1
|
Lu Z, Zhu Q, Bai Y, Zhao X, Wang H, Peng X, Luo Z, Zhang Y. A fungal pathogen secretes a cell wall-associated β-N-acetylhexosaminidase that is co-expressed with chitinases to contribute to infection of insects. PEST MANAGEMENT SCIENCE 2024. [PMID: 38771009 DOI: 10.1002/ps.8185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/23/2024] [Accepted: 05/07/2024] [Indexed: 05/22/2024]
Abstract
BACKGROUND β-N-acetylhexosaminidases (HEXs) are widely distributed in fungi and involved in cell wall chitin metabolism and utilization of chitin-containing substrates. However, details of the fungal pathogens-derived HEXs in the interaction with their hosts remain limited. RESULTS An insect nutrients-induced β-N-acetylhexosaminidase, BbHex1, was identified from the entomopathogenic fungus Beauveria bassiana, which was involved in cell wall modification and degradation of insect cuticle. BbHex1 was localized to cell wall and secreted, and displayed enzyme activity to degrade the chitinase-hydrolyzed product (GlcNAc)2. Disruption of BbHex1 resulted in a significant decrease in the level of cell wall chitin in the presence of insect nutrients and during infection of insects, with impaired ability to penetrate insect cuticle, accompanying downregulated cell wall metabolism-involved and cuticle-degrading chitinase genes. However, the opposite phenotypes were examined in the gene overexpression strain. Distinctly altered cell wall structures caused by BbHex1 mutation and overexpression led to the easy activation and evasion (respectively) of insect immune response during fungal infection. As a result, BbHex1 contributed to fungal virulence. Bioinformatics analysis revealed that promoters of some co-expressed chitinase genes with the BbHex1 promoter shared conserved transcription factors Skn7, Msn2 and Ste12, and CreA-binding motifs, implying co-regulation of those genes with BbHex1. CONCLUSION These data support a mechanism that the fungal pathogen specifically expresses BbHex1, which is co-expressed with chitinases to modify cell wall for evasion of insect immune recognition and to degrade insect cuticle, and contributes to the fungal virulence against insects. © 2024 Society of Chemical Industry.
Collapse
Affiliation(s)
- Zhuoyue Lu
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, People's Republic of China
| | - Qiankuan Zhu
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, People's Republic of China
| | - Yuting Bai
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, People's Republic of China
| | - Xin Zhao
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, People's Republic of China
| | - Huifang Wang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, People's Republic of China
| | - Xinxin Peng
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, People's Republic of China
| | - Zhibing Luo
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, People's Republic of China
| | - Yongjun Zhang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, People's Republic of China
| |
Collapse
|
2
|
Kan Y, He Z, Keyhani NO, Li N, Huang S, Zhao X, Liu P, Zeng F, Li M, Luo Z, Zhang Y. A network of transcription factors in complex with a regulating cell cycle cyclin orchestrates fungal oxidative stress responses. BMC Biol 2024; 22:81. [PMID: 38609978 PMCID: PMC11015564 DOI: 10.1186/s12915-024-01884-3] [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: 07/03/2023] [Accepted: 04/05/2024] [Indexed: 04/14/2024] Open
Abstract
BACKGROUND Response to oxidative stress is universal in almost all organisms and the mitochondrial membrane protein, BbOhmm, negatively affects oxidative stress responses and virulence in the insect fungal pathogen, Beauveria bassiana. Nothing further, however, is known concerning how BbOhmm and this phenomenon is regulated. RESULTS Three oxidative stress response regulating Zn2Cys6 transcription factors (BbOsrR1, 2, and 3) were identified and verified via chromatin immunoprecipitation (ChIP)-qPCR analysis as binding to the BbOhmm promoter region, with BbOsrR2 showing the strongest binding. Targeted gene knockout of BbOsrR1 or BbOsrR3 led to decreased BbOhmm expression and consequently increased tolerances to free radical generating compounds (H2O2 and menadione), whereas the ΔBbOsrR2 strain showed increased BbOhmm expression with concomitant decreased tolerances to these compounds. RNA and ChIP sequencing analysis revealed that BbOsrR1 directly regulated a wide range of antioxidation and transcription-associated genes, negatively affecting the expression of the BbClp1 cyclin and BbOsrR2. BbClp1 was shown to localize to the cell nucleus and negatively mediate oxidative stress responses. BbOsrR2 and BbOsrR3 were shown to feed into the Fus3-MAPK pathway in addition to regulating antioxidation and detoxification genes. Binding motifs for the three transcription factors were found to partially overlap in the promoter region of BbOhmm and other target genes. Whereas BbOsrR1 appeared to function independently, co-immunoprecipitation revealed complex formation between BbClp1, BbOsrR2, and BbOsrR3, with BbClp1 partially regulating BbOsrR2 phosphorylation. CONCLUSIONS These findings reveal a regulatory network mediated by BbOsrR1 and the formation of a BbClp1-BbOsrR2-BbOsrR3 complex that orchestrates fungal oxidative stress responses.
Collapse
Affiliation(s)
- Yanze Kan
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
| | - Zhangjiang He
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
- Biochemical Engineering Center of Guizhou Province, Guizhou University, Guiyang, 50025, People's Republic of China
| | - Nemat O Keyhani
- Department of Biological Sciences, University of Illinois, Chicago, IL, 60607, USA
| | - Ning Li
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
| | - Shuaishuai Huang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
| | - Xin Zhao
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
| | - Pengfei Liu
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
| | - Fanqin Zeng
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
| | - Min Li
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
| | - Zhibing Luo
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China
| | - Yongjun Zhang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, 400715, People's Republic of China.
- Key Laboratory of Entomology and Pest Control Engineering, Beibei Culture Collection of Chongqing Agricultural Microbiology, Chongqing, 400715, People's Republic of China.
| |
Collapse
|
3
|
Hong S, Shang J, Sun Y, Tang G, Wang C. Fungal infection of insects: molecular insights and prospects. Trends Microbiol 2024; 32:302-316. [PMID: 37778923 DOI: 10.1016/j.tim.2023.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/27/2023] [Accepted: 09/12/2023] [Indexed: 10/03/2023]
Abstract
Entomopathogenic fungi (EPF) distribute in different fungal phyla with variable host ranges and play essential role in regulating insect populations by infecting hosts via cuticle penetration. The representative ascomycete EPF of Metarhizium and Beauveria species have been widely used in mechanistic investigations of fungus-insect interactions and as ecofriendly mycoinsecticides. Here, we review the function of diverse genes, pathways, and secondary metabolites associated with EPF stepwise infections. In particular, emerging evidence has shown that EPF have to outcompete insect ectomicrobiotas prior to penetrating cuticles, and subvert or evade host antifungal immunity by using effector-like proteins and chemicals like plant pathogens. Future prospects are discussed for a better understanding of fungal pathobiology, which will provide novel insights into microbe-animal interactions.
