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McCutcheon JP, Garber AI, Spencer N, Warren JM. How do bacterial endosymbionts work with so few genes? PLoS Biol 2024; 22:e3002577. [PMID: 38626194 PMCID: PMC11020763 DOI: 10.1371/journal.pbio.3002577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2024] Open
Abstract
The move from a free-living environment to a long-term residence inside a host eukaryotic cell has profound effects on bacterial function. While endosymbioses are found in many eukaryotes, from protists to plants to animals, the bacteria that form these host-beneficial relationships are even more diverse. Endosymbiont genomes can become radically smaller than their free-living relatives, and their few remaining genes show extreme compositional biases. The details of how these reduced and divergent gene sets work, and how they interact with their host cell, remain mysterious. This Unsolved Mystery reviews how genome reduction alters endosymbiont biology and highlights a "tipping point" where the loss of the ability to build a cell envelope coincides with a marked erosion of translation-related genes.
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Affiliation(s)
- John P. McCutcheon
- Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Arkadiy I. Garber
- Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Noah Spencer
- Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Jessica M. Warren
- Biodesign Institute and School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
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2
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Liang P, Ning J, Wang W, Zhu P, Gui L, Xie W, Zhang Y. Catalase promotes whitefly adaptation to high temperature by eliminating reactive oxygen species. INSECT SCIENCE 2023; 30:1293-1308. [PMID: 36478361 DOI: 10.1111/1744-7917.13157] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/04/2022] [Accepted: 11/25/2022] [Indexed: 06/17/2023]
Abstract
Thermal stress usually leads to excessive production of reactive oxygen species (ROS) in all aerobic organisms. Catalases (CAT) are the key antioxidant enzymes, which act as the first line of defense against ROS in the antioxidant pathway. The highly invasive and widely distributed whitefly Bemisia tabaci MED damages plants by feeding as well as by transmitting many plant viruses. Previous studies have shown that strong adaptability to high temperature helps explain the spread of MED around the world. However, the mechanism underlying high temperature adaptation of this pest is not well understood. In this study, 6 CAT genes were identified from the MED genome and transcriptome dataset, among which BtCAT1, BtCAT2, and BtCAT3 were found to be highly expressed in adults. The expression of BtCAT1, BtCAT2, or BtCAT3 increased with induction temperature and induction time. The MED was exposed with mean high temperature (30 °C or 35 °C) and a short-term extremely high temperature (39 °C or 41 °C) after the silencing of BtCAT1, BtCAT2, or BtCAT3 to significantly increased ROS levels by at least 0.5 times and significantly decreased survival rate and fecundity of MED adults. The ROS level in the treated specimens gradually returned to a normal level after 24 h at 25 °C, but the survival rate still declined significantly. Taken together, our results demonstrate that CAT could help B. tabaci adapt to long-term mean high temperatures and short-term extremely high temperatures by eliminating excessive ROS.
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Affiliation(s)
- Peng Liang
- Forewarning and Management of Agricultural and Forestry Pests, Hubei Engineering Technology Center, Institute of Insect, College of Agriculture, Yangtze University, Jingzhou, Hubei Province, China
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jie Ning
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Wenlu Wang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Pu Zhu
- Jinhua Academy of Agricultural Sciences, Jinhua, Zhejiang, China
| | - Lianyou Gui
- Forewarning and Management of Agricultural and Forestry Pests, Hubei Engineering Technology Center, Institute of Insect, College of Agriculture, Yangtze University, Jingzhou, Hubei Province, China
| | - Wen Xie
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Youjun Zhang
- Forewarning and Management of Agricultural and Forestry Pests, Hubei Engineering Technology Center, Institute of Insect, College of Agriculture, Yangtze University, Jingzhou, Hubei Province, China
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
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3
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Cornwallis CK, van 't Padje A, Ellers J, Klein M, Jackson R, Kiers ET, West SA, Henry LM. Symbioses shape feeding niches and diversification across insects. Nat Ecol Evol 2023; 7:1022-1044. [PMID: 37202501 PMCID: PMC10333129 DOI: 10.1038/s41559-023-02058-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 03/15/2023] [Indexed: 05/20/2023]
Abstract
For over 300 million years, insects have relied on symbiotic microbes for nutrition and defence. However, it is unclear whether specific ecological conditions have repeatedly favoured the evolution of symbioses, and how this has influenced insect diversification. Here, using data on 1,850 microbe-insect symbioses across 402 insect families, we found that symbionts have allowed insects to specialize on a range of nutrient-imbalanced diets, including phloem, blood and wood. Across diets, the only limiting nutrient consistently associated with the evolution of obligate symbiosis was B vitamins. The shift to new diets, facilitated by symbionts, had mixed consequences for insect diversification. In some cases, such as herbivory, it resulted in spectacular species proliferation. In other niches, such as strict blood feeding, diversification has been severely constrained. Symbioses therefore appear to solve widespread nutrient deficiencies for insects, but the consequences for insect diversification depend on the feeding niche that is invaded.
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Affiliation(s)
| | - Anouk van 't Padje
- Amsterdam Institute for Life and Environment, section Ecology and Evolution, Vrije Universiteit, Amsterdam, the Netherlands
- Laboratory of Genetics, Wageningen University and Research, Wageningen, the Netherlands
| | - Jacintha Ellers
- Amsterdam Institute for Life and Environment, section Ecology and Evolution, Vrije Universiteit, Amsterdam, the Netherlands
| | - Malin Klein
- Amsterdam Institute for Life and Environment, section Ecology and Evolution, Vrije Universiteit, Amsterdam, the Netherlands
| | - Raphaella Jackson
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - E Toby Kiers
- Amsterdam Institute for Life and Environment, section Ecology and Evolution, Vrije Universiteit, Amsterdam, the Netherlands
| | - Stuart A West
- Department of Biology, University of Oxford, Oxford, UK
| | - Lee M Henry
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK.
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4
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McMunn MS, Hudson AI, Zemenick AT, Egerer M, Bennett L, Philpott SM, Vannette RL. Thermal sensitivity and seasonal change in the gut microbiome of a desert ant, Cephalotes rohweri. FEMS Microbiol Ecol 2022; 98:6596280. [PMID: 35641145 DOI: 10.1093/femsec/fiac062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 05/12/2022] [Accepted: 05/24/2022] [Indexed: 11/14/2022] Open
Abstract
Microorganisms within ectotherms must withstand the variable body temperatures of their hosts. Shifts in host body temperature resulting from climate change have the potential to shape ectotherm microbiome composition. Microbiome compositional changes occurring in response to temperature in nature have not been frequently examined, restricting our ability to predict microbe-mediated ectotherm responses to climate change. In a set of field-based observations, we characterized gut bacterial communities and thermal exposure across a population of desert arboreal ants (Cephalotes rohweri). In a paired growth chamber experiment, we exposed ant colonies to variable temperature regimes differing by 5 °C for three months. We found that the abundance and composition of ant-associated bacteria were sensitive to elevated temperatures in both field and laboratory experiments. We observed a subset of taxa that responded similarly to temperature in the experimental and observational study, suggesting a role of seasonal temperature and local temperature differences amongst nests in shaping microbiomes within the ant population. Bacterial mutualists in the genus Cephaloticoccus (Opitutales: Opitutaceae) were especially sensitive to change in temperature-decreasing in abundance in naturally warm summer nests and warm growth chambers. We also report the discovery of a member of the Candidate Phlya Radiation (Phylum: Gracilibacteria), a suspected epibiont, found in low abundance within the guts of this ant species.
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Affiliation(s)
- Marshall S McMunn
- Department of Environmental Studies, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.,Department of Entomology and Nematology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
| | - Asher I Hudson
- Center for Population Biology, Department of Evolution and Ecology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
| | - Ash T Zemenick
- Department of Entomology and Nematology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.,Sagehen Creek Field Station, University of California Berkeley, 11616 Sage Hen Rd, Truckee, CA, 96161, USA
| | - Monika Egerer
- Department of Environmental Studies, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA.,Technical University of Munich, TUM School of Life Sciences, Hans Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
| | - Lucas Bennett
- Department of Wildlife, Fish, and Conservation Biology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
| | - Stacy M Philpott
- Department of Environmental Studies, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA, 95064, USA
| | - Rachel L Vannette
- Department of Entomology and Nematology, University of California, Davis, One Shields Avenue, Davis, California 95616, USA
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5
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Parr CL, Bishop TR. The response of ants to climate change. GLOBAL CHANGE BIOLOGY 2022; 28:3188-3205. [PMID: 35274797 PMCID: PMC9314018 DOI: 10.1111/gcb.16140] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/06/2022] [Indexed: 06/12/2023]
Abstract
Ants (Hymenoptera: Formicidae) are one of the most dominant terrestrial organisms worldwide. They are hugely abundant, both in terms of sheer numbers and biomass, on every continent except Antarctica and are deeply embedded within a diversity of ecological networks and processes. Ants are also eusocial and colonial organisms-their lifecycle is built on the labor of sterile worker ants who support a small number of reproductive individuals. Given the climatic changes that our planet faces, we need to understand how various important taxonomic groups will respond; this includes the ants. In this review, we synthesize the available literature to tackle this question. The answer is complicated. The ant literature has focused on temperature, and we broadly understand the ways in which thermal changes may affect ant colonies, populations, and communities. In general, we expect that species living in the Tropics, and in thermally variable microhabitats, such as the canopy and leaf litter environments, will be negatively impacted by rising temperatures. Species living in the temperate zones and those able to thermally buffer their nests in the soil or behaviorally avoid higher temperatures, however, are likely to be unaffected or may even benefit from a changed climate. How ants will respond to changes to other abiotic drivers associated with climate change is largely unknown, as is the detail on how altered ant populations and communities will ramify through their wider ecological networks. We discuss how eusociality may allow ants to adapt to, or tolerate, climate change in ways that solitary organisms cannot and we identify key geographic and phylogenetic hotspots of climate vulnerability and resistance. We finish by emphasizing the key research questions that we need to address moving forward so that we may fully appreciate how this critical insect group will respond to the ongoing climate crisis.
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Affiliation(s)
- Catherine L. Parr
- Department of Earth, Ocean and Ecological SciencesUniversity of LiverpoolLiverpoolUK
- Department of Zoology and EntomologyUniversity of PretoriaPretoriaSouth Africa
- School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandWitsSouth Africa
| | - Tom R. Bishop
- Department of Zoology and EntomologyUniversity of PretoriaPretoriaSouth Africa
- School of BiosciencesCardiff UniversityCardiffUK
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6
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Pons I, González Porras MÁ, Breitenbach N, Berger J, Hipp K, Salem H. For the road: calibrated maternal investment in light of extracellular symbiont transmission. Proc Biol Sci 2022; 289:20220386. [PMID: 35473381 PMCID: PMC9043728 DOI: 10.1098/rspb.2022.0386] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Faithful transmission of beneficial symbionts is critical for the persistence of mutualisms. Many insect groups rely on extracellular routes that require microbial symbionts to survive outside the host during transfer. However, given a prolonged aposymbiotic phase in offspring, how do mothers mitigate the risk of symbiont loss due to unsuccessful transmission? Here, we investigated symbiont regulation and reacquisition during extracellular transfer in the tortoise beetle, Chelymorpha alternans (Coleoptera: Cassidinae). Like many cassidines, C. alternans relies on egg caplets to vertically propagate its obligate symbiont Candidatus Stammera capleta. On average, each caplet is supplied with 12 symbiont-bearing spheres where Stammera is embedded. We observe limited deviation (±2.3) in the number of spheres allocated to each caplet, indicating strict maternal control over symbiont supply. Larvae acquire Stammera 1 day prior to eclosion but are unable to do so after hatching, suggesting that a specific developmental window governs symbiont uptake. Experimentally manipulating the number of spheres available to each egg revealed that a single sphere is sufficient to ensure successful colonization by Stammera relative to the 12 typically packaged within a caplet. Collectively, our findings shed light on a tightly regulated symbiont transmission cycle optimized to ensure extracellular transfer.
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Affiliation(s)
- Inès Pons
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
| | | | - Noa Breitenbach
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Jürgen Berger
- Electron Microscopy Facility, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Katharina Hipp
- Electron Microscopy Facility, Max Planck Institute for Biology, Tübingen 72076, Germany
| | - Hassan Salem
- Mutualisms Research Group, Max Planck Institute for Biology, Tübingen 72076, Germany
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7
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Wang D, Huang Z, Billen J, Zhang G, He H, Wei C. Complex co-evolutionary relationships between cicadas and their symbionts. Environ Microbiol 2021; 24:195-211. [PMID: 34927333 DOI: 10.1111/1462-2920.15829] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 11/29/2022]
Abstract
Previous evidence suggests that cicadas lacking Hodgkinia may harbour the yeast-like fungal symbionts (YLS). Here, we reinforce an earlier conclusion that the pathogenic ancestor of YLS independently infected different cicada lineages instead of the common ancestor of Cicadidae. Five independent replacement events in the loss of Hodgkinia/acquisition of YLS and seven other replacement events of YLS (from an Ophiocordyceps fungus to another Ophiocordyceps fungus) are hypothesised to have occurred within the sampled cicada taxa. The divergence time of YLS lineages was later than that of corresponding cicada lineages. The rapid shift of diversification rates of YLS and related cicada-parasitizing Ophiocordyceps began at approximately 32.94 Ma, and the diversification rate reached the highest value at approximately 24.82 Ma, which corresponds to the cooling climate changes at the Eocene-Oligocene boundary and the Oligocene-Miocene transition respectively. Combined with related acquisition/replacement events of YLS occurred during the cooling-climate periods, we hypothesise that the cooling-climate changes impacted the interactions between cicadas and related Ophiocordyceps, which coupled with the unusual life cycle and the differentiation of cicadas may finally led to the diversification of YLS in Cicadidae. Our results contribute to a better understanding of the evolutionary transition of YLS from entomopathogenic fungi in insects.
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Affiliation(s)
- Dandan Wang
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.,State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Zhi Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, 712100, China.,Key Laboratory of National Forestry and Grassland Administration for Control of Forest Biological Disasters in Western China, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Johan Billen
- Zoological Institute, University of Leuven, Naamsestraat 59, Leuven, B-3000, Belgium
| | - Guoyun Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Hong He
- Key Laboratory of National Forestry and Grassland Administration for Control of Forest Biological Disasters in Western China, College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Cong Wei
- Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, 712100, China.,State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling, Shaanxi, 712100, China
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8
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Decline in symbiont-dependent host detoxification metabolism contributes to increased insecticide susceptibility of insects under high temperature. THE ISME JOURNAL 2021; 15:3693-3703. [PMID: 34188180 PMCID: PMC8630103 DOI: 10.1038/s41396-021-01046-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 02/06/2023]
Abstract
The interactions between insects and their bacterial symbionts are shaped by a variety of abiotic factors, including temperature. As global temperatures continue to break high records, a great deal of uncertainty surrounds how agriculturally important insect pests and their symbionts may be affected by elevated temperatures, and its implications for future pest management. In this study, we examine the role of bacterial symbionts in the brown planthopper Nilaparvata lugens response to insecticide (imidacloprid) under different temperature scenarios. Our results reveal that the bacterial symbionts orchestrate host detoxification metabolism via the CncC pathway to promote host insecticide resistance, whereby the symbiont-inducible CncC pathway acts as a signaling conduit between exogenous abiotic stimuli and host metabolism. However, this insect-bacterial partnership function is vulnerable to high temperature, which causes a significant decline in host-bacterial content. In particular, we have identified the temperature-sensitive Wolbachia as a candidate player in N. lugens detoxification metabolism. Wolbachia-dependent insecticide resistance was confirmed through a series of insecticide assays and experiments comparing Wolbachia-free and Wolbachia-infected N. lugens and also Drosophila melanogaster. Together, our research reveals elevated temperatures negatively impact insect-bacterial symbiosis, triggering adverse consequences on host response to insecticide (imidacloprid) and potentially other xenobiotics.
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9
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Abstract
The intestinal microbiome influences host health, and its responsiveness to diet and disease is increasingly well studied. However, our understanding of the factors driving microbiome variation remain limited. Temperature is a core factor that controls microbial growth, but its impact on the microbiome remains to be fully explored. Although commonly assumed to be a constant 37°C, normal body temperatures vary across the animal kingdom, while individual body temperature is affected by multiple factors, including circadian rhythm, age, environmental temperature stress, and immune activation. Changes in body temperature via hypo- and hyperthermia have been shown to influence the gut microbiota in a variety of animals, with consistent effects on community diversity and stability. It is known that temperature directly modulates the growth and virulence of gastrointestinal pathogens; however, the effect of temperature on gut commensals is not well studied. Further, body temperature can influence other host factors, such as appetite and immunity, with indirect effects on the microbiome. In this minireview, we discuss the evidence linking body temperature and the intestinal microbiome and their implications for microbiome function during hypothermia, heat stress, and fever.
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Affiliation(s)
- Kelsey E. Huus
- Department of Microbiome Science, Max Planck Institute for Developmental Biology, Tübingen, Germany
- Cluster of Excellence - Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
| | - Ruth E. Ley
- Department of Microbiome Science, Max Planck Institute for Developmental Biology, Tübingen, Germany
- Cluster of Excellence - Controlling Microbes to Fight Infections, University of Tübingen, Tübingen, Germany
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10
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Perreau J, Moran NA. Genetic innovations in animal-microbe symbioses. Nat Rev Genet 2021; 23:23-39. [PMID: 34389828 DOI: 10.1038/s41576-021-00395-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/28/2021] [Indexed: 02/07/2023]
Abstract
Animal hosts have initiated myriad symbiotic associations with microorganisms and often have maintained these symbioses for millions of years, spanning drastic changes in ecological conditions and lifestyles. The establishment and persistence of these relationships require genetic innovations on the parts of both symbionts and hosts. The nature of symbiont innovations depends on their genetic population structure, categorized here as open, closed or mixed. These categories reflect modes of inter-host transmission that result in distinct genomic features, or genomic syndromes, in symbionts. Although less studied, hosts also innovate in order to preserve and control symbiotic partnerships. New capabilities to sequence host-associated microbial communities and to experimentally manipulate both hosts and symbionts are providing unprecedented insights into how genetic innovations arise under different symbiont population structures and how these innovations function to support symbiotic relationships.
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Affiliation(s)
- Julie Perreau
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
| | - Nancy A Moran
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA.
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11
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Williams TJ, Allen MA, Ivanova N, Huntemann M, Haque S, Hancock AM, Brazendale S, Cavicchioli R. Genome Analysis of a Verrucomicrobial Endosymbiont With a Tiny Genome Discovered in an Antarctic Lake. Front Microbiol 2021; 12:674758. [PMID: 34140946 PMCID: PMC8204192 DOI: 10.3389/fmicb.2021.674758] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/23/2021] [Indexed: 01/25/2023] Open
Abstract
Organic Lake in Antarctica is a marine-derived, cold (−13∘C), stratified (oxic-anoxic), hypersaline (>200 gl–1) system with unusual chemistry (very high levels of dimethylsulfide) that supports the growth of phylogenetically and metabolically diverse microorganisms. Symbionts are not well characterized in Antarctica. However, unicellular eukaryotes are often present in Antarctic lakes and theoretically could harbor endosymbionts. Here, we describe Candidatus Organicella extenuata, a member of the Verrucomicrobia with a highly reduced genome, recovered as a metagenome-assembled genome with genetic code 4 (UGA-to-Trp recoding) from Organic Lake. It is closely related to Candidatus Pinguicocccus supinus (163,218 bp, 205 genes), a newly described cytoplasmic endosymbiont of the freshwater ciliate Euplotes vanleeuwenhoeki (Serra et al., 2020). At 158,228 bp (encoding 194 genes), the genome of Ca. Organicella extenuata is among the smallest known bacterial genomes and similar to the genome of Ca. Pinguicoccus supinus (163,218 bp, 205 genes). Ca. Organicella extenuata retains a capacity for replication, transcription, translation, and protein-folding while lacking any capacity for the biosynthesis of amino acids or vitamins. Notably, the endosymbiont retains a capacity for fatty acid synthesis (type II) and iron–sulfur (Fe-S) cluster assembly. Metagenomic analysis of 150 new metagenomes from Organic Lake and more than 70 other Antarctic aquatic locations revealed a strong correlation in abundance between Ca. Organicella extenuata and a novel ciliate of the genus Euplotes. Like Ca. Pinguicoccus supinus, we infer that Ca. Organicella extenuata is an endosymbiont of Euplotes and hypothesize that both Ca. Organicella extenuata and Ca. Pinguicocccus supinus provide fatty acids and Fe-S clusters to their Euplotes host as the foundation of a mutualistic symbiosis. The discovery of Ca. Organicella extenuata as possessing genetic code 4 illustrates that in addition to identifying endosymbionts by sequencing known symbiotic communities and searching metagenome data using reference endosymbiont genomes, the potential exists to identify novel endosymbionts by searching for unusual coding parameters.
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Affiliation(s)
- Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Michelle A Allen
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Natalia Ivanova
- U.S. Department of Energy Joint Genome Institute, Berkeley, CA, United States
| | - Marcel Huntemann
- U.S. Department of Energy Joint Genome Institute, Berkeley, CA, United States
| | - Sabrina Haque
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Alyce M Hancock
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Sarah Brazendale
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
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12
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Mankowski ME, Morrell JJ, Lebow PK. Effects on Brood Development in the Carpenter Ant Camponotus vicinus Mayr after Exposure to the Yeast Associate Schwanniomyces polymorphus Kloecker. INSECTS 2021; 12:520. [PMID: 34199749 PMCID: PMC8229963 DOI: 10.3390/insects12060520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/27/2021] [Accepted: 06/02/2021] [Indexed: 12/03/2022]
Abstract
The yeast Schwanniomyces polymorphus is associated with the infrabuccal pocket in the carpenter ant Camponotus vicinus (Hymenoptera: Formicidae), but its role in ant development is poorly defined. The potential effects of this yeast on brood development were examined on sets of larval groups and workers over a 12 week period. Worker-larval sets were fed variations of a completely artificial, holidic diet and exposed or not exposed to live S. polymorphus. Worker-larval sets in half of the experiment were defaunated using a two-step heat and chemical process. Brood development and number of adult ants produced were significantly affected by the heat/chemical defaunation process. Compared to worker-larval groups fed a basal, complete diet, all treatments resulted in no or deleterious larval development. Brood weights and number of worker ants produced from the original larval sets at initiation were significantly higher in non-defaunated ant groups fed a diet lacking both B vitamins and cholesterol and exposed to live S. polymorphus. We propose that this yeast may help ants to more efficiently assimilate nutrients when fed nutrient-deficient diets, particularly those deficient in sterols.
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Affiliation(s)
- Mark E. Mankowski
- Forest Products Laboratory Starkville, USDA Forest Service, Starkville, MS 39759, USA
| | - Jeffrey J. Morrell
- Centre Timber Durability and Design Life, University of the Sunshine Coast, Sippy Downs, QLD 4102, Australia;
| | - Patricia K. Lebow
- Forest Products Laboratory Madison, USDA Forest Service, Madison, WI 53726, USA;
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13
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Ma CS, Ma G, Pincebourde S. Survive a Warming Climate: Insect Responses to Extreme High Temperatures. ANNUAL REVIEW OF ENTOMOLOGY 2021; 66:163-184. [PMID: 32870704 DOI: 10.1146/annurev-ento-041520-074454] [Citation(s) in RCA: 135] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Global change includes a substantial increase in the frequency and intensity of extreme high temperatures (EHTs), which influence insects at almost all levels. The number of studies showing the ecological importance of EHTs has risen in recent years, but the knowledge is rather dispersed in the contemporary literature. In this article, we review the biological and ecological effects of EHTs actually experienced in the field, i.e., when coupled to fluctuating thermal regimes. First, we characterize EHTs in the field. Then, we summarize the impacts of EHTs on insects at various levels and the processes allowing insects to buffer EHTs. Finally, we argue that the mechanisms leading to positive or negative impacts of EHTs on insects can only be resolved from integrative approaches considering natural thermal regimes. Thermal extremes, perhaps more than the gradual increase in mean temperature, drive insect responses to climate change, with crucial impacts on pest management and biodiversity conservation.
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Affiliation(s)
- Chun-Sen Ma
- Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; ,
| | - Gang Ma
- Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China; ,
| | - Sylvain Pincebourde
- Institut de Recherche sur la Biologie de l'Insecte, UMR 7261, CNRS, Université de Tours, 37200 Tours, France;
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14
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Lemoine MM, Engl T, Kaltenpoth M. Microbial symbionts expanding or constraining abiotic niche space in insects. CURRENT OPINION IN INSECT SCIENCE 2020; 39:14-20. [PMID: 32086000 DOI: 10.1016/j.cois.2020.01.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/07/2020] [Accepted: 01/13/2020] [Indexed: 05/06/2023]
Abstract
In addition to their well-studied contributions to their host's nutrition, digestion, and defense, microbial symbionts of insects are increasingly found to affect their host's response toward abiotic stressors. In particular, symbiotic microbes can reduce or enhance tolerance to temperature extremes, improve desiccation resistance by aiding cuticle biosynthesis and sclerotization, and detoxify heavy metals. As such, individual symbionts or microbial communities can expand or constrain the abiotic niche space of their host and determine its adaptability to fluctuating environments. In light of the increasing impact of humans on climate and environment, a better understanding of host-microbe interactions is necessary to predict how different insect species will respond to changes in abiotic conditions.
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Affiliation(s)
- Marion M Lemoine
- Department of Evolutionary Ecology, Institute for Organismic and Molecular Evolution (iomE), Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Tobias Engl
- Department of Evolutionary Ecology, Institute for Organismic and Molecular Evolution (iomE), Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany
| | - Martin Kaltenpoth
- Department of Evolutionary Ecology, Institute for Organismic and Molecular Evolution (iomE), Johannes Gutenberg University, Hanns-Dieter-Hüsch-Weg 15, 55128 Mainz, Germany.
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15
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Renoz F, Pons I, Hance T. Evolutionary responses of mutualistic insect-bacterial symbioses in a world of fluctuating temperatures. CURRENT OPINION IN INