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Wang X, Yuan Q, He L, Wang Z, Li G, Wang Z, Liu H. Biological and physiological effects in Bemisia tabaci feeding on tomatoes endophytically colonized by Beauveria bassiana. PEST MANAGEMENT SCIENCE 2024; 80:4085-4097. [PMID: 38587112 DOI: 10.1002/ps.8121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 03/28/2024] [Accepted: 04/01/2024] [Indexed: 04/09/2024]
Abstract
BACKGROUND Entomopathogenic fungi (EPF) treatment of plants may affect the survival and feeding preferences of herbivorous pests. However, comprehensive studies on the fitness across their entire life cycle, feeding behavior, and physiological changes in herbivores consuming EPF-treated plants within the tripartite interactions of EPF, plants, and pests are still limited. In this study, we utilized life tables, electrical penetration graph (EPG), and metabolomics to uncover the biological and physiological characteristics of Bemisia tabaci on tomato plants inoculated with Beauveria bassiana through root irrigation. RESULTS Our study indicated that Beauveria bassiana Bb252 can penetrate the entire tissue from the point of inoculation, primarily colonizing the intercellular spaces and vascular tissue. However, this colonization is temporary, lasting no more than 35 days. Moreover, the population fitness and feeding behavior of Bemisia tabaci on tomato plants treated with Beauveria bassiana via root irrigation were significantly affected, showing a substantial 41.4% decrease in net reproductive rate (R0), a notable reduction in watery salivation, and shortened phloem ingestion. Lastly, we observed a significant decrease in hormones and amino acids of whiteflies that fed on Beauveria bassiana-treated tomato plants by root irrigation. CONCLUSIONS Our results indicated that the endophyte, Beauveria bassiana Bb252, reduced demographic fitness of Bemisia tabaci by altering its hormones and amino acids levels. These findings enhance our understanding of multitrophic interactions in integrated pest management. © 2024 Society of Chemical Industry.
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Affiliation(s)
- Xian Wang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River, Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Qian Yuan
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River, Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Liqiang He
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River, Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Zhou Wang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River, Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Guangyun Li
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River, Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Ziying Wang
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River, Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
| | - Huai Liu
- Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River, Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
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Luo XC, Yu L, Xu SY, Ying SH, Feng MG. Photoreactivation Activities of Rad5, Rad16A and Rad16B Help Beauveria bassiana to Recover from Solar Ultraviolet Damage. J Fungi (Basel) 2024; 10:420. [PMID: 38921406 PMCID: PMC11205155 DOI: 10.3390/jof10060420] [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: 04/07/2024] [Revised: 06/02/2024] [Accepted: 06/12/2024] [Indexed: 06/27/2024] Open
Abstract
In budding yeast, Rad5 and Rad7-Rad16 play respective roles in the error-free post-replication repair and nucleotide excision repair of ultraviolet-induced DNA damage; however, their homologs have not yet been studied in non-yeast fungi. In the fungus Beauveria bassiana, a deficiency in the Rad7 homolog, Rad5 ortholog and two Rad16 paralogs (Rad16A/B) instituted an ability to help the insect-pathogenic fungus to recover from solar UVB damage through photoreactivation. The fungal lifecycle-related phenotypes were not altered in the absence of rad5, rad16A or rad16B, while severe defects in growth and conidiation were caused by the double deletion of rad16A and rad16B. Compared with the wild-type and complemented strains, the mutants showed differentially reduced activities regarding the resilience of UVB-impaired conidia at 25 °C through a 12-h incubation in a regime of visible light plus dark (L/D 3:9 h or 5:7 h for photoreactivation) or of full darkness (dark reactivation) mimicking a natural nighttime. The estimates of the median lethal UVB dose LD50 from the dark and L/D treatments revealed greater activities of Rad5 and Rad16B than of Rad16A and additive activities of Rad16A and Rad16B in either NER-dependent dark reactivation or photorepair-dependent photoreactivation. However, their dark reactivation activities were limited to recovering low UVB dose-impaired conidia but were unable to recover conidia impaired by sublethal and lethal UVB doses as did their photoreactivation activities at L/D 3:9 or 5:7, unless the night/dark time was doubled or further prolonged. Therefore, the anti-UV effects of Rad5, Rad16A and Rad16B in B. bassiana depend primarily on photoreactivation and are mechanistically distinct from those for their yeast homologs.
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Affiliation(s)
| | | | | | | | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China; (X.-C.L.); (L.Y.); (S.-Y.X.); (S.-H.Y.)
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Reyes-Haro L, Prince G, Granja-Travez RS, Chandler D. Phenotypic and genotypic characterization of fifty strains of Beauveria spp. (Ascomycota, Cordycipitaceae) fungal entomopathogens from diverse geographic origins against the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). PEST MANAGEMENT SCIENCE 2024. [PMID: 38864555 DOI: 10.1002/ps.8230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 06/13/2024]
Abstract
BACKGROUND The diamondback moth (DBM) (Plutella xylostella) causes large losses to global crop production. Conventional insecticides are losing effectiveness due to resistance. Consequently, there is a growing interest in sustainable control methods like entomopathogenic fungi (EPF) in Integrated Pest Management. However, the field efficacy of fungi varies due to environmental influences. In this study, a group of 50 Beauveria strains sourced from different locations were characterized by genotype and phenotype with respect to their conidial production, temperature and UV-B radiation tolerance, and virulence against DBM. RESULTS Phylogenetic analysis revealed two distinct species: Beauveria bassiana (84%) and B. pseudobassiana (16%). Most strains showed optimal growth between 25 °C and 28 °C, with germination severely affected at 10 °C and 33 °C. Notably, 44% displayed high resistance to UV-B radiation (5.94 kJ m-2), with germination rates between 60.9% and 88.1%. Geographical origin showed no correlation with temperature or UV radiation tolerance. In virulence experiments, 52% of strains caused mortality rates exceeding 80% in DBM second instars at 7 days after exposure to a 4 mL conidial suspension (107 conidia/mL). CONCLUSION Survival under environmental conditions is crucial for EPF-based commercial products against DBM. Results suggest strain tolerance to environmental stressors is more tied to specific micro-climatic factors than geographical origin. Each strain exhibited unique characteristics; for example, the most virulent strain (#29) was highly UV-sensitive. Therefore, characterizing diverse strains provides essential genotypic and phenotypic insights, which are fundamental for understanding their role as biocontrol agents while facilitating efficient biopesticide product development and uptake. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Laura Reyes-Haro
- Warwick Crop Centre, School of Life Sciences, University of Warwick, Warwick, UK
| | - Gillian Prince
- Warwick Crop Centre, School of Life Sciences, University of Warwick, Warwick, UK
| | | | - David Chandler
- Warwick Crop Centre, School of Life Sciences, University of Warwick, Warwick, UK
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Lima VH, Matugawa AT, Mascarin GM, Fernandes ÉKK. Complex nitrogen sources from agro-industrial byproducts: impact on production, multi-stress tolerance, virulence, and quality of Beauveria bassiana blastospores. Microbiol Spectr 2024; 12:e0404023. [PMID: 38700331 PMCID: PMC11237575 DOI: 10.1128/spectrum.04040-23] [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: 11/26/2023] [Accepted: 03/28/2024] [Indexed: 05/05/2024] Open
Abstract
We investigated the impact of various complex organic nitrogen sources on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like single cells called blastospores. Specifically, we examined yeast extract, autolyzed yeast, inactive yeast, cottonseed flour, corn bran, and corn gluten meal as nitrogen compounds with different carbon-to-nitrogen (C:N) ratios. Our comprehensive analysis encompassed blastospore production, tolerance to abiotic stresses, shelf stability after drying, and virulence against mealworm larvae, crucial attributes for developing effective blastospore-based biopesticides. Notably, cottonseed flour emerged as the optimal nitrogen source, yielding up to 2.5 × 109 blastospores/mL within 3 days in a bioreactor. These blastospores exhibited the highest tolerance to heat stress and UV-B radiation exposure. The endogenous C:N ratio in blastospore composition was also impacted by nitrogen sources. Bioassays with mealworm larvae demonstrated that blastospores from cottonseed flour were the most virulent, achieving faster lethality (lower LT50) and requiring a lower inoculum (LC50). Importantly, blastospores produced with cottonseed flour displayed extended viability during storage, surpassing the retention of viability compared to those from autolyzed yeast over 180 days at 4°C. Despite differences in storage viability, both nitrogen sources conferred similar long-term blastospore bioactivity against mealworms. In summary, this research advances our understanding of the crucial impact of complex organic nitrogen selection on the phenotypic traits of blastospores in association with their intracellular C:N ratio, contributing to the production of ecologically fit, shelf-stable, and virulent propagules for effective pest biocontrol programs. IMPORTANCE Biological control through entomopathogenic fungi provides essential ecological services in the integrated management of agricultural pests. In the context of submerged liquid fermentation, the nutritional composition significantly influences the ecological fitness, virulence and quality of these fungi. This study specifically explores the impact of various complex organic nitrogen sources derived from agro-industrial byproducts on the submerged liquid fermentation of Beauveria bassiana, a versatile entomopathogenic fungus known for producing hydrophilic yeast-like blastospores. Notably, manipulating the nitrogen source during submerged cultivation can influence the quality, fitness, and performance of blastospores. This research identifies cottonseed flour as the optimal low-cost nitrogen source, contributing to increased production yields, enhanced multi-stress tolerance, heightened virulence with extended shelf life and long-term bioactivity. These findings deepen our understanding of the critical role of nitrogen compound selection in liquid media formulation, facilitating the production of ecologically fit and virulent blastospores for more effective pest biocontrol programs.
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Affiliation(s)
- Valesca Henrique Lima
- Programa de Pós-graduação em Ciência Animal, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | | | - Gabriel Moura Mascarin
- Laboratório de Microbiologia Ambiental, Embrapa Meio Ambiente, Jaguariúna, São Paulo, Brazil
| | - Éverton Kort Kamp Fernandes
- Programa de Pós-graduação em Ciência Animal, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
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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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Gagnon AÈ, Fortier AM, Audette C. Biological Control and Habitat Management for the Control of Onion Thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), in Onion Production in Quebec, Canada. INSECTS 2024; 15:232. [PMID: 38667362 PMCID: PMC11050518 DOI: 10.3390/insects15040232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/19/2024] [Accepted: 03/21/2024] [Indexed: 04/28/2024]
Abstract
Onion thrips (Thrips tabaci) can pose a significant threat to onion crops, causing leaf damage, reduced bulb size and quality, and yield loss during severe infestations. Conventional insecticide use has been the primary method for managing this pest species, but the efficacy of this approach is inconsistent. Furthermore, emerging pest resistance is a growing concern in some regions. This two-year field study aimed to assess the effectiveness of several pest management strategies in controlling onion thrips populations and limiting their impact on onion yields. The strategies tested consisted of habitat manipulations (including flower strips and straw mulch), biological control agents (Stratiolaelaps scimitus, Neoseiulus cucumeris, Amblyseius swirskii, and Beauveria bassiana), as well as physical barrier control methods (exclusion nets, kaolin, and mineral oil). Habitat manipulation techniques, particularly the use of flower strips, reduced thrips populations by up to 50% and increased onion yields by 25%. In contrast, exclusion nets had a detrimental effect on onion yields, and the other alternative control methods produced results comparable to those obtained for untreated controls. When used alone, biological control agents were not effective at maintaining thrips populations below economically damaging levels. This study offers valuable insights into effective and sustainable pest management practices for the onion industry.