Collapse
Affiliation(s)
- Song Hong
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Junmei Shang
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaneli Sun
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guirong Tang
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chengshu Wang
- Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China; CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China; School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
| |
Collapse
|
4
|
Ma M, Luo J, Li C, Eleftherianos I, Zhang W, Xu L. A life-and-death struggle: interaction of insects with entomopathogenic fungi across various infection stages. Front Immunol 2024; 14:1329843. [PMID: 38259477 PMCID: PMC10800808 DOI: 10.3389/fimmu.2023.1329843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 12/15/2023] [Indexed: 01/24/2024] Open
Abstract
Insects constitute approximately 75% of the world's recognized fauna, with the majority of species considered as pests. Entomopathogenic fungi (EPF) are parasitic microorganisms capable of efficiently infecting insects, rendering them potent biopesticides. In response to infections, insects have evolved diverse defense mechanisms, prompting EPF to develop a variety of strategies to overcome or circumvent host defenses. While the interaction mechanisms between EPF and insects is well established, recent findings underscore that their interplay is more intricate than previously thought, especially evident across different stages of EPF infection. This review primarily focuses on the interplay between EPF and the insect defense strategies, centered around three infection stages: (1) Early infection stage: involving the pre-contact detection and avoidance behavior of EPF in insects, along with the induction of behavioral responses upon contact with the host cuticle; (2) Penetration and intra-hemolymph growth stage: involving the initiation of intricate cellular and humoral immune functions in insects, while symbiotic microbes can further contribute to host resistance; (3) Host insect's death stage: involving the ultimate confrontation between pathogens and insects. Infected insects strive to separate themselves from the healthy population, while pathogens rely on the infected insects to spread to new hosts. Also, we discuss a novel pest management strategy underlying the cooperation between EPF infection and disturbing the insect immune system. By enhancing our understanding of the intricate interplay between EPF and the insect, this review provides novel perspectives for EPF-mediated pest management and developing effective fungal insecticides.
Collapse
Affiliation(s)
- Meiqi Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Jing Luo
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Chong Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| | - Ioannis Eleftherianos
- Infection and Innate Immunity Laboratory, Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Washington, DC, United States
| | - Wei Zhang
- National Key Laboratory of Green Pesticide, Key Laboratory of Green Pesticide and Agricultural Bioengineering (Ministry of Education), Guizhou University, Guiyang, China
| | - Letian Xu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, China
| |
Collapse
|
5
|
Huang S, Zhao X, Luo Z, Tang X, Zhou Y, Keyhani N, Zhang Y. Fungal co-expression network analyses identify pathogen gene modules associated with host insect invasion. Microbiol Spectr 2023; 11:e0180923. [PMID: 37656157 PMCID: PMC10581046 DOI: 10.1128/spectrum.01809-23] [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: 05/05/2023] [Accepted: 07/06/2023] [Indexed: 09/02/2023] Open
Abstract
The broad host range fungal insect pathogen, Beauveria bassiana, has been commercialized as an alternative to chemical insecticides for pest control worldwide. B. bassiana represents a unique model system with which to examine host-pathogen interactions, and a wide range of genes and processes have been studied. However, significant aspects of virulence, particularly on the genomic scale, remain poorly studied. Here, we have combined available transcriptomes with three newly generated data sets for a combined total analysis of 76 deep-sequenced samples covering growth, development, stress responses, and infection during the life cycle of B. bassiana. Co-expression network analyses resulted in the identification of gene modules enriched during two critical stages of the infection process, namely (i) cuticle penetration and (ii) in vivo hyphal body (dimorphic transition) growth capable of avoiding innate and humoral immune defenses. These analyses identify unique signatures of metabolism, signaling, secondary metabolite production, host defense suppression, membrane reorganization, effector production, and secretion for each stage, including genetic regulators and epigenetic patterns. These data provide a comprehensive framework for understanding and probing fungal adaptations to its pathogenic life cycle and expand the candidate repertoire for continued dissection of the host-pathogen interaction. IMPORTANCE Insect fungal pathogens have evolved unique strategies for overcoming host structural and immunological defenses that span from the sclerotized cuticle to innate and humoral cellular responses. Two critical stages of the infection process involve (i) cuticle penetration and (ii) immune evasion within the insect hemocoel. A set of 76 global transcriptomic data for B. bassiana that include the cuticle penetration and hemocoel growth stages were analyzed for patterns (gene modules) of expression, yielding unique insights into these different life stages. These analyses integrate gene networks involved in fungal development, stress response and pathogenesis to further the systematic understanding of the global processes integral to the unique adaptation employed by fungal pathogens of insects.
Collapse
Affiliation(s)
- Shuaishuai Huang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, China
- Key Laboratory of Biodiversity and Environment on the Qinghai-Tibet Plateau (Ministry of Education), School of Ecology and Environment, Tibet University, Tibet, China
| | - Xin Zhao
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, China
| | - Zhibing Luo
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, China
| | - Xiaohan Tang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, China
| | - Yonghong Zhou
- Key Laboratory of Biodiversity and Environment on the Qinghai-Tibet Plateau (Ministry of Education), School of Ecology and Environment, Tibet University, Tibet, China
| | - Nemat Keyhani
- Department of Biological Sciences, University of Illinois, Chicago, Illinois, USA
| | - Yongjun Zhang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, China
| |
Collapse
|
6
|
Wang H, Lu Z, Keyhani NO, Deng J, Zhao X, Huang S, Luo Z, Jin K, Zhang Y. Insect fungal pathogens secrete a cell wall-associated glucanase that acts to help avoid recognition by the host immune system. PLoS Pathog 2023; 19:e1011578. [PMID: 37556475 PMCID: PMC10441804 DOI: 10.1371/journal.ppat.1011578] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 08/21/2023] [Accepted: 07/25/2023] [Indexed: 08/11/2023] Open
Abstract
Fungal insect pathogens have evolved diverse mechanisms to evade host immune recognition and defense responses. However, identification of fungal factors involved in host immune evasion during cuticular penetration and subsequent hemocoel colonization remains limited. Here, we report that the entomopathogenic fungus Beauveria bassiana expresses an endo-β-1,3-glucanase (BbEng1) that functions in helping cells evade insect immune recognition/ responses. BbEng1 was specifically expressed during infection, in response to host cuticle and hemolymph, and in the presence of osmotic or oxidative stress. BbEng1 was localized to the fungal cell surface/ cell wall, where it acts to remodel the cell wall pathogen associated molecular patterns (PAMPs) that can trigger host defenses, thus facilitating fungal cell evasion of host immune defenses. BbEng1 was secreted where it could bind to fungal cells. Cell wall β-1,3-glucan levels were unchanged in ΔBbEng1 cells derived from in vitro growth media, but was elevated in hyphal bodies, whereas glucan levels were reduced in most cell types derived from the BbEng1 overexpressing strain (BbEng1OE). The BbEng1OE strain proliferated more rapidly in the host hemocoel and displayed higher virulence as compared to the wild type parent. Overexpression of their respective Eng1 homologs or of BbEng1 in the insect fungal pathogens, Metarhizium robertsii and M. acridum also resulted in increased virulence. Our data support a mechanism by which BbEng1 helps the fungal pathogen to evade host immune surveillance by decreasing cell wall glucan PAMPs, promoting successful fungal mycosis.
