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So LH, Jirakkakul J, Salaipeth L, Toopaang W, Amnuaykanjanasin A. TOR Signaling Tightly Regulated Vegetative Growth, Conidiation, Oxidative Stress Tolerance and Entomopathogenicity in the Fungus Beauveria bassiana. Microorganisms 2023; 11:2129. [PMID: 37763973 PMCID: PMC10537155 DOI: 10.3390/microorganisms11092129] [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: 07/10/2023] [Revised: 08/11/2023] [Accepted: 08/15/2023] [Indexed: 09/29/2023] Open
Abstract
Beauveria bassiana degenerates after repeated subcultures, demonstrating declined conidiation and insect virulence. The target of rapamycin (TOR) kinase conserved among eukaryotes is the master regulator of cellular physiology and is likely involved in culture degeneration. Indeed, the levels of TOR-associated proteins increase over successive subcultures. Here, CRISPR/Cas9 locus engineering introduced the inducible Tet-On promoter upstream of the TOR kinase 2 gene tor2 in B. bassiana. The mutant PTet-Ontor2 'T41' was verified for the Tet-On integration via PCR analyses and provided a model for evaluating the fungal phenotypes according to the tor2 expression levels, induced by doxycycline (Dox) concentrations. At 0 µg·mL-1 of Dox, T41 had 68% of the wild type's (WT) tor2 expression level, hampered radial growth and relatively lower levels of oxidative stress tolerance, conidiation and virulence against Spodoptera exigua, compared to those under the presence of Dox. A low dose of Dox at 0.1-1 µg·mL-1 induced tor2 upregulation in T41 by up to 91% compared to 0 µg·mL-1 of Dox, resulting in significant increases in radial growth by 8-10% and conidiation by 8-27%. At 20 µg·mL-1 of Dox, which is 132% higher than T41's tor2 expression level at 0 µg·mL-1 of Dox, T41 showed an increased oxidative stress tolerance and a decrease in growth inhibition under iron replete by 62%, but its conidiation significantly dropped by 47% compared to 0 µg·mL-1 of Dox. T41 at 20 µg·mL-1 of Dox had a strikingly increased virulence (1.2 day lower LT50) against S. exigua. The results reflect the crucial roles of TOR kinase in the vegetative growth, conidiation, pathogenicity and oxidative stress tolerance in B. bassiana. Since TOR upregulation is correlated with culture degeneration in multiple subcultures, our data suggest that TOR signaling at relatively low levels plays an important role in growth and development, but at moderate to high levels could contribute to some degenerated phenotypes, e.g., those found in successive subcultures.
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Affiliation(s)
- Lai-Hong So
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Paholyothin Rd., Tambon Khlong Nueng, Amphoe Khlong Luang, Pathum Thani 12120, Thailand (W.T.)
- School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi, Bangkok 10140, Thailand; (J.J.); (L.S.)
| | - Jiraporn Jirakkakul
- School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi, Bangkok 10140, Thailand; (J.J.); (L.S.)
| | - Lakha Salaipeth
- School of Bioresources and Technology, King Mongkut’s University of Technology Thonburi, Bangkok 10140, Thailand; (J.J.); (L.S.)
| | - Wachiraporn Toopaang
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Paholyothin Rd., Tambon Khlong Nueng, Amphoe Khlong Luang, Pathum Thani 12120, Thailand (W.T.)
| | - Alongkorn Amnuaykanjanasin
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), 113 Thailand Science Park, Paholyothin Rd., Tambon Khlong Nueng, Amphoe Khlong Luang, Pathum Thani 12120, Thailand (W.T.)
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Navarro‐Velasco GY, Di Pietro A, López‐Berges MS. Constitutive activation of TORC1 signalling attenuates virulence in the cross-kingdom fungal pathogen Fusarium oxysporum. MOLECULAR PLANT PATHOLOGY 2023; 24:289-301. [PMID: 36840362 PMCID: PMC10013769 DOI: 10.1111/mpp.13292] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 06/18/2023]
Abstract
The filamentous fungus Fusarium oxysporum causes vascular wilt disease in a wide range of plant species and opportunistic infections in humans. Previous work suggested that invasive growth in this pathogen is controlled by environmental cues such as pH and nutrient status. Here we investigated the role of Target Of Rapamycin Complex 1 (TORC1), a global regulator of eukaryotic cell growth and development. Inactivation of the negative regulator Tuberous Sclerosis Complex 2 (Tsc2), but not constitutive activation of the positive regulator Gtr1, in F. oxysporum resulted in inappropriate activation of TORC1 signalling under nutrient-limiting conditions. The tsc2Δ mutants showed reduced colony growth on minimal medium with different nitrogen sources and increased sensitivity to cell wall or high temperature stress. Furthermore, these mutants were impaired in invasive hyphal growth across cellophane membranes and exhibited a marked decrease in virulence, both on tomato plants and on the invertebrate animal host Galleria mellonella. Importantly, invasive hyphal growth in tsc2Δ strains was rescued by rapamycin-mediated inhibition of TORC1. Collectively, these results reveal a key role of TORC1 signalling in the development and pathogenicity of F. oxysporum and suggest new potential targets for controlling fungal infections.
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Affiliation(s)
- Gesabel Yaneth Navarro‐Velasco
- Departamento de GenéticaUniversidad de CórdobaCórdobaSpain
- Present address:
Centro de Investigación e Información de Medicamentos y Tóxicos, Facultad de MedicinaUniversidad de PanamáPanama CityPanama
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Components of TOR and MAP kinase signaling control chemotropism and pathogenicity in the fungal pathogen Verticillium dahliae. Microbiol Res 2023; 271:127361. [PMID: 36921400 DOI: 10.1016/j.micres.2023.127361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/03/2023] [Accepted: 03/10/2023] [Indexed: 03/13/2023]
Abstract
Filamentous fungi can sense useful resources and hazards in their environment and direct growth of their hyphae accordingly. Chemotropism ensures access to nutrients, contact with other individuals (e.g., for mating), and interaction with hosts in the case of pathogens. Previous studies have revealed a complex chemotropic sensing landscape during host-pathogen interactions, but the underlying molecular machinery remains poorly characterized. Here we studied mechanisms controlling directed hyphal growth of the important plant-pathogenic fungus Verticillium dahliae towards different chemoattractants. We found that the homologs of the Rag GTPase Gtr1 and the GTPase-activating protein Tsc2, an activator and a repressor of the TOR kinase respectively, play important roles in hyphal chemotropism towards nutrients, plant-derived signals, and heterologous α-pheromone of Fusarium oxysporum. Furthermore, important roles of these regulators were identified in fungal development and pathogenicity. We also found that the mitogen-activated protein kinase (MAPK) Fus3 is required for chemotropism towards nutrients, while the G protein-coupled receptor (GPCR) Ste2 and the MAPK Slt2 control chemosensing of plant-derived signals and α-pheromone. Our study establishes V. dahliae as a suitable model system for the analysis of fungal chemotropism and discovers new components of chemotropic signaling during growth and host-pathogen interactions of V. dahliae.
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Xiao Z, Zhao Q, Li W, Gao L, Liu G. Strain improvement of Trichoderma harzianum for enhanced biocontrol capacity: Strategies and prospects. Front Microbiol 2023; 14:1146210. [PMID: 37125207 PMCID: PMC10134904 DOI: 10.3389/fmicb.2023.1146210] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/20/2023] [Indexed: 05/02/2023] Open
Abstract
In the control of plant diseases, biocontrol has the advantages of being efficient and safe for human health and the environment. The filamentous fungus Trichoderma harzianum and its closely related species can inhibit the growth of many phytopathogenic fungi, and have been developed as commercial biocontrol agents for decades. In this review, we summarize studies on T. harzianum species complex from the perspective of strain improvement. To elevate the biocontrol ability, the production of extracellular proteins and compounds with antimicrobial or plant immunity-eliciting activities need to be enhanced. In addition, resistance to various environmental stressors should be strengthened. Engineering the gene regulatory system has the potential to modulate a variety of biological processes related to biocontrol. With the rapidly developing technologies for fungal genetic engineering, T. harzianum strains with increased biocontrol activities are expected to be constructed to promote the sustainable development of agriculture.
