1
|
Hermann KM, Grünberger A, Patel AV. Polyvinyl alcohol coating releasing fungal blastospores improves kill effect of attract-and-kill beads. AMB Express 2023; 13:72. [PMID: 37432529 DOI: 10.1186/s13568-023-01575-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 06/22/2023] [Indexed: 07/12/2023] Open
Abstract
Polyvinyl alcohol (PVA) is a biodegradable, water-soluble polymer with excellent film forming properties, commonly studied or used as tablet coating, food packaging or controlled release fertilizers. Attract-and-kill (AK) beads are sustainable, microbial alternatives to synthetic soil insecticides, whose onset of lethal effect largely depend on how fast the encapsulated entomopathogenic fungus forms virulent conidia. Therefore, the objective of this study was to develop a water-soluble coating accelerating the kill effect of AK beads by immediately releasing virulent Metarhizium brunneum CB15-III blastospores. We assessed three PVA types (PVA 4-88, 8-88, 10-98) which differed in their degree of hydrolysis or molecular weight for their ability to release viable blastospores from thin films after drying at 60-40 °C, and examined how polyethylene glycol and soy-lecithin impact the blastospore survival. Finally, we evaluated the effectiveness of coated AK beads in a bioassay against Tenebrio molitor larvae. The blastospore release rate quadrupled within the first 5 min with decreasing molecular weight and degree of hydrolysis, with PVA 4-88 releasing 79 ± 19% blastospores. Polyethylene glycol and soy-lecithin significantly increased the blastospore survival to 18-28% for all three PVA types. Coated beads exhibited a uniform, 22.4 ± 7.3 µm thin coating layer, with embedded blastospores, as confirmed by scanning electron microscopy. The blastospore coating increased the mortality rate of T. molitor larvae over uncoated AK beads, decreasing the median lethal time from 10 to 6 days. Consequently, the blastospore coating accelerated the kill effect of regular AK beads. These findings pave the way to enhanced pest control efficacy from coated systems such as beads or seeds.
Collapse
Affiliation(s)
- Katharina M Hermann
- Faculty of Engineering and Mathematics, Fermentation and Formulation of Biologicals and Chemicals, Hochschule Bielefeld - University of Applied Sciences and Arts, Bielefeld, Germany
- Faculty of Technology, Multiscale Bioengineering, Bielefeld University, Bielefeld, Germany
| | - Alexander Grünberger
- Faculty of Technology, Multiscale Bioengineering, Bielefeld University, Bielefeld, Germany
| | - Anant V Patel
- Faculty of Engineering and Mathematics, Fermentation and Formulation of Biologicals and Chemicals, Hochschule Bielefeld - University of Applied Sciences and Arts, Bielefeld, Germany.
| |
Collapse
|
2
|
Peng T, Yue P, Ma WB, Zhao ML, Guo JL, Tong XX. Growth characteristics and phylogenetic analysis of the isolate mycelium, Ophiocordyceps sinensis. Biologia (Bratisl) 2023. [DOI: 10.1007/s11756-023-01393-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
|
3
|
Optimization of Submerged Culture Parameters of the Aphid Pathogenic Fungus Fusarium equiseti Based on Sporulation and Mycelial Biomass. Microorganisms 2023; 11:microorganisms11010190. [PMID: 36677481 PMCID: PMC9865567 DOI: 10.3390/microorganisms11010190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/14/2023] Open
Abstract
Fusarium equiseti (JMF-01), as an entomopathogenic fungus, can effectively control agricultural pests and has the potential to be a biocontrol agent. To promote mycelial growth and sporulation, we investigated the optimal submerged culture conditions for F. equiseti. In this study, we used the single-factor method and Box-Behnken design and determined the virulence of the submerged culture against Myzus persicae after optimization. As a result, the highly significant factors affecting the spore concentration of strain JMF-01 were the primary inoculum density and the initial pH, and the highly significant factor affecting the mycelial biomass was the medium-to-flask ratio. The highest mycelial biomass value was 0.35 g when the incubation time was 5.68 days, the initial pH was 5.11, the medium-to-flask ratio was 0.43, and 1 mL of the primary inoculum with spore density of 0.97 × 107 conidia/mL was added. When the incubation time was 6.32 days, the initial pH was 4.46, the medium-to-flask ratio was 0.35, the primary inoculum density was 1.32 × 107 conidia/mL of 1 mL, and the highest spore concentration of 6.49 × 108 blastospores/mL was obtained. Compared with the unoptimized medium conditions, the optimized submerged culture had the highest mycelial biomass and spore concentration, which were 3.46 and 2.06 times higher, respectively. The optimized submerged culture was highly pathogenic toward M. persicae, reaching a 95% mortality rate. Our results provide optimal submerged culture conditions for F. equiseti and lay the basis for later research to expand production for pest control.
