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Kolp MR, de Anda Acosta Y, Brewer W, Nichols HL, Goldstein EB, Tallapragada K, Parker BJ. Pathogen-microbiome interactions and the virulence of an entomopathogenic fungus. Appl Environ Microbiol 2024; 90:e0229323. [PMID: 38786361 DOI: 10.1128/aem.02293-23] [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: 12/20/2023] [Accepted: 05/03/2024] [Indexed: 05/25/2024] Open
Abstract
Bacteria shape interactions between hosts and fungal pathogens. In some cases, bacteria associated with fungi are essential for pathogen virulence. In other systems, host-associated microbiomes confer resistance against fungal pathogens. We studied an aphid-specific entomopathogenic fungus called Pandora neoaphidis in the context of both host and pathogen microbiomes. Aphids host several species of heritable bacteria, some of which confer resistance against Pandora. We first found that spores that emerged from aphids that harbored protective bacteria were less virulent against subsequent hosts and did not grow on plate media. We then used 16S amplicon sequencing to study the bacterial microbiome of fungal mycelia and spores during plate culturing and host infection. We found that the bacterial community is remarkably stable in culture despite dramatic changes in pathogen virulence. Last, we used an experimentally transformed symbiont of aphids to show that Pandora can acquire host-associated bacteria during infection. Our results uncover new roles for bacteria in the dynamics of aphid-pathogen interactions and illustrate the importance of the broader microbiological context in studies of fungal pathogenesis. IMPORTANCE Entomopathogenic fungi play important roles in the population dynamics of many insect species. Understanding the factors shaping entomopathogen virulence is critical for agricultural management and for the use of fungi in pest biocontrol. We show that heritable bacteria in aphids, which confer protection to their hosts against fungal entomopathogens, influence virulence against subsequent hosts. Aphids reproduce asexually and are typically surrounded by genetically identical offspring, and thus these effects likely shape the dynamics of fungal disease in aphid populations. Furthermore, fungal entomopathogens are known to rapidly lose virulence in lab culture, complicating their laboratory use. We show that this phenomenon is not driven by changes in the associated bacterial microbiome. These results contribute to our broader understanding of the aphid model system and shed light on the biology of the Entomophthorales-an important but understudied group of fungi.
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Affiliation(s)
- Matthew R Kolp
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
- Richard A. Gillespie College of Veterinary Medicine, Lincoln Memorial University, Harrogate, Tennessee, USA
| | | | - William Brewer
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Holly L Nichols
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Elliott B Goldstein
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Keertana Tallapragada
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, Tennessee, USA
| | - Benjamin J Parker
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
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Li Y, Wang S, Zhang K, Yin Y, Zhang X, Zhang Q, Kong X, Tang L, Zhang R, Zhang Z. Serratia marcescens in the intestine of housefly larvae inhibits host growth by interfering with gut microbiota. Parasit Vectors 2023; 16:196. [PMID: 37301969 DOI: 10.1186/s13071-023-05781-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 04/20/2023] [Indexed: 06/12/2023] Open
Abstract
BACKGROUND The structure of gut microbiota is highly complex. Insects have ubiquitous associations with intestinal symbiotic bacteria, which play essential roles. Thus, understanding how changes in the abundance of a single bacterium interfere with bacterial interactions in the insect's gut is important. METHODS Here, we analyzed the effects of Serratia marcescens on the growth and development of housefly larvae using phage technology. We used 16S rRNA gene sequencing technology to explore dynamic diversity and variation in gut bacterial communities and performed plate confrontation assays to study the interaction between S. marcescens and intestinal microorganisms. Furthermore, we performed phenoloxidase activity assay, crawling assay, and trypan blue staining to explore the negative effects of S. marcescens on housefly larvae's humoral immunity, motility, and intestinal organization. RESULTS The growth and development of housefly larvae were inhibited after feeding on S. marcescens, and their intestinal bacterial composition changed with increasing abundance of Providencia and decreasing abundance of Enterobacter and Klebsiella. Meanwhile, the depletion of S. marcescens by phages promoted the reproduction of beneficial bacteria. CONCLUSIONS In our study, using phage as a tool to regulate the abundance of S. marcescens, we highlighted the mechanism by which S. marcescens inhibits the growth and development of housefly larvae and illustrated the importance of intestinal flora for larval development. Furthermore, by studying the dynamic diversity and variation in gut bacterial communities, we improved our understanding of the possible relationship between the gut microbiome and housefly larvae when houseflies are invaded by exogenous pathogenic bacteria.