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Affiliation(s)
- Annie-Ève Gagnon
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, 430 Gouin Boulevard, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada;
| | - Anne-Marie Fortier
- Compagnie de Recherche Phytodata Inc., 291 Rue de la Coopérative, Sherrington, QC J0L 2N0, Canada;
| | - Carolane Audette
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, 430 Gouin Boulevard, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada;
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Fernández-Bravo M, Bonnet J, Quesada-Moraga E, Garrido-Jurado I. Imperfect match between radiation exposure times required for conidial viability loss and infective capacity reduction attenuate UV-B impact on Beauveria bassiana. PEST MANAGEMENT SCIENCE 2024; 80:1557-1565. [PMID: 37964642 DOI: 10.1002/ps.7889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/26/2023] [Accepted: 11/15/2023] [Indexed: 11/16/2023]
Abstract
BACKGROUND UV-B radiation represents a significant challenge for the widespread use of entomopathogenic fungi in pest management. This study focused on research of the asynchronous response between virulence and conidial viability against Ceratitis capitata adults using specific statistical models. Moreover, it was also investigated whether the observed differences in susceptibility to UV-B radiation in in vitro assays among three selected isolates of Beauveria bassiana were reflected in the above-mentioned asynchrony. RESULTS While the irradiation of the three isolates of B. bassiana was associated with a significant loss of conidial viability, their virulence was not significantly affected compared to nonirradiated treatments when exposed to 1200 mW m-2 for 6 h before or after the inoculation of C. capitata. In fact, the irradiation time needed to reduce the mortality to 50% compared to the controls was 34.69 h for EABb 10/225-Fil, 16.36 h for EABb 09/20-Fil, and 24.59 h for EABb 09/28-Fil. Meanwhile, the irradiation time necessary to reduce conidial viability to 50% was 9.89 h for EABb 10/225-Fil, 8.74 h for EABb 09/20-Fil, and 4.71 h for EABb 09/28-Fil. CONCLUSION These results highlight the importance of modeling the response of entomopathogenic fungi virulence and conidial susceptibility when exposed to UV-B radiation for the selection of environmentally competent isolates, regardless of the results obtained in previous in vitro assays on conidial germination. This strategic approach is critical in overcoming the challenges posed by UV-B radiation and holds the key to realizing the full potential of entomopathogenic fungi in pest management. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- María Fernández-Bravo
- Agricultural Entomology, Department of Agronomy, Excellence Unit María de Maeztu (DAUCO), ETSIAM, University of Cordoba, Córdoba, Spain
| | - Jolijn Bonnet
- Agricultural Entomology, Department of Agronomy, Excellence Unit María de Maeztu (DAUCO), ETSIAM, University of Cordoba, Córdoba, Spain
| | - Enrique Quesada-Moraga
- Agricultural Entomology, Department of Agronomy, Excellence Unit María de Maeztu (DAUCO), ETSIAM, University of Cordoba, Córdoba, Spain
| | - Inmaculada Garrido-Jurado
- Agricultural Entomology, Department of Agronomy, Excellence Unit María de Maeztu (DAUCO), ETSIAM, University of Cordoba, Córdoba, Spain
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Yu L, Xu SY, Luo XC, Ying SH, Feng MG. High photoreactivation activities of Rad2 and Rad14 in recovering insecticidal Beauveria bassiana from solar UV damage. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2024; 251:112849. [PMID: 38277960 DOI: 10.1016/j.jphotobiol.2024.112849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/28/2023] [Accepted: 01/21/2024] [Indexed: 01/28/2024]
Abstract
Anti-ultraviolet (UV) roles of Rad2 and Rad14 depend on nucleotide excision repair (NER) of UV-induced DNA lesions in budding yeast but remain unexplored yet in filamentous fungi. Here, nucleus-specific Rad2 and Rad14 orthologs are shown to recover Beauveria bassiana, a main source of wide-spectrum mycoinsecticides, from solar UV damage through photorepair-depending photoreactivation. As a photorepair index, photoreactivation (germination) rates of lethal UVB dose-irradiated conidia via a 3- or 5-h light plus 9- or 7-h dark incubation at 25 °C were drastically reduced in the Δrad2 and Δrad14 mutants versus a wild-type strain. As an NER index, nighttime-mimicking 12-h dark reactivation rates of low UVB dose-impaired conidia decreased sharply compared to the corresponding photoreactivation rates in the presence or absence of either ortholog, indicating that its extant NER activity was limited to recovering light UVB damage in the field. The high photoreactivation activity of either Rad2 or Rad14 was derived from its tight link to a large protein complex formed by photolyase regulators and other anti-UV proteins through multiple protein-protein interactions revealed by yeast two-hybrid assays. Therefore, Rad2 and Rad14 recover B. bassiana from solar UV damage through photoreactiovation in vivo that depends primarily on photorepair, although they contribute little to the fungal lifecycle-related phenotypes. These findings unveil a novel scenario distinguished from the NER-depending anti-UV roles of Rad2 and Rad14 in the model yeast and broaden a biological basis crucial for rational application of fungal insecticides to improve pest control efficacy via feasible recovery of solar UV damage.
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Affiliation(s)
- Lei Yu
- 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
| | - Xin-Cheng Luo
- 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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Sun YX, Zhang BX, Zhang WT, Wang Q, Toufeeq S, Rao XJ. UV-induced mutagenesis of Beauveria bassiana (Hypocreales: Clavicipitaceae) yields two hypervirulent isolates with different transcriptomic profiles. PEST MANAGEMENT SCIENCE 2023. [PMID: 36914429 DOI: 10.1002/ps.7452] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/31/2023] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND The fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) can infest over 300 plant species and cause huge economic losses. Beauveria bassiana (Hypocreales: Clavicipitaceae) is one of the most widely used entomopathogenic fungi (EPF). Unfortunately, the efficacy of B. bassiana against S. frugiperda is quite low. Hypervirulent EPF isolates can be obtained by ultraviolet (UV)-irradiation. Here we report on the UV-induced mutagenesis and transcriptomic analysis of B. bassiana. RESULTS The wild-type (WT) B. bassiana (ARSEF2860) was exposed to UV light to induce mutagenesis. Two mutants (named 6M and 8M) showed higher growth rates, conidial yields, and germination rates compared to the WT strain. The mutants showed higher levels of tolerance to osmotic, oxidative, and UV stresses. The mutants showed higher protease, chitinase, cellulose, and chitinase activities than WT. Both WT and mutants were compatible with the insecticides matrine, spinetoram, and chlorantraniliprole, but incompatible with emamectin benzoate. Insect bioassays showed that both mutants were more virulent against S. frugiperda and the greater wax moth Galleria mellonella. Transcriptomic profiles of the WT and mutants were determined by RNA-sequencing. The differentially expressed genes (DEGs) were identified. The gene set enrichment analysis (GSEA), protein-protein interaction (PPI) network, and hub gene analysis revealed virulence-related genes. CONCLUSION Our data demonstrate that UV-irradiation is a very efficient and economical technique to improve the virulence and stress resistance of B. bassiana. Comparative transcriptomic profiles of the mutants provide insights into virulence genes. These results provide new ideas for improving the genetic engineering and field efficacy of EPF. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Yan-Xia Sun
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, China
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Hefei, China
| | - Bang-Xian Zhang
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, China
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Hefei, China
- Department of Science and Technology, Chuzhou University, Chuzhou, China
| | - Wen-Ting Zhang
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, China
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Hefei, China
| | - Qian Wang
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, China
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Hefei, China
| | - Shahzad Toufeeq
- Key Laboratory of Insect Development and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Xiang-Jun Rao
- Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, School of Plant Protection, Anhui Agricultural University, Hefei, China
- Anhui Province Key Laboratory of Integrated Pest Management on Crops, Hefei, China
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Proteomic Analysis of a Hypervirulent Mutant of the Insect-Pathogenic Fungus Metarhizium anisopliae Reveals Changes in Pathogenicity and Terpenoid Pathways. Microbiol Spectr 2022; 10:e0076022. [PMID: 36314906 PMCID: PMC9769655 DOI: 10.1128/spectrum.00760-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Metarhizium anisopliae is a commercialized entomopathogenic fungus widely used for the control of insect pests. Significant efforts have been expended to screen and/or select for isolates that display increased virulence toward target insect hosts. UV-induced mutagenesis has resulted in the isolation of a number of hypervirulent M. anisopliae mutants; however, the underlying mechanisms that have led to the desired phenotype have yet to be characterized. Here, we performed a comparative proteomic analysis of an M. anisopliae UV-induced hypervirulent mutant (MaUV-HV) and its wild-type parent using tandem mass tag (TMT)-based quantitative proteomics. A total of 842 differentially abundant proteins were identified, with 360 being more abundant in the hypervirulent mutant and 482 in the wild-type parent. In terms of differential abundance, the critical pathways affected included those involved in secondary metabolite production, virulence, and stress response. In addition, a number of genes involved in terpenoid biosynthesis pathways were identified as significantly mutated in the MaUV-HV strain. In particular, mutations in the farnesyl pyrophosphate synthase (FPPS1) and geranylgeranyl diphosphate synthase (GGPPS5) genes were seen. The effects of the FPPS1 mutation were confirmed via the construction and characterization of a targeted gene knockout strain (ΔMaFPPS1). The overall effects of the mutations were increased resistance to UV stress, faster growth, and increased virulence. These results provide mechanistic insights and new avenues for modulating fungal virulence in efforts to increase the biological control potential of insect-pathogenic fungi. IMPORTANCE The mechanisms that underlie and contribute to microbial (fungal) virulence are known to be varied; however, the identification of contributing pathways beyond known virulence factors remains difficult. Using TMT-based proteomic analyses, changes in the proteomes of an M. anisopliae hypervirulent mutant and its wild-type parent were determined. These data revealed alterations in pathogenicity, stress, and growth/developmental pathways, as well as pathways not previously known to affect virulence. These include terpenoid pathways that can be manipulated to increase the efficacy of fungal insect biological control agents for increased sustainable pest control.
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Fuentes E, Pérez-Velón D, Prieto B. Effects of changes in UV-B radiation levels on biofilm-forming organisms commonly found in cultural heritage surfaces. ENVIRONMENTAL RESEARCH 2022; 214:114061. [PMID: 35985488 DOI: 10.1016/j.envres.2022.114061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/18/2022] [Accepted: 08/03/2022] [Indexed: 06/15/2023]
Abstract
Accurate measuring and monitoring methods available since the 1980s have shown that the amount of Ultraviolet B (UV-B) radiation reaching the Earth's surface has increased as a result of degradation of the ozone layer. Since the adoption of the Montreal Protocol in 1987, ozone levels have been recovering successfully. However, in the context of the current climate change, other factors such as changes in cloud patterns and an increased incidence of natural disasters (e.g. fires) may be disrupting this recovery. The present study aimed to investigate the effects of different UV-B radiation levels on biofilms colonising heritage monuments. For this purpose, the effects of current UV-B levels on a biofilm composed of Synechocystis sp. (a cyanobacterium), Bracteacoccus minor (a green alga) and Fusarium sp. (a fungus) were compared at three points along a South-North transect: Portugal, Galicia (NW Spain) and Ireland (from highest to lowest UV-B radiation, respectively). Increased levels of UV-B radiation caused changes in the growth, physiological state and composition of subaerial biofilms, with cyanobacteria being more resistant than green algae to high levels of UV-B. A reduction of fungal growth and extracellular polymer substances (EPS) production was also observed, related to the reduction of biofilm aggregation at high UV-B levels.
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Affiliation(s)
- Elsa Fuentes
- Departamento Edafoloxía e Química Agrícola, Facultad de Farmacia, Universidade Santiago de Compostela, 15782 Santiago de Compostela, Spain.
| | - Diana Pérez-Velón
- Departamento Edafoloxía e Química Agrícola, Facultad de Farmacia, Universidade Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Beatriz Prieto
- Departamento Edafoloxía e Química Agrícola, Facultad de Farmacia, Universidade Santiago de Compostela, 15782 Santiago de Compostela, Spain
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12
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Willden SA, Ugine TA, Loeb GM. The effect of UVB-blocking plastics on the efficacy of Beauveria bassiana and a conventional product against Lygus lineolaris on low tunnel strawberry. PEST MANAGEMENT SCIENCE 2022; 78:4268-4277. [PMID: 35716065 DOI: 10.1002/ps.7046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/14/2022] [Accepted: 06/18/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Effective, safe and practical biocontrol options are greatly needed for combating Lygus lineolaris on protected culture strawberry. This study demonstrated how ultaviolet (UV)-selective plastics can improve the efficacy of the fungal biocontrol agent Beauveria bassiana (Mycotrol) compared to the conventional insecticide acetamiprid (Assail) against L. lineolaris on low tunnel strawberry. RESULTS We found that UVB-blocking treatments improved B. bassiana spore viability in both in vitro and in vivo laboratory experiments. In the field, survival of Mycotrol-treated sentinel L. lineolaris was lowest under UVB-blocking low tunnels, but this did not translate into significant differences among covering treatments in local L. lineolaris density or fruit damage. In contrast, applying the product Assail resulted in the lowest L. lineolaris density and highest quality yield compared to Mycotrol sprays. This was especially pronounced under low tunnels of any UV-limiting plastic. CONCLUSIONS This study indicates that growing under low tunnels is a useful tool to improve the efficacy of conventional products and biopesticides containing microbial biocontrol agents. The efficacy of both products was improved under low tunnels, and specifically under UVB-blocking plastics for Mycotrol containing B. bassiana. However, there was little evidence that UVB plastics resulted in lower L. lineolaris densities and proportion of damaged fruit for either product in the field. Therefore we conclude that growing under any plastic covering is likely to benefit growers, but the economic value of growing under UVB tunnels is unclear. © 2022 Society of Chemical Industry.
