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Li F, Zhang J, Zhong H, Yu K, Chen J. Comprehensive Insights into the Remarkable Function and Regulatory Mechanism of FluG during Asexual Development in Beauveria bassiana. Int J Mol Sci 2024; 25:6261. [PMID: 38892450 PMCID: PMC11173134 DOI: 10.3390/ijms25116261] [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: 04/29/2024] [Revised: 05/24/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
Asexual development is the main propagation and transmission mode of Beauveria bassiana and the basis of its pathogenicity. The regulation mechanism of conidiation and the key gene resources for utilization are key links to improving the conidia yield and quality of Beauveria bassiana. Their clarification may promote the industrialization of fungal pesticides. Here, we compared the regulation of morphology, resistance to external stress, virulence, and nutrient utilization capacity between the upstream developmental regulatory gene fluG and the key genes brlA, abaA, and wetA in the central growth and development pathway. The results showed that the ΔbrlA and ΔabaA mutants completely lost the capacity to conidiate and that the ΔwetA mutant had seriously reduced conidiation capacity. Although the deletion of fluG did not reduce the conidiation ability as much as deletions of brlA, abaA, and wetA, it significantly reduced the fungal response to external stress, virulence, and nutrient utilization, while the deletion of the three other genes had little effect. Via transcriptome analysis and screening the yeast nuclear system library, we found that the differentially expressed genes in the ΔfluG mutants were concentrated in the signaling pathways of ABC transporters, propionate metabolism, tryptophan metabolism, DNA replication, mismatch repair, and fatty acid metabolism. FluG directly acted on 40 proteins that were involved in various signaling pathways such as metabolism, oxidative stress, and cell homeostasis. The analysis indicated that the regulatory function of fluG was mainly involved in DNA replication, cell homeostasis, fungal growth and metabolism, and the response to external stress. Our results revealed the biological function of fluG in asexual development and the responses to several environmental stresses as well as its influence on the asexual development regulatory network in B. bassiana.
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Affiliation(s)
| | - Juefeng Zhang
- Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (F.L.); (H.Z.); (K.Y.)
| | | | | | - Jianming Chen
- Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (F.L.); (H.Z.); (K.Y.)
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2
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He R, Wei P, Odiba AS, Gao L, Usman S, Gong X, Wang B, Wang L, Jin C, Lu G, Fang W. Amino sugars influence Aspergillus fumigatus cell wall polysaccharide biosynthesis, and biofilm formation through interfering galactosaminogalactan deacetylation. Carbohydr Polym 2024; 324:121511. [PMID: 37985096 DOI: 10.1016/j.carbpol.2023.121511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 11/22/2023]
Abstract
Aspergillus fumigatus is a ubiquitous fungal pathogen responsible for a significant number of deaths annually due to invasive aspergillosis infection. While the utilization of diverse carbon sources, including amino sugars, has been explored in other fungi, its impact on A. fumigatus remains uncharted territory. In this study, we investigated A. fumigatus responses to glucose (Glc), glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) as carbon sources. GlcN inhibited growth, reduced sporulation and delayed germination, while GlcNAc had no such effects. Both amino sugars induced alterations in cell wall composition, leading to a reduction in glucan and galactomannan levels while increasing chitin and mannan content, rendering A. fumigatus susceptible to cell wall stress and osmotic stress. GlcN repressed biofilm formation via downregulation of galactosaminogalactan (GAG) cluster genes, notably agd3, which encodes a GAG-specific deacetylase. Moreover, GlcN increased biofilm susceptibility to echinocandins, suggesting its potential for enhancing the effectiveness of antifungal treatments. This study sheds light on the multifaceted effects of amino sugars on A. fumigatus, encompassing growth, cell wall biosynthesis, and biofilm formation, offering promising avenues for innovative aspergillosis treatment strategies.
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Affiliation(s)
- Rui He
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China; Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Pingzhen Wei
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Arome Solomon Odiba
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Linlu Gao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Sayed Usman
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China; Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Xiufang Gong
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Bin Wang
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China
| | - Linqi Wang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Cheng Jin
- Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guangtao Lu
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China
| | - Wenxia Fang
- College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China; Institute of Biological Sciences and Technology, Guangxi Academy of Sciences, Nanning, Guangxi, China.