Collapse
|
4
|
Pires D, Vicente CSL, Inácio ML, Mota M. The Potential of Esteya spp. for the Biocontrol of the Pinewood Nematode, Bursaphelenchus xylophilus. Microorganisms 2022; 10:microorganisms10010168. [PMID: 35056617 PMCID: PMC8781088 DOI: 10.3390/microorganisms10010168] [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: 12/15/2021] [Revised: 01/07/2022] [Accepted: 01/12/2022] [Indexed: 01/21/2023] Open
Abstract
The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease (PWD) and a quarantine organism in many countries. Managing PWD involves strict regulations and heavy contingency plans, and present climate change scenarios predict a spread of the disease. The urgent need for sustainable management strategies has led to an increasing interest in promising biocontrol agents capable of suppressing the PWN, like endoparasitic nematophagous fungi of the Esteya genus. Here, we review different aspects of the biology and ecology of these nematophagous fungi and provide future prospects.
Collapse
Affiliation(s)
- David Pires
- Instituto Nacional de Investigação Agrária e Veterinária (INIAV, I.P.), 2780-159 Oeiras, Portugal;
- Mediterranean Institute for Agriculture, Environment and Development (MED), University of Évora, Pólo da Mitra, Apartado 94, 7006-554 Evora, Portugal;
| | - Cláudia S. L. Vicente
- Mediterranean Institute for Agriculture, Environment and Development (MED), University of Évora, Pólo da Mitra, Apartado 94, 7006-554 Evora, Portugal;
- Correspondence: (C.S.L.V.); (M.L.I.)
| | - Maria L. Inácio
- Instituto Nacional de Investigação Agrária e Veterinária (INIAV, I.P.), 2780-159 Oeiras, Portugal;
- GREEN-IT Bioresources for Sustainability, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
- Correspondence: (C.S.L.V.); (M.L.I.)
| | - Manuel Mota
- Mediterranean Institute for Agriculture, Environment and Development (MED), University of Évora, Pólo da Mitra, Apartado 94, 7006-554 Evora, Portugal;
| |
Collapse
|
5
|
Zhu Y, Mao Y, Ma T, Wen X. Effect of culture conditions on conidia production and enhancement of environmental stress resistance of Esteya vermicola in solid-state fermentation. J Appl Microbiol 2020; 131:404-412. [PMID: 33305527 DOI: 10.1111/jam.14964] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/11/2020] [Accepted: 12/02/2020] [Indexed: 11/29/2022]
Abstract
AIMS Esteya vermicola is an endoparasitic fungus producing lunate conidia, which kill pine wood nematode (PWN), and PWN could cause pine wilt disease (PWD). The aims of this study were to increase production and confirm the resistance (temperature and UV irradiation) of lunate conidia, and further determine the effective concentrations of conidia infecting PWN. METHODS AND RESULTS In this study, rice was used as a carrier to absorb conidial suspension to propagate conidia. The optimal conditions for lunate conidia production were 25°C temperature, 9 days of culture time, 2 : 1 rice/distilled water ratio and 10% inoculum size. The germination rate of E. vermicola cultured on potato dextrose agar was influenced by UV irradiation, similar to growth on rice. Esteya vermicola cultured on rice under heat stress might be more suitable for application in the field. The concentration (1 × 108 conidia per ml) to kill PWN had the highest infectivity among the four conidia concentrations tested after 3 days of inoculation. CONCLUSIONS This study showed a rice substrate-supported high-quality conidia production and the optimal infectivity concentration of E. vermicola. SIGNIFICANCE AND IMPACT OF THE STUDY These results provide the necessary process of an economical and efficient biological control strategy against PWD.