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Affiliation(s)
- Ziyang Xiao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Qinqin Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Wei Li
- Shanghai Tobacco Group Beijing Cigarette Factory Co., Ltd., Beijing, China
| | - Liwei Gao
- Tobacco Research Institute of Chinese Academy of Agricultural Sciences, Qingdao, China
- Liwei Gao,
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- *Correspondence: Guodong Liu,
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The Rheb GTPase promotes pheromone blindness via a TORC1-independent pathway in the phytopathogenic fungus Ustilago maydis. PLoS Genet 2022; 18:e1010483. [DOI: 10.1371/journal.pgen.1010483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 11/28/2022] [Accepted: 10/17/2022] [Indexed: 11/15/2022] Open
Abstract
The target of the rapamycin (TOR) signaling pathway plays a negative role in controlling virulence in phytopathogenic fungi. However, the actual targets involved in virulence are currently unknown. Using the corn smut fungus Ustilago maydis, we tried to address the effects of the ectopic activation of TOR on virulence. We obtained gain-of-function mutations in the Rheb GTPase, one of the conserved TOR kinase regulators. We have found that unscheduled activation of Rheb resulted in the alteration of the proper localization of the pheromone receptor, Pra1, and thereby pheromone insensitivity. Since pheromone signaling triggers virulence in Ustilaginales, we believe that the Rheb-induced pheromone blindness was responsible for the associated lack of virulence. Strikingly, although these effects required the concourse of the Rsp5 ubiquitin ligase and the Art3 α-arrestin, the TOR kinase was not involved. Several eukaryotic organisms have shown that Rheb transmits environmental information through TOR-dependent and -independent pathways. Therefore, our results expand the range of signaling manners at which environmental conditions could impinge on the virulence of phytopathogenic fungi.
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Abbas A, Mubeen M, Zheng H, Sohail MA, Shakeel Q, Solanki MK, Iftikhar Y, Sharma S, Kashyap BK, Hussain S, del Carmen Zuñiga Romano M, Moya-Elizondo EA, Zhou L. Trichoderma spp. Genes Involved in the Biocontrol Activity Against Rhizoctonia solani. Front Microbiol 2022; 13:884469. [PMID: 35694310 PMCID: PMC9174946 DOI: 10.3389/fmicb.2022.884469] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/27/2022] [Indexed: 11/15/2022] Open
Abstract
Rhizoctonia solani is a pathogen that causes considerable harm to plants worldwide. In the absence of hosts, R. solani survives in the soil by forming sclerotia, and management methods, such as cultivar breeding, crop rotations, and fungicide sprays, are insufficient and/or inefficient in controlling R. solani. One of the most challenging problems facing agriculture in the twenty-first century besides with the impact of global warming. Environmentally friendly techniques of crop production and improved agricultural practices are essential for long-term food security. Trichoderma spp. could serve as an excellent example of a model fungus to enhance crop productivity in a sustainable way. Among biocontrol mechanisms, mycoparasitism, competition, and antibiosis are the fundamental mechanisms by which Trichoderma spp. defend against R. solani, thereby preventing or obstructing its proliferation. Additionally, Trichoderma spp. induce a mixed induced systemic resistance (ISR) or systemic acquired resistance (SAR) in plants against R. solani, known as Trichoderma-ISR. Stimulation of every biocontrol mechanism involves Trichoderma spp. genes responsible for encoding secondary metabolites, siderophores, signaling molecules, enzymes for cell wall degradation, and plant growth regulators. Rhizoctonia solani biological control through genes of Trichoderma spp. is summarized in this paper. It also gives information on the Trichoderma-ISR in plants against R. solani. Nonetheless, fast-paced current research on Trichoderma spp. is required to properly utilize their true potential against diseases caused by R. solani.
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Affiliation(s)
- Aqleem Abbas
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Mustansar Mubeen
- Department of Plant Pathology, College of Agriculture, University of Sargodha, Sargodha, Pakistan
| | - Hongxia Zheng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Muhammad Aamir Sohail
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | - Qaiser Shakeel
- Department of Plant Pathology, Faculty of Agriculture and Environment, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Manoj Kumar Solanki
- Plant Cytogenetics and Molecular Biology Group, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - Yasir Iftikhar
- Department of Plant Pathology, College of Agriculture, University of Sargodha, Sargodha, Pakistan
- *Correspondence: Yasir Iftikhar,
| | - Sagar Sharma
- Plant Cytogenetics and Molecular Biology Group, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - Brijendra Kumar Kashyap
- Department of Biotechnology Engineering, Institute of Engineering and Technology, Bundelkhand University, Jhansi, India
| | - Sarfaraz Hussain
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, China
| | | | | | - Lei Zhou
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- Lei Zhou,
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