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Recart W, Bernhard R, Ng I, Garcia K, Fleming-Davies AE. Meta-Analysis of the Effects of Insect Pathogens: Implications for Plant Reproduction. Pathogens 2023; 12:pathogens12020347. [PMID: 36839619 PMCID: PMC9958737 DOI: 10.3390/pathogens12020347] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/11/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
Despite extensive work on both insect disease and plant reproduction, there is little research on the intersection of the two. Insect-infecting pathogens could disrupt the pollination process by affecting pollinator population density or traits. Pathogens may also infect insect herbivores and change herbivory, potentially altering resource allocation to plant reproduction. We conducted a meta-analysis to (1) summarize the literature on the effects of pathogens on insect pollinators and herbivores and (2) quantify the extent to which pathogens affect insect traits, with potential repercussions for plant reproduction. We found 39 articles that fit our criteria for inclusion, extracting 218 measures of insect traits for 21 different insect species exposed to 25 different pathogens. We detected a negative effect of pathogen exposure on insect traits, which varied by host function: pathogens had a significant negative effect on insects that were herbivores or carried multiple functions but not on insects that solely functioned as pollinators. Particular pathogen types were heavily studied in certain insect orders, with 7 of 11 viral pathogen studies conducted in Lepidoptera and 5 of 9 fungal pathogen studies conducted in Hymenoptera. Our results suggest that most studies have focused on a small set of host-pathogen pairs. To understand the implications for plant reproduction, future work is needed to directly measure the effects of pathogens on pollinator effectiveness.
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Affiliation(s)
- Wilnelia Recart
- Biology Department, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
- Correspondence:
| | - Rover Bernhard
- Biology Department, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
- Biology Department, Lewis and Clark College, 615 S. Palatine Hill Road, Portland, OR 97219, USA
| | - Isabella Ng
- Biology Department, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
| | - Katherine Garcia
- Biology Department, University of San Diego, 5998 Alcala Park, San Diego, CA 92110, USA
- Environmental Sciences Department, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0021, USA
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Higashi CHV, Nichols WL, Chevignon G, Patel V, Allison SE, Kim KL, Strand MR, Oliver KM. An aphid symbiont confers protection against a specialized RNA virus, another increases vulnerability to the same pathogen. Mol Ecol 2023; 32:936-950. [PMID: 36458425 PMCID: PMC10107813 DOI: 10.1111/mec.16801] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022]
Abstract
Insects often harbour heritable symbionts that provide defence against specialized natural enemies, yet little is known about symbiont protection when hosts face simultaneous threats. In pea aphids (Acyrthosiphon pisum), the facultative endosymbiont Hamiltonella defensa confers protection against the parasitoid, Aphidius ervi, and Regiella insecticola protects against aphid-specific fungal pathogens, including Pandora neoaphidis. Here, we investigated whether these two common aphid symbionts protect against a specialized virus A. pisum virus (APV), and whether their antifungal and antiparasitoid services are impacted by APV infection. We found that APV imposed large fitness costs on symbiont-free aphids and these costs were elevated in aphids also housing H. defensa. In contrast, APV titres were significantly reduced and costs to APV infection were largely eliminated in aphids with R. insecticola. To our knowledge, R. insecticola is the first aphid symbiont shown to protect against a viral pathogen, and only the second arthropod symbiont reported to do so. In contrast, APV infection did not impact the protective services of either R. insecticola or H. defensa. To better understand APV biology, we produced five genomes and examined transmission routes. We found that moderate rates of vertical transmission, combined with horizontal transfer through food plants, were the major route of APV spread, although lateral transfer by parasitoids also occurred. Transmission was unaffected by facultative symbionts. In summary, the presence and species identity of facultative symbionts resulted in highly divergent outcomes for aphids infected with APV, while not impacting defensive services that target other enemies. These findings add to the diverse phenotypes conferred by aphid symbionts, and to the growing body of work highlighting extensive variation in symbiont-mediated interactions.
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Affiliation(s)
| | - William L Nichols
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Germain Chevignon
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Vilas Patel
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Suzanne E Allison
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Kyungsun Lee Kim
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Michael R Strand
- Department of Entomology, University of Georgia, Georgia, Athens, USA
| | - Kerry M Oliver
- Department of Entomology, University of Georgia, Georgia, Athens, USA
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An X, Zhang W, Ye C, Smagghe G, Wang JJ, Niu J. Discovery of a widespread presence bunyavirus that may have symbiont-like relationships with different species of aphids. INSECT SCIENCE 2022; 29:1120-1134. [PMID: 34874617 DOI: 10.1111/1744-7917.12989] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/01/2021] [Accepted: 11/17/2021] [Indexed: 06/13/2023]
Abstract
Aphids are important agricultural pests, vectors of many plant viruses and have sophisticated relationships with symbiotic microorganisms. Abundant asymptomatic RNA viruses have been reported in aphids due to the application of RNA-seq, but aphid-virus interactions remain unclear. Bunyavirales is the most abundant RNA virus order, which can infect mammals, arthropods, and plants. However, many bunyaviruses have specific hosts, such as insects. Here, we discovered 18 viruses from 10 aphid species by RNA-seq. Importantly, a widespread presence bunyavirus, Aphid bunyavirus 1 (ABV-1), was determined to have a wide host range, infecting and replicating in all 10 tested aphid species. ABV-1 may be transmitted horizontally during feeding on plant leaves and vertically through reproduction. In a comparison of the physiological parameters of ABV-1high and ABV-1low strains of pea aphid, higher ABV-1 titers reduced the total nymphal duration and induced the reproduction. Moreover, viral titer significantly affected the lipid and protein contents in pea aphids. In summary, we proposed that ABV-1 may have stable symbiont-like relationships with aphids, and these observations may provide a new direction for studying bunyaviruses in aphids and establishing a model for virus-aphid interactions.
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Affiliation(s)
- Xin An
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Wei Zhang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Chao Ye
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Guy Smagghe
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Jin-Jun Wang
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
| | - Jinzhi Niu
- Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing, China
- International Joint Laboratory of China-Belgium on Sustainable Crop Pest Control, Academy of Agricultural Sciences, Southwest University, Chongqing, China
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