PMCID: PMC7337030 DOI: 10.7717/peerj.9472] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 06/12/2020] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Xyleborus affinis Eichhoff (Coleoptera: Curculionidae) is an ambrosia beetle reported to affect avocado trees (Persea americana Mill.). The use of the entomopathogenic fungus (EPF) Beauveria bassiana (Bals.-Criv.) Vuill. for ambrosia beetle control represents an alternative to insecticides. METHODS This study was designed in two stages to select B. bassiana strains with potential to control X. affinis females. In the first stage, 19 B. bassiana Mexican strains from EPF collection, isolated from Coleoptera (CHE-CNRCB, http://www.gob.mx/senasica/documentos/coleccion-de-hongos-entomopatogenos), were tested. Analyses included radial growth rate, conidial yield, spore germination, and germ tube length. Results were analysed by Principal Component Analysis (PCA) to identify clusters within favourable growth phenotypes. For the second stage, 10 selected strains were re-analysed for virulence-related metabolic characteristic, including cell wall-bound cuticle-degrading enzymes-Pr1-like proteases and β-N-acetyl glucosaminidases (NAGase) chitinases, conidial hydrophobicity and monopolar germination parameters. A second PCA analysis was run for those virulence parameters analysed, and upon results strains CHE-CNRCB 44, 171, 431 and 485 were selected and tested against X. affinis females. Females were treated with a 1 × 108 conidia mL-1 suspension (recommended rate), using a Potter Tower. RESULTS All strains showed insecticidal activity, inducing up to 58% mortality; about 30% dead beetles developed aerial mycelia (CHE-CNRCB 485) and the fastest mortality rate was t0 = 1.95 (CHE-CNRCB 44). CONCLUSION Since all selected strains showed virulence against X. affinis females, results indicated the possibility of selecting B. bassiana strains based on multiple metabolic attributes, as a preliminary test to perform bioassays against order-related target insects.
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Affiliation(s)
- Jesús E. Castrejón-Antonio
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, San Nicolás de los Garza, Nuevo León, México
| | - Patricia Tamez-Guerra
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, San Nicolás de los Garza, Nuevo León, México
| | | | - Maria J. Ek-Ramos
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Biológicas, San Nicolás de los Garza, Nuevo León, México
| | - Paul M. Garza-López
- Instituto de Ciencias Agropecuarias, Universidad Autónoma del Estado de Hidalgo, Tulancingo, Hidalgo, México
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12
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Enhancement of Sphingolipid Synthesis Improves Osmotic Tolerance of Saccharomyces cerevisiae. Appl Environ Microbiol 2020; 86:AEM.02911-19. [PMID: 32033944 PMCID: PMC7117927 DOI: 10.1128/aem.02911-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 01/29/2020] [Indexed: 12/12/2022] Open
Abstract
To enhance the growth performance of Saccharomyces cerevisiae under osmotic stress, mutant XCG001, which tolerates up to 1.5 M NaCl, was isolated through adaptive laboratory evolution (ALE). Comparisons of the transcriptome data of mutant XCG001 and the wild-type strain identified ELO2 as being associated with osmotic tolerance. In the ELO2 overexpression strain (XCG010), the contents of inositol phosphorylceramide (IPC; t18:0/26:0), mannosylinositol phosphorylceramide [MIPC; t18:0/22:0(2OH)], MIPC (d18:0/22:0), MIPC (d20:0/24:0), mannosyldiinositol phosphorylceramide [M(IP)2C; d20:0/26:0], M(IP)2C [t18:0/26:0(2OH)], and M(IP)2C [d20:0/26:0(2OH)] increased by 88.3 times, 167 times, 63.3 times, 23.9 times, 27.9 times, 114 times, and 208 times at 1.0 M NaCl, respectively, compared with the corresponding values of the control strain XCG002. As a result, the membrane integrity, cell growth, and cell survival rate of strain XCG010 increased by 24.4% ± 1.0%, 21.9% ± 1.5%, and 22.1% ± 1.1% at 1.0 M NaCl, respectively, compared with the corresponding values of the control strain XCG002 (wild-type strain with a control plasmid). These findings provided a novel strategy for engineering complex sphingolipids to enhance osmotic tolerance.IMPORTANCE This study demonstrated a novel strategy for the manipulation of membrane complex sphingolipids to enhance S. cerevisiae tolerance to osmotic stress. Elo2, a sphingolipid acyl chain elongase, was related to osmotic tolerance through transcriptome analysis of the wild-type strain and an osmosis-tolerant strain generated from ALE. Overexpression of ELO2 increased the content of complex sphingolipid with longer acyl chain; thus, membrane integrity and osmotic tolerance improved.
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Zhu J, Wu F, Yue S, Chen C, Song S, Wang H, Zhao M. Functions of reactive oxygen species in apoptosis and ganoderic acid biosynthesis in Ganoderma lucidum. FEMS Microbiol Lett 2019; 366:5714084. [PMID: 31967638 DOI: 10.1093/femsle/fnaa015] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 01/21/2020] [Indexed: 12/26/2022] Open
Abstract
Ganoderma lucidum is a medicinal fungus that is widely used in traditional medicine. Fungal PacC is recognized as an important transcription factor that functions during adaptation to environmental pH, fungal development and secondary metabolism. Previous studies have revealed that GlPacC plays important roles in mycelial growth, fruiting body development and ganoderic acid (GA) biosynthesis. In this study, using a terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay, we found that the apoptosis level was increased when PacC was silenced. The transcript and activity levels of caspase-like proteins were significantly increased in the PacC-silenced (PacCi) strains compared with the control strains. Silencing PacC also resulted in an increased reactive oxygen species (ROS) levels (∼2-fold) and decreased activity levels of enzymes involved in the antioxidant system. Further, we found that the intracellular ROS levels contributed to apoptosis and GA biosynthesis. Adding N-acetyl-cysteine and vitamin C decreased intracellular ROS and resulted in the inhibition of apoptosis in the PacCi strains. Additionally, the GA biosynthesis was different between the control strains and the PacCi strains after intracellular ROS was eliminated. Taken together, the findings showed that silencing PacC can result in an intracellular ROS burst, which increases cell apoptosis and GA biosynthesis levels. Our study provides novel insight into the functions of PacC in filamentous fungi.
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Affiliation(s)
- Jing Zhu
- Key Laboratory of Edible Mushroom Processing, Ministry of Agriculture; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Fengli Wu
- Key Laboratory of Edible Mushroom Processing, Ministry of Agriculture; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Sining Yue
- Key Laboratory of Edible Mushroom Processing, Ministry of Agriculture; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Chen Chen
- Key Laboratory of Edible Mushroom Processing, Ministry of Agriculture; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Shuqi Song
- Key Laboratory of Edible Mushroom Processing, Ministry of Agriculture; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Hui Wang
- Key Laboratory of Edible Mushroom Processing, Ministry of Agriculture; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
| | - Mingwen Zhao
- Key Laboratory of Edible Mushroom Processing, Ministry of Agriculture; Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, P.R. China
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Moonjely S, Zhang X, Fang W, Bidochka MJ. Metarhizium robertsii ammonium permeases (MepC and Mep2) contribute to rhizoplane colonization and modulates the transfer of insect derived nitrogen to plants. PLoS One 2019; 14:e0223718. [PMID: 31618269 PMCID: PMC6795453 DOI: 10.1371/journal.pone.0223718] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 09/26/2019] [Indexed: 12/14/2022] Open
Abstract
The endophytic insect pathogenic fungi (EIPF) Metarhizium promotes plant growth through symbiotic association and the transfer of insect-derived nitrogen. However, little is known about the genes involved in this association and the transfer of nitrogen. In this study, we assessed the involvement of six Metarhizium robertsii genes in endophytic, rhizoplane and rhizospheric colonization with barley roots. Two ammonium permeases (MepC and Mep2) and a urease, were selected since homologous genes in arbuscular mycorrhizal fungi were reported to play a pivotal role in nitrogen mobilization during plant root colonization. Three other genes were selected on the basis on RNA-Seq data that showed high expression levels on bean roots, and these encoded a hydrophobin (Hyd3), a subtilisin-like serine protease (Pr1A) and a hypothetical protein. The root colonization assays revealed that the deletion of urease, hydrophobin, subtilisin-like serine protease and hypothetical protein genes had no impact on endophytic, rhizoplane and rhizospheric colonization at 10 or 20 days. However, the deletion of MepC resulted in significantly increased rhizoplane colonization at 10 days whereas ΔMep2 showed increased rhizoplane colonization at 20 days. In addition, the nitrogen transporter mutants also showed significantly higher 15N incorporation of insect derived nitrogen in barley leaves in the presence of nutrients. Insect pathogenesis assay revealed that disruption of MepC, Mep2, urease did not reduce virulence toward insects. The enhanced rhizoplane colonization of ΔMep2 and ΔMepC and insect derived nitrogen transfer to plant hosts suggests the role of MepC and Mep2 in Metarhizium-plant symbiosis.
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Affiliation(s)
- Soumya Moonjely
- Department of Biological Sciences, Brock University, St. Catharines, ON Canada
| | - Xing Zhang
- Institute of Microbiology, Zhejiang University, Hangzhou, China
| | - Weiguo Fang
- Institute of Microbiology, Zhejiang University, Hangzhou, China
| | - Michael J. Bidochka
- Department of Biological Sciences, Brock University, St. Catharines, ON Canada
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Li L, Chen S, Gao M, Ding B, Zhang J, Zhou Y, Liu Y, Yang H, Wu Q, Chen F. Acidic conditions induce the accumulation of orange Monascus pigments during liquid-state fermentation of Monascus ruber M7. Appl Microbiol Biotechnol 2019; 103:8393-8402. [DOI: 10.1007/s00253-019-10114-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/14/2019] [Accepted: 08/30/2019] [Indexed: 12/12/2022]
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16
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MaPacC, a pH-responsive transcription factor, negatively regulates thermotolerance and contributes to conidiation and virulence in Metarhizium acridum. Curr Genet 2019; 66:397-408. [DOI: 10.1007/s00294-019-01032-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 08/13/2019] [Accepted: 08/20/2019] [Indexed: 12/15/2022]
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17
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The pH sensing receptor AopalH plays important roles in the nematophagous fungus Arthrobotrys oligospora. Fungal Biol 2019; 123:547-554. [PMID: 31196524 DOI: 10.1016/j.funbio.2019.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 04/24/2019] [Accepted: 05/09/2019] [Indexed: 01/01/2023]
Abstract
There is well-conserved PacC/Rim101 signaling among ascomycete fungi to mediate environmental pH sensing. For pathogenic fungi, this pathway not only enables fungi to grow over a wide pH range, but it also determines whether these fungi can successfully colonize and invade the targeted host. Within the pal/PacC pathway, palH is a putative ambient pH sensor with a seven-transmembrane domain. To characterize the function of a palH homolog, AopalH, in the nematophagous fungus Arthrobotrys oligospora, we knocked out the encoding gene of AopalH through homologous recombination, and the transformants exhibited slower growth rates, greater sensitivities to cationic and hyperoxidation stresses, as well as reduced conidiation and reduced trap formation, suggesting that the pH regulatory system has critical functions in nematophagous fungi. Our results provide novel insights into the mechanisms of pH response and regulation in fungi.
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18
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Luo Z, Zhang T, Liu P, Bai Y, Chen Q, Zhang Y, Keyhani NO. The Beauveria bassiana Gas3 β-Glucanosyltransferase Contributes to Fungal Adaptation to Extreme Alkaline Conditions. Appl Environ Microbiol 2018; 84:e01086-18. [PMID: 29802184 PMCID: PMC6052264 DOI: 10.1128/aem.01086-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 05/17/2018] [Indexed: 12/20/2022] Open
Abstract
Fungal β-1,3-glucanosyltransferases are cell wall-remodeling enzymes implicated in stress response, cell wall integrity, and virulence, with most fungal genomes containing multiple members. The insect-pathogenic fungus Beauveria bassiana displays robust growth over a wide pH range (pH 4 to 10). A random insertion mutant library screening for increased sensitivity to alkaline (pH 10) growth conditions resulted in the identification and mapping of a mutant to a β-1,3-glucanosyltransferase gene (Bbgas3). Bbgas3 expression was pH dependent and regulated by the PacC transcription factor, which activates genes in response to neutral/alkaline growth conditions. Targeted gene knockout of Bbgas3 resulted in reduced growth under alkaline conditions, with only minor effects of increased sensitivity to cell wall stress (Congo red and calcofluor white) and no significant effects on fungal sensitivity to oxidative or osmotic stress. The cell walls of ΔBbgas3 aerial conidia were thinner than those of the wild-type and complemented strains in response to alkaline conditions, and β-1,3-glucan antibody and lectin staining revealed alterations in cell surface carbohydrate epitopes. The ΔBbgas3 mutant displayed alterations in cell wall chitin and carbohydrate content in response to alkaline pH. Insect bioassays revealed impaired virulence for the ΔBbgas3 mutant depending upon the pH of the media on which the conidia were grown and harvested. Unexpectedly, a decreased median lethal time to kill (LT50, i.e., increased virulence) was seen for the mutant using intrahemocoel injection assays using conidia grown at acidic pH (5.6). These data show that BbGas3 acts as a pH-responsive cell wall-remodeling enzyme involved in resistance to extreme pH (>9).IMPORTANCE Little is known about adaptations required for growth at high (>9) pH. Here, we show that a specific fungal membrane-remodeling β-1,3-glucanosyltransferase gene (Bbgas3) regulated by the pH-responsive PacC transcription factor forms a critical aspect of the ability of the insect-pathogenic fungus Beauveria bassiana to grow at extreme pH. The loss of Bbgas3 resulted in a unique decreased ability to grow at high pH, with little to no effects seen with respect to other stress conditions, i.e., cell wall integrity and osmotic and oxidative stress. However, pH-dependent alternations in cell wall properties and virulence were noted for the ΔBbgas3 mutant. These data provide a mechanistic insight into the importance of the specific cell wall structure required to stabilize the cell at high pH and link it to the PacC/Pal/Rim pH-sensing and regulatory system.
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Affiliation(s)
- Zhibing Luo
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Tongbing Zhang
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Pengfei Liu
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Yuting Bai
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Qiyan Chen
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Yongjun Zhang
- Academy of Agricultural Sciences, Southwest University, Chongqing, People's Republic of China
- Biotechnology Research Center, Southwest University, Chongqing, People's Republic of China
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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19
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Keyhani NO. Lipid biology in fungal stress and virulence: Entomopathogenic fungi. Fungal Biol 2018; 122:420-429. [DOI: 10.1016/j.funbio.2017.07.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/11/2017] [Accepted: 07/13/2017] [Indexed: 12/17/2022]
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20
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Virgilio S, Bertolini MC. Functional diversity in the pH signaling pathway: an overview of the pathway regulation in Neurospora crassa. Curr Genet 2017; 64:529-534. [DOI: 10.1007/s00294-017-0772-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 10/20/2017] [Accepted: 10/25/2017] [Indexed: 10/18/2022]
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21
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Luo Z, Ren H, Mousa JJ, Rangel DEN, Zhang Y, Bruner SD, Keyhani NO. The PacC transcription factor regulates secondary metabolite production and stress response, but has only minor effects on virulence in the insect pathogenic fungus Beauveria bassiana. Environ Microbiol 2017; 19:788-802. [PMID: 28083986 DOI: 10.1111/1462-2920.13648] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 11/15/2016] [Accepted: 12/15/2016] [Indexed: 11/29/2022]
Abstract
The PacC transcription factor is an important component of the fungal ambient pH-responsive regulatory system. Loss of pacC in the insect pathogenic fungus Beauveria bassiana resulted in an alkaline pH-dependent decrease in growth and pH-dependent increased susceptibility to osmotic (salt, sorbitol) stress and SDS. Extreme susceptibility to Congo Red was noted irrespective of pH, and ΔBbpacC conidia showed subtle increases in UV susceptibility. The ΔBbPacC mutant showed a reduced ability to acidify media during growth due to failure to produce oxalic acid. The ΔBbPacC mutant also did not produce the insecticidal compound dipicolinic acid, however, production of a yellow-colored compound was noted. The compound, named bassianolone B, was purified and its structure determined. Despite defects in growth, stress resistance, and oxalate/insecticidal compound production, only a small decrease in virulence was seen for the ΔBbpacC strain in topical insect bioassays using larvae from the greater waxmoth, Galleria mellonella or adults of the beetle, Tenebrio molitor. However, slightly more pronounced decreases were seen in virulence via intrahemcoel injection assays (G. mellonella) and in assays using T. molitor larvae. These data suggest important roles for BbpacC in mediating growth at alkaline pH, regulating secondary metabolite production, and in targeting specific insect stages.
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Affiliation(s)
- Zhibing Luo
- Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China.,Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, 32611, USA
| | - Hui Ren
- Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China
| | - Jarrod J Mousa
- Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA
| | - Drauzio E N Rangel
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 746050-50, Brazil
| | - Yongjun Zhang
- Biotechnology Research Center, Southwest University, Chongqing, 400716, P. R. China
| | - Steven D Bruner
- Department of Chemistry, University of Florida, Gainesville, FL, 32611, USA
| | - Nemat O Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, 32611, USA.,Genetic Engineering Research Center School of Life Sciences, Chongqing University, Chongqing, 400045, P.R. China
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Zhu J, Zhu XG, Ying SH, Feng MG. Effect of vacuolar ATPase subunit H (VmaH) on cellular pH, asexual cycle, stress tolerance and virulence in Beauveria bassiana. Fungal Genet Biol 2016; 98:52-60. [PMID: 28011319 DOI: 10.1016/j.fgb.2016.12.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 12/11/2016] [Accepted: 12/19/2016] [Indexed: 12/23/2022]
Abstract
Vacuolar ATPase (V-ATPase) is a conserved multi-subunit protein complex that mediates intracellular acidification in fungi. Here we show functional diversity of V-ATPase subunit H (BbVmaH) in Beauveria bassiana, a filamentous fungal insect pathogen. Deletion of BbvmaH resulted in elevated vacuolar pH, increased Ca2+ level in cytosol but not in vacuoles, accelerated culture acidification and reduced accumulation of extracellular ammonia. Aerial conidiation and submerged blastospore production were largely delayed and reduced in the deletion mutant, respectively, accompanied with a significant delay in conidial germination, alterations of conidia and blastospores in morphology, size and/or density, and severe growth defects in minimal media with different carbon and nitrogen sources. Despite null responses to osmotic, oxidative and cell wall perturbing stresses, the deletion mutant showed increased sensitivity to Ca2+, Zn2+ and Cu2+ during growth while its conidia were less tolerant to a wet-heat stress at 45°C and UV-B irradiation. Intracellular glycerol and mannitol contents also decreased significantly. Its virulence to Galleria mellonella larvae was significantly attenuated when conidia were topically applied for normal cuticle infection or injected into haemocoel for cuticle-bypassing infection. All phenotypic changes were restored by targeted gene complementation. Our results indicate that BbVmaH plays an important role in sustaining not only vacuolar acidification but also cytosolic calcium accumulation, ambient pH homeostasis, in vitro asexual cycle and virulence in B. bassiana.
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Affiliation(s)
- Jing Zhu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xiao-Guan Zhu
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
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