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Affiliation(s)
| | - Todd A Ugine
- Department of Entomology, Cornell University, Ithaca, NY, USA
| | - Gregory M Loeb
- Department of Entomology, Cornell AgriTech, Geneva, NY, USA
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13
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Physiological and Molecular Response Modifications by Ultraviolet-C Radiation in Plutella xylostella and Its Compatibility with Cordyceps fumosorosea. Int J Mol Sci 2022; 23:ijms23179800. [PMID: 36077199 PMCID: PMC9456147 DOI: 10.3390/ijms23179800] [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: 06/30/2022] [Revised: 08/19/2022] [Accepted: 08/24/2022] [Indexed: 11/21/2022] Open
Abstract
Ultraviolet-C (UV-C) radiation significantly impacts living organisms. UV-C radiation can also be used as a pest management tool. Therefore, this study was designed to investigate the effect of UV-C radiation on the physiology and gene expression level of Plutella xylostella, a destructive vegetable pest. Results showed that, after exposure to UV-C radiation for 3, 6, 12, and 24 h, the activity of SOD (superoxide dismutase) and CAT (catalase) of P. xylostella increased, while the activity of PPO (polyphenol oxidase), POD (peroxidase), AChE (acetylcholinesterase), CarE (carboxylesterase), and ACP (acid phosphatase) decreased with increased exposure time. Correlation coefficient analyses indicated that the activity of CAT correlated positively, while PPO and CarE correlated negatively, with exposure time. Gene regulation analysis via qRT-PCR confirmed a significant increase in regulation in CAT, CarE, and PPO-related genes. We also investigated the effect of UV-C exposure on the virulence of Cordyceps fumosorosea against P. xylostella. Here, results indicated that when the fungal treatment was applied to larvae before UV-C radiation, the virulence of C. fumosorosea was significantly reduced. However, this decline in virulence of C. fumosorosea due to UV-C exposure remained only for one generation, and no effect was observed on secondary infection. On the other hand, when larvae were exposed to UV-C radiation before fungal application, the mortality rate significantly increased as the exposure time to UV-C radiation increased. From the current study, it could be concluded that UV-C exposure suppressed the immunity to P. xylostella, which later enhanced the virulence of entomopathogenic fungi. Moreover, the study also suggested that UV irradiation is an effective pest management tool that could be incorporated into pest management strategies, which could help reduce pesticide application, be economically beneficial for the farmer, and be environmentally safe.
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14
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Wong HJ, Mohamad-Fauzi N, Rizman-Idid M, Convey P, Smykla J, Alias SA. UV-B-induced DNA damage and repair pathways in polar Pseudogymnoascus sp. from the Arctic and Antarctic regions and their effects on growth, pigmentation, and coniodiogenesis. Environ Microbiol 2022; 24:3164-3180. [PMID: 35621047 DOI: 10.1111/1462-2920.16073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 05/13/2022] [Accepted: 05/13/2022] [Indexed: 11/30/2022]
Abstract
Solar radiation regulates most biological activities on Earth. Prolonged exposure to solar UV radiation can cause deleterious effects by inducing two major types of DNA damage, namely cyclobutane pyrimidine dimers (CPDs) and pyrimidine 6-4 pyrimidone photoproducts (6-4PPs). These lesions may be repaired by the photoreactivation (Phr) and nucleotide excision repair (NER) pathways; however, the principal UV-induced DNA repair pathway is not known in the fungal genus Pseudogymnoascus. In this study, we demonstrated that an unweighted UV-B dosage of 1.6 kJ m-2 d-1 significantly reduced fungal growth rates (by between 22 and 35%) and inhibited conidia production in a 10 d exposure. The comparison of two DNA repair conditions, light or dark, which respectively induced photoreactivation (Phr) and nucleotide excision repair (NER), showed that the UV-B induced CPDs were repaired significantly more rapidly in light than in dark conditions. The expression levels of two DNA repair genes, RAD2 and PHR1 (encoding a protein in NER and Phr, respectively) demonstrated that NER rather than Phr was primarily activated for repairing UV-B-induced DNA damage in these Pseudogymnoascus strains. In contrast, Phr was inhibited after exposure to UV-B radiation, suggesting that PHR1 may have other functional roles. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Hao Jie Wong
- Laboratory of Gene Regulation Research, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara, Japan
| | - Nuradilla Mohamad-Fauzi
- Institute of Ocean and Earth Sciences, Institute for Advanced Studies, Universiti Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia.,Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia.,National Antarctic Research Centre, Institute for Advanced Studies, Universiti Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia
| | - Mohammed Rizman-Idid
- Institute of Ocean and Earth Sciences, Institute for Advanced Studies, Universiti Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia.,National Antarctic Research Centre, Institute for Advanced Studies, Universiti Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia
| | - Peter Convey
- British Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge, United Kingdom.,National Antarctic Research Centre, Institute for Advanced Studies, Universiti Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia.,Department of Zoology, University of Johannesburg, Auckland Park, South Africa
| | - Jerzy Smykla
- Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33, Kraków, Poland
| | - Siti Aisyah Alias
- Institute of Ocean and Earth Sciences, Institute for Advanced Studies, Universiti Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia.,National Antarctic Research Centre, Institute for Advanced Studies, Universiti Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia
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15
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Wang Y, Fan Q, Wang D, Zou WQ, Tang DX, Hongthong P, Yu H. Species Diversity and Virulence Potential of the Beauveria bassiana Complex and Beauveria scarabaeidicola Complex. Front Microbiol 2022; 13:841604. [PMID: 35317260 PMCID: PMC8934399 DOI: 10.3389/fmicb.2022.841604] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/14/2022] [Indexed: 12/02/2022] Open
Abstract
Beauveria is a very important fungal resource. Some Beauveria species have great economic and ecological value. Through surveying Beauveria in China and Thailand over the past 4 years, 15 Beauveria spp. were collected and identified. Three new species—namely, B. polyrhachicola, B. songmingensis, and B. subscarabaeidicola—were described and illustrated based on morphological characteristics and molecular data. The phylogenetic positions of the 15 species were evaluated according to phylogenetic inferences based on six loci (nrSSU, nrLSU, TEF, RPB1, RPB2, and Bloc). Nine species of Beauveria in our study were isolated from adult scarab beetles (Coleoptera: Scarabaeidae). The pathogenicity of the isolates from the B. bassiana complex and B. scarabaeidicola complex was determined with three bioassays using B. mori and T. molitor larvae, in addition to Protaetia brevitarsis adults. The results indicated that the B. bassiana complex isolates had great potential in the biocontrol of the three insects; by contrast, the B. scarabaeidicola complex isolates showed obvious host specificity and low virulence.
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Affiliation(s)
- Yao Wang
- Yunnan Herbal Laboratory, School of Ecology and Environmental Science, Yunnan University, Kunming, China
- The International Joint Research Center for Sustainable Utilization of Cordyceps Bioresources in China and Southeast Asia, Yunnan University, Kunming, China
| | - Qi Fan
- Yunnan Herbal Laboratory, School of Ecology and Environmental Science, Yunnan University, Kunming, China
- The International Joint Research Center for Sustainable Utilization of Cordyceps Bioresources in China and Southeast Asia, Yunnan University, Kunming, China
| | - Dong Wang
- Yunnan Herbal Laboratory, School of Ecology and Environmental Science, Yunnan University, Kunming, China
- The International Joint Research Center for Sustainable Utilization of Cordyceps Bioresources in China and Southeast Asia, Yunnan University, Kunming, China
| | - Wei-Qiu Zou
- Yunnan Herbal Laboratory, School of Ecology and Environmental Science, Yunnan University, Kunming, China
- The International Joint Research Center for Sustainable Utilization of Cordyceps Bioresources in China and Southeast Asia, Yunnan University, Kunming, China
| | - De-Xiang Tang
- Yunnan Herbal Laboratory, School of Ecology and Environmental Science, Yunnan University, Kunming, China
- The International Joint Research Center for Sustainable Utilization of Cordyceps Bioresources in China and Southeast Asia, Yunnan University, Kunming, China
| | - Preeyanat Hongthong
- Faculty of Agricultural Technology, Rajamangala University of Technology, Thanyaburi, Thailand
| | - Hong Yu
- Yunnan Herbal Laboratory, School of Ecology and Environmental Science, Yunnan University, Kunming, China
- The International Joint Research Center for Sustainable Utilization of Cordyceps Bioresources in China and Southeast Asia, Yunnan University, Kunming, China
- *Correspondence: Hong Yu,
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Enhancing the Biocontrol Potential of the Entomopathogenic Fungus in Multiple Respects via the Overexpression of a Transcription Factor Gene MaSom1. J Fungi (Basel) 2022; 8:jof8020105. [PMID: 35205860 PMCID: PMC8879238 DOI: 10.3390/jof8020105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 12/22/2022] Open
Abstract
Entomopathogenic fungi play important roles in the control of populations of agricultural and disease vector pests in nature. The shortcomings of mycoinsecticides for pest management in the field cannot be completely overcome by improving single biocontrol properties of fungi. Therefore, enhancing the biocontrol potential of entomopathogenic fungi in multiple respects by genetic engineering is desirable. Transcription factors are usually involved in various important processes during fungal growth and pathogenesis via regulating a series of genes, and are important candidates for fungal improvement via genetic engineering. Herein, overexpression of MaSom1, a key transcription factor gene in the cAMP/PKA pathway, improves the biocontrol traits of Metarhizium acridum in multiple respects. When compared with WT, the MaSom1-overexpression strains exhibit enhanced tolerances to UV-B and heat shock, with increased mean 50% inhibition times by 66.9% and 155.2%, respectively. Advanced conidiation emerged accompanied by increased conidial yield up to 3.89 times after 3-day incubation for the MaSom1-overexpression strains compared to WT. Furthermore, when compared with WT, the virulence of the MaSom1-overexpression strains was also increased with the mean 50% lethality times reduced by 21.8% to 23.8%. Taken together, the MaSom1-overexpression improved the biocontrol potential of M. acridum in multiple respects. Our results provide insights into the application of key transcription factors for genetic engineering and offer a credible way to further improve the biocontrol potential of entomopathogenic fungi.
