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García Riaño JL, Barrera GP, Hernández LC, Villamizar LF. Microsclerotia from Metarhizium robertsii: Production, ultrastructural analysis, robustness, and insecticidal activity. Fungal Biol 2024; 128:1643-1656. [PMID: 38575237 DOI: 10.1016/j.funbio.2024.01.006] [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: 08/16/2023] [Revised: 12/28/2023] [Accepted: 01/19/2024] [Indexed: 04/06/2024]
Abstract
Microsclerotia (MS) are considered one of the most promising propagules for use as active ingredients in biopesticides due to their tolerance to abiotic factors and ability to produce infective conidia for the control of pests. Therefore, the objective of this research was to establish the conditions required to induce the formation of microsclerotia in Metarhizium robertsii Mt004 and to study its development process, tolerance to abiotic factors and insecticidal activity of MS-derived conidia. M. robertsii started to form hyphal aggregates after 2 days and looked more compact after 8 days. MS were mature and pigmented after 20 days. The final yield was 2.0 × 103 MS/mL and MS size varied between 356.9 and 1348.4 μm. Ultrastructure analysis revealed that mature MS contained only a few live cells embedded in an extracellular matrix. Mature MS were more tolerance to UV-B radiation, heat and storage trials than conidia from Solid State Fermentation. MS-derived conidia were as virulent as conidia against Diatraea saccharalis larvae. These results showed that MS are promising propagules for the development of more persistent and efficient biopesticides for harsh environmental conditions. Our findings provide a baseline for production and a better understanding of microsclerotia development in M. robertsii strains.
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Affiliation(s)
- Jennifer Lorena García Riaño
- Corporación Colombiana de Investigación Agropecuaria - Agrosavia. Centro de Investigación Tibaitatá, Cundinamarca, Mosquera, 250047, Colombia; Universidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Química, Carrera 30 # 45, Bogotá, D.C., 111321, Colombia.
| | - Gloria Patricia Barrera
- Corporación Colombiana de Investigación Agropecuaria - Agrosavia. Centro de Investigación Tibaitatá, Cundinamarca, Mosquera, 250047, Colombia
| | - Leonardo Castellanos Hernández
- Universidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Química, Carrera 30 # 45, Bogotá, D.C., 111321, Colombia
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de Lima PPDABM, Fiorotti J, Paulino PG, Corval ARDC, Mesquita E, Corrêa TA, Lopes ADSC, Oliveira RJVD, Santos HA, Bittencourt VREP, Angelo IDC, Golo PS. Metarhizium pingshaense photolyase expression and virulence to Rhipicephalus microplus after UV-B exposure. J Basic Microbiol 2024; 64:94-105. [PMID: 37696778 DOI: 10.1002/jobm.202300346] [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: 06/20/2023] [Revised: 08/18/2023] [Accepted: 08/28/2023] [Indexed: 09/13/2023]
Abstract
The current study examined the impact of ultraviolet (UV)-B radiation in Metarhizium pingshaense blastospores' photolyase expression and their virulence against Rhipicephalus microplus. Blastospores were exposed to UV under laboratory and field conditions. Ticks were treated topically with fungal suspension and exposed to UV-B in the laboratory for three consecutive days. The expression of cyclobutane pyrimidine dimmers (CPDs)-photolyase gene maphr1-2 in blastospores after UV exposure followed by white light exposure was accessed after 0, 8, 12, 24, 36, and 48 h. Average relative germination of blastospores 24 h after in vitro UV exposure was 8.4% lower than 48 h. Despite this, the relative germination of blastospores exposed to UV in the field 18 h (95.7 ± 0.3%) and 28 h (97.3 ± 0.8%) after exposure were not different (p > 0.05). Ticks treated with fungus and not exposed to UV exhibited 0% survival 10 days after the treatment, while fungus-treated ticks exposed to UV exhibited 50 ± 11.2% survival. Expression levels of maphr1-2 8, 12, and 24 h after UV-B exposure were not different from time zero. Maphr1-2 expression peak in M. pingshaense blastospores occurred 36 h after UV-B exposure, in the proposed conditions and times analyzed, suggesting repair mechanisms other than CPD-mediated-photoreactivation might be leading blastospores' germination from 0 to 24 h.