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Affiliation(s)
- Ying Li
- School of Basic Medical Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China
- Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, (Shandong Academy of Medical Sciences), Shandong First Medical University, No. 619, Changchen Road, Taian, 271016, Shandong, China
| | - Shumin Wang
- School of Basic Medical Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China
- School of Life Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China
| | - Kexin Zhang
- School of Basic Medical Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China
- Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, (Shandong Academy of Medical Sciences), Shandong First Medical University, No. 619, Changchen Road, Taian, 271016, Shandong, China
| | - Yansong Yin
- School of Basic Medical Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China
- Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, (Shandong Academy of Medical Sciences), Shandong First Medical University, No. 619, Changchen Road, Taian, 271016, Shandong, China
| | - Xinyu Zhang
- School of Basic Medical Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China
- Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, (Shandong Academy of Medical Sciences), Shandong First Medical University, No. 619, Changchen Road, Taian, 271016, Shandong, China
| | - Qian Zhang
- School of Basic Medical Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China
- Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, (Shandong Academy of Medical Sciences), Shandong First Medical University, No. 619, Changchen Road, Taian, 271016, Shandong, China
| | - Xinxin Kong
- School of Basic Medical Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China
- Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, (Shandong Academy of Medical Sciences), Shandong First Medical University, No. 619, Changchen Road, Taian, 271016, Shandong, China
| | - Luyao Tang
- Weifang Medical University, Weifang, 261021, Shandong, China
| | - Ruiling Zhang
- School of Basic Medical Science, (Shandong Academy of Medical Sciences), Shandong First Medical University, Taian, 271016, Shandong, China.
- Collaborative Innovation Center for the Origin and Control of Emerging Infectious Diseases, (Shandong Academy of Medical Sciences), Shandong First Medical University, No. 619, Changchen Road, Taian, 271016, Shandong, China.
| | - Zhong Zhang
- Weifang Medical University, Weifang, 261021, Shandong, China.
- The First Affiliated Hospital of Shandong First Medical University, Jinan, 250014, Shandong, China.
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3
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Characterization of bacterial communities associated with blood-fed and starved tropical bed bugs, Cimex hemipterus (F.) (Hemiptera): a high throughput metabarcoding analysis. Sci Rep 2021; 11:8465. [PMID: 33875727 PMCID: PMC8055992 DOI: 10.1038/s41598-021-87946-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/07/2021] [Indexed: 02/02/2023] Open
Abstract
With the development of new metagenomic techniques, the microbial community structure of common bed bugs, Cimex lectularius, is well-studied, while information regarding the constituents of the bacterial communities associated with tropical bed bugs, Cimex hemipterus, is lacking. In this study, the bacteria communities in the blood-fed and starved tropical bed bugs were analysed and characterized by amplifying the v3-v4 hypervariable region of the 16S rRNA gene region, followed by MiSeq Illumina sequencing. Across all samples, Proteobacteria made up more than 99% of the microbial community. An alpha-proteobacterium Wolbachia and gamma-proteobacterium, including Dickeya chrysanthemi and Pseudomonas, were the dominant OTUs at the genus level. Although the dominant OTUs of bacterial communities of blood-fed and starved bed bugs were the same, bacterial genera present in lower numbers were varied. The bacteria load in starved bed bugs was also higher than blood-fed bed bugs.