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17
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Sutanto KD, Husain M, Rasool KG, Malik AF, Al-Qahtani WH, Aldawood AS. Persistency of Indigenous and Exotic Entomopathogenic Fungi Isolates under Ultraviolet B (UV-B) Irradiation to Enhance Field Application Efficacy and Obtain Sustainable Control of the Red Palm Weevil. INSECTS 2022; 13:103. [PMID: 35055945 PMCID: PMC8780514 DOI: 10.3390/insects13010103] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/05/2022] [Accepted: 01/07/2022] [Indexed: 11/16/2022]
Abstract
The red palm weevil Rhynchophorus ferrugineus Olivier (Coleoptera: Dryophthoridae) has become a key invasive pest and major threat to the palm tree worldwide. Several entomopathogenic fungi are used in insect biological control programs. In the present study, persistency of different local and exotic fungal isolates of Beauveria bassiana and Metarhizium anisopliae was evaluated under UV-B irradiation with different exposure intervals. Several factors, including ultraviolet (UV) light, significantly decrease germination rate of fungi, as UV penetrates and damages their DNA. Several studies have investigated that UV-resistant conidia germinate better under harsh environmental conditions. Seven local and exotic fungi isolates ("BbSA-1", "BbSA-2", "BbSA-3", "MaSA-1", "BbIDN-1", "MaIDN-1", and "MaIDN-2") were tested in the current study under UV-B irradiation having different UV exposure times (i.e., 15, 30, 60, 120, 180, 240, and 300 min). The colony-forming unit (CFU) in each isolate was used to calculate the survival rate. Results indicated that survival rate of all the isolates decreased under UV-B irradiation for all exposure times compared to no exposure to UV-B irradiation. The CFU number decreased as the exposure time increased. Fungi isolates "MaSA-1", "BbSA-1", "BbSA-2", "MaIDN-1", and "MaIDN-2" could persist after 300 min exposure to UV-B, while the remaining isolates, such as "BbIDN-1", and "BbSA-3", could not persist after 300 min exposure to UV-B. The ultimate objective of the present research was to explore an ultraviolet-tolerant fungal isolate that might be useful in the field application for the sustainable management of the red palm weevil, which has become a key invasive pest in many regions rather than its native range. Most of the fungus isolates studied in the present work were collected from Saudi Arabia's Al-Qatif region, where the red palm weevil has infested more than ten thousand trees, worth millions of riyals.
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Affiliation(s)
- Koko Dwi Sutanto
- Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia; (K.D.S.); (K.G.R.); (A.S.A.)
| | - Mureed Husain
- Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia; (K.D.S.); (K.G.R.); (A.S.A.)
| | - Khawaja Ghulam Rasool
- Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia; (K.D.S.); (K.G.R.); (A.S.A.)
| | - Akhmad Faisal Malik
- Directorate of Estate Crops Protection, Ministry of Agriculture, Jakarta 12550, Indonesia;
| | - Wahidah Hazza Al-Qahtani
- Department of Food Sciences and Nutrition, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia;
| | - Abdulrahman Saad Aldawood
- Department of Plant Protection, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia; (K.D.S.); (K.G.R.); (A.S.A.)
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18
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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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19
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Couceiro JDC, Fatoretto MB, Demétrio CGB, Meyling NV, Delalibera Í. UV-B Radiation Tolerance and Temperature-Dependent Activity Within the Entomopathogenic Fungal Genus Metarhizium in Brazil. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:645737. [PMID: 37744102 PMCID: PMC10512313 DOI: 10.3389/ffunb.2021.645737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 02/15/2021] [Indexed: 09/26/2023]
Abstract
Metarhizium comprises a phylogenetically diverse genus of entomopathogenic fungi. In Brazil, Metarhizium anisopliae s.str. subclade Mani 2 is predominantly isolated from insects, while M. robertsii and M. brunneum mostly occur in the soil environment. Solar radiation and high temperatures are important abiotic factors that can be detrimental to fungal propagules. We hypothesized that among 12 Brazilian isolates of Metarhizium spp., M. anisopliae Mani 2 (n = 6), being adapted to abiotic conditions of the phylloplane, is more tolerant to UV light and high temperatures than M. robertsii (n = 3) and M. brunneum (n = 3). Inoculum of each isolate was exposed to UV-B for up to 8 h and viability evaluated 48 h later. After 8 h under UV-B, most of the isolates had germination rates below 5%. Discs of mycelia were incubated at different temperatures, and diameter of colonies were recorded for 12 days. Mycelia of M. robertsii isolates grew faster at 33 °C, while M. anisopliae and M. brunneum grew most at 25 °C. Dry conidia were incubated at 20, 25 or 40 °C for 12 days, and then viabilities were examined. At 40 °C, conidia of five M. anisopliae isolates were the most tolerant. In the three experiments, considerable intra- and inter-specific variability was detected. The results indicate that conclusions about tolerance to these abiotic factors should be made only at the isolate level.
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Affiliation(s)
- Joel da Cruz Couceiro
- Laboratory of Pathology and Microbial Control of Insects, Department of Entomology and Acarology, “Luiz de Queiroz” College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, Brazil
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maíra Blumer Fatoretto
- Department of Exact Sciences, “Luiz de Queiroz” College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, Brazil
| | - Clarice Garcia Borges Demétrio
- Department of Exact Sciences, “Luiz de Queiroz” College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, Brazil
| | - Nicolai Vitt Meyling
- Section for Organismal Biology, Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ítalo Delalibera
- Laboratory of Pathology and Microbial Control of Insects, Department of Entomology and Acarology, “Luiz de Queiroz” College of Agriculture, University of São Paulo (ESALQ/USP), Piracicaba, Brazil
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20
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Rosana ARR, Pokorny S, Klutsch JG, Ibarra-Romero C, Sanichar R, Engelhardt D, van Belkum MJ, Erbilgin N, Bohlmann J, Carroll AL, Vederas JC. Selection of entomopathogenic fungus Beauveria bassiana (Deuteromycotina: Hyphomycetes) for the biocontrol of Dendroctonus ponderosae (Coleoptera: Curculionidae, Scolytinae) in Western Canada. Appl Microbiol Biotechnol 2021. [PMID: 33590267 DOI: 10.1007/s00253-021-11172-7/published] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2023]
Abstract
The mountain pine beetle, Dendroctonus ponderosae, has infested over ~16 Mha of pine forests in British Columbia killing >50% of mature lodgepole pine, Pinus contorta, trees in affected stands. At present, it is functionally an invasive species in Alberta, killing and reproducing in evolutionarily naïve populations of lodgepole pine (P. contorta), novel jack pine (P. banksiana), and their hybrids. The entomopathogenic fungus Beauveria bassiana has shown some potential as a biocontrol agent of several bark beetle species. In this study, nine isolates of B. bassiana were examined for insect virulence characteristics, including conidiation rate, pigmentation, and infection rate in laboratory-reared D. ponderosae, to assess for their potential as biocontrol agents. The strains were categorized into three phenotypic groups based on pigmentation, conidial density, and myceliation rate. Virulence screening utilizing insect-based agar medium (D. ponderosae and European honeybee Apis mellifera carcasses) revealed no difference in selection of fungal growth. However, infection studies on D. ponderosae and A. mellifera showed contrasting results. In vivo A. mellifera infection model revealed ~5% mortality, representing the natural death rate of the hive population, whereas laboratory-reared D. ponderosae showed 100% mortality and mycosis. The LT50 (median lethal time 50) ranges from 2 to 5 ± 0.33 days, and LT100 ranges from 4 to 6 ± 0.5 days. We discuss the selective advantages of the three phenotypic groups in terms of virulence, pigmentation, conidial abundance, and tolerance to abiotic factors like UV and host tree monoterpenes. These results can further provide insights into the development of several phenotypically diverse B. bassiana strains in controlling the spread of the invasive D. ponderosae in Western Canada. KEY POINTS: • Three B. bassiana morphotype groups have been demonstrated to kill D. ponderosae. • A range of effective lethal times (LT50 and LT100) was established against D. ponderosae. • Variable tolerance to UV light and pine monoterpenes were observed in B. bassiana.
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Affiliation(s)
| | - Stanley Pokorny
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Jennifer G Klutsch
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | | | - Randy Sanichar
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Daniel Engelhardt
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Marco J van Belkum
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada
| | - Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, Edmonton, AB, T6G 2E3, Canada
| | - Joerg Bohlmann
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Allan L Carroll
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - John C Vederas
- Department of Chemistry, University of Alberta, Edmonton, AB, T6G 2G2, Canada.
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Selection of entomopathogenic fungus Beauveria bassiana (Deuteromycotina: Hyphomycetes) for the biocontrol of Dendroctonus ponderosae (Coleoptera: Curculionidae, Scolytinae) in Western Canada. Appl Microbiol Biotechnol 2021; 105:2541-2557. [PMID: 33590267 DOI: 10.1007/s00253-021-11172-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/25/2021] [Accepted: 02/03/2021] [Indexed: 10/22/2022]
Abstract
The mountain pine beetle, Dendroctonus ponderosae, has infested over ~16 Mha of pine forests in British Columbia killing >50% of mature lodgepole pine, Pinus contorta, trees in affected stands. At present, it is functionally an invasive species in Alberta, killing and reproducing in evolutionarily naïve populations of lodgepole pine (P. contorta), novel jack pine (P. banksiana), and their hybrids. The entomopathogenic fungus Beauveria bassiana has shown some potential as a biocontrol agent of several bark beetle species. In this study, nine isolates of B. bassiana were examined for insect virulence characteristics, including conidiation rate, pigmentation, and infection rate in laboratory-reared D. ponderosae, to assess for their potential as biocontrol agents. The strains were categorized into three phenotypic groups based on pigmentation, conidial density, and myceliation rate. Virulence screening utilizing insect-based agar medium (D. ponderosae and European honeybee Apis mellifera carcasses) revealed no difference in selection of fungal growth. However, infection studies on D. ponderosae and A. mellifera showed contrasting results. In vivo A. mellifera infection model revealed ~5% mortality, representing the natural death rate of the hive population, whereas laboratory-reared D. ponderosae showed 100% mortality and mycosis. The LT50 (median lethal time 50) ranges from 2 to 5 ± 0.33 days, and LT100 ranges from 4 to 6 ± 0.5 days. We discuss the selective advantages of the three phenotypic groups in terms of virulence, pigmentation, conidial abundance, and tolerance to abiotic factors like UV and host tree monoterpenes. These results can further provide insights into the development of several phenotypically diverse B. bassiana strains in controlling the spread of the invasive D. ponderosae in Western Canada. KEY POINTS: • Three B. bassiana morphotype groups have been demonstrated to kill D. ponderosae. • A range of effective lethal times (LT50 and LT100) was established against D. ponderosae. • Variable tolerance to UV light and pine monoterpenes were observed in B. bassiana.
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Wu S, Toews MD, Oliveira-Hofman C, Behle RW, Simmons AM, Shapiro-Ilan DI. Environmental Tolerance of Entomopathogenic Fungi: A New Strain of Cordyceps javanica Isolated from a Whitefly Epizootic Versus Commercial Fungal Strains. INSECTS 2020; 11:insects11100711. [PMID: 33080830 PMCID: PMC7602971 DOI: 10.3390/insects11100711] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/10/2020] [Accepted: 10/14/2020] [Indexed: 12/20/2022]
Abstract
Simple Summary Whiteflies are significant pests of cotton and vegetables in southeastern USA. In previous studies, we isolated and identified a new strain of entomopathogenic fungus that caused epizootics among whiteflies in cotton fields of Southern Georgia, USA. The objective of this study was to test the level of tolerance of this new strain to environmental conditions as compared to commercial fungal strains. We exposed the new strain and three commercially available strains of biopesticides (BotaniGard, Met52, and PFR-97) to different temperatures and strong ultraviolet (UV) radiation before examining post-treatment viability and virulence against a common model organism for insect pathology, the greater wax moth larvae. We found that the new strain had similar levels of activity to commercial strains at moderate temperatures, but higher tolerance than PFR-97 to extremely low and high temperatures and strong UV intensity. These findings suggest that the new fungal strain has potential for commercial development as an alternative to PFR-97 for managing certain types of insect pests. Abstract A new strain of Cordyceps javanica (wf GA17) was observed causing widespread epizootics among whiteflies in Southern Georgia in 2017. The tolerance of conidia to environmental factors including variable temperature and ultraviolet (UV) light was compared between this strain and three commercial strains of entomopathogenic fungi (Metarhizium brunneum F52, Cordyceps fumosorosea Apopka97, and Beauveria bassiana GHA). Under 10–30 °C, C. javanica wf GA17 responded similarly to other fungi, with the highest virulence against Galleria mellonella at 25 °C, followed by 20, 30, and 15 °C; lowest virulence was observed at 10 °C. At 35 °C and 40 °C, C. javanica wf GA17 had lower tolerance than M. brunneum F52 and B. bassiana GHA, but was superior to C. fumosorosea Apopka97 in conidia viability and post-treatment virulence. After exposure to −20 °C for 56 d, C. javanica wf GA17 exhibited lower germination than M. brunneum F52 and lower virulence than M. brunneum F52 and B. bassiana GHA, but higher germination and virulence than C. fumosorosea Apopka97. Following exposure to strong UV light, viability and virulence of all fungi were reduced with increasing exposure periods. Increased environmental tolerance of C. javanica wf GA17 over C. fumosorosea Apopka97 suggests that the new strain could have applicability for commercial pest management.
