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Gomes SA, Carolino AT, Teodoro TBP, Silva GA, Bitencourt RDOB, Silva CP, Alkhaibari AM, Butt TM, Samuels RI. The Potential of Metarhizium anisopliae Blastospores to Control Aedes aegypti Larvae in the Field. J Fungi (Basel) 2023; 9:759. [PMID: 37504747 PMCID: PMC10381131 DOI: 10.3390/jof9070759] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 07/15/2023] [Accepted: 07/16/2023] [Indexed: 07/29/2023] Open
Abstract
Entomopathogenic fungi are promising as an environmentally benign alternative to chemical pesticides for mosquito control. The current study investigated the virulence of Metarhizium anisopliae blastospores against Aedes aegypti under both laboratory and field conditions. Virulence bioassays of conidia and blastospores were conducted in the laboratory, while field simulation bioassays were conducted under two conditions: totally shaded (TS) or partially shaded (PS). In the first bioassay (zero h), the larvae were added to the cups shortly after the preparation of the blastospores, and in the subsequent assays, larvae were added to the cups 3, 6, 9, and 12 days later. The survival of the larvae exposed to blastospores in the laboratory was zero on day two, as was the case for the larvae exposed to conidia on the sixth day. Under TS conditions, zero survival was seen on the third day of the bioassay. Under PS conditions, low survival rates were recorded on day 7. For the persistence bioassay under PS conditions, low survival rates were also observed. Metarhizium anisopliae blastospores were more virulent to Ae. aegypti larvae than conidia in the laboratory. Blastospores remained virulent under field simulation conditions. However, virulence rapidly declined from the third day of field bioassays. Formulating blastospores in vegetable oil could protect these propagules when applied under adverse conditions. This is the first time that blastospores have been tested against mosquito larvae under simulated field conditions, and the current study could be the basis for the development of a new biological control agent.
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Affiliation(s)
- Simone Azevedo Gomes
- Laboratório de Entomologia e Fitopatologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil
| | - Aline Teixeira Carolino
- Laboratório de Entomologia e Fitopatologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil
| | - Thais Berçot Pontes Teodoro
- Laboratório de Entomologia e Fitopatologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil
| | - Gerson Adriano Silva
- Laboratório de Entomologia e Fitopatologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil
| | - Ricardo de Oliveira Barbosa Bitencourt
- Laboratório de Entomologia e Fitopatologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil
| | - Carlos Peres Silva
- Departamento de Bioquímica, Universidade Federal de Santa Catarina, Florianópolis 88040-900, Brazil
| | - Abeer M Alkhaibari
- Department of Biology, Faculty of Science, University of Tabuk, Tabuk 71491, Saudi Arabia
| | - Tariq M Butt
- Department of Biosciences, Swansea University, Swansea SA2 8PB, UK
| | - Richard Ian Samuels
- Laboratório de Entomologia e Fitopatologia, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Rio de Janeiro 28013-602, Brazil
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Gotti IA, Moreira CC, Delalibera I, De Fine Licht HH. Blastospores from Metarhizium anisopliae and Metarhizium rileyi Are Not Always as Virulent as Conidia Are towards Spodoptera frugiperda Caterpillars and Use Different Infection Mechanisms. Microorganisms 2023; 11:1594. [PMID: 37375096 DOI: 10.3390/microorganisms11061594] [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: 04/26/2023] [Revised: 05/31/2023] [Accepted: 06/01/2023] [Indexed: 06/29/2023] Open
Abstract
Infective conidia from entomopathogenic fungi are widely used to control insect pests. Many entomopathogenic fungi also produce yeast-like cells called blastospores under specific liquid culture conditions that can directly infect insects. However, little is known about the biological and genetic factors that allow blastospores to infect insects and make them potentially effective for biological control in the field. Here, we show that while the generalist Metarhizium anisopliae produces a higher number of and smaller blastospores, the Lepidoptera specialist M. rileyi produces fewer propagules with a higher cell volume under high-osmolarity conditions. We compared the virulence of blastospores and conidia of these two Metarhizium species towards the economically important caterpillar pest Spodoptera frugiperda. Conidia and blastospores from M. anisopliae were equally infectious, but acted slower, and killed fewer insects than M. rileyi conidia and blastospores did, where M. rielyi conidia had the highest virulence. Using comparative transcriptomics during propagule penetration of insect cuticles, we show that M. rileyi blastospores express more virulence-related genes towards S. frugiperda than do M. anisopliae blastospores. In contrast, conidia of both fungi express more virulence-related oxidative stress factors than blastospores. Our results highlight that blastospores use a different virulence mechanism than conidia use, which may be explored in new biological control strategies.