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Affiliation(s)
- Pamella Pryscila de A B M de Lima
- Programa de Pós-Graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Jessica Fiorotti
- Programa de Pós-Graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto SP, Brazil
| | - Patrícia G Paulino
- Programa de Pós-Graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Amanda R da C Corval
- Programa de Pós-Graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Emily Mesquita
- Programa de Pós-Graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Thaís A Corrêa
- Programa de Pós-Graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Adriani da S C Lopes
- Programa de Pós-Graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, Rio de Janeiro, Brazil
| | - Rafael José V de Oliveira
- Laboratório de Bioprocessos, Centro de Tecnologias Estratégicas do Nordeste (CETENE), Recife, Pernambuco, Brazil
| | - Huarrisson A Santos
- Departamento de Epidemiologia e Saúde Pública, Instituto de Veterinária, UFRRJ, Seropédica, Rio de Janeiro, Brazil
| | - Vânia R E P Bittencourt
- Departamento de Parasitologia Animal, Instituto de Veterinária, UFRRJ, Seropédica, Rio de Janeiro, Brazil
| | - Isabele da C Angelo
- Departamento de Epidemiologia e Saúde Pública, Instituto de Veterinária, UFRRJ, Seropédica, Rio de Janeiro, Brazil
| | - Patrícia S Golo
- Departamento de Parasitologia Animal, Instituto de Veterinária, UFRRJ, Seropédica, Rio de Janeiro, Brazil
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Wu S, Toews MD, Behle RW, Barman AK, Sparks AN, Simmons AM, Shapiro-Ilan DI. Post-Application Field Persistence and Efficacy of Cordyceps javanica against Bemisia tabaci. J Fungi (Basel) 2023; 9:827. [PMID: 37623598 PMCID: PMC10455680 DOI: 10.3390/jof9080827] [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: 06/17/2023] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 08/26/2023] Open
Abstract
Previously, Cordyceps javanica Wf GA17, a causing agent of whitefly epizootics in southern Georgia, demonstrated superior temperature tolerance and higher virulence against the whitefly Bemisia tabaci than commercial strains in the laboratory. The post-application persistence and efficacy of this fungus against B. tabaci were compared with that of the commercially available C. javanica Apopka97 strain over a two-year field study in cotton and vegetable crops. When blastospores of both strains were applied alone, whitefly populations were not effectively suppressed. Thus, JMS stylet oil was added to fungal treatments for enhancing efficacy and persistence. For 0-day samples, all fungal treatments caused similar but significant levels of immature mortality regardless of fungal strain, propagule form (conidia vs. blastospores), and application method (alone or mixed with JMS). In follow-up samplings, Wf GA17 blastospores + JMS achieved higher control levels than other treatments in some trials, but the efficacy did not last long. The JMS oil alone caused significant mortality and suppressed whiteflies. Over 90% of spores lost viability 24 h after treatment in all fungal treatments. Across evaluation times, there was no difference between the two fungal strains (conidia or blastospores, alone or combined with JMS), but conidia persisted better than blastospores for both strains. Overall, the field persistence and efficacy of C. javanica did not last long; therefore, improved delivery methods and formulations are needed for enhancement.
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Affiliation(s)
- Shaohui Wu
- Department of Entomology, University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA; (S.W.); (A.K.B.); (A.N.S.)
| | - Michael D. Toews
- Department of Entomology, University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA; (S.W.); (A.K.B.); (A.N.S.)
| | - Robert W. Behle
- National Center for Agricultural Utilization Research, USDA-ARS, 1815 N. University St., Peoria, IL 61604, USA;
| | - Apurba K. Barman
- Department of Entomology, University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA; (S.W.); (A.K.B.); (A.N.S.)
| | - Alton N. Sparks
- Department of Entomology, University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA; (S.W.); (A.K.B.); (A.N.S.)