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Affiliation(s)
- Shaohui Wu
- Department of Entomology, University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA;
| | - Michael D. Toews
- Department of Entomology, University of Georgia, 2360 Rainwater Road, Tifton, GA 31793, USA;
- Correspondence: (M.D.T.); (D.I.S.-I.)
| | - Camila Oliveira-Hofman
- USDA–ARS, Southeastern Fruit and Tree Nut Research Laboratory, 21 Dunbar Road, Byron, GA 31008, USA;
| | - Robert W. Behle
- USDA–ARS, National Center for Agricultural Utilization Research, Crop BioProtection Research Unit, 1815 N. University St., Peoria, IL 61604, USA;
| | - Alvin M. Simmons
- USDA–ARS, U.S. Vegetable Laboratory, 2700 Savannah Highway, Charleston, SC 29414, USA;
| | - David I. Shapiro-Ilan
- USDA–ARS, Southeastern Fruit and Tree Nut Research Laboratory, 21 Dunbar Road, Byron, GA 31008, USA;
- Correspondence: (M.D.T.); (D.I.S.-I.)
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Zhao Y, Cheng P, Zhang Y, Wang H. Proteomic Analysis of UV-B-Induced Virulence-Mutant Strains of Puccinia striiformis f. sp. tritici Based on iTRAQ Technology. Front Microbiol 2020; 11:542961. [PMID: 33133029 PMCID: PMC7562792 DOI: 10.3389/fmicb.2020.542961] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 09/14/2020] [Indexed: 11/22/2022] Open
Abstract
The emergence of new physiological races of Puccinia striiformis f. sp. tritici (Pst) causing wheat stripe rust can lead to the loss of resistance of wheat cultivars to stripe rust, thus resulting in severe losses in wheat yield. In this study, after the germination of urediospores of three Pst strains including the original strain (CYR32, a dominant physiological race of Pst in China) and two virulence-mutant strains (CYR32-5 and CYR32-61) acquired from CYR32 via UV-B radiation, proteomic analysis based on isobaric tags for relative and absolute quantification (iTRAQ) technology was performed on the strains. A total of 2,271 proteins were identified, and 59, 74, and 64 differentially expressed proteins (DEPs) were acquired in CYR32-5 vs. CYR32, CYR32-61 vs. CYR32, and CYR32-61 vs. CYR32-5, respectively. The acquired DEPs were mainly involved in energy metabolism, carbon metabolism, and cellular substance synthesis. Furthermore, quantitative reverse transcription PCR assays were used to determine the relative expression of the 6, 7, and 1 DEPs of CYR32-5 vs. CYR32, CYR32-61 vs. CYR32, and CYR32-61 vs. CYR32-5, respectively, at the transcriptional level. The relative expression levels of one, five, and one gene, respectively, encoding the DEPs, were consistent with the corresponding protein abundance determined by iTRAQ technology. Compared with CYR32, the DEPs associated with energy metabolism and stress—including E3JWK6, F4S0Z3, and A8N2Q4—were up-regulated in the mutant strains. The results indicated that the virulence-mutant strains CYR32-5 and CYR32-61 had more tolerance to stress than the original strain CYR32. The results obtained in this study are of great significance for exploring the virulence variation mechanisms of Pst, monitoring the changes in Pst populations, breeding new disease-resistant wheat cultivars, and managing wheat stripe rust sustainably.
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Affiliation(s)
- Yaqiong Zhao
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Pei Cheng
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Yuzhu Zhang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Haiguang Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
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Khun KK, Wilson BAL, Stevens MM, Huwer RK, Ash GJ. Integration of Entomopathogenic Fungi into IPM Programs: Studies Involving Weevils (Coleoptera: Curculionoidea) Affecting Horticultural Crops. INSECTS 2020; 11:E659. [PMID: 32992798 PMCID: PMC7599691 DOI: 10.3390/insects11100659] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 11/30/2022]
Abstract
Weevils are significant pests of horticultural crops and are largely managed with insecticides. In response to concerns about negative impacts of synthetic insecticides on humans and the environment, entomopathogenic fungi (EPF) have been developed as an alternative method of control, and as such appear to be "ready-made" components of integrated pest management (IPM) programs. As the success of pest control requires a thorough knowledge of the biology of the pests, this review summarises our current knowledge of weevil biology on nut trees, fruit crops, plant storage roots, and palm trees. In addition, three groups of life cycles are defined based on weevil developmental habitats, and together with information from studies of EPF activity on these groups, we discuss the tactics for integrating EPF into IPM programs. Finally, we highlight the gaps in the research required to optimise the performance of EPF and provide recommendations for the improvement of EPF efficacy for the management of key weevils of horticultural crops.
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Affiliation(s)
- Kim Khuy Khun
- Faculty of Agronomy, Royal University of Agriculture, P.O. Box 2696, Dangkor District, Phnom Penh, Cambodia
- Centre for Crop Health, Institute for Life Sciences and the Environment, University of Southern Queensland, Toowoomba, Queensland 4350, Australia; (B.A.L.W.); (G.J.A.)
| | - Bree A. L. Wilson
- Centre for Crop Health, Institute for Life Sciences and the Environment, University of Southern Queensland, Toowoomba, Queensland 4350, Australia; (B.A.L.W.); (G.J.A.)
| | - Mark M. Stevens
- NSW Department of Primary Industries, Yanco Agricultural Institute, Yanco, New South Wales 2703, Australia;
- Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, New South Wales 2650, Australia
| | - Ruth K. Huwer
- NSW Department of Primary Industries, Wollongbar Primary Industries Institute, Wollongbar, New South Wales 2477, Australia;
| | - Gavin J. Ash
- Centre for Crop Health, Institute for Life Sciences and the Environment, University of Southern Queensland, Toowoomba, Queensland 4350, Australia; (B.A.L.W.); (G.J.A.)
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Bernardo CDC, Pereira-Junior RA, Luz C, Mascarin GM, Kamp Fernandes ÉK. Differential susceptibility of blastospores and aerial conidia of entomopathogenic fungi to heat and UV-B stresses. Fungal Biol 2020; 124:714-722. [PMID: 32690253 DOI: 10.1016/j.funbio.2020.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/15/2020] [Accepted: 04/20/2020] [Indexed: 01/21/2023]
Abstract
We investigated the comparative susceptibility to heat and UV-B radiation of blastospores and aerial conidia of Metarhizium spp. (Metarhizium robertsii IP 146, Metarhizium anisopliae s.l. IP 363 and Metarhizium acridum ARSEF 324) and Beauveria bassiana s.l. (IP 361 and CG 307). Conidia and blastospores were produced in solid or liquid Adámek-modified medium, respectively, and then exposed to heat (45 ± 0.2 °C) in a range of 0 (control) to 360 min; the susceptibility of fungal propagules to heat exposures was assessed to express relative viability. Similarly, both propagules of each isolate were also exposed to a range of 0 (control) to 8.1 kJ m-2 under artificial UV-B radiation. Our results showed that fungal isolates, propagule types and exposure time or dose of the stressor source play critical roles in fungal survival challenged with UV-B and heat. Conidia of ARSEF 324, IP 363, IP 146 and IP 361 exposed to heat survived significantly longer than their blastospores, except for blastospores of CG 307. Conidia and blastospores of IP 146 and IP 363 were equally tolerant to UV-B radiation. We claim that blastospores of certain isolates may be promising candidates to control arthropod pests in regions where heat and UV-B are limiting environmental factors.
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Affiliation(s)
- Cíntia das Chagas Bernardo
- Departamento de Biociências e Tecnologia, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 74690-900, Brazil
| | - Ronaldo Alves Pereira-Junior
- Departamento de Biociências e Tecnologia, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 74690-900, Brazil
| | - Christian Luz
- Departamento de Biociências e Tecnologia, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 74690-900, Brazil
| | - Gabriel Moura Mascarin
- Laboratório de Microbiologia Ambiental, Embrapa Meio Ambiente, Jaguariúna, SP, 13820-000, Brazil
| | - Éverton Kort Kamp Fernandes
- Departamento de Biociências e Tecnologia, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 74690-900, Brazil.
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UV sensitivity of Beauveria bassiana and Metarhizium anisopliae isolates under investigation as potential biological control agents in South African citrus orchards. Fungal Biol 2019; 124:304-310. [PMID: 32389292 DOI: 10.1016/j.funbio.2019.08.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 12/29/2022]
Abstract
Seven indigenous entomopathogenic fungal isolates were identified as promising biocontrol agents of key citrus pests including false codling moth, Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae), citrus thrips, Scirtothrips aurantii Faure (Thysanoptera: Thripidae) and citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae) under laboratory conditions. Even though field trials using the two most virulent isolates (Beauveria bassiana G Ar 17 B3 and Metarhizium anisopliae FCM Ar 23 B3) against soil-dwelling life stages of T. leucotreta were positive, foliar application against citrus mealybugs and thrips, has been disappointing. Thus, the UV sensitivity of the seven initial promising isolates (four B. bassiana and three M. anisopliae) in comparison with two commercial isolates (M. anisopliae ICIPE 69 and B. bassiana PPRI 5339) and their formulated products were investigated in this study. All isolates investigated were highly sensitive to UV radiation, and a 2 h exposure to simulated full-spectrum solar radiation at 0.3 W/m2 killed conidia of all tested isolates. Nonetheless, variability in susceptibility was found amongst isolates after exposure for 1 h. The most virulent M. anisopliae isolate, FCM Ar 23 B3, was the most susceptible to UV radiation with <3 % relative germination, 48-51 h post-exposure. Whilst isolates of the two mycoinsecticides showed similar susceptibility to UV radiation, their formulated products (vegetable oil and emulsifiable concentrate) were tolerant, when tested for 1 h. These findings indicate that a suitable UV protectant formulation of these fungi or a different application strategy will be required for success against P. citri and S. aurantii.
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27
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Which came first: The disease or the pest? Is there a host mediated spread of Beauveria bassiana (Ascomycota: Hypocreales) by invasive palm pests? J Invertebr Pathol 2019; 162:26-42. [PMID: 30735763 DOI: 10.1016/j.jip.2019.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 01/29/2019] [Accepted: 01/31/2019] [Indexed: 12/27/2022]
Abstract
The red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) is threatening the palm family worldwide, causing important economic losses. Current tactics to manage the weevil are largely based on chemical control, although the use of pesticides is hampered by several environmental constraints. Since the first introduction of RPW in Spain in 1996 and during its progressive spread around the Mediterranean basin, the number of reports of natural infection of RPW populations by entomopathogenic fungi (EPF) has been rising for 15 years, and this rise could support a pest-mediated EPF spread. To challenge this hypothesis, we assessed the usefulness of the region of elongation factor 1-alpha (EF1-α), Bloc nuclear intergenic region (Bloc) and inter simple sequence repeat (ISSR) markers, alone or in combination, to infer the relationships among Mediterranean Beauveria and Metarhizium strains isolated from the RPW. Second, the effect of abiotic factors, such as temperature, humidity and UV-B radiation, on the germination and growth of these EPFs strains as a function of their genealogy and geographic origin were determined. Finally, the pathogenicity of strains from different genetic clades was evaluated against larvae and adults of R. ferrugineus. The phylogenetic analysis based on the EF-1α gene identified eight different sequences among 24 fungal isolates of four fungal species. Similar clades were clustered when Bloc and ISSR analyses were performed. The results showed that strains of different origins were clustered in the same clade, and this outcome could be explained by an RPW-mediated EPF spread that was also influenced by time, geographical and other RPW related factors. Neither the response to abiotic factors nor virulence to RPW larvae and adults were related to the sequence type, with all B. bassiana strains well adapted to Mediterraneam climatic conditions. Taken together, these findings may help to select the best strain for RPW management.