Collapse
Affiliation(s)
- Y Zhu
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, Guangdong Province, PR China
| | - Y Mao
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, Guangdong Province, PR China
| | - T Ma
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, Guangdong Province, PR China
| | - X Wen
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, Guangdong Province, PR China
| |
Collapse
|
6
|
Wang HH, Yin C, Gao J, Tao R, Wang CY, Li YX, Guo LP, Wang Z, Sung CK. Development of a Real-Time TaqMan PCR Method for Absolute Quantification of the Biocontrol Agent Esteya vermicola. PLANT DISEASE 2020; 104:1694-1700. [PMID: 32310719 DOI: 10.1094/pdis-10-19-2076-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Esteya vermicola has been used as an effective biocontrol agent for the management of the pinewood nematode, Bursaphelenchus xylophilus. Tools for monitoring the colonization and parasitism patterns of E. vermicola are required for the development of highly effective biocontrol strategies. Because the TaqMan PCR technique is effective for quantification of species in environmental samples, a real-time PCR-based methodology was developed for absolute quantification of E. vermicola via internal standard addition and extrapolation of DNA quantity to hyphal length. Primers and a probe for the 28S ribosomal RNA gene of E. vermicola were designed, and nested TaqMan real-time PCR-based quantification was performed. In addition, internal standard-based yield measurement was correlated to the absolute quantity of target genomic DNA. Moreover, an extrapolation curve obtained by optical microscopy and image analysis of the mycelia was constructed for the measurement of fungal hyphal length. The absolute quantification method developed in the present study provides a sensitive and accurate technique to quantify fungal density in either wood or other substrate samples and can be used as an effective tool for future studies of biocontrol agents.
Collapse
Affiliation(s)
- Hai-Hua Wang
- Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejeon 34134, South Korea
| | - Can Yin
- Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejeon 34134, South Korea
| | - Jie Gao
- Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejeon 34134, South Korea
| | - Ran Tao
- Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejeon 34134, South Korea
| | - Chun-Yan Wang
- College of Forestry, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Yong-Xia Li
- Research Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing 100091, China
| | - Lan-Ping Guo
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Zhen Wang
- State Key Laboratory Breeding Base of Dao-di Herbs, National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China
- College of Pharmacy, Linyi University, Linyi City 276000, Shandong, China
| | - Chang-Keun Sung
- Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejeon 34134, South Korea
| |
Collapse
|
7
|
Alkhaibari AM, Carolino AT, Bull JC, Samuels RI, Butt TM. Differential Pathogenicity of Metarhizium Blastospores and Conidia Against Larvae of Three Mosquito Species. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:696-704. [PMID: 28399202 DOI: 10.1093/jme/tjw223] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 11/28/2016] [Indexed: 06/07/2023]
Abstract
Biorational insecticides are being increasingly used in integrated pest management programs. In laboratory bioassays, the pathogenicity of blastospores and conidia of the entomopathogenic fungus Metarhizium brunneum ARSEF 4556 was evaluated against larvae of three mosquito species. Three propagule concentrations (1 × 106, 1 × 107, and 1 × 108 spores ml - 1) were used in the bioassays. Results showed that Aedes aegypti had lower survival rates when exposed to blastospores than when exposed to conidia, whereas the converse was true for Culex quinquefasciatus larvae. Anopheles stephensi larvae survival rates were similar when exposed to blastospores and conidia, except at the higher doses, where blastospores were more virulent. Several assays showed little difference in mortalities when using either 1 × 107 or 1 × 108 spores ml - 1, suggesting a threshold above which no higher control levels or economic benefit would be achieved. When tested at the lowest dose, the LT50 of Cx. quinquefasciatus using blastospores, wet conidia, and dry conidia was 3.2, 1.9, and 4.4 d, respectively. The LT50 of Ae. aegypti using blastospores, wet conidia, and dry conidia was 1.3, 3.3, and 6.2 d, respectively. The LT50 of An. stephensi using blastospores, wet conidia, and dry conidia was 2.0, 1.9, and 2.1 d, respectively. These observations suggest that for optimized control, two different formulations of the fungus may be needed when treating areas where there are mixed populations of Aedes, Anopheles, and Culex.
Collapse
Affiliation(s)
- A M Alkhaibari
- Department of Biosciences College of Science, Swansea University Singleton Park, Swansea SA2 8PP, UK (; ; )
| | - A T Carolino
- Department of Entomology and Plant Pathology, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro 28016-602, Brazil (; )
| | - J C Bull
- Department of Biosciences College of Science, Swansea University Singleton Park, Swansea SA2 8PP, UK (; ; )
| | - R I Samuels
- Department of Entomology and Plant Pathology, State University of North Fluminense, Campos dos Goytacazes, Rio de Janeiro 28016-602, Brazil (; )
| | - T M Butt
- Department of Biosciences College of Science, Swansea University Singleton Park, Swansea SA2 8PP, UK (; ; )
| |
Collapse
|
8
|
Muñiz-Paredes F, Miranda-Hernández F, Loera O. Production of conidia by entomopathogenic fungi: from inoculants to final quality tests. World J Microbiol Biotechnol 2017; 33:57. [DOI: 10.1007/s11274-017-2229-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/13/2017] [Indexed: 10/20/2022]
|
9
|
Metarhizium brunneum Blastospore Pathogenesis in Aedes aegypti Larvae: Attack on Several Fronts Accelerates Mortality. PLoS Pathog 2016; 12:e1005715. [PMID: 27389584 PMCID: PMC4936676 DOI: 10.1371/journal.ppat.1005715] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 06/01/2016] [Indexed: 11/19/2022] Open
Abstract
Aedes aegypti is the vector of a wide range of diseases (e.g. yellow fever, dengue, Chikungunya and Zika) which impact on over half the world’s population. Entomopathogenic fungi such as Metarhizium anisopliae and Beauveria bassiana have been found to be highly efficacious in killing mosquito larvae but only now are the underlying mechanisms for pathogenesis being elucidated. Recently it was shown that conidia of M. anisopliae caused stress induced mortality in Ae. aegypti larvae, a different mode of pathogenicity to that normally seen in terrestrial hosts. Blastospores constitute a different form of inoculum produced by this fungus when cultured in liquid media and although blastospores are generally considered to be more virulent than conidia no evidence has been presented to explain why. In our study, using a range of biochemical, molecular and microscopy methods, the infection process of Metarhizium brunneum (formerly M. anisopliae) ARSEF 4556 blastospores was investigated. It appears that the blastospores, unlike conidia, readily adhere to and penetrate mosquito larval cuticle. The blastospores are readily ingested by the larvae but unlike the conidia are able infect the insect through the gut and rapidly invade the haemocoel. The fact that pathogenicity related genes were upregulated in blastospores exposed to larvae prior to invasion, suggests the fungus was detecting host derived cues. Similarly, immune and defence genes were upregulated in the host prior to infection suggesting mosquitoes were also able to detect pathogen-derived cues. The hydrophilic blastospores produce copious mucilage, which probably facilitates adhesion to the host but do not appear to depend on production of Pr1, a cuticle degrading subtilisin protease, for penetration since protease inhibitors did not significantly alter blastospore virulence. The fact the blastospores have multiple routes of entry (cuticle and gut) may explain why this form of the inoculum killed Ae. aegypti larvae in a relatively short time (12-24hrs), significantly quicker than when larvae were exposed to conidia. This study shows that selecting the appropriate form of inoculum is important for efficacious control of disease vectors such as Ae. aegypti. Mosquitoes transmit a range of diseases which have a profound impact on human health. Aedes aegypti vectors dengue, one of the fastest emerging diseases and, more recently, the Zika virus, which has been linked to thousands of birth defects over the last two years in Brazil. Insect pathogenic fungi such as Metarhizium brunneum are effective in killing mosquito adults and larvae. They exhibit much plasticity, producing aerial conidia on solid substrates and blastospores in liquid media. We not only show that blastospores are more virulent than conidia but present evidence explaining why they are more aggressive. The blastospore mode of pathogenesis differs from that of conidia in several ways. Firstly, blastospores appear to be more dependent on entry using mechanical force than by secretion of cuticle degrading proteases such as Pr1. Blastospores produce copious mucilage which ensures that many spores attach to the cuticle. They are also readily ingested and able to penetrate the gut wall rapidly and colonize the haemocoel. Multiple entry points and gross damage to the cuticle and gut results in rapid larval death. Conidia neither adhere to the cuticle nor germinate in the gut but cause Pr1 stress induced mortality, which takes a slightly longer time. Blastopores, therefore, have greater potential for the control of Ae. aegypti larvae in mosquito control programmes
Collapse
|
10
|
Chu WH, Dou Q, Chu HL, Wang HH, Sung CK, Wang CY. Research advance on Esteya vermicola, a high potential biocontrol agent of pine wilt disease. Mycol Prog 2015. [DOI: 10.1007/s11557-015-1137-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|