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Hu Y, Yang X, Tai B, Wang G, Zhang X, Yin Y, Xing F. Bacillus amyloliquefaciens A-1 inhibiting fungal spoilage in agricultural products is improved by metabolic engineering of enhancing surfactin yield. Food Res Int 2024; 175:113752. [PMID: 38129052 DOI: 10.1016/j.foodres.2023.113752] [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: 07/25/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023]
Abstract
Fungi and subsequent mycotoxins contamination in agricultural products have caused enormous losses and great harm to human and animal health. Biological control has attracted the attention of researchers due to its advantages, including mild conditions, low cost, high efficiency and low nutrient loss. In this study, a newly isolated strain Bacillus amyloliquefaciens A-1 (A-1), was screened for its ability to inhibit the growth and Aflatoxin B1 (AFB1) production of Aspergillus flavus NRRL 3357. Electron microscopy results revealed that mycelium and conidia of A. flavus were destroyed by A-1, affecting hyphae, cell walls, cell membranes and organelles. RNA-seq analysis indicated disturbance in gene expression profiles of A. flavus, including amino acid degradation and starch and sucrose metabolism pathways. Importantly, the biosynthesis of AFB1 was significantly inhibited by the down-regulation of key regulatory genes, aflR and aflS, and the simultaneous down-regulation of most structural genes. Genome analysis predicted six secondary metabolites biosynthetic gene clusters. Then, four surfactin synthesized by cluster C were identified as the main active substance of A-1 using HPLC-Q-TOF-MS. The addition of alanine, threonine, Fe2+ increased surfactin production. Notably, the overexpression of comX also improved surfactin production. The vivo test results indicated that A-1 could significantly inhibit the decay of pear by Aspergillus westerdijkiae, and the mildew of maize and peanuts. Especially, the overexpression of comX in A-1 could enhance the inhibitory activity. In conclusion, the inhibition mechanism of A-1 was revealed, and comX was found can improve the production of surfactin and subsequent activities, which provides the scientific basis for the development of biocontrol agents to reduce spoilage in agricultural products.
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Affiliation(s)
- Yafan Hu
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Xu Yang
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Bowen Tai
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Gang Wang
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
| | - Xinlong Zhang
- Shandong Xinfurui Agricultural Science and Technology Co., Ltd. Liaocheng 252000, PR China
| | - Yixuan Yin
- Shandong Xinfurui Agricultural Science and Technology Co., Ltd. Liaocheng 252000, PR China
| | - Fuguo Xing
- Key Laboratory of Agro-products Quality and Safety Control in Storage and Transport Process, Ministry of Agriculture and Rural Affairs / Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China.
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Zhang JG, Xu SY, Ying SH, Feng MG. Only one of three hydrophobins (Hyd1-3) contributes to conidial hydrophobicity and insect pathogenicity of Metarhizium robertsii. J Invertebr Pathol 2023; 201:108006. [PMID: 37844657 DOI: 10.1016/j.jip.2023.108006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/22/2023] [Accepted: 10/12/2023] [Indexed: 10/18/2023]
Abstract
Class I/II hydrophobins constitute a family of small amphiphilic proteins that mediate cell hydrophobicity and adhesion to host or substrata and have pleiotropic effects in filamentous fungi. Here we report that only class I Hyd1 is essential for conidial hydrophobicity and insect pathogenicity among three hydrophobins (Hyd1-3) characterized in Metarhizium robertsii, an insect-pathogenic fungus. Aerial conidiation levels of three Δhyd1 mutants were much more reduced in 5-day-old cultures than in 7-day-old cultures, which were wettable (hydrophilic), but restored to a wild-type level in 15-day-old cultures. The Δhyd1 mutants were compromised in conidial quality, including significant decreases in hydrophobicity (58%), adhesion to insect cuticle (36%), insect pathogenicity via normal cuticle infection (37%), UVB resistance (20%), and heat tolerance (10%). In contrast, none of all examined phenotypes were affected in the null mutants of hyd2 and hyd3. Intriguingly, micromorphology and integrity of hydrophobin rodlet bundles on conidial coat were not affected in all mutant and wild-type strains, but the rodlet bundles were disordered in the absence of hyd1, suggesting a link of the disorder to the decreased hydrophobicity. Therefore, Hyd1 mediates the fungal hydrophobicity and plays an important role in conidial quality control and insect-pathogenic lifecycle. Class I Hyd2 and class II Hyd3 seem functionally redundant in M. robertsii.