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28
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Kaiser D, Bacher S, Mène‐Saffrané L, Grabenweger G. Efficiency of natural substances to protect Beauveria bassiana conidia from UV radiation. PEST MANAGEMENT SCIENCE 2019; 75:556-563. [PMID: 30221461 PMCID: PMC6587961 DOI: 10.1002/ps.5209] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 09/04/2018] [Accepted: 09/12/2018] [Indexed: 05/12/2023]
Abstract
BACKGROUND Solar radiation is assumed to be a major factor limiting the efficacy of entomopathogenic fungi used as biocontrol agents in open field applications. We evaluated 12 natural UV-protective co-formulants for their effect on the survival of UV-exposed Beauveria bassiana spores on agar plates, colza leaf discs and in the field. RESULTS Colony-forming unit (CFU) counts of unformulated conidia on agar plates and leaf discs dropped to ≤ 50% after exposure to UV radiation. The highest UV protection was achieved with humic acid, which provided > 90% protection of UV-B-exposed conidia in laboratory experiments. In the field, 10% humic acid increased spore persistence up to 87% at 7 days after application. Sesame and colza oil also provided high UV protection in both assays (> 73% and > 70%, respectively). CONCLUSIONS This study shows that it is possible to increase the persistence of B. bassiana spores under exposure to UV radiation by formulation with natural UV-protective additives. UV protectants might, therefore, increase the efficacy of entomopathogenic fungi as biocontrol agents in open field applications. © 2018 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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Affiliation(s)
- Deborah Kaiser
- Department of Plant ProtectionAgroscopeZurichSwitzerland
| | - Sven Bacher
- Department of BiologyUniversity of FribourgFribourgSwitzerland
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Falvo ML, Albornoz Medina P, Rodrigues J, López Lastra CC, García JJ, Fernandes ÉKK, Luz C. Effect of UV-B Irradiation on Water-Suspended Metarhizium anisopliae s.l. (Hypocreales: Clavicipitaceae) Conidia and Their Larvicidal Activity in Aedes aegypti (Diptera: Culicidae). JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:1330-1333. [PMID: 29750411 DOI: 10.1093/jme/tjy071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Indexed: 06/08/2023]
Abstract
Ultraviolet (UV) radiation is a key limiting factor for biological pest control with entomopathogenic fungi. While little is known about the impact of UV on Metarhizium anisopliae Metchnikoff (Sorokin) (Hypocreales: Clavicipitaceae) conidia in aquatic mosquito-breeding sites, this study determined the effect of UV-B on the viability and virulence of M. anisopliae sensu lato (s.l.) strain IP 46 in the laboratory against Aedes aegypti (L.) (Diptera: Culicidae) larvae. Conidia were treated in cups under defined water depths (0, 1, 2, and 3 cm) to six different UV-B doses (0, 0.657, 1.971, 3.942, 7.884, 11.826, or 15.768 kJ m-2) at 27 ± 2°C. The ability of treated conidia to germinate up to 24 h postexposure on PDAY + benomyl + chloramphenicol medium at 25 ± 1°C was adversely affected by higher doses of UV-B radiation regardless of the water depth. Germination, however, did not fall below 70% regardless of the test conditions. In fact, conidial virulence against second-instar larvae was not affected by either the water depth (F3,84 = 0.3, P = 0.85) or any tested levels of UV-B radiation (F6,21 ≤ 1.2, P ≥ 0.39) including those distinctly higher than might be expected for tropical sites. These findings strengthen previous observations that IP 46 has significant potential for use against A. aegypti larvae, even when exposed to elevated UV-B irradiance levels in the small breeding sites that are common for this important vector.
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Affiliation(s)
- Marianel L Falvo
- Instituto de Patologia Tropical e Saúde Pública (IPTSP), Universidade Federal de Goiás (UFG), Goiânia, Goiás, Brasil
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE), Universidad Nacional de La Plata-CONICET, La Plata, Buenos Aires, Argentina
| | - Patricia Albornoz Medina
- Instituto de Patologia Tropical e Saúde Pública (IPTSP), Universidade Federal de Goiás (UFG), Goiânia, Goiás, Brasil
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE), Universidad Nacional de La Plata-CONICET, La Plata, Buenos Aires, Argentina
| | - Juscelino Rodrigues
- Instituto de Patologia Tropical e Saúde Pública (IPTSP), Universidade Federal de Goiás (UFG), Goiânia, Goiás, Brasil
| | - Claudia C López Lastra
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE), Universidad Nacional de La Plata-CONICET, La Plata, Buenos Aires, Argentina
| | - Juan J García
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE), Universidad Nacional de La Plata-CONICET, La Plata, Buenos Aires, Argentina
| | - Éverton K K Fernandes
- Instituto de Patologia Tropical e Saúde Pública (IPTSP), Universidade Federal de Goiás (UFG), Goiânia, Goiás, Brasil
| | - Christian Luz
- Instituto de Patologia Tropical e Saúde Pública (IPTSP), Universidade Federal de Goiás (UFG), Goiânia, Goiás, Brasil
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Mascarin GM, Alves Pereira-Junior R, Fernandes ÉKK, Quintela ED, Dunlap CA, Arthurs SP. Phenotype responses to abiotic stresses, asexual reproduction and virulence among isolates of the entomopathogenic fungus Cordyceps javanica (Hypocreales: Cordycipitaceae). Microbiol Res 2018; 216:12-22. [PMID: 30269851 DOI: 10.1016/j.micres.2018.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/20/2018] [Accepted: 08/02/2018] [Indexed: 12/26/2022]
Abstract
Selecting entomopathogenic fungal isolates with resilience to environmental stresses, optimal mass production characteristics, and with high virulence to target pests favors the development of mycopesticides. A case in point, Cordyceps (= Isaria) javanica has been extensively investigated for non-chemical control of whiteflies worldwide. We phylogenetically characterized 11 native C. javanica isolates from Northeastern and Central Brazil. These isolates were screened for tolerance to heat-shock, UV-B radiation, osmotic and oxidative stresses, as well as conidial production on cereal grain and insecticidal activity against the whitefly Bemisia tabaci (MEAM 1) in the laboratory. All isolates were pathogenic to whiteflies and significant (3-fold) differences in median lethal concentration were observed among isolates. Furthermore, pronounced differences among isolates were found for stress factors and conidial production. Using principal component analysis, our results highlighted three major clusters formed by isolates (i) resistant to osmotic and oxidative stress, (ii) resilient to UV-B, and (iii) with high virulence, conidial production and heat tolerance. Overall, isolate CG1228 performed best based on multi-stress resistance, mass production and virulence attributes in the laboratory. This study highlights the importance of exploring natural variation in entomopathogenic fungi for selection of appropriate isolates for effective biocontrol of insect pests coupled with mass production characteristics and abiotic stress tolerances.
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Affiliation(s)
- Gabriel Moura Mascarin
- Embrapa Meio Ambiente, Rodovia SP-340, km 127.5, S/N - Tanquinho Velho, Jaguariúna, SP, 13820-000, Brazil.
| | | | - Éverton Kort Kamp Fernandes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 74605-050, Brazil
| | - Eliane Dias Quintela
- Embrapa Arroz e Feijão, Rodovia GO-462, km 12, Zona Rural, C.P. 179, Santo Antônio de Goiás, GO, 75375-000, Brazil
| | - Christopher A Dunlap
- United States Department of Agriculture, Agriculture Research Service, Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, 1815 N. University St, Peoria, IL 61604, USA
| | - Steven Paul Arthurs
- Department of Entomology, Texas A&M University, College Station TX, 77843-2475, USA
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Pedrini N. Molecular interactions between entomopathogenic fungi (Hypocreales) and their insect host: Perspectives from stressful cuticle and hemolymph battlefields and the potential of dual RNA sequencing for future studies. Fungal Biol 2018; 122:538-545. [DOI: 10.1016/j.funbio.2017.10.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 10/11/2017] [Accepted: 10/13/2017] [Indexed: 12/12/2022]
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Pereira-Junior RA, Huarte-Bonnet C, Paixão FRS, Roberts DW, Luz C, Pedrini N, Fernandes ÉKK. Riboflavin induces Metarhizium spp. to produce conidia with elevated tolerance to UV-B, and upregulates photolyases, laccases and polyketide synthases genes. J Appl Microbiol 2018; 125:159-171. [PMID: 29473986 DOI: 10.1111/jam.13743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/07/2018] [Accepted: 02/18/2018] [Indexed: 11/30/2022]
Abstract
AIMS The effect of nutritional supplementation of two Metarhizium species with riboflavin (Rb) during production of conidia was evaluated on (i) conidial tolerance (based on germination) to UV-B radiation and on (ii) conidial expression following UV-B irradiation, of enzymes known to be active in photoreactivation, viz., photolyase (Phr), laccase (Lac) and polyketide synthase (Pks). METHODS AND RESULTS Metarhizium acridum (ARSEF 324) and Metarhizium robertsii (ARSEF 2575) were grown either on (i) potato dextrose agar medium (PDA), (ii) PDA supplemented with 1% yeast extract (PDAY), (iii) PDA supplemented with Rb (PDA+Rb), or (iv) PDAY supplemented with Rb (PDAY+Rb). Resulting conidia were exposed to 866·7 mW m-2 of UV-B Quaite-weighted irradiance to total doses of 3·9 or 6·24 kJ m-2 . Some conidia also were exposed to 16 klux of white light (WL) after being irradiated, or not, with UV-B to investigate the role of possible photoreactivation. Relative germination of conidia produced on PDA+Rb (regardless Rb concentration) or on PDAY and exposed to UV-B was higher compared to conidia cultivated on PDA without Rb supplement, or to conidia suspended in Rb solution immediately prior to UV-B exposure. The expression of MaLac3 and MaPks2 for M. acridum, as well as MrPhr2, MrLac1, MrLac2 and MrLac3 for M. robertsii was higher when the isolates were cultivated on PDA+Rb and exposed to UV-B followed by exposure to WL, or exposed to WL only. CONCLUSIONS Rb in culture medium increases the UV-B tolerance of M. robertsii and M. acridum conidia, and which may be related to increased expression of Phr, Lac and Pks genes in these conidia. SIGNIFICANCE AND IMPACT OF THE STUDY The enhanced UV-B tolerance of Metarhizium spp. conidia produced on Rb-enriched media may improve the effectiveness of these fungi in biological control programs.
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Affiliation(s)
- R A Pereira-Junior
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil.,Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Universidad Nacional de La Plata - CONICET, La Plata, Buenos Aires, Argentina
| | - C Huarte-Bonnet
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil.,Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Universidad Nacional de La Plata - CONICET, La Plata, Buenos Aires, Argentina
| | - F R S Paixão
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil.,Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Universidad Nacional de La Plata - CONICET, La Plata, Buenos Aires, Argentina
| | - D W Roberts
- Department of Biology, Utah State University, Logan, UT, USA
| | - C Luz
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil
| | - N Pedrini
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Universidad Nacional de La Plata - CONICET, La Plata, Buenos Aires, Argentina
| | - É K K Fernandes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil
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A Laboratory Assessment of Two Local Strains of the Beauveria bassiana (Bals.) Vuill. against the Tetranychus urticae (Acari: Tetranychidae) and Their Potential as a Mycopesticide. J Pathog 2017; 2017:7628175. [PMID: 29250446 PMCID: PMC5698815 DOI: 10.1155/2017/7628175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 10/09/2017] [Indexed: 12/02/2022] Open
Abstract
This study was conducted to assess highly pathogenic Beauveria bassiana isolates to be used in biocontrol and to determine their potentials as mycopesticide. For this purpose, two B. bassiana isolates, which were locally isolated from T. urticae, were chosen. Firstly, three suspensions were investigated at the degree of humidity of 65 ± 5% and 100% RH. Secondly, these strains were selected according to their tendency to mass production, tolerance to UV radiation, and capability of producing spore at the different temperatures. Finally, identification of the selected isolate was performed by using ITS rDNA analysis. Both tested fungal isolates were pathogenic to the T. urticae. Mycelial growths of isolate AT076 at 20°C and 30°C were found to be greater than isolate AT007. It was observed that isolate AT076 had more spore production with 1.61 × 107 spore/disc at 30°C and 44.33% germination after UV radiation for 15 min. The numbers of spores per 5 mm disk area for isolates AT076 and AT007 were found to be 1.2 × 106 and 1.0 × 106. These results show that isolate AT076 was more virulent and more UV-tolerant and had higher tendency to mass production compared to isolate AT007 against T. urticae. As a result of this study, isolate AT076 can be used in the biocontrol as mycopesticide.