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Affiliation(s)
- Isabella Alice Gotti
- Department of Entomology and Acarology, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba 13418-260, Brazil
- R&D Microbiologicals Department, Koppert Biological Systems Brazil, Piracicaba 13400-970, Brazil
| | - Camila Costa Moreira
- R&D Microbiologicals Department, Koppert Biological Systems Brazil, Piracicaba 13400-970, Brazil
| | - Italo Delalibera
- Department of Entomology and Acarology, "Luiz de Queiroz" College of Agriculture, University of São Paulo, Piracicaba 13418-260, Brazil
| | - Henrik H De Fine Licht
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, 1165 Copenhagen, Denmark
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Sant Anna Iwanicki N, Delalibera Júnior I, de Carvalho LLB, Eilenberg J, De Fine Licht HH. Comparative transcriptomics of growth metabolism and virulence reveal distinct morphogenic profiles of yeast-like cells and hyphae of the fungus Metarhizium rileyi. Fungal Genet Biol 2023; 164:103766. [PMID: 36513262 DOI: 10.1016/j.fgb.2022.103766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022]
Abstract
Metarhizium rileyiis an entomopathogenic fungus with a narrow host range which distinguishes it from other Metarhiziumspecies with broad host ranges. This species is also unique because the initial yeast-like growth on solid media is only observed in liquid culture in other Metharizium species. A lack of knowledge about the metabolism and genetic signatures of M. rileyiduring this yeast-like phase on solid and in liquid media is a bottleneck for its large-scale production as a commercial biocontrol agent.In this study wefound that M. rileyiyeast-like cells produced on solid medium infected and killed the important insect pest Spodoptera frugiperda with comparable efficiency as yeast-like cells grown in liquid medium. Secondly, we used comparative transcriptomic analysis to investigate theactive genes and genomic signatures of the M. rileyi yeast-like morphotypes produced on solid and in liquid media. Yeast-like cells grown in liquid medium had upregulated genes relating specifically to signal transduction andparticular membrane transporters. Thirdly, we compared the transcriptomic profiles of yeast-like phases of M. rileyi with those of M. anisopliae. The yeast-like phase of M. rileyi grown on solid medium upregulated unique genes not found in otherMetarhiziumspecies including specific membrane proteins and several virulence factors. Orthologous genes associated with heat shock protein, iron permease, membrane proteins and key virulence traits (e.g. collagen-like protein Mcl1) were upregulated in both species. Comparative transcriptome analyses of gene expression showed more differences than similarities between M. anisopliae and M. rileyi yeast-like cells.
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Affiliation(s)
- Natasha Sant Anna Iwanicki
- Department of Entomology and Acarology, Escola Superior de Agricultura 'Luiz de Queiroz', University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP CEP 13418-900, Brazil.
| | - Italo Delalibera Júnior
- Department of Entomology and Acarology, Escola Superior de Agricultura 'Luiz de Queiroz', University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP CEP 13418-900, Brazil
| | - Lana L B de Carvalho
- Department of Entomology and Acarology, Escola Superior de Agricultura 'Luiz de Queiroz', University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP CEP 13418-900, Brazil
| | - Jørgen Eilenberg
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark
| | - Henrik H De Fine Licht
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark.
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Delivery and effectiveness of entomopathogenic fungi for mosquito and tick control: current knowledge and research challenges. Acta Trop 2022; 234:106627. [DOI: 10.1016/j.actatropica.2022.106627] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/12/2022] [Accepted: 07/28/2022] [Indexed: 02/07/2023]
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Silva DM, de Souza VHM, Moral RDA, Delalibera Júnior I, Mascarin GM. Production of Purpureocillium lilacinum and Pochonia chlamydosporia by Submerged Liquid Fermentation and Bioactivity against Tetranychus urticae and Heterodera glycines through Seed Inoculation. J Fungi (Basel) 2022; 8:511. [PMID: 35628766 PMCID: PMC9145524 DOI: 10.3390/jof8050511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/10/2022] [Accepted: 05/11/2022] [Indexed: 02/04/2023] Open
Abstract
Pochoniachlamydosporia and Purpureocilliumlilacinum are fungal bioagents used for the sustainable management of plant parasitic nematodes. However, their production through submerged liquid fermentation and their use in seed treatment have been underexplored. Therefore, our goal was to assess the effect of different liquid media on the growth of 40 isolates of P. lilacinum and two of P. chlamydosporia. The most promising isolates tested were assessed for plant growth promotion and the control of the two-spotted spider mite (Tetranychus urticae) and the soybean cyst nematode (Heterodera glycines). Most isolates produced > 108 blastospores mL−1 and some isolates produced more than 104 microsclerotia mL−1. Microsclerotia of selected isolates were used to inoculate common bean (Phaseolus vulgaris L.) seeds in greenhouse trials. All fungal isolates reduced the T. urticae fecundity in inoculated plants through seed treatment, while P. chlamydosporia ESALQ5406 and P. lilacinum ESALQ2593 decreased cyst nematode population. Purpureocillium lilacinum was more frequently detected in soil, whereas P. chlamydosporia colonized all plant parts. Pochonia chlamydosporia ESALQ5406 improved the root development of bean plants. These findings demonstrate the possibility of producing submerged propagules of P. chlamydosporia and P. lilacinum by liquid culture, and greenhouse trials support the applicability of fungal microsclerotia in seed treatment to control P. vulgaris pests.
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Affiliation(s)
- Daniela Milanez Silva
- Department of Entomology and Acarology, Escola Superior de Agricultura “Luiz de Queiroz”, University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba 13418-900, SP, Brazil; (D.M.S.); (I.D.J.)
| | - Victor Hugo Moura de Souza
- Crop Science Centre, Department of Plant Sciences, University of Cambridge, Lawrence Weaver Rd., Cambridge CB30 LE, UK;
| | - Rafael de Andrade Moral
- Department of Mathematics and Statistics, Maynooth University, W23 F2H6 Maynooth, Co. Kildare, Ireland
| | - Italo Delalibera Júnior
- Department of Entomology and Acarology, Escola Superior de Agricultura “Luiz de Queiroz”, University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba 13418-900, SP, Brazil; (D.M.S.); (I.D.J.)
| | - Gabriel Moura Mascarin
- Laboratory of Environmental Microbiology, Brazilian Agricultural Research Corporation, Embrapa Environment, Rodovia SP 340, KM 127.5, Jaguariúna 13918-110, SP, Brazil
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Iwanicki NSA, Mascarin GM, Moreno SG, Eilenberg J, Delalibera I. Development of novel spray-dried and air-dried formulations of Metarhizium robertsii blastospores and their virulence against Dalbulus maidis. Appl Microbiol Biotechnol 2021; 105:7913-7933. [PMID: 34550438 DOI: 10.1007/s00253-021-11576-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 08/25/2021] [Accepted: 08/26/2021] [Indexed: 10/20/2022]
Abstract
The present research addressed spray-drying and air-drying techniques applied to Metarhizium robertsii blastospores to develop wettable powder (WP) formulations. We investigated the effect of co-formulants on blastospore viability during drying and assessed the wettability and stability of formulations in water. The effect of oxygen-moisture absorbers was studied on the shelf life of these formulations stored at 26 °C and 4 °C for up to 90 days. Additionally, we determined the virulence of the best spray-dried and air-dried formulations against the corn leafhopper Dalbulus maidis. While sucrose and skim milk played an essential role as osmoprotectants in preserving air-dried blastospores, maltodextrin, skim milk, and bentonite were crucial to attain high cell survival during spray drying. The lowest wettability time was achieved with spray-dried formulations containing less Ca-lignin, while charcoal powder amount was positively associated with formulation stability. The addition of oxygen-moisture absorbers inside sealed packages increased from threefold to fourfold the half-life times of air-dried and spray-dried formulations at both storage temperatures. However, the half-life times of all blastospore-based formulations were shorter than 3 months regardless of temperature and packaging system. Spray-dried and air-dried WP formulations were as virulent as fresh blastopores against D. maydis adults sprayed with 5 × 107 blastospores mL-1 that induced 87.8% and 70.6% mortality, respectively. These findings bring innovative advancement for M. robertsii blastospore formulation through spray-drying and underpin the importance of adding protective matrices coupled to oxygen-moisture absorbers to extend cell viability during either cold or non-refrigerated storage. KEY POINTS: • Cost-effective wettable powder formulations of M. robertsii blastospores were developed. • Bioefficacy of formulations against the corn leafhopper was comparable to fresh blastospores. • Cold storage and dual oxygen-moisture absorber are critical for extended shelf life.
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Affiliation(s)
- Natasha Sant Anna Iwanicki
- Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz, " University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP CEP, 13418-900, Brazil.
| | - Gabriel Moura Mascarin
- Laboratory of Environmental Microbiology, Brazilian Agricultural Research Corporation, Embrapa Environment, Rodovia SP 340, Km 127.5, Jaguariúna, 13918-110, Brazil.
| | - Sara Giro Moreno
- Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz, " University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP CEP, 13418-900, Brazil
| | - Jørgen Eilenberg
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark
| | - Italo Delalibera
- Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz, " University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP CEP, 13418-900, Brazil
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Desiccation-tolerant fungal blastospores: From production to application. CURRENT RESEARCH IN BIOTECHNOLOGY 2021. [DOI: 10.1016/j.crbiot.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Corval ARC, Mesquita E, Corrêa TA, Silva CDSR, Bitencourt RDOB, Fernandes ÉKK, Bittencourt VREP, Roberts DW, Gôlo PS. UV-B tolerances of conidia, blastospores, and microsclerotia of Metarhizium spp. entomopathogenic fungi. J Basic Microbiol 2020; 61:15-26. [PMID: 33616987 DOI: 10.1002/jobm.202000515] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/30/2020] [Accepted: 11/21/2020] [Indexed: 11/09/2022]
Abstract
The aim of the present study was to analyze ten native Metarhizium spp. isolates as to their UV-B tolerances. Comparisons included: different fungal propagules (conidia, blastospores, or microsclerotia [MS]); conidia in aqueous suspensions or in 10% mineral oil-in-water emulsions; and conidia mixed with different types of soil. The UV-B effect was expressed as the germination of conidia or culturability of blastospores and MS relative to nongerminated propagules. Metarhizium anisopliae LCM S05 exhibited high tolerance as blastospores and/or MS, but not as conidia; LCM S10 and LCM S08 had positive results with MS or conidia but not blastospores. The formulations with 10% mineral oil did not always protect Metarhizium conidia against UV-B. Conidia of LCM S07, LCM S08, and LCM S10 exhibited the best results when in aqueous suspensions, 24 h after UV-B exposure. In general, conidia mixed with soil and exposed to UV-B yielded similar number of colony forming units as conidia from unexposed soil, regardless the soil type. It was not possible to predict which type of propagule would be the most UV-B tolerant for each fungal isolate; in conclusion, many formulations and propagule types should be investigated early in the development of new fungal biocontrol products.
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Affiliation(s)
- Amanda R C Corval
- Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Emily Mesquita
- Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Thaís A Corrêa
- Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Cárita de S R Silva
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Ricardo de O B Bitencourt
- Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Éverton K K Fernandes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | - Vânia R E P Bittencourt
- Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil.,Departamento de Parasitologia Animal, Instituto de Veterinária, Seropédica, Rio de Janeiro, Brazil
| | | | - Patrícia S Gôlo
- Programa de Pós-Graduação em Ciências Veterinárias, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil.,Departamento de Parasitologia Animal, Instituto de Veterinária, Seropédica, Rio de Janeiro, Brazil
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da Cunha LP, Casciatori FP, Vicente IV, Garcia RL, Thoméo JC. Metarhizium anisopliae conidia production in packed-bed bioreactor using rice as substrate in successive cultivations. Process Biochem 2020. [DOI: 10.1016/j.procbio.2020.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Iwanicki NS, Júnior ID, Eilenberg J, De Fine Licht HH. Comparative RNAseq Analysis of the Insect-Pathogenic Fungus Metarhizium anisopliae Reveals Specific Transcriptome Signatures of Filamentous and Yeast-Like Development. G3 (BETHESDA, MD.) 2020; 10:2141-2157. [PMID: 32354703 PMCID: PMC7341153 DOI: 10.1534/g3.120.401040] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 04/24/2020] [Indexed: 11/18/2022]
Abstract
The fungus Metarhizium anisopliae is a facultative insect pathogen used as biological control agent of several agricultural pests worldwide. It is a dimorphic fungus that is able to display two growth morphologies, a filamentous phase with formation of hyphae and a yeast-like phase with formation of single-celled blastospores. Blastospores play an important role for M. anisopliae pathogenicity during disease development. They are formed solely in the hemolymph of infected insects as a fungal strategy to quickly multiply and colonize the insect's body. Here, we use comparative genome-wide transcriptome analyses to determine changes in gene expression between the filamentous and blastospore growth phases in vitro to characterize physiological changes and metabolic signatures associated with M. anisopliae dimorphism. Our results show a clear molecular distinction between the blastospore and mycelial phases. In total 6.4% (n = 696) out of 10,981 predicted genes in M. anisopliae were differentially expressed between the two phases with a fold-change > 4. The main physiological processes associated with up-regulated gene content in the single-celled yeast-like blastospores during liquid fermentation were oxidative stress, amino acid metabolism (catabolism and anabolism), respiration processes, transmembrane transport and production of secondary metabolites. In contrast, the up-regulated gene content in hyphae were associated with increased growth, metabolism and cell wall re-organization, which underlines the specific functions and altered growth morphology of M. anisopliae blastospores and hyphae, respectively. Our study revealed significant transcriptomic differences between the metabolism of blastospores and hyphae. These findings illustrate important aspects of fungal morphogenesis in M. anisopliae and highlight the main metabolic activities of each propagule under in vitro growth conditions.
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Affiliation(s)
- Natasha Sant'Anna Iwanicki
- Department of Entomology and Acarology, ESALQ- University of São Paulo, Av Padua Dias, 11-P.O. Box 9-13418-900, Piracicaba, SP, Brazil and
| | - Italo Delalibera Júnior
- Department of Entomology and Acarology, ESALQ- University of São Paulo, Av Padua Dias, 11-P.O. Box 9-13418-900, Piracicaba, SP, Brazil and
| | - Jørgen Eilenberg
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Henrik H De Fine Licht
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
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Iwanicki NSA, Mascarin GM, Moreno SG, Eilenberg J, Delalibera Júnior I. Growth kinetic and nitrogen source optimization for liquid culture fermentation of Metarhizium robertsii blastospores and bioefficacy against the corn leafhopper Dalbulus maidis. World J Microbiol Biotechnol 2020; 36:71. [PMID: 32350696 DOI: 10.1007/s11274-020-02844-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 04/17/2020] [Indexed: 02/07/2023]
Abstract
The cosmopolitan entomopathogenic and root endophytic fungus Metarhizium robertsii has a versatile lifestyle and during liquid fermentation undergoes a dimorphic transformation from hyphae to conidia or microsclerotia, or from hyphae to blastospores. In all cases, these processes are mediated by environmental and nutritional cues. Blastospores could be used in spray applications to control arthropod pests above ground and may serve as an attractive alternative to the traditional solid-grown aerial conidial spores of Metarhizium spp. found in commercial products. Nitrogen is a vital nutrient in cell metabolism and growth; however, it is the expensive component in liquid cultures of entomopathogenic fungi. Our goals in this study were to optimize nitrogen sources and titers for maximum production of M. robertsii blastospores cultured in shake flasks at highly aerated conditions and to further determine their virulence against the corn leafhopper Dalbulus maidis, an important vector of serious pathogens in maize crops worldwide. Our fermentation studies revealed that the low-cost corn steep liquor (CSL) was the most suitable nitrogen source to improve blastospore growth in M. robertsii. The growth kinetic assays determined the optimal titer of 80 g L-1 and a yield up to 4.7 × 108 cells mL-1 within 5 days of cultivation (3 days preculture and 2 days culture), at a total cost of US$0.30 L-1. Moreover, the blastospore growth kinetic was strongly dependent on glucose and nitrogen consumptions accompanied by a slight drop in the culture pH. Insect bioassays evidenced a high virulence of these blastospores, either as dried or fresh cells, to D. maidis adults fed on maize plants. Our findings provide insights into the nutritional requirements for optimal and cost-efficient production of M. robertsii blastospores and elucidate the potential of blastospores as an ecofriendly tool against the corn leafhopper.
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Affiliation(s)
- Natasha Sant Anna Iwanicki
- Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP, 13418-900, Brazil.
| | - Gabriel Moura Mascarin
- Laboratory of Environmental Microbiology, Brazilian Agricultural Research Corporation, Embrapa Environment, Rodovia SP 340, Km 127.5, Jaguariúna, 13820-000, Brazil.
| | - Sara Giro Moreno
- Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP, 13418-900, Brazil
| | - Jørgen Eilenberg
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark
| | - Italo Delalibera Júnior
- Department of Entomology and Acarology, Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo (ESALQ-USP), Av. Pádua Dias, 11, C.P. 9, Piracicaba, SP, 13418-900, Brazil
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