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Affiliation(s)
- Jin-Guan Zhang
- 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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Bai N, Xie M, Liu Q, Zhu Y, Yang X, Zhang KQ, Yang J. AoMedA has a complex regulatory relationship with AoBrlA, AoAbaA, and AoWetA in conidiation, trap formation, and secondary metabolism in the nematode-trapping fungus Arthrobotrys oligospora. Appl Environ Microbiol 2023; 89:e0098323. [PMID: 37655869 PMCID: PMC10537773 DOI: 10.1128/aem.00983-23] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 07/13/2023] [Indexed: 09/02/2023] Open
Abstract
The asexual sporulation of filamentous fungi is an important mechanism for their reproduction, survival, and pathogenicity. In Aspergillus and several filamentous fungi, BrlA, AbaA, and WetA are the key elements of a central regulatory pathway controlling conidiation, and MedA is a developmental modifier that regulates temporal expression of central regulatory genes; however, their roles are largely unknown in nematode-trapping (NT) fungi. Arthrobotrys oligospora is a representative NT fungus, which can capture nematodes by producing adhesive networks (traps). Here, we characterized the function of AoMedA and three central developmental regulators (AoBrlA, AoAbaA, and AoWetA) in A. oligospora by gene disruption, phenotypic comparison, and multi-omics analyses, as these regulators are required for conidiation and play divergent roles in mycelial development, trap formation, lipid droplet accumulation, vacuole assembly, and secondary metabolism. A combined analysis of phenotypic traits and transcriptome showed that AoMedA and AoWetA are involved in the regulation of peroxisome, endocytosis, and autophagy. Moreover, yeast one-hybrid analysis showed that AoBrlA can regulate AoMedA, AoAbaA, and AoWetA, whereas AoMedA and AoAbaA can regulate AoWetA. Our results highlight the important roles of AoMedA, AoBrlA, AoAbaA, and AoWetA in conidiation, mycelia development, trap formation, and pathogenicity of A. oligospora and provide a basis for elucidating the relationship between conidiation and trap formation of NT fungi. IMPORTANCE Conidiation is the most common reproductive mode for many filamentous fungi and plays an essential role in the pathogenicity of fungal pathogens. Nematode-trapping (NT) fungi are a special group of filamentous fungi owing to their innate abilities to capture and digest nematodes by producing traps (trapping devices). Sporulation plays an important role in the growth and reproduction of NT fungi, and conidia are the basic components of biocontrol reagents for controlling diseases caused by plant-parasitic nematodes. Arthrobotrys oligospora is a well-known NT fungus and is a routinely used model fungus for probing the interaction between fungi and nematodes. In this study, the functions of four key regulators (AoMedA, AoBrlA, AoAbaA, and AoWetA) involved in conidiation were characterized in A. oligospora. A complex interaction between AoMedA and three central regulators was noted; these regulators are required for conidiation and trap formation and play a pleiotropic role in multiple intracellular activities. Our study first revealed the role of AoMedA and three central regulators in conidiation, trap formation, and pathogenicity of A. oligospora, which contributed to elucidating the regulatory mechanism of conidiation in NT fungi and helped in developing effective reagents for biocontrol of nematodes.
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Affiliation(s)
- Na Bai
- State Key Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Meihua Xie
- School of Resource, Environment and Chemistry, Chuxiong Normal University, Chuxiong, China
| | - Qianqian Liu
- State Key Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Yingmei Zhu
- State Key Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Xuewei Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Ke-Qin Zhang
- State Key Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
| | - Jinkui Yang
- State Key Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, School of Life Sciences, Yunnan University, Kunming, China
- School of Life Sciences, Yunnan University, Kunming, China
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6
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Zhang YL, Peng H, Zhang K, Ying SH, Feng MG. Divergent roles of Rad4 and Rad23 homologs in Metarhizium robertsii's resistance to solar ultraviolet damage. Appl Environ Microbiol 2023; 89:e0099423. [PMID: 37655890 PMCID: PMC10537586 DOI: 10.1128/aem.00994-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 07/13/2023] [Indexed: 09/02/2023] Open
Abstract
The anti-ultraviolet (UV) role of a Rad4-Rad23-Rad33 complex in budding yeast relies on nucleotide excision repair (NER), which is mechanistically distinct from photorepair of DNA lesions generated under solar UV irradiation but remains poorly known in filamentous fungi. Here, two nucleus-specific Rad4 paralogs (Rad4A and Rad4B) and nucleocytoplasmic shuttling Rad23 ortholog are functionally characterized by multiple analyses of their null mutants in Metarhizium robertsii, an entomopathogenic fungus lacking Rad33. Rad4A was proven to interact with Rad23 and contribute significantly more to conidial UVB resistance (90%) than Rad23 (65%). Despite no other biological function, Rad4A exhibited a very high activity in photoreactivation of UVB-impaired/inactivated conidia by 5-h light exposure due to its interaction with Rad10, an anti-UV protein clarified previously to have acquired a similar photoreactivation activity through its interaction with a photolyase in M. robertsii. The NER activity of Rad4A or Rad23 was revealed by lower reactivation rates of moderately impaired conidia after 24-h dark incubation but hardly observable at the end of 12-h dark incubation, suggesting an infeasibility of its NER activity in the field where nighttime is too short. Aside from a remarkable contribution to conidial UVB resistance, Rad23 had pleiotropic effect in radial growth, aerial conidiation, antioxidant response, and cell wall integrity but no photoreactivation activity. However, Rad4B proved redundant in function. The high photoreactivation activity of Rad4A unveils its essentiality for M. robertsii's fitness to solar UV irradiation and is distinct from the yeast homolog's anti-UV role depending on NER. IMPORTANCE Resilience of solar ultraviolet (UV)-impaired cells is crucial for the application of fungal insecticides based on formulated conidia. Anti-UV roles of Rad4, Rad23, and Rad33 rely upon nucleotide excision repair (NER) of DNA lesions in budding yeast. Among two Rad4 paralogs and Rad23 ortholog characterized in Metarhizium robertsii lacking Rad33, Rad4A contributes to conidial UVB resistance more than Rad23, which interacts with Rad4A rather than functionally redundant Rad4B. Rad4A acquires a high activity in photoreactivation of conidia severely impaired or inactivated by UVB irradiation through its interaction with Rad10, another anti-UV protein previously proven to interact with a photorepair-required photolyase. The NER activity of either Rad4A or Rad23 is seemingly extant but unfeasible under field conditions. Rad23 has pleiotropic effect in the asexual cycle in vitro but no photoreactivation activity. Therefore, the strong anti-UV role of Rad4A depends on photoreactivation, unveiling a scenario distinct from the yeast homolog's NER-reliant anti-UV role.
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Affiliation(s)
- Yi-Lu Zhang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Han Peng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ke Zhang
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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Wang P, Yang G, Shi N, Zhao C, Hu F, Coutts RHA, Kotta-Loizou I, Huang B. A novel partitivirus orchestrates conidiation, stress response, pathogenicity, and secondary metabolism of the entomopathogenic fungus Metarhizium majus. PLoS Pathog 2023; 19:e1011397. [PMID: 37216409 DOI: 10.1371/journal.ppat.1011397] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 05/01/2023] [Indexed: 05/24/2023] Open
Abstract
Mycoviruses are widely present in all major groups of fungi but those in entomopathogenic Metarhizium spp. remain understudied. In this investigation, a novel double-stranded (ds) RNA virus is isolated from Metarhizium majus and named Metarhizium majus partitivirus 1 (MmPV1). The complete genome sequence of MmPV1 comprises two monocistronic dsRNA segments (dsRNA 1 and dsRNA 2), which encode an RNA-dependent RNA polymerase (RdRp) and a capsid protein (CP), respectively. MmPV1 is classified as a new member of the genus Gammapartitivirus in the family Partitiviridae based on phylogenetic analysis. As compared to an MmPV1-free strain, two isogenic MmPV1-infected single-spore isolates were compromised in terms of conidiation, and tolerance to heat shock and UV-B irradiation, while these phenotypes were accompanied by transcriptional suppression of multiple genes involved in conidiation, heat shock response and DNA damage repair. MmPV1 attenuated fungal virulence since infection resulted in reduced conidiation, hydrophobicity, adhesion, and cuticular penetration. Additionally, secondary metabolites were significantly altered by MmPV1 infection, including reduced production of triterpenoids, and metarhizins A and B, and increased production of nitrogen and phosphorus compounds. However, expression of individual MmPV1 proteins in M. majus had no impact on the host phenotype, suggesting insubstantive links between defective phenotypes and a single viral protein. These findings indicate that MmPV1 infection decreases M. majus fitness to its environment and its insect-pathogenic lifestyle and environment through the orchestration of the host conidiation, stress tolerance, pathogenicity, and secondary metabolism.
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Affiliation(s)
- Ping Wang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Guogen Yang
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, School of Plant Protection, Anhui Agricultural University, Hefei, China
| | - Najie Shi
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Cheng Zhao
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Fenglin Hu
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
| | - Robert H A Coutts
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Ioly Kotta-Loizou
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Bo Huang
- Anhui Provincial Key Laboratory of Microbial Pest Control, Anhui Agricultural University, Hefei, China
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Zhang JG, Zhang K, Xu SY, Ying SH, Feng MG. Essential Role of WetA, but No Role of VosA, in Asexual Development, Conidial Maturation and Insect Pathogenicity of Metarhizium robertsii. Microbiol Spectr 2023; 11:e0007023. [PMID: 36916980 PMCID: PMC10100841 DOI: 10.1128/spectrum.00070-23] [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: 01/05/2023] [Accepted: 02/28/2023] [Indexed: 03/16/2023] Open
Abstract
Conidial maturation, which is crucial for conidial quality, is controlled by the asexual development activator WetA and the downstream, velvety protein VosA in Aspergillus. Their orthologs have proved functional in conidial quality control of Beauveria bassiana, as seen in Aspergillus, but are functionally unexplored, in Metarhizium robertsii, another hypocrealean insect pathogen. Here, WetA and VosA prove essential and nonessential for M. robertsii's life cycle, respectively. Disruption of wetA increased hyphal sensitivity to oxidative stress and Congo red-induced cell wall stress, but had little impact on radial growth. The ΔwetA mutant was severely compromised in conidiation capacity and conidial quality, which was featured by slower germination, decreased UV resistance, reduced hydrophobicity, and deformed hydrophobin rodlet bundles that were assembled onto conidial coat. The mutant's virulence was greatly attenuated via normal infection due to a blockage of infection-required cellular processes. All examined phenotypes were unaffected for the ΔvosA mutant. Intriguingly, mannitol was much less accumulated in the 7- and 15-day-old cultures of ΔwetA and ΔvosA than of control strains, while accumulated trehalose was not detectable at all, revealing little a link of intracellular polyol accumulation to conidial maturation. Transcriptomic analysis revealed differential regulation of 160 genes (up/down ratio: 72:88) in ΔwetA. These genes were mostly involved in cellular component, biological process, and molecular function but rarely associated with asexual development. Conclusively, WetA plays a relatively conserved role in M. robertsii's spore surface structure, and also a differentiated role in some other cellular processes associated with conidial maturation. VosA is functionally redundant in M. robertsii unlike its ortholog in B. bassiana. IMPORTANCE WetA and VosA regulate conidiation and conidial maturation required for the life cycle of Beauveria bassiana, like they do in Aspergillus, but remain functionally unexplored in Metarhizium robertsii, another hypocrealean pathogen considered to have evolved insect pathogenicity ~130 million years later than B. bassiana. This study reveals a similar role of WetA ortholog in asexual development, conidial maturation, and insect pathogenicity, and also its distinctive role in mediating some other conidial maturation-related cellular events, but has functional redundancy of VosA in M. robertsii. The maturation process vital for conidial quality proves dependent on a role of WetA in spore wall assembly but is independent of its role in intracellular polyol accumulation. Transcriptomic analysis reveals a link of WetA to 160 genes involved in cellular component, biological process, and molecular function. Our study unveils that M. robertsii WetA or VosA is functionally differential or different from those learned in B. bassiana and other ascomycetes.
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Affiliation(s)
- Jin-Guan Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ke Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Si-Yuan Xu
- MOE Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Sheng-Hua Ying
- MOE Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ming-Guang Feng
- MOE Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
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SNARE Protein AoSec22 Orchestrates Mycelial Growth, Vacuole Assembly, Trap Formation, Stress Response, and Secondary Metabolism in Arthrobotrys oligospora. J Fungi (Basel) 2023; 9:jof9010075. [PMID: 36675896 PMCID: PMC9863257 DOI: 10.3390/jof9010075] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 12/31/2022] [Accepted: 12/31/2022] [Indexed: 01/06/2023] Open
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) facilitate intracellular vesicle trafficking and membrane fusion in eukaryotes and play a vital role in fungal growth, development, and pathogenicity. However, the functions of SNAREs are still largely unknown in nematode-trapping fungi. Arthrobotrys oligospora is a representative species of nematode-trapping fungi that can produce adhesive networks (traps) for nematode predation. In this study, we characterized AoSec22 in A. oligospora, a homolog of the yeast SNARE protein Sec22. Deletion of Aosec22 resulted in remarkable reductions in mycelial growth, the number of nuclei, conidia yield, and trap formation, especially for traps that failed to develop mature three-dimensional networks. Further, absence of Aosec22 impaired fatty acid utilization, autophagy, and stress tolerance; in addition, the vacuoles became small and fragmented in the hyphal cells of the ∆Aosec22 mutant, and large vacuoles failed to form. The reduced sporulation capacity correlated with the transcriptional repression of several sporulation-related genes, and the impaired accumulation of lipid droplets is in line with the transcriptional repression of several genes involved in fatty acid oxidation. Moreover, absence of Aosec22 remarkably impaired secondary metabolism, resulting in 4717 and 1230 compounds upregulated and downregulated in the ∆Aosec22 mutant, respectively. Collectively, our data highlighted that the SNARE protein AoSec22 plays a pleiotropic role in mycelial growth and development, vacuole assembly, lipid metabolism, stress response, and secondary metabolism; in particular, it is required for the proper development of traps in A. oligospora.
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