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Noskov YA, Kabilov MR, Polenogova OV, Yurchenko YA, Belevich OE, Yaroslavtseva ON, Alikina TY, Byvaltsev AM, Rotskaya UN, Morozova VV, Glupov VV, Kryukov VY. A Neurotoxic Insecticide Promotes Fungal Infection in Aedes aegypti Larvae by Altering the Bacterial Community. MICROBIAL ECOLOGY 2021; 81:493-505. [PMID: 32839879 DOI: 10.1007/s00248-020-01567-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/27/2020] [Indexed: 06/11/2023]
Abstract
Symbiotic bacteria have a significant impact on the formation of defensive mechanisms against fungal pathogens and insecticides. The microbiome of the mosquito Aedes aegypti has been well studied; however, there are no data on the influence of insecticides and pathogenic fungi on its structure. The fungus Metarhizium robertsii and a neurotoxic insecticide (avermectin complex) interact synergistically, and the colonization of larvae with hyphal bodies is observed after fungal and combined (conidia + avermectins) treatments. The changes in the bacterial communities (16S rRNA) of Ae. aegypti larvae under the influence of fungal infection, avermectin toxicosis, and their combination were studied. In addition, we studied the interactions between the fungus and the predominant cultivable bacteria in vitro and in vivo after the coinfection of the larvae. Avermectins increased the total bacterial load and diversity. The fungus decreased the diversity and insignificantly increased the bacterial load. Importantly, avermectins reduced the relative abundance of Microbacterium (Actinobacteria), which exhibited a strong antagonistic effect towards the fungus in in vitro and in vivo assays. The avermectin treatment led to an increased abundance of Chryseobacterium (Flavobacteria), which exerted a neutral effect on mycosis development. In addition, avermectin treatment led to an elevation of some subdominant bacteria (Pseudomonas) that interacted synergistically with the fungus. We suggest that avermectins change the bacterial community to favor the development of fungal infection.
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Affiliation(s)
- Y A Noskov
- Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630091.
- National Research Tomsk State University, Tomsk, Russia, 634050.
| | - M R Kabilov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630090
| | - O V Polenogova
- Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630091
| | - Y A Yurchenko
- Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630091
| | - O E Belevich
- Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630091
| | - O N Yaroslavtseva
- Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630091
| | - T Y Alikina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630090
| | - A M Byvaltsev
- Novosibirsk State University, Novosibirsk, Russia, 630090
| | - U N Rotskaya
- Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630091
| | - V V Morozova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630090
| | - V V Glupov
- Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630091
| | - V Y Kryukov
- Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630091
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5
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Heydari S, Siavoshi F, Sarrafnejad A, Malekzadeh R. Coniochaeta fungus benefits from its intracellular bacteria to form biofilm and defend against other fungi. Arch Microbiol 2021; 203:1357-1366. [PMID: 33386870 DOI: 10.1007/s00203-020-02122-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/10/2020] [Accepted: 11/18/2020] [Indexed: 11/30/2022]
Abstract
During cultivation of a gastric fungus, Coniochaeta polymorpha, growth of Nocardia colonies on top of the fungal culture raised the question whether bacteria originated from inside of fungus. In this study, the likelihood of intracellular origin of bacteria as well as interaction of two microorganisms was assessed. Fluorescence and electron microscopy showed occurrence of several bacterial cells in fungal cytoplasm. A thick biofilm was observed on the surface of co-culture compared with thin one on bacterial and none on fungal monocultures. Field emission scanning electron microscopy (FESEM) micrographs of co-culture showed a dense network of fungal and bacterial cells embedded in a slime-like layer. Dual cultures revealed antagonistic activity of both fungus and bacteria against three Candida species. These findings indicate that Nocardia isolate identified in this study originated from the inside of fungus C. polymorpha. Intracellular bacteria could benefit the fungal host by producing a rigid biofilm and an antifungal compound.
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Affiliation(s)
- Samira Heydari
- Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran
| | - Farideh Siavoshi
- Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran.