| | - Alvin M. Simmons
- U.S. Vegetable Laboratory, USDA-ARS, 2700 Savannah Highway, Charleston, SC 29414, USA;
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Meirelles LN, Mesquita E, Corrêa TA, Bitencourt RDOB, Oliveira JL, Fraceto LF, Camargo MG, Bittencourt VREP. Encapsulation of entomopathogenic fungal conidia: evaluation of stability and control potential of Rhipicephalus microplus. Ticks Tick Borne Dis 2023; 14:102184. [PMID: 37105010 DOI: 10.1016/j.ttbdis.2023.102184] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 03/31/2023] [Accepted: 04/01/2023] [Indexed: 04/29/2023]
Abstract
The use of chemical acaricides is the primary strategy to control tick infestations. Nonetheless, chemical resistance in ticks has been reported. Thus, complementary methods such as biological control using entomopathogenic fungi (EPF) have been investigated. EPF, although efficient, have their viability compromised when applied under natural conditions, which indicates that formulation development is essential. Some researchers have demonstrated the efficacy of ionic gelation in protecting EPF against deleterious abiotic factors. In the present study, we conducted the ionic gelation technique to encapsulate Metarhizium anisopliae (Metschn.) Sorokin (Hypocreales: Clavicipitaceae) conidia in 2% (EC 2%) and 3% (EC 3%) sodium alginate. Next, the quantity and viability of encapsulated conidia (EC) were determined. The morphology of particles was characterized by using Scanning Electron Microscopy (SEM). EC and non-encapsulated conidia (NEC) were stored at room temperature (26.8 °C) and in the freezer (-11.9 °C) to shelf-life testing. For UV-B irradiance tolerance and thermotolerance tests, EC and NEC were exposed to UV-B (6.0 or 8.0 kJ m - 2) and heat (42 ºC). In addition, biological parameters of Rhipicephalus microplus Canestrini (Acari: Ixodidae) engorged females exposed to EC were evaluated. The particles presented a spherical shape, more homogeneous (EC 2%) or heterogeneous (EC 3%). Encapsulation decreased (4.8×) the conidial concentration and did not affect their viability. On the other hand, encapsulation increased the shelf life of conidia at room temperature as well as their UV-B tolerance and thermotolerance (6 h). The fungal particles decreased the biological parameters of females more significantly than the NEC. As far as we know, we reported for the first time the use of the ionic gelation to encapsulate entomopathogenic fungi toward controlling R. microplus.
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Affiliation(s)
- Laura Nobrega Meirelles
- Program in Veterinary Sciences, Veterinary Institute, Federal Rural University of Rio de Janeiro, Rodovia BR 465, s/n, Seropédica, RJ 23897-000, Brazil.
| | - Emily Mesquita
- Program in Veterinary Sciences, Veterinary Institute, Federal Rural University of Rio de Janeiro, Rodovia BR 465, s/n, Seropédica, RJ 23897-000, Brazil.
| | - Thaís Almeida Corrêa
- Program in Veterinary Sciences, Veterinary Institute, Federal Rural University of Rio de Janeiro, Rodovia BR 465, s/n, Seropédica, RJ 23897-000, Brazil.
| | - Ricardo de Oliveira Barbosa Bitencourt
- Program in Veterinary Sciences, Veterinary Institute, Federal Rural University of Rio de Janeiro, Rodovia BR 465, s/n, Seropédica, RJ 23897-000, Brazil.
| | - Jhones Luiz Oliveira
- Environmental Nanotechnology Laboratory, Institute of Science and Technology of Sorocaba, São Paulo State University, Av. Três de Março, 511 - Alto da Boa Vista, Sorocaba, SP 18087-180, Brazil.
| | - Leonardo Fernandes Fraceto
- Environmental Nanotechnology Laboratory, Institute of Science and Technology of Sorocaba, São Paulo State University, Av. Três de Março, 511 - Alto da Boa Vista, Sorocaba, SP 18087-180, Brazil.
| | - Mariana Guedes Camargo
- Department of Animal Parasitology, Veterinary Institute, Federal Rural University of Rio de Janeiro, Rodovia BR 465, s/n, Seropédica, RJ 23897-000, Brazil.
| | - Vânia Rita Elias Pinheiro Bittencourt
- Department of Animal Parasitology, Veterinary Institute, Federal Rural University of Rio de Janeiro, Rodovia BR 465, s/n, Seropédica, RJ 23897-000, Brazil.
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da Paixão FRS, Muniz ER, Catão AML, Santos TR, Luz C, Marreto RN, Mascarin GM, Fernandes ÉKK. Microsclerotial pellets of Metarhizium spp.: thermotolerance and bioefficacy against the cattle tick. Appl Microbiol Biotechnol 2023; 107:2263-2275. [PMID: 36929189 DOI: 10.1007/s00253-023-12467-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/21/2023] [Accepted: 02/25/2023] [Indexed: 03/18/2023]
Abstract
The cattle tick, Rhipicephalus microplus (Acari: Ixodidae), is a multi-billion dollar ectoparasite of global importance affecting beef and milk production. Submerged cultures of cosmopolitan entomopathogenic fungal species of the genus Metarhizium typically produce microsclerotia that provide both long-term survival and environmental resistance. Microsclerotia hold great potential as an unconventional active propagule to control this tick under laboratory and semi-field conditions. However, heat stress caused especially by elevated temperatures poses a critical environmental constraint for the successful development and efficacy of microsclerotia under tropical conditions. First, we screened six strains of Metarhizium anisopliae, Metarhizium robertsii and Metarhizium humberi for their ability to produce microsclerotia by submerged liquid cultivation. In addition, we assessed the biological fitness and bioefficacy of dried microsclerotial pellets under amenable (27 °C) and heat-stressed (32 °C) incubation against engorged adult females of R. microplus. Microsclerotia in pelletized formulation prepared with carriers based on diatomaceous earth and microcrystalline cellulose exhibited conidial production at different extents according to the fungal strain and the incubation temperature, but most strains displayed reduced sporogenesis when exposed to 32 °C. Engorged tick females exposed to sporulated microsclerotia from pelletized M. anisopliae CG47 or IP 119 had fewer number of hatching larvae in comparison to the control group, irrespective of the incubation temperature tested. The minimum dosage of microsclerotial pellets that effectively reduced hatchability of tick larvae was estimated to be 2 mg per plate (equivalent to 6.0 kg per hectare). Metarhizium microsclerotial pellets exhibited significant tolerance to 32 °C and pronounced acaricidal activity against this economically important ectoparasite of cattle, even under simulated environmental heat stress. KEY POINTS: • Heat stress affects conidial production by microsclerotia of most pelletized Metarhizium strains • Heat stress does not impair the acaricidal performance of pelletized microsclerotia • Pellet formulation of Metarhizium microsclerotia is a promising mycoacaricide.
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Affiliation(s)
- Flávia Regina Santos da Paixão
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Elen Regozino Muniz
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Alaine Maria Lopes Catão
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | | | - Christian Luz
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Ricardo Neves Marreto
- Faculdade de Farmácia, Universidade Federal de Goiás, Goiânia, GO, 74605-170, Brazil
| | - Gabriel Moura Mascarin
- Laboratory of Environmental Microbiology, Embrapa Environment, SP 340 Road, Km 127.5, Tanquinho Velho, Jaguariúna, SP, 13918-110, Brazil.
| | - Éverton Kort Kamp Fernandes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil.
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Conidial Emulsion Formulation and Thermal Storability of Metarhizium anisopliae against Red Palm Weevil, Rhynchophorusferrugineus Olivier (Coleoptera: Dryophthoridae). Microorganisms 2022; 10:microorganisms10071460. [PMID: 35889178 PMCID: PMC9320691 DOI: 10.3390/microorganisms10071460] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 07/10/2022] [Accepted: 07/11/2022] [Indexed: 02/04/2023] Open
Abstract
Industrial crops including coconut palm and other palm species are seriously infested by red palm weevil (RPW), resulting in significant economic damage globally. Therefore, this study aimed to develop a mycoinsecticide utilizing conidia of Metarhizium anisopliae to control RPW and sought to investigate a new emulsion formulation for the influences of storage temperature and heat stress on conidia germination in an oil-in-glycerol emulsion system. The mycoinsecticide is an emulsion formulation which comprises an oil carrier, non-ionic surfactants, water, and glycerol, which was optimized by premixing the oil and non-ionic surfactant in different weight ratios (1:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4: 6, 3: 7, 2:8, 1:9, and 0:1). From three selected oil-in-glycerol formulations, F25 was more stable in storage and had a smaller particle size (between 154.3 and 236.4 nm in diameter) and stable zeta potential (above + 30 mV) with low surface tension (29.83 ± 0.24 mN/m to 30.72 ± 0.11 mN/m at room temperature. Extended conidial viability was observed at 4 °C overall; the emulsion formulation maintained 12–15% conidial viability until the eighth week at room temperature. Heat of over 30 °C showed an inhibitory effect on conidial germination. This study revealed that the oil-in-glycerol formulation was stable and able to prolong conidial shelf life as compared to non-formulated conidia.
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Carneiro ADS, Mesquita E, Meirelles LN, Bittencourt VREP, Golo PS. Compatibility of different Metarhizium spp. propagules with synthetic acaricides for controlling Rhipicephalus microplus. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA = BRAZILIAN JOURNAL OF VETERINARY PARASITOLOGY : ORGAO OFICIAL DO COLEGIO BRASILEIRO DE PARASITOLOGIA VETERINARIA 2022; 31:e018221. [PMID: 35384990 PMCID: PMC9901882 DOI: 10.1590/s1984-29612022018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 02/23/2022] [Indexed: 11/22/2022]
Abstract
The inappropriate use of synthetic acaricides has selected resistant Rhipicephalus microplus populations. The present study evaluated the compatibility of different Metarhizium spp. propagules (conidia, blastospores, and microsclerotia) by incubating them with synthetic acaricides (amitraz, deltamethrin, and a combination of cypermethrin, chlorpyrifos, and citronellal) for 1 h, 5 h, 10 h, and 24 h. Conidia and microsclerotia of the tested isolates were usually more tolerant to synthetic acaricides than blastospores. Our study also analyzed the in vitro effect of deltamethrin associated with fungal propagules for controlling a population of R. microplus females that were not susceptible to this synthetic acaricide. The use of entomopathogenic fungi in association with deltamethrin in this tick population caused a greater tick control than did the use of the fungus or the synthetic acaricide separately.
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Affiliation(s)
- Adriani da Silva Carneiro
- Programa de Pós-graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro - UFRRJ, Seropédica, RJ, Brasil
| | - Emily Mesquita
- Programa de Pós-graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro - UFRRJ, Seropédica, RJ, Brasil
| | - Laura Nóbrega Meirelles
- Programa de Pós-graduação em Ciências Veterinárias, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro - UFRRJ, Seropédica, RJ, Brasil
| | | | - Patrícia Silva Golo
- Departamento de Parasitologia Animal, Instituto de Veterinária, Universidade Federal Rural do Rio de Janeiro - UFRRJ, Seropédica, RJ, Brasil
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Santos TR, da Paixão FRS, Catão AML, Muniz ER, Ribeiro-Silva CS, Taveira SF, Luz C, Mascarin GM, Fernandes ÉKK, Marreto RN. Inorganic pellets containing microsclerotia of Metarhizium anisopliae: a new technological platform for the biological control of the cattle tick Rhipicephalus microplus. Appl Microbiol Biotechnol 2021; 105:5001-5012. [PMID: 34100979 DOI: 10.1007/s00253-021-11372-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/10/2021] [Accepted: 05/26/2021] [Indexed: 02/07/2023]
Abstract
This study was sought to devise pellets containing inorganic materials and microsclerotia of Metarhizium anisopliae strain IP 119 for biological control of Rhipicephalus microplus, the most economically important tick in Brazilian cattle industry. In addition, we evaluated the storage stability of the pellets, their tolerance to ultraviolet radiation (UV-B), and efficacy against ticks under laboratory conditions. Fungal microsclerotia were produced by liquid culture fermentation and mixed with pre-selected inorganic matrices: vermiculite powder, diatomaceous earth, and colloidal silicon dioxide (78:20:2, w/w/w). The microsclerotial pellets were then prepared by a two-stage process involving extrusion and spheronization. Pellet size averaged 525.53 ± 7.74 μm, with a sphericity index of 0.72 ± 0.01, while biomass constituents did not affect the wet mass properties. Conidial production from microsclerotial pellets upon rehydration ranged from 1.85 × 109 to 1.97 × 109 conidia g-1 with conidial viability ≥ 93%. Conidial production from pellets stored at 4 °C was invariable for up to 21 days. Unformulated microsclerotia and microsclerotial pellets were extremely tolerant to UV-B compared with aerial conidia. Engorged tick females exposed to conidia from sporulated pellets applied to soil samples and upon optimal rehydration exhibited shorter oviposition time length, shorter life span, and reduced number of hatched larvae. In summary, microsclerotial pellets of M. anisopliae IP 119 effectively suppressed R. microplus and showed outstanding UV-B tolerance in laboratory tests. Prospectively, this formulation prototype is promising for targeting the non-parasitic stage of this tick on outdoor pasture fields and may offer a novel mycoacaricide for its sustainable management. KEY POINTS: • Pellets with microsclerotia and inorganic materials are innovative for tick control. • Metarhizium microsclerotia show superior UV-B tolerance in relation to conidia. • Pellets of Metarhizium microsclerotia produce infective conidia against ticks.
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Affiliation(s)
- Thainá Rodrigues Santos
- Faculdade de Farmácia, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Flávia Regina Santos da Paixão
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Alaine Maria Lopes Catão
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Elen Regozino Muniz
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Cárita Souza Ribeiro-Silva
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Stephania Fleury Taveira
- Faculdade de Farmácia, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Christian Luz
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil
| | - Gabriel Moura Mascarin
- Laboratório de Microbiologia Ambiental, Embrapa Meio Ambiente, Jaguariúna, SP, 13918-110, Brazil
| | - Éverton Kort Kamp Fernandes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil.
| | - Ricardo Neves Marreto
- Faculdade de Farmácia, Universidade Federal de Goiás, Avenida Esperança s/n, Campus Samambaia, Goiânia, GO, 74690-900, Brazil.
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Paixão FRS, Huarte-Bonnet C, Ribeiro-Silva CDS, Mascarin GM, Fernandes ÉKK, Pedrini N. Tolerance to Abiotic Factors of Microsclerotia and Mycelial Pellets From Metarhizium robertsii, and Molecular and Ultrastructural Changes During Microsclerotial Differentiation. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:654737. [PMID: 37744155 PMCID: PMC10512246 DOI: 10.3389/ffunb.2021.654737] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 03/05/2021] [Indexed: 09/26/2023]
Abstract
Metarhizium species fungi are able to produce resistant structures termed microsclerotia, formed by compact and melanized threads of hyphae. These propagules are tolerant to desiccation and produce infective conidia; thus, they are promising candidates to use in biological control programs. In this study, we investigated the tolerance to both ultraviolet B (UV-B) radiation and heat of microsclerotia of Metarhizium robertsii strain ARSEF 2575. We also adapted the liquid medium and culture conditions to obtain mycelial pellets from the same isolate in order to compare these characteristics between both types of propagules. We followed the peroxisome biogenesis and studied the oxidative stress during differentiation from conidia to microsclerotia by transmission electron microscopy after staining with a peroxidase activity marker and by the expression pattern of genes potentially involved in these processes. We found that despite their twice smaller size, microsclerotia exhibited higher dry biomass, yield, and conidial productivity than mycelial pellets, both with and without UV-B and heat stresses. From the 16 genes measured, we found an induction after 96-h differentiation in the oxidative stress marker genes MrcatA, MrcatP, and Mrgpx; the peroxisome biogenesis factors Mrpex5 and Mrpex14/17; and the photoprotection genes Mrlac1 and Mrlac2; and Mrlac3. We concluded that an oxidative stress scenario is induced during microsclerotia differentiation in M. robertsii and confirmed that because of its tolerance to desiccation, heat, and UV-B, this fungal structure could be an excellent candidate for use in biological control of pests under tropical and subtropical climates where heat and UV radiation are detrimental to entomopathogenic fungi survival and persistence.
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Affiliation(s)
- Flávia R. S. Paixão
- Instituto de Investigaciones Bioquímicas de La Plata, Centro Científico Tecnológico La Plata Consejo Nacional de Investigaciones Científicas y Técnicas–Universidad Nacional de La Plata, La Plata, Argentina
| | - Carla Huarte-Bonnet
- Instituto de Investigaciones Bioquímicas de La Plata, Centro Científico Tecnológico La Plata Consejo Nacional de Investigaciones Científicas y Técnicas–Universidad Nacional de La Plata, La Plata, Argentina
| | | | - Gabriel M. Mascarin
- Laboratório de Microbiologia Ambiental, Empresa Brasileira de Pesquisa Agropecuária–Embrapa Meio Ambiente, Jaguariúna, Brazil
| | - Éverton K. K. Fernandes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Brazil
| | - Nicolás Pedrini
- Instituto de Investigaciones Bioquímicas de La Plata, Centro Científico Tecnológico La Plata Consejo Nacional de Investigaciones Científicas y Técnicas–Universidad Nacional de La Plata, La Plata, Argentina
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Marciano AF, Mascarin GM, Franco RFF, Golo PS, Jaronski ST, Fernandes ÉKK, Bittencourt VREP. Innovative granular formulation of Metarhizium robertsii microsclerotia and blastospores for cattle tick control. Sci Rep 2021; 11:4972. [PMID: 33654152 PMCID: PMC7925645 DOI: 10.1038/s41598-021-84142-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/08/2021] [Indexed: 11/09/2022] Open
Abstract
The tick Rhipicephalus microplus poses a serious threat to the cattle industry, resulting in economic losses aggravated by tick resistance to chemical acaricides. Strains of Metarhizium spp., a well-known group of entomopathogenic fungi, can contribute to managing this ectoparasite. We explored two novel granular, microsclerotia- or blastospores-based formulations of Metarhizium robertsii for R. microplus control under semi-field conditions. Fungal persistence in soil was also observed for 336 days. The experiment used pots of Urochloa decumbens cv. Basilisk grass, treated with 0.25 or 0.5 mg of granular formulation/cm2 (25 or 50 kg/ha) applied to the soil surface prior to transferring engorged tick females onto the treated soil. The fungal granules yielded more conidia with subsequent sporulation under controlled indoor conditions than in the outdoor environment, where the levels of fungus rapidly declined over time. Metarhizium-root colonization ranged from 25 to 66.7% depending on the propagule and rate. Fungal formulations significantly reduced the number of tick larvae during the humid season, reaching at least 64.8% relative efficacy. Microsclerotia or blastospores-granular formulations of M. robertsii can reduce the impact of R. microplus, and thus prove to be a promising tool in the control of ticks.
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Affiliation(s)
- Allan Felipe Marciano
- Department of Animal Parasitology, Veterinary Institute, Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil.
| | - Gabriel Moura Mascarin
- Laboratory of Environmental Microbiology, Brazilian Agricultural Research Corporation, Embrapa Environment, Jaguariúna, São Paulo, 13918-110, Brazil.
| | - Renato Felipe Ferreira Franco
- Institute of Tropical Pathology and Public Health, Federal University of Goiás (UFG), Goiânia, Goiás, 74690-900, Brazil
| | - Patrícia Silva Golo
- Department of Animal Parasitology, Veterinary Institute, Federal Rural University of Rio de Janeiro, Seropédica, Rio de Janeiro, 23897-000, Brazil
| | | | - Éverton Kort Kamp Fernandes
- Institute of Tropical Pathology and Public Health, Federal University of Goiás (UFG), Goiânia, Goiás, 74690-900, Brazil
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