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Fernández-Bravo M, Flores-León A, Calero-López S, Gutiérrez-Sánchez F, Valverde-García P, Quesada-Moraga E. UV-B radiation-related effects on conidial inactivation and virulence against Ceratitis capitata (Wiedemann) (Diptera; Tephritidae) of phylloplane and soil Metarhizium sp. strains. J Invertebr Pathol 2017; 148:142-151. [PMID: 28668256 DOI: 10.1016/j.jip.2017.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 06/26/2017] [Accepted: 06/27/2017] [Indexed: 10/19/2022]
Abstract
Recent studies have demonstrated the presence of Metarhizium species on the epigeal areas of weeds and woody plants in various Mediterranean ecosystems, and the question arises whether isolates from the phylloplane, which experiences greater exposure to environmental UV-B radiation than soil isolates do, could have better UV-B radiation tolerance. The in vitro response of 18 Metarhizium strains isolated from phylloplane and soil of several Mediterranean ecosystems to UV-B radiation and the in vitro and in vivo effects of UV-B radiation on the viability and virulence of a selected M. brunneum strain against C. capitata were determined. The conidial germination, culturability and colony growth of these strains exposed to 1200mWm-2 for 2, 4 or 6h were evaluated. Germination rates below 30% and poor conidia recovery rates were observed for all strains. However, no relationship between the Metarhizium species or isolation habitat and the effect of UV-B radiation was found. Strain EAMa 01/58-Su, which showed a high tolerance to UV-B inactivation in terms of relative germination, was subsequently selected to investigate the UV-B related effects on virulence toward C. capitata adults. In a series of bioassays, the virulence and viability was determined using pure dry conidia, which were irradiated with 1200mWm-2 for 6h prior or after adult flies were inoculated, which resulted in a significant 84.7-86.4% decrease in conidial viability but only a slightly significant reduction of virulence, with 100.0% and 91.4% adult mortality rates and 4.6 and 5.9days average survival time for the no UV-B and UV-B treatments, respectively. A second series of experiments was performed to determine whether the UV-B effects on strain EAMa 01/58-Su were dose- or exposure time-dependent. Adult flies were inoculated with five doses (1.0×104-1.0×108conidiaml-1) and then irradiated at 1200mWm-2 for 6h, and similar LC50 values, 3.8×107 and 4.3×107conidiaml-1, were determined for the UV-B and no UV-B treatments, respectively. However, the LT50 values for flies inoculated with 1.0×108conidiaml-1 and with1.0×107conidiaml-1 were 15.1% and 30.8% longer for UV-B treatments than no UV-B treatments, respectively. Next, adult flies were treated with 1.0×108conidiaml-1 and then exposed to 1200mWm-2 for 0, 6, 12, 24, 36 and 48h, and the relationships among exposure time and conidia viability and fly mortality losses were determined. The exposure time for adult flies at 1200mWm-2 to achieve a 50% reduction in fly mortality was 47.2h, which was longer than that of 5.6h required for a 50% reduction in conidia viability. Our results show that the UV-B radiation significantly affected the virulence of EAMa 01/58-Su strain against C. capitata adults, with this effect being dependent on the exposure time but not related to fungal dosage.
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Affiliation(s)
- María Fernández-Bravo
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Building C4 Celestino Mutis, 14071 Cordoba, Spain
| | - Alejandro Flores-León
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Building C4 Celestino Mutis, 14071 Cordoba, Spain
| | - Salvador Calero-López
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Building C4 Celestino Mutis, 14071 Cordoba, Spain
| | - Fernando Gutiérrez-Sánchez
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Building C4 Celestino Mutis, 14071 Cordoba, Spain
| | - Pablo Valverde-García
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Building C4 Celestino Mutis, 14071 Cordoba, Spain
| | - Enrique Quesada-Moraga
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Building C4 Celestino Mutis, 14071 Cordoba, Spain.
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Falvo M, Pereira-Junior R, Rodrigues J, López Lastra C, García J, Fernandes É, Luz C. UV-B radiation reducesin vitrogermination ofMetarhizium anisopliaes.l. but does not affect virulence in fungus-treatedAedes aegyptiadults and development on dead mosquitoes. J Appl Microbiol 2016; 121:1710-1717. [DOI: 10.1111/jam.13309] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/02/2016] [Accepted: 09/25/2016] [Indexed: 11/26/2022]
Affiliation(s)
- M.L. Falvo
- Instituto de Patologia Tropical e Saúde Pública (IPTSP); Universidade Federal de Goiás; Goiânia (UFG) GO Brasil
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE); Universidad Nacional de La Plata-CONICET; La Plata Buenos Aires Argentina
| | - R.A. Pereira-Junior
- Instituto de Patologia Tropical e Saúde Pública (IPTSP); Universidade Federal de Goiás; Goiânia (UFG) GO Brasil
| | - J. Rodrigues
- Instituto de Patologia Tropical e Saúde Pública (IPTSP); Universidade Federal de Goiás; Goiânia (UFG) GO Brasil
| | - C.C. López Lastra
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE); Universidad Nacional de La Plata-CONICET; La Plata Buenos Aires Argentina
| | - J.J. García
- Centro de Estudios Parasitológicos y de Vectores (CEPAVE); Universidad Nacional de La Plata-CONICET; La Plata Buenos Aires Argentina
| | - É.K.K. Fernandes
- Instituto de Patologia Tropical e Saúde Pública (IPTSP); Universidade Federal de Goiás; Goiânia (UFG) GO Brasil
| | - C. Luz
- Instituto de Patologia Tropical e Saúde Pública (IPTSP); Universidade Federal de Goiás; Goiânia (UFG) GO Brasil
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Fernández-Bravo M, Garrido-Jurado I, Valverde-García P, Enkerli J, Quesada-Moraga E. Responses to abiotic environmental stresses among phylloplane and soil isolates of Beauveria bassiana from two holm oak ecosystems. J Invertebr Pathol 2016; 141:6-17. [PMID: 27693652 DOI: 10.1016/j.jip.2016.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 09/21/2016] [Accepted: 09/28/2016] [Indexed: 11/25/2022]
Abstract
The response of entomopathogenic mitosporic ascomycete (EMAs) to abiotic stresses might be adapted to the microhabitats in which they inhabit. In phylloplane, these organisms are more exposed to such stresses than they are in soil, which may have led to adaptation to this environment. In the present work, we investigate whether Beauveria bassiana genotype or isolation habitat, i.e., soil or phylloplane, within the same geographic area influences their responses to key environmental stresses, such as temperature, moisture and ultraviolet radiation (UV-B), which can affect their successful use in microbial control. Twenty isolates of B. bassiana obtained from the soil and phylloplane in two ecosystems from southern Spain (holm oak dehesa and a reforested area) were selected to study the population distribution of these isolates and evaluate their thermal, humidity and UV-B requirements. Molecular characterization was conducted by using elongation factor-1α (EF-1α), the intergenic nuclear region Bloc and 15 microsatellite primers. The cluster analysis based on concatenated EF-1α and Bloc sequences grouped the 20 isolates into five clades within B. basiana, with Clades a, b, d and e containing both soil and phylloplane isolates and Clade c including three phylloplane isolates. The dendrogram and the minimal spanning network generated from the genetic distances among multilocus genotypes showed four divergent groups corresponding to the five clades obtained based on the sequence data (Clades b and d were represented in the same group), with a high degree of shared alleles within groups and few alleles shared among groups. Although no relationship was found between MLG and the habitat (soil or phylloplane) of isolation, isolates grouped into Clade c, all of which were collected from phylloplane, formed a separate group of MLGs. To investigate our hypothesis, the responses to temperature (germination and colony growth evaluated in the range 15-35°C), water activity (conidia germination evaluated against values of aw between 1 and 0.862) and UV-B exposure (conidia exposed to 920 or 1200mWm-2 for 2, 4 or 6h) of the soil and phylloplane isolates from the five clades were investigated. No associations of isolate-specific genetic or physiological characteristics with isolate habitat, i.e., soil or phylloplane, were found. These results provide no support for the hypothesis that EMAs strains from the phylloplane have evolved to resist unfavourable environmental conditions.
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Affiliation(s)
- María Fernández-Bravo
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, Spain
| | - Inmaculada Garrido-Jurado
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, Spain
| | - Pablo Valverde-García
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, Spain
| | - Jürg Enkerli
- Molecular Ecology, Institute for Sustainability Sciences, Agroscope, Reckenholzstrasse 191, 8046 Zurich, Switzerland
| | - Enrique Quesada-Moraga
- Department of Agricultural and Forestry Sciences, ETSIAM, University of Cordoba, Campus de Rabanales, Edificio C4 Celestino Mutis, 14071 Cordoba, Spain.
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Mascarin GM, Jaronski ST. The production and uses of Beauveria bassiana as a microbial insecticide. World J Microbiol Biotechnol 2016; 32:177. [PMID: 27628337 DOI: 10.1007/s11274-016-2131-3] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 08/20/2016] [Indexed: 12/19/2022]
Abstract
Among invertebrate fungal pathogens, Beauveria bassiana has assumed a key role in management of numerous arthropod agricultural, veterinary and forestry pests. Beauveria is typically deployed in one or more inundative applications of large numbers of aerial conidia in dry or liquid formulations, in a chemical paradigm. Mass production is mainly practiced by solid-state fermentation to yield hydrophobic aerial conidia, which remain the principal active ingredient of mycoinsecticides. More robust and cost-effective fermentation and formulation downstream platforms are imperative for its overall commercialization by industry. Hence, where economics allow, submerged liquid fermentation provides alternative method to produce effective and stable propagules that can be easily formulated as dry stable preparations. Formulation also continues to be a bottleneck in the development of stable and effective commercial Beauveria-mycoinsecticides in many countries, although good commercial formulations do exist. Future research on improving fermentation and formulation technologies coupled with the selection of multi-stress tolerant and virulent strains is needed to catalyze the widespread acceptance and usefulness of this fungus as a cost-effective mycoinsecticide. The role of Beauveria as one tool among many in integrated pest management, rather than a stand-alone management approach, needs to be better developed across the range of crop systems. Here, we provide an overview of mass-production and formulation strategies, updated list of registered commercial products, major biocontrol programs and ecological aspects affecting the use of Beauveria as a mycoinsecticide.
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Affiliation(s)
- Gabriel Moura Mascarin
- EMBRAPA Rice and Beans, Rod. GO-462, km 12, Zona Rural, St. Antônio de Goiás, GO, 75375-000, Brazil.
| | - Stefan T Jaronski
- United States Department of Agriculture, Agriculture Research Service, Pest Management Research Unit, Northern Plains Agricultural Research Laboratory, 1500 N. Central Avenue, Sidney, MT, 59270, USA
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Zhao J, Yao R, Wei Y, Huang S, Keyhani NO, Huang Z. Screening of Metarhizium anisopliae UV-induced mutants for faster growth yields a hyper-virulent isolate with greater UV and thermal tolerances. Appl Microbiol Biotechnol 2016; 100:9217-9228. [DOI: 10.1007/s00253-016-7746-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/07/2016] [Accepted: 07/19/2016] [Indexed: 01/09/2023]
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Metabolic responses of Beauveria bassiana to hydrogen peroxide-induced oxidative stress using an LC-MS-based metabolomics approach. J Invertebr Pathol 2016; 137:1-9. [DOI: 10.1016/j.jip.2016.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 12/23/2022]
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Oliveira MTD, Monteiro AC, Scala Júnior NL, Barbosa JC, Mochi DA. Sensibilidade de isolados de fungos entomopatogênicos às radiações solar, ultravioleta e à temperatura. ARQUIVOS DO INSTITUTO BIOLÓGICO 2016. [DOI: 10.1590/1808-1657000042014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
RESUMO: Este trabalho teve por objetivo avaliar a sensibilidade de isolados dos fungos Metarhizium anisopliae (Metsch.) Sorok. e Beauveria bassiana (Bals). Vuill. ao efeito das radiações solar e ultravioleta e da temperatura. Conídios dos isolados foram expostos, por vários períodos, aos raios de um simulador solar em diversas irradiâncias e a uma lâmpada de raios ultravioleta germicida. Os conídios do isolado de M. anisopliae foram também expostos às temperaturas de 19,5; 24,2 e 31,0ºC, e os do isolado de B. bassiana a 19,4; 20,8 e 28,3ºC, e 18,7; 23,8 e 30,9ºC. Avaliou-se a germinação de conídios pelo teste de viabilidade. Os isolados dos fungos se mostraram bastantes sensíveis aos raios do simulador solar e aos raios ultravioleta. A germinação de ambos sofreu significativa redução a partir de 30 minutos de exposição à radiação do simulador solar. O efeito mais severo foi evidenciado pelo isolado de B. bassiana, com grande redução da germinação dos conídios em todas as irradiâncias testadas. A sensibilidade à radiação ultravioleta também foi grande, pois ocorreu acentuada redução da germinação dos conídios do isolado de M. anisopliae (38,2%) e de B. bassiana (65%) já aos 30 segundos de exposição. A temperatura afetou a viabilidade de ambos os fungos. Temperaturas entre 23,8 e 31ºC favoreceram a germinação dos conídios, enquanto temperaturas próximas de 20ºC dificultaram a germinação.