| | - Abdolfattah Sarrafnejad
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Malekzadeh
- Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran, Iran
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6
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Kryukov VY, Kabilov MR, Smirnova N, Tomilova OG, Tyurin MV, Akhanaev YB, Polenogova OV, Danilov VP, Zhangissina SK, Alikina T, Yaroslavtseva ON, Glupov VV. Bacterial decomposition of insects post-Metarhizium infection: Possible influence on plant growth. Fungal Biol 2019; 123:927-935. [PMID: 31733735 DOI: 10.1016/j.funbio.2019.09.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 09/24/2019] [Accepted: 09/30/2019] [Indexed: 12/26/2022]
Abstract
Strains of entomopathogenic fungi may have substantial differences in their final stages of mycosis. Insect cadavers are usually overgrown with mycelium after colonization of the insect body, but in many cases, bacterial decomposition of the colonized hosts occurs. We used two Metarhizium robertsii strains in the work: Mak-1 (cadavers become overgrown with mycelium and conidia) and P-72 (cadavers decay after fungal colonization). We conducted a comparative analysis of gut and cadaver microbiota in Colorado potato beetle larvae using 16S rRNA gene sequencing after infection with these strains. In addition, we estimated the content of different forms of nitrogen in cadavers and the influence of cadavers on the growth of Solanum lycopersicum on sand substrates under laboratory conditions. It was shown that infections did not lead to a significant shift in the midgut bacterial communities of infected insects compared to those of untreated insects. Importantly, bacterial communities were similar in both types of cadaver, with predominantly enterobacteria. Decomposing cadavers (P-72) were characterized by increased nitrate and ammonium, and they had a stronger growth-promoting effect on plants compared to cadavers overgrown with mycelium and conidia (Mak-1). We also estimated the colonization and growth of plants after treatment with conidia of both strains cultivated on artificial medium. Both cultures successfully colonized plants, but strain P-72 showed stronger growth promotion than Mak-1. We propose that the use of deviant strains that are unable to sporulate on cadavers leads to a faster (though only passive) flow of nitrogen from killed insects to plants.
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Affiliation(s)
- Vadim Y Kryukov
- Institute of Systematics and Ecology of Animals SB RAS, Frunze str., 11, 630091 Novosibirsk, Russia.
| | - Marsel R Kabilov
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Lavrentiev av. 8, Novosibirsk 630090, Russia
| | - Natalya Smirnova
- Institute of Soil Science and Agrochemistry SB RAS, Lavrentiev av. 8/2, Novosibirsk 630090, Russia
| | - Oksana G Tomilova
- Institute of Systematics and Ecology of Animals SB RAS, Frunze str., 11, 630091 Novosibirsk, Russia
| | - Maksim V Tyurin
- Institute of Systematics and Ecology of Animals SB RAS, Frunze str., 11, 630091 Novosibirsk, Russia
| | - Yuriy B Akhanaev
- Institute of Systematics and Ecology of Animals SB RAS, Frunze str., 11, 630091 Novosibirsk, Russia
| | - Olga V Polenogova
- Institute of Systematics and Ecology of Animals SB RAS, Frunze str., 11, 630091 Novosibirsk, Russia
| | - Viktor P Danilov
- Siberian Federal Scientific Centre of Agro-Bio Technologies (SFSCA) of the RAS, Novosibirsk Region, Krasnoobsk, PO Box 463, 630501, Russia
| | - Saule K Zhangissina
- Institute of Cytology and Genetics SB RAS, Lavrentyev av. 10, Novosibirsk 630090, Russia
| | - Tatiana Alikina
- Institute of Soil Science and Agrochemistry SB RAS, Lavrentiev av. 8/2, Novosibirsk 630090, Russia
| | - Olga N Yaroslavtseva
- Institute of Systematics and Ecology of Animals SB RAS, Frunze str., 11, 630091 Novosibirsk, Russia
| | - Viktor V Glupov
- Institute of Systematics and Ecology of Animals SB RAS, Frunze str., 11, 630091 Novosibirsk, Russia
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7
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Boucias DG, Zhou Y, Huang S, Keyhani NO. Microbiota in insect fungal pathology. Appl Microbiol Biotechnol 2018; 102:5873-5888. [PMID: 29802479 DOI: 10.1007/s00253-018-9089-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 05/10/2018] [Accepted: 05/10/2018] [Indexed: 12/17/2022]
Abstract
Significant progress has been made in the biochemical and genetic characterization of the host-pathogen interaction mediated by insect pathogenic fungi, with the most widely studied being the Ascomycetes (Hypocrealean) fungi, Metarhizium robertsii and Beauveria bassiana. However, few studies have examined the consequences and effects of host (insect) microbes, whether compatible or antagonistic, on the development and survival of entomopathogenic fungi. Host microbes can act on the insect cuticular surface, within the gut, in specialized insect microbe hosting structures, and within cells, and they include a wide array of facultative and/or obligate exosymbionts and endosymbionts. The insect microbiome differs across developmental stages and in response to nutrition (e.g., different plant hosts for herbivores) and environmental conditions, including exposure to chemical insecticides. Here, we review recent advances indicating that insect-pathogenic fungi have evolved a spectrum of strategies for exploiting or suppressing host microbes, including the production of antimicrobial compounds that are expressed at discrete stages of the infection process. Conversely, there is increasing evidence that some insects have acquired microbes that may be specialized in the production of antifungal compounds to combat infection by (entomopathogenic) fungi. Consideration of the insect microbiome in fungal insect pathology represents a new frontier that can help explain previously obscure ecological and pathological aspects of the biology of entomopathogenic fungi. Such information may lead to novel approaches to improving the efficacy of these organisms in pest control efforts.
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Affiliation(s)
- Drion G Boucias
- Entomology and Nematology Department, University of Florida, Gainesville, FL, 32611, USA
| | - Yonghong Zhou
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA
| | - Shuaishuai Huang
- 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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8
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Kai K. Bacterial quorum sensing in symbiotic and pathogenic relationships with hosts. Biosci Biotechnol Biochem 2018; 82:363-371. [PMID: 29424268 DOI: 10.1080/09168451.2018.1433992] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Gram-negative bacteria communicate with each other by producing and sensing diffusible signaling molecules. This mechanism is called quorum sensing (QS) and regulates many bacterial activities from gene expression to symbiotic/pathogenic interactions with hosts. Therefore, the elucidation and control of bacterial QS systems have been attracted increasing attention over the past two decades. The most common QS signals in Gram-negative bacteria are N-acyl homoserine lactones (AHLs). There are also bacteria that employ different QS systems, for example, the plant pathogen Ralstonia solanacearum utilizes 3-hydroxy fatty acid methyl esters as its QS signals. The QS system found in the endosymbiotic bacterium associated with the fungus Mortierella alpina, the development of an affinity pull-down method for AHL synthases, and the elucidation of a unique QS circuit in R. solanacearum are discussed herein.
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Affiliation(s)
- Kenji Kai
- a Graduate School of Life and Environmental Sciences , Osaka Prefecture University , Osaka , Japan
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9
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Hatting JL, Moore SD, Malan AP. Microbial control of phytophagous invertebrate pests in South Africa: Current status and future prospects. J Invertebr Pathol 2018; 165:54-66. [PMID: 29427636 DOI: 10.1016/j.jip.2018.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 01/26/2018] [Accepted: 02/06/2018] [Indexed: 01/08/2023]
Abstract
Invertebrate pests pose a significant threat to food security on the African continent. In response, South Africa has become one of the largest importers of chemical pesticides in sub-Saharan Africa, with several hundred active ingredients registered. To address the over-reliance on such chemicals, the South African Department of Agriculture, Forestry and Fisheries (DAFF) has eliminated or restricted several pesticides since the late 1970s. The recent launch of the South African National Bio-Economy Strategy and establishment of the South African Bioproducts Organisation (SABO), together with new guidelines for registration of biopesticides in 2015, also support this endeavour. Concurrently, entomopathogen-related research and bioproduct development has increased over the past decade. Currently, 31 products (seven manufactured locally) are registered under the Fertilizers, Farm Feeds, Agricultural Remedies and Stock Remedies Act 36 of 1947. Commercially important microbes include Beauveria bassiana (Cordycipitaceae), Metarhizium anisopliae (Clavicipitaceae), Cydia pomonella granulovirus, Cryptophlebia leucotreta granulovirus, Helicoverpa armigera nucleopolyhedrovirus (Baculoviridae) and Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai (Bacillaceae). Both parasitic and entomopathogenic nematodes (EPNs) show potential for development as bioinsecticides with one commercial EPN product, based on Heterorhabditis bacteriophora (Heterorhabditidae), registered under the Act. Rapid scientific progression, supported by a favourable legislative environment, should facilitate further advances in microbial control of phytophagous invertebrate pests in South Africa.
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Affiliation(s)
- Justin L Hatting
- Agricultural Research Council-Small Grain, Bethlehem 9700, South Africa.
| | - Sean D Moore
- Citrus Research International, Port Elizabeth 6065, South Africa; Centre for Biological Control, Department of Zoology and Entomology, Rhodes University, Grahamstown 6140, South Africa
| | - Antoinette P Malan
- Department of Conservation Ecology and Entomology, Stellenbosch University, 7602, South Africa
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