Collapse
Affiliation(s)
- Huifang Wang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People’s Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Academy of Agricultural Sciences, Southwest University, Chongqing, People’s Republic of China
| | - Zhuoyue Lu
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People’s Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Academy of Agricultural Sciences, Southwest University, Chongqing, People’s Republic of China
| | - Nemat O. Keyhani
- Department of Biological Sciences, University of Illinois, Chicago, Illinois, United States of America
| | - Juan Deng
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People’s Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Academy of Agricultural Sciences, Southwest University, Chongqing, People’s Republic of China
| | - Xin Zhao
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People’s Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Academy of Agricultural Sciences, Southwest University, Chongqing, People’s Republic of China
| | - Shuaishuai Huang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People’s Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Academy of Agricultural Sciences, Southwest University, Chongqing, People’s Republic of China
| | - Zhibing Luo
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People’s Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Academy of Agricultural Sciences, Southwest University, Chongqing, People’s Republic of China
| | - Kai Jin
- Genetic Engineering Research Center, School of Life Sciences, Chongqing University, Chongqing, People’s Republic of China
| | - Yongjun Zhang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), College of Plant Protection, Southwest University, Chongqing, People’s Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, Academy of Agricultural Sciences, Southwest University, Chongqing, People’s Republic of China
| |
Collapse
|
7
|
Zhao X, Jiang Y, Wang H, Lu Z, Huang S, Luo Z, Zhang L, Lv T, Tang X, Zhang Y. Fus3/Kss1-MAP kinase and Ste12-like control distinct biocontrol-traits besides regulation of insect cuticle penetration via phosphorylation cascade in a filamentous fungal pathogen. PEST MANAGEMENT SCIENCE 2023; 79:2611-2624. [PMID: 36890107 DOI: 10.1002/ps.7446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/22/2022] [Accepted: 03/08/2023] [Indexed: 06/02/2023]
Abstract
BACKGROUND Homolog of the yeast Fus3/Kss1 mitogen-activated protein kinase (MAPK) pathway and its target transcription factor, Ste12-like, are involved in penetration of host cuticle/pathogenicity in many ascomycete pathogens. However, details of their interaction during fungal infection, as well as their controlled other virulence-associated traits, are unclear. RESULTS Ste12-like (BbSte12) and Fus3/Kss1 MAPK homolog (Bbmpk1) interacted in nucleus, and phosphorylation of BbSte12 by Bbmpk1 was essential for penetration of insect cuticle in an insect fungal pathogen, Beauveria bassiana. However, some distinct biocontrol-traits were found to be mediated by Ste12 and Bbmpk1. In contrast to ΔBbmpk1 colony that grew more rapid than wild-type strain, inactivation of BbSte12 resulted in the opposite phenotype, which was consistent with their different proliferation rates in insect hemocoel after direct injection of conidia bypass the cuticle. Reduced conidial yield with decreased hydrophobicity was examined in both mutants, however they displayed distinct conidiogenesis, accompanying with differently altered cell cycle, distinct hyphal branching and septum formation. Moreover, ΔBbmpk1 showed increased tolerance to oxidative agent, whereas the opposite phenotype was seen for ΔBbSte12 strain. RNA sequencing analysis revealed that Bbmpk1 controlled 356 genes depending on BbSte12 during cuticle penetration, but 1077 and 584 genes were independently controlled by Bbmpk1 and BbSte12. CONCLUSION BbSte12 and Bbmpk1 separately participate in additional pathways for control of conidiation, growth and hyphal differentiation, as well as oxidative stress response besides regulating cuticle penetration via phosphorylation cascade. © 2023 Society of Chemical Industry.
Collapse
Affiliation(s)
- Xin Zhao
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Yahui Jiang
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Huifang Wang
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Zhuoyue Lu
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Shuaishuai Huang
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Zhibing Luo
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Liuyi Zhang
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Ting Lv
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Xiaohan Tang
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| | - Yongjun Zhang
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, P. R. China
| |
Collapse
|
8
|
Yue Y, Deng J, Wang H, Lv T, Dou W, Jiao Y, Peng X, Zhang Y. Two Secretory T2 RNases Act as Cytotoxic Factors Contributing to the Virulence of an Insect Fungal Pathogen. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:7069-7081. [PMID: 37122240 DOI: 10.1021/acs.jafc.3c01617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
RNase T2 members are secreted by several pathogens or parasites during infection, playing various roles in pathogen-host interaction. However, functions of those members in biocontrol microbes targeting their hosts are still unknown. Here, we report that an insect fungal pathogen, Beauveria bassiana, produces two secretory RNase T2 members that act as cytotoxic factors, which were examined by insect bioassays using the targeted gene(s) disruption and overexpression strains. Overexpression strains displayed dramatically increased virulence, which was concurrent with few fungal cells and hemocytes in hemocoel, suggesting a cytotoxicity of the overexpressed gene products. In vitro assays using yeast-expressed proteins verified the cytotoxicity of the two members against insect cells, to which the cytotoxic effect was dependent on their RNases enzyme activities and glycosylation modification. Moreover, the excessive humoral immune responses triggered by the two ribonucleases were examined. These results suggested prospects of these two T2 ribonucleases for improvement of biocontrol agents.
Collapse
Affiliation(s)
- Yong Yue
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Biotechnology Research Center, Southwest University, Chongqing 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Southwest University, Chongqing 400715, People's Republic of China
| | - Juan Deng
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Biotechnology Research Center, Southwest University, Chongqing 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Southwest University, Chongqing 400715, People's Republic of China
| | - Huifang Wang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Biotechnology Research Center, Southwest University, Chongqing 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Southwest University, Chongqing 400715, People's Republic of China
| | - Ting Lv
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Biotechnology Research Center, Southwest University, Chongqing 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Southwest University, Chongqing 400715, People's Republic of China
| | - Wei Dou
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Biotechnology Research Center, Southwest University, Chongqing 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Southwest University, Chongqing 400715, People's Republic of China
| | - Yufei Jiao
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Biotechnology Research Center, Southwest University, Chongqing 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Southwest University, Chongqing 400715, People's Republic of China
| | - Xinxin Peng
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Biotechnology Research Center, Southwest University, Chongqing 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Southwest University, Chongqing 400715, People's Republic of China
| | - Yongjun Zhang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River (Ministry of Education), Biotechnology Research Center, Southwest University, Chongqing 400715, People's Republic of China
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Southwest University, Chongqing 400715, People's Republic of China
| |
Collapse
|
9
|
Deng J, Lu Z, Wang H, Li N, Song G, Zhu Q, Sun J, Zhang Y. A secretory phospholipase A2 of a fungal pathogen contributes to lipid droplet homeostasis, assimilation of insect-derived lipids, and repression of host immune responses. INSECT SCIENCE 2022; 29:1685-1702. [PMID: 35276754 DOI: 10.1111/1744-7917.13029] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
Secretory phospholipase A2s (sPLA2s) are found in a wide range of organisms from bacteria to higher plants and animals and are involved in varied and cellular processes. However, roles of these enzymes in microbial pathogens remain unclear. Here, an sPLA2 (BbPLA2) was characterized in the filamentous insect pathogenic fungus, Beauveria bassiana. BbPLA2 was exclusively expressed in insect hemolymph-derived cells (hyphal bodies), and its expression was induced by insect-derived nutrients and lipids, and nutrient starvation. High levels of secretion of BbPLA2 were observed as well as its distribution in hyphal body lipid drops (LDs). Overexpression of BbPLA2 increased the ability of B. bassiana to utilize insect-derived nutrients and lipids, and promoted LD accumulation, indicating functions for BbPLA2 in mediating LD homeostasis and assimilation of insect-derived lipids. Strains overexpressing BbPLA2 showed moderately increased virulence, including more efficient penetration of the insect cuticle and evasion of host immune responses as compared to the wild type strain. In addition, B. bassiana-activated host immune genes were downregulated in the BbPLA2 overexpression strain, but upregulated by infections with a ΔBbPLA2 strain. These data demonstrate that BbPLA2 contributes to LD homeostasis, assimilation of insect-derived lipids, and repression of host immune responses.
Collapse
Affiliation(s)
- Juan Deng
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Zhuoyue Lu
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Huifang Wang
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Ning Li
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Guimei Song
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Qiankuan Zhu
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- College of Plant Protection, Southwest University, Chongqing, China
| | - Jingxin Sun
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Yongjun Zhang
- Biotechnology Research Center, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- College of Plant Protection, Southwest University, Chongqing, China
| |
Collapse
|
10
|
Bautista‐Guerrero A, Lara‐Diaz RA, Pihen V, Bandala ER, Sanchez‐Sala JL. Isolation and test of novel yeast strains with lignin usage capability and phenolic compound resistance. Microbiologyopen 2022; 11:e1326. [PMID: 36314751 PMCID: PMC9562823 DOI: 10.1002/mbo3.1326] [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] [Received: 06/01/2022] [Accepted: 10/01/2022] [Indexed: 11/06/2022] Open
Abstract
Five yeast fungi strains (i.e., two Cryptococcus albidus, one Candida guillermondii, and two Candida tropicalis) were isolated from sugarcane and tested for their use of lignin as sole carbon source and their potential to grow in the presence of phenol and phenol derivatives (i.e., pentachlorophenol and p‐nitrophenol). The full set of isolated yeasts showed ligninolytic activity, achieving at least 36% lignin degradation after 25 days. The C. albidus JS‐B1 strain had the highest ligninolytic activity, achieving 27% lignin degradation within 4 days. This increased activity was associated with the production of ligninolytic laccase enzymes. All the tested yeast fungi strains showed growth in the presence of high concentrations of phenolic compounds (i.e., 900 mg/L phenol, 200 mg/L p‐nitrophenol, 50 mg/L pentachlorophenol) and showed significant potential for lignin and lignin by‐product degradation. Each of these five strains has the potential to be used in biological treatment processes for contaminated effluents from paper pulping and bleaching or phenol and phenol‐derivative biodegradation processes for other industrial wastewater effluents.
Collapse
Affiliation(s)
- Anaid Bautista‐Guerrero
- Department of Civil and Environmental Engineering, Engineering SchoolUniversidad de las Americas PueblaPueblaMexico
| | - Rene A. Lara‐Diaz
- Department of Chemistry and Food Engineering, Engineering SchoolUniversidad de las Americas PueblaPueblaMexico
| | - Valérie Pihen
- Department of Civil and Environmental Engineering, Engineering SchoolUniversidad de las Americas PueblaPueblaMexico
| | - Erick R. Bandala
- Division of Hydrologic SciencesDesert Research InstituteLas VegasNevadaUSA
| | - Jose Luis Sanchez‐Sala
- Department of Chemistry and Biological Sciences, Sciences SchoolUniversidad de las Americas PueblaPueblaMexico
| |
Collapse
|
11
|
Abstract
The entomopathogenic fungus Beauveria bassiana is a typical filamentous fungus and has been used for pest biocontrol. Conidia are the main active agents of fungal pesticides; however, we know little about conidial developmental mechanisms and less about maturation mechanisms. We found that a Zn2Cys6 transcription factor of B. bassiana (named BbCmr1) was mainly expressed in late-stage conidia and was involved in conidium maturation regulation. Deletion of Bbcmr1 impaired the conidial cell wall and resulted in a lower conidial germination rate under UV (UV), heat shock, H2O2, Congo red (CR) and SDS stresses compared to the wild type. Transcription levels of the genes associated with conidial wall components and trehalose synthase were significantly reduced in the ΔBbcmr1 mutant. Further analysis found that BbCmr1 functions by upregulating BbWetA, a well-known transcription factor in the central development of BrlA-AbaA-WetA. The expression of Bbcmr1 was positively regulated by BbBrlA. These results indicated that BbCmr1 played important roles in conidium maturation by interacting with the central development pathway, which provided insight into the conidial development networks in B. bassiana. IMPORTANCE Conidium maturation is a pivotal event in conidial development and affects fungal survival ability under various biotic/abiotic stresses. Although many transcription factors have been reported to regulate conidial development, we know little about the molecular mechanism of conidium maturation. Here, we demonstrated that the transcription factor BbCmr1 of B. bassiana was involved in conidium maturation, regulating cell wall structure, the expression of cell wall-related proteins, and trehalose synthesis. BbCmr1 orchestrated conidium maturation by interplaying with the central development pathway BrlA-AbaA-WetA. BbBrlA positively regulated the expression of Bbcmr1, and the latter positively regulated BbwetA expression, which forms a regulatory network mediating conidial development. This finding was critical to understand the molecular regulatory networks of conidial development in B. bassiana and provided avenues to engineer insect fungal pathogens with high-quality conidia.
Collapse
|
12
|
Ding JL, Hou J, Feng MG, Ying SH. Transcriptomic analyses reveal comprehensive responses of insect hemocytes to mycopathogen Beauveria bassiana, and fungal virulence-related cell wall protein assists pathogen to evade host cellular defense. Virulence 2021; 11:1352-1365. [PMID: 33017218 PMCID: PMC7549920 DOI: 10.1080/21505594.2020.1827886] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Entomopathogenic fungi naturally infect insect hosts in environment. Fungal invasion and host immune defense are still in the progress of co-evolution. In this study, entomopathogenic fungus Beauveria bassiana and lepidopteran insect Galleria mellonella were used to investigate host cellular immunity and fungal strategy to evade host defense. First of all, genome-wide expression revealed the transcriptomic responses of hemocytes to insect mycopathogen, which dynamically varied during infection process. Enrichment analysis indicated that differentially expressed genes were primarily involved in metabolism, cellular process and immune system. Notably, cellular response involved a series of hydrolytic enzyme and antimicrobial peptide genes which were sorted together in clustering analysis. In B. bassiana, a cell-wall protein gene (BbCwp) contributes to fungal development in host hemocoel and virulence. RT-qPCR analyses indicated that infection by ΔBbCwp mutant strain caused the up-regulated expression of a series of immunity-related genes, including β-1, 3-glucan recognition protein, hydrolytic enzyme and antimicrobial peptide genes. Disruption of BbCwp resulted in a significant change in conidial lectin-binding feature and the enhanced encapsulation by the host hemocytes. After being treated with hydrolytic enzymes, ΔBbCwp mutant displayed a significantly enhanced sensitivity to osmotic and oxidative stresses. In conclusion, fungal invasion initiates comprehensive physiological responses in the host hemocytes. For mycopathogen, cell-wall protein plays an important role in fungal evasion of immunity defense and colonization in host. Our studies provide an initial framework for exploring more mechanistic details about the fungus–host interaction.
Collapse
Affiliation(s)
- Jin-Li Ding
- Institute of Microbiology, College of Life Sciences, Zhejiang University , Hangzhou, China
| | - Jia Hou
- Institute of Microbiology, College of Life Sciences, Zhejiang University , Hangzhou, China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University , Hangzhou, China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University , Hangzhou, China
| |
Collapse
|
13
|
Qin X, Zhao X, Huang S, Deng J, Li X, Luo Z, Zhang Y. Pest management via endophytic colonization of tobacco seedlings by the insect fungal pathogen Beauveria bassiana. PEST MANAGEMENT SCIENCE 2021; 77:2007-2018. [PMID: 33342046 DOI: 10.1002/ps.6229] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/19/2020] [Accepted: 12/20/2020] [Indexed: 05/23/2023]
Abstract
BACKGROUND It has been suggested that entomopathogenic fungi can be introduced into plants as endophytes potentially leading to insect control. Here, we sought to identify specific strains of the insect pathogenic fungus, Beauveria bassiana that would form endophytic associations with tobacco (Nicotiana benthamiana) benefitting host plant growth and/or resistance against insect pests and pathogens. RESULTS Tobacco seeds were inoculated with six different B. bassiana strains and entophytic colonization, plant growth, and resistance to pathogens and insect pests were evaluated over a 50 day-period. Although all the strains could colonize seedlings, 90% seedling colonization was seen for four strains. Fungal cells could be detected in stems more readily than in leaf and root tissues. Colonization by B. bassiana boosted plant growth with an increased photosynthetic rate, chlorophyll content, and stomatal and trichome density seen in fungal treated plants. Tobacco seedlings colonized by specific B. bassiana strains displayed significantly increased tolerance/resistance against bacterial and fungal pathogens. B. bassiana-colonized seedlings also displayed higher resistance to aphids (Myzus persicae) as compared to untreated controls. Colonization by B. bassiana was shown to trigger both of the salicylic acid (SA) and jasmonate acid (JA) defense pathways, but SA pathway was upregulated much more than JA pathway for some of the tested strains. CONCLUSION Specific strains of B. bassiana can be introduced into host plants as endophytes, resulting in promotion of host plant growth, increased resistance to microbial pathogens, and/or increased resistance to insect pests. © 2020 Society of Chemical Industry.
Collapse
Affiliation(s)
- Xu Qin
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, P. R. China
| | - Xin Zhao
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, P. R. China
| | - Shuaishuai Huang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, P. R. China
| | - Juan Deng
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, P. R. China
| | - Xuebing Li
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, P. R. China
| | - Zhibing Luo
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, P. R. China
| | - Yongjun Zhang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, P. R. China
| |
Collapse
|
14
|
Mascarin GM, Iwanicki NS, Ramirez JL, Delalibera Í, Dunlap CA. Transcriptional Responses of Beauveria bassiana Blastospores Cultured Under Varying Glucose Concentrations. Front Cell Infect Microbiol 2021; 11:644372. [PMID: 33842391 PMCID: PMC8024584 DOI: 10.3389/fcimb.2021.644372] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/09/2021] [Indexed: 11/17/2022] Open
Abstract
Culturing the entomopathogenic fungus, Beauveria bassiana, under high glucose concentrations coupled with high aeration results in a fungal developmental shift from hyphal growth to mostly blastospores (yeast-like cells). The underlying molecular mechanisms involved in this shift remain elusive. A systematic transcriptome analysis of the differential gene expression was preformed to uncover the fungal transcriptomic response to osmotic and oxidative stresses associated with the resulting high blastospore yield. Differential gene expression was compared under moderate (10% w/v) and high (20% w/v) glucose concentrations daily for three days. The RNAseq-based transcriptomic results depicted a higher proportion of downregulated genes when the fungus was grown under 20% glucose than 10%. Additional experiments explored a broader glucose range (4, 8, 12, 16, 20% w/v) with phenotype assessment and qRT-PCR transcript abundance measurements of selected genes. Antioxidant, calcium transport, conidiation, and osmosensor-related genes were highly upregulated in higher glucose titers (16-20%) compared to growth in lower glucose (4-6%) concentrations. The class 1 hydrophobin gene (Hyd1) was highly expressed throughout the culturing. Hyd1 is known to be involved in spore coat rodlet layer assembly, and indicates that blastospores or another cell type containing hydrophobin 1 is expressed in the haemocoel during the infection process. Furthermore, we found implications of the HOG signaling pathway with upregulation of homologous genes Ssk2 and Hog1 for all fermentation time points under hyperosmotic medium (20% glucose). These findings expand our knowledge of the molecular mechanisms behind blastospore development and may help facilitate large-scale industrial production of B. bassiana blastospores for pest control applications.
Collapse
Affiliation(s)
- Gabriel Moura Mascarin
- Laboratory of Environmental Microbiology, Brazilian Agricultural Research Corporation, Embrapa Environment, Jaguariúna, Brazil
| | - Natasha Sant'Anna Iwanicki
- Department of Entomology and Acarology, "Luiz de Queiroz" College of Agriculture/University of São Paulo (ESALQ/USP), Piracicaba, Brazil
| | - Jose Luis Ramirez
- Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agriculture Research Service, Peoria, IL, United States
| | - Ítalo Delalibera
- Department of Entomology and Acarology, "Luiz de Queiroz" College of Agriculture/University of São Paulo (ESALQ/USP), Piracicaba, Brazil
| | - Christopher A Dunlap
- Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, United States Department of Agriculture, Agriculture Research Service, Peoria, IL, United States
| |
Collapse
|
15
|
Zhao X, Luo T, Huang S, Peng N, Yin Y, Luo Z, Zhang Y. A novel transcription factor negatively regulates antioxidant response, cell wall integrity and virulence in the fungal insect pathogen, Beauveria bassiana. Environ Microbiol 2021; 23:4908-4924. [PMID: 33432709 DOI: 10.1111/1462-2920.15397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 01/01/2023]
Abstract
Genomic data have identified a class of fungal specific transcription factors (FsTFs) that are thought to regulate unique aspects of fungal gene expression, although the functions of many of these proteins remain unknown. Here, a novel FsTF (BbStf1), which features a leucine zipper dimerization domain and a fungal transcription factor regulatory middle homology region, was characterized in Beauveria bassiana, a filamentous insect fungal pathogen. Transcriptional activation and nuclear localization were experimentally confirmed for BbStf1. Disruption of Bbstf1 resulted in increased tolerance to oxidative stress and cell wall perturbation, accompanied by increased peroxidase (POD) and superoxide dismutase (SOD) activities and ratio of reduced/oxidized glutathione (GSH/GSSG), and by thickened cell wall and altered composition. Gene expression profile analysis revealed that transcription patterns of antioxidant enzyme and cell wall integrity-involved genes were altered in the ∆Bbstf1, including some BbStf1-targeted genes clarified with evidence. The ∆Bbstf1 strain displayed greater virulence to Galleria mellonella in the bioassays through both topical infection and intrahaemocoel injection due to more rapid proliferation in the haemocoel as compared to the wild-type strain. Altogether, BbStf1 acts as a negative regulator of antioxidant response, cell wall integrity and virulence in B. bassiana.
Collapse
Affiliation(s)
- Xin Zhao
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, 400715, People's Republic of China
| | - Tingying Luo
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, 400715, People's Republic of China
| | - Shuaishuai Huang
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, 400715, People's Republic of China
| | - Ning Peng
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, 400715, People's Republic of China
| | - Ying Yin
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, 400715, People's Republic of China
| | - Zhibing Luo
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, 400715, People's Republic of China
| | - Yongjun Zhang
- Academy of Agricultural Sciences, Biotechnology Research Center, Southwest University, Chongqing, 400715, People's Republic of China
| |
Collapse
|
16
|
Lu Z, Deng J, Wang H, Zhao X, Luo Z, Yu C, Zhang Y. Multifunctional role of a fungal pathogen-secreted laccase 2 in evasion of insect immune defense. Environ Microbiol 2021; 23:1256-1274. [PMID: 33393158 DOI: 10.1111/1462-2920.15378] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/25/2020] [Accepted: 12/26/2020] [Indexed: 11/29/2022]
Abstract
Laccases are widely present in bacteria, fungi, plants and invertebrates and involved in a variety of physiological functions. Here, we report that Beauveria bassiana, an economic important entomopathogenic fungus, secretes a laccase 2 (BbLac2) during infection that detoxifies insect immune response-generated reactive oxygen species (ROS) and interferes with host immune phenoloxidase (PO) activation. BbLac2 is expressed in fungal cells during proliferation in the insect haemocoel and can be found to distribute on the surface of haemolymph-derived in vivo fungal hyphal bodies or be secreted. Targeted gene-knockout of BbLac2 increased fungal sensitivity to oxidative stress, decreased virulence to insect, and increased host PO activity. Strains overexpressing BbLac2 showed increased virulence, with reduced host PO activity and lowered ROS levels in infected insects. In vitro assays revealed that BbLac2 could eliminate ROS and oxidize PO substrates (phenols), verifying the enzymatic functioning of the protein in detoxification of cytotoxic ROS and interference with the PO cascade. Moreover, BbLac2 acted as a cell surface protein that masked pathogen associated molecular patterns (PAMPs), enabling the pathogen to evade immune recognition. Our data suggest a multifunctional role for fungal pathogen-secreted laccase 2 in evasion of insect immune defenses.
Collapse
Affiliation(s)
- Zhuoyue Lu
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, 400715, P. R. China
| | - Juan Deng
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, 400715, P. R. China
| | - Huifang Wang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, 400715, P. R. China
| | - Xin Zhao
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, 400715, P. R. China
| | - Zhibing Luo
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, 400715, P. R. China
| | - Chenxi Yu
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, 400715, P. R. China
| | - Yongjun Zhang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Southwest University, Chongqing, 400715, P. R. China
| |
Collapse
|
17
|
Huang A, Lu M, Ling E, Li P, Wang C. A M35 family metalloprotease is required for fungal virulence against insects by inactivating host prophenoloxidases and beyond. Virulence 2021; 11:222-237. [PMID: 32079481 PMCID: PMC7051145 DOI: 10.1080/21505594.2020.1731126] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
A diverse family of metalloproteases (MPs) is distributed in eukaryotes. However, the functions of MPs are still understudied. We report that seven MPs belonging to the M35 family are encoded in the genome of the insect pathogenic fungus Metarhizium robertsii. By gene deletions and insect bioassays, we found that one of the M35-family MPs, i.e. MrM35-4, is required for fungal virulence against insect hosts. MrM35-4 is a secretable enzyme and shows a proteolytic activity implicated in facilitating fungal penetration of insect cuticles. After gene rescue and overexpression, insect bioassays indicated that MrM35-4 contributes to inhibiting insect cuticular and hemocyte melanization activities. Enzymatic cleavage assays revealed that the recombinant prophenoloxidases PPO1 and PPO2 of Drosophila melanogaster could be clipped by MrM35-4 in a manner differing from a serine protease that can activate PPO activities. In addition, it was found that MrM35-4 is involved in suppressing antifungal gene expression in insects. Consistent with the evident apoptogenic effect of MrM35-4 on host cells, we found that the PPO mutant flies differentially succumbed to the infections of the wild-type and mutant strains of M. robertsii. Thus, MrM35-4 plays a multifaceted role beyond targeting PPOs during fungus-insect interactions, which represents a previously unsuspected strategy employed by Metarhizium to outmaneuver insect immune defenses.
Collapse
Affiliation(s)
- Antian Huang
- School of Life Science and Technology, Tongji University, Shanghai, China.,CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Mengting Lu
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Erjun Ling
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ping Li
- School of Life Science and Technology, Tongji University, Shanghai, China
| | - Chengshu Wang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China.,CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| |
Collapse
|
18
|
Xiao G, Tang G, Wang C. Congruence Amidst Discordance between Sequence and Protein-Content Based Phylogenies of Fungi. J Fungi (Basel) 2020; 6:jof6030134. [PMID: 32823730 PMCID: PMC7559059 DOI: 10.3390/jof6030134] [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] [Received: 07/19/2020] [Revised: 08/05/2020] [Accepted: 08/11/2020] [Indexed: 11/16/2022] Open
Abstract
Amid the genomic data explosion, phylogenomic analysis has resolved the tree of life of different organisms, including fungi. Genome-wide clustering has also been conducted based on gene content data that can lighten the issue of the unequal evolutionary rate of genes. In this study, using different fungal species as models, we performed phylogenomic and protein-content (PC)-based clustering analysis. The obtained sequence tree reflects the phylogenetic trajectory of examined fungal species. However, 15 PC-based trees constructed from the Pfam matrices of the whole genomes, four protein families, and ten subcellular locations largely failed to resolve the speciation relationship of cross-phylum fungal species. However, lifestyle and taxonomic associations were more or less evident between closely related fungal species from PC-based trees. Pairwise congruence tests indicated that a varied level of congruent or discordant relationships were observed between sequence- and PC-based trees, and among PC-based trees. It was intriguing to find that a few protein family and subcellular PC-based trees were more topologically similar to the phylogenomic tree than was the whole genome PC-based phylogeny. In particular, a most significant level of congruence was observed between sequence- and cell wall PC-based trees. Cophylogenetic analysis conducted in this study may benefit the prediction of the magnitude of evolutionary conservation, interactive associations, or networking between different family or subcellular proteins.
Collapse
Affiliation(s)
- Guohua Xiao
- School of Computer Science, Fudan University, Shanghai 200433, China;
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China;
| | - Guirong Tang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China;
| | - Chengshu Wang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China;
- CAS Center for Excellence in Biotic interactions, University of Chinese Academy of Sciences, Beijing 100049, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Correspondence:
| |
Collapse
|
19
|
Brivio MF, Mastore M. When Appearance Misleads: The Role of the Entomopathogen Surface in the Relationship with Its Host. INSECTS 2020; 11:E387. [PMID: 32585858 PMCID: PMC7348879 DOI: 10.3390/insects11060387] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/18/2020] [Accepted: 06/20/2020] [Indexed: 12/14/2022]
Abstract
Currently, potentially harmful insects are controlled mainly by chemical synthetic insecticides, but environmental emergencies strongly require less invasive control techniques. The use of biological insecticides in the form of entomopathogenic organisms is undoubtedly a fundamental resource for the biological control of insect pests in the future. These infectious agents and endogenous parasites generally act by profoundly altering the host's physiology to death, but their success is closely related to the neutralization of the target insect's immune response. In general, entomopathogen parasites, entomopathogenic bacteria, and fungi can counteract immune processes through the effects of secretion/excretion products that interfere with and damage the cells and molecules typical of innate immunity. However, these effects are observed in the later stages of infection, whereas the risk of being recognized and neutralized occurs very early after penetration and involves the pathogen surface components and molecular architecture; therefore, their role becomes crucial, particularly in the earliest pathogenesis. In this review, we analyze the evasion/interference strategies that entomopathogens such as the bacterium Bacillus thuringiensis, fungi, nematocomplexes, and wasps implement in the initial stages of infection, i.e., the phases during which body or cell surfaces play a key role in the interaction with the host receptors responsible for the immunological discrimination between self and non-self. In this regard, these organisms demonstrate evasive abilities ascribed to their body surface and cell wall; it appears that the key process of these mechanisms is the capability to modify the surface, converting it into an immunocompatible structure, or interaction that is more or less specific to host factors.
Collapse
Affiliation(s)
- Maurizio Francesco Brivio
- Laboratory of Comparative Immunology and Parasitology, Department of Theoretical and Applied Sciences, University of Insubria, 21100 Varese, Italy;
| | | |
Collapse
|
20
|
Zhao X, Yang X, Lu Z, Wang H, He Z, Zhou G, Luo Z, Zhang Y. MADS-box transcription factor Mcm1 controls cell cycle, fungal development, cell integrity and virulence in the filamentous insect pathogenic fungus Beauveria bassiana. Environ Microbiol 2019; 21:3392-3416. [PMID: 30972885 DOI: 10.1111/1462-2920.14629] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 04/09/2019] [Indexed: 12/15/2022]
Abstract
MADS-box transcription factor Mcm1 plays crucial roles in regulating mating processes and pathogenesis in some fungi. However, its roles are varied in fungal species, and its function remains unclear in entomopathogenic fungi. Here, Mcm1 orthologue, Bbmcm1, was characterized in a filamentous entomopathogenic fungus, Beauveria bassiana. Disruption of Bbmcm1 resulted in a distinct reduction in growth with abnormal conidiogenesis, and a significant decrease in conidial viability with abnormal germination. ΔBbmcm1 displayed impaired cell integrity, with distorted cell wall structure and altered cell wall component. Abnormal cell cycle was detected in ΔBbmcm1 with longer G2 /M phase but shorter G1 /G0 and S phases in unicellular blastospores, and sparser septa in multicellular hyphae, which might be responsible for defects in development and differentiation due to the regulation of cell cycle-involved genes, as well as the corresponding cellular events-associated genes. Dramatically decreased virulence was examined in ΔBbmcm1, with impaired ability to escape haemocyte encapsulation, which was consistent with markedly reduced cuticle-degrading enzyme production by repressing their coding genes, and downregulated fungal effector protein-coding genes, suggesting a novel role of Mcm1 in interaction with host insect. These data indicate that Mcm1 is a crucial regulator of development, cell integrity, cell cycle and virulence in insect fungal pathogens.
Collapse
Affiliation(s)
- Xin Zhao
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, People's Republic of China
| | - Xingju Yang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, People's Republic of China
| | - Zhuoyue Lu
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, People's Republic of China
| | - Huifang Wang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, People's Republic of China
| | - Zhangjiang He
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, People's Republic of China
| | - Guangyan Zhou
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, People's Republic of China
| | - Zhibing Luo
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, People's Republic of China
| | - Yongjun Zhang
- Biotechnology Research Center, State Cultivation Base of Crop Stress Biology for Southern Mountainous Land of Southwest University, Academy of Agricultural Sciences, Southwest University, Chongqing, 400715, People's Republic of China
| |
Collapse
|
21
|
Wang H, He Z, Luo L, Zhao X, Lu Z, Luo T, Li M, Zhang Y. An aldo-keto reductase, Bbakr1, is involved in stress response and detoxification of heavy metal chromium but not required for virulence in the insect fungal pathogen, Beauveria bassiana. Fungal Genet Biol 2018; 111:7-15. [DOI: 10.1016/j.fgb.2018.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 12/28/2017] [Accepted: 01/02/2018] [Indexed: 01/28/2023]
|
22
|
He Z, Zhao X, Lu Z, Wang H, Liu P, Zeng F, Zhang Y. Comparative transcriptome and gene co-expression network analysis reveal genes and signaling pathways adaptively responsive to varied adverse stresses in the insect fungal pathogen, Beauveria bassiana. J Invertebr Pathol 2018; 151:169-181. [DOI: 10.1016/j.jip.2017.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/07/2017] [Accepted: 12/15/2017] [Indexed: 11/27/2022]
|
23
|
Cen K, Li B, Lu Y, Zhang S, Wang C. Divergent LysM effectors contribute to the virulence of Beauveria bassiana by evasion of insect immune defenses. PLoS Pathog 2017; 13:e1006604. [PMID: 28873459 PMCID: PMC5600412 DOI: 10.1371/journal.ppat.1006604] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/15/2017] [Accepted: 08/24/2017] [Indexed: 12/29/2022] Open
Abstract
The lysin motif (LysM) containing proteins can bind chitin and are ubiquitous in various organisms including fungi. In plant pathogenic fungi, a few LysM proteins have been characterized as effectors to suppress chitin-induced immunity in plant hosts and therefore contribute to fungal virulence. The effector mechanism is still questioned in fungus-animal interactions. In this study, we found that LysM proteins are also present in animal pathogenic fungi and have evolved divergently. The genome of the insect pathogen Beauveria bassiana encodes 12 LysM proteins, and the genes were differentially transcribed by the fungus when grown in different conditions. Deletion of six genes that were expressed by the fungus growing in insects revealed that two, Blys2 and Blys5, were required for full fungal virulence. Both proteins could bind chitin and Blys5 (containing two LysM domains) could additionally bind chitosan and cellulose. Truncation analysis of Blys2 (containing five LysM domains) indicated that the combination of LysM domains could determine protein-binding affinity and specificity for different carbohydrates. Relative to the wild-type strain, loss of Blys2 or Blys5 could impair fungal propagation in insect hemocoels and lead to the upregulation of antifungal gene in insects. Interestingly, the virulence defects of ΔBlys2 and ΔBlys5 could be fully restored by complementation with the Slp1 effector from the rice blast fungus Magnaporthe oryzae. In contrast to Slp1 and Blys2, Blys5 could potentially protect fungal hyphae against chitinase hydrolysis. The results of this study not only advance the understanding of LysM protein evolution but also establish the effector mechanism of fungus-animal interactions. Insect pathogenic fungi are of importance for both applied and basic research. Relative to the advances in understanding fungus-plant interactions, the mechanisms of the molecular pathogenesis of entomopathogenic fungi are rather limitedly understood. In particular, the machinery of effector-mediated inhibition of host immunity has not been well established in fungus-insect interactions. LysM effectors have been characterized as virulence factors in plant pathogens to suppress chitin-triggered immunity in plants. We found that the divergent LysM proteins are also present in animal pathogens. By using the insect pathogen Beauveria bassiana as a model, we revealed that two of 12 encoded LysM protein genes Blys2 and Blys5 that were transcribed by the fungus growing in insects are required for full fungal virulence against insect hosts. Interestingly, the virulence defects of ΔBys2 and ΔBys5 could be fully restored by complementation with the divergent Slp1 effector from the plant pathogen Magnaporthe oryzae. Both Blys2 and Blys5 can deregulate insect immune responses, and the latter can additionally protect fungal cells from chitinase hydrolysis. The findings of this study establish the contribution of LysM effectors to fungal virulence against insect hosts.
Collapse
Affiliation(s)
- Kai Cen
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Bing Li
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yuzhen Lu
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Siwei Zhang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Chengshu Wang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
| |
Collapse
|