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Moraes APRD, Salles CMCD, Bittencourt VREP, Bittencourt AJ. Antimicrobial activity of Stomoxys calcitrans against Beauveria bassiana sensu lato isolates. REVISTA BRASILEIRA DE PARASITOLOGIA VETERINARIA 2015; 24:331-9. [PMID: 26444064 DOI: 10.1590/s1984-29612015064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study had the aims of evaluating the antimicrobial characteristics of Stomoxys calcitrans (Diptera: Muscidae) larvae against the fungal isolates CG138, CG228 and ESALQ986 of Beauveria bassiana sensu lato (Balsamo-Crivelli) Vuillemin, 1912 (Hypocreales: Cordycipitaceae). S. calcitrans eggs, larvae and pupae were exposed to these same isolates. Statistical analysis showed that the immature stages of S. calcitrans were not susceptible to the fungal isolates used, regardless of the exposure method. Diffusion test on solid culture medium reveled that macerated S. calcitrans larvae exposed to isolate CG138 reduced CG138 fungal development. The analysis of the chromatographic profiles indicated that the macerate or mucus of larvae of the control group and the groups exposed to the isolate CG138 presented different profiles. Reduced development of the isolate CG138 on the larvae cuticle was observed by means of scanning electron microscopy.
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The International Symposium on Fungal Stress: ISFUS. Curr Genet 2015; 61:479-87. [DOI: 10.1007/s00294-015-0501-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 06/03/2015] [Indexed: 01/25/2023]
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Fernandes ÉKK, Rangel DEN, Braga GUL, Roberts DW. Tolerance of entomopathogenic fungi to ultraviolet radiation: a review on screening of strains and their formulation. Curr Genet 2015; 61:427-40. [PMID: 25986971 DOI: 10.1007/s00294-015-0492-z] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/03/2015] [Accepted: 04/25/2015] [Indexed: 11/28/2022]
Abstract
Ultraviolet radiation from sunlight is probably the most detrimental environmental factor affecting the viability of entomopathogenic fungi applied to solar-exposed sites (e.g., leaves) for pest control. Most entomopathogenic fungi are sensitive to UV radiation, but there is great inter- and intraspecies variability in susceptibility to UV. This variability may reflect natural adaptations of isolates to their different environmental conditions. Selecting strains with outstanding natural tolerance to UV is considered as an important step to identify promising biological control agents. However, reports on tolerance among the isolates used to date must be analyzed carefully due to considerable variations in the methods used to garner the data. The current review presents tables listing many studies in which different methods were applied to check natural and enhanced tolerance to UV stress of numerous entomopathogenic fungi, including several well-known isolates of these fungi. The assessment of UV tolerance is usually conducted with conidia using dose-response methods, wherein the UV dose is calculated simply by multiplying the total irradiance by the period (time) of exposure. Although irradiation from lamps seldom presents an environmentally realistic spectral distribution, laboratory tests circumvent the uncontrollable circumstances associated with field assays. Most attempts to increase field persistence of microbial agents have included formulating conidia with UV protectants; however, in many cases, field efficacy of formulated fungi is still not fully adequate for dependable pest control.
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Affiliation(s)
- Éverton K K Fernandes
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, 746050-50, Brazil,
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Braga GUL, Rangel DEN, Fernandes ÉKK, Flint SD, Roberts DW. Molecular and physiological effects of environmental UV radiation on fungal conidia. Curr Genet 2015; 61:405-25. [PMID: 25824285 DOI: 10.1007/s00294-015-0483-0] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 03/05/2015] [Accepted: 03/13/2015] [Indexed: 02/07/2023]
Abstract
Conidia are specialized structures produced at the end of the asexual life cycle of most filamentous fungi. They are responsible for fungal dispersal and environmental persistence. In pathogenic species, they are also involved in host recognition and infection. Conidial production, survival, dispersal, germination, pathogenicity and virulence can be strongly influenced by exposure to solar radiation, although its effects are diverse and often species dependent. UV radiation is the most harmful and mutagenic waveband of the solar spectrum. Direct exposure to solar radiation for a few hours can kill conidia of most fungal species. Conidia are killed both by solar UV-A and UV-B radiation. In addition to killing conidia, which limits the size of the fungal population and its dispersion, exposures to sublethal doses of UV radiation can reduce conidial germination speed and virulence. The focus of this review is to provide an overview of the effects of solar radiation on conidia and on the major systems involved in protection from and repair of damage induced by solar UV radiation. The efforts that have been made to obtain strains of fungi of interest such as entomopathogens more tolerant to solar radiation will also be reviewed.
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Affiliation(s)
- Gilberto U L Braga
- Departamento de Análises Clínicas, Toxicológicas E Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil,
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Stress tolerance and virulence of insect-pathogenic fungi are determined by environmental conditions during conidial formation. Curr Genet 2015; 61:383-404. [PMID: 25791499 DOI: 10.1007/s00294-015-0477-y] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/29/2015] [Accepted: 01/30/2015] [Indexed: 01/07/2023]
Abstract
The virulence to insects and tolerance to heat and UV-B radiation of conidia of entomopathogenic fungi are greatly influenced by physical, chemical, and nutritional conditions during mycelial growth. This is evidenced, for example, by the stress phenotypes of Metarhizium robertsii produced on various substrates. Conidia from minimal medium (Czapek's medium without sucrose), complex medium, and insect (Lepidoptera and Coleoptera) cadavers had high, moderate, and poor tolerance to UV-B radiation, respectively. Furthermore, conidia from minimal medium germinated faster and had increased heat tolerance and were more virulent to insects than those from complex medium. Low water-activity or alkaline culture conditions also resulted in production of conidia with high tolerance to heat or UV-B radiation. Conidia produced on complex media exhibited lower stress tolerance, whereas those from complex media supplemented with NaCl or KCl (to reduce water activity) were more tolerant to heat and UV-B than those from the unmodified complex medium. Osmotic and nutritive stresses resulted in production of conidia with a robust stress phenotype, but also were associated with low conidial yield. Physical conditions such as growth under illumination, hypoxic conditions, and heat shock before conidial production also induced both higher UV-B and heat tolerance; but conidial production was not decreased. In conclusion, physical and chemical parameters, as well as nutrition source, can induce great variability in conidial tolerance to stress for entomopathogenic fungi. Implications are discussed in relation to the ecology of entomopathogenic fungi in the field, and to their use for biological control. This review will cover recent technologies on improving stress tolerance of entomopathogenic fungi for biological control of insects.
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de Menezes HD, Massola NS, Flint SD, Silva GJ, Bachmann L, Rangel DEN, Braga GUL. Growth under visible light increases conidia and mucilage production and tolerance to UV-B radiation in the plant pathogenic fungus Colletotrichum acutatum. Photochem Photobiol 2015; 91:397-402. [PMID: 25535947 DOI: 10.1111/php.12410] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 12/14/2014] [Indexed: 11/29/2022]
Abstract
Light conditions can influence fungal development. Some spectral wavebands can induce conidial production, whereas others can kill the conidia, reducing the population size and limiting dispersal. The plant pathogenic fungus Colletotrichum acutatum causes anthracnose in several crops. During the asexual stage on the host plant, Colletototrichum produces acervuli with abundant mucilage-embedded conidia. These conidia are responsible for fungal dispersal and host infection. This study examined the effect of visible light during C. acutatum growth on the production of conidia and mucilage and also on the UV tolerance of these conidia. Conidial tolerance to an environmentally realistic UV irradiance was determined both in conidia surrounded by mucilage on sporulating colonies and in conidial suspension. Exposures to visible light during fungal growth increased production of conidia and mucilage as well as conidial tolerance to UV. Colonies exposed to light produced 1.7 times more conidia than colonies grown in continuous darkness. The UV tolerances of conidia produced under light were at least two times higher than conidia produced in the dark. Conidia embedded in the mucilage on sporulating colonies were more tolerant of UV than conidia in suspension that were washed free of mucilage. Conidial tolerance to UV radiation varied among five selected isolates.
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Affiliation(s)
- Henrique D de Menezes
- Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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Ortiz-Urquiza A, Luo Z, Keyhani NO. Improving mycoinsecticides for insect biological control. Appl Microbiol Biotechnol 2014; 99:1057-68. [DOI: 10.1007/s00253-014-6270-x] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 01/03/2023]
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48
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Azevedo RF, Souza RK, Braga GU, Rangel DE. Responsiveness of entomopathogenic fungi to menadione-induced oxidative stress. Fungal Biol 2014; 118:990-5. [DOI: 10.1016/j.funbio.2014.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 08/29/2014] [Accepted: 09/12/2014] [Indexed: 11/25/2022]
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Qin Y, Ortiz-Urquiza A, Keyhani NO. A putative methyltransferase, mtrA, contributes to development, spore viability, protein secretion and virulence in the entomopathogenic fungus Beauveria bassiana. Microbiology (Reading) 2014; 160:2526-2537. [DOI: 10.1099/mic.0.078469-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The filamentous fungus, Beauveria bassiana, is a ubiquitously distributed insect pathogen, currently used as an alternative to chemical pesticides for pest control. Conidiospores are the means by which the fungus disseminates in the environment, and these cells also represent the infectious agent most commonly used in field applications. Little, however, is known concerning the molecular basis for maintenance of spore viability, a critical feature for survival and persistence. Here, we report on the role of a putative methyltransferase, BbmtrA, in conidial viability, normal fungal growth and development, and virulence, via characterization of a targeted gene knockout strain. Loss of BbmtrA resulted in pleiotropic effects including reduced germination, growth and conidiation, with growing mycelia displaying greater branching than the WT parent. Conidial viability dramatically decreased over time, with <5 % of the cells remaining viable after 30 days as compared with >80 % of the WT. Reduced production of extracellular proteins was also observed for the ΔBbmtrA mutant, including protease/peptidases, glycoside hydrolases and the hyd1 hydrophobin. The latter was further confirmed by hyd1 gene expression analysis. Insect bioassays using the greater wax moth, Galleria mellonella, further revealed that the ΔBbmtrA strain was attenuated in virulence and failed to sporulate on host cadavers. These data support a global role for mtrA in fungal physiological processes.
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Affiliation(s)
- Yuqi Qin
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
- National Glycoengineering Research Center and State Key Laboratory of Microbial Technology, Shandong University, Jinan, 250100, PR China
| | - Almudena Ortiz-Urquiza
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Nemat O. Keyhani
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
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Ortiz-Urquiza A, Keyhani NO. Stress response signaling and virulence: insights from entomopathogenic fungi. Curr Genet 2014; 61:239-49. [DOI: 10.1007/s00294-014-0439-9] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/01/2014] [Accepted: 07/14/2014] [Indexed: 01/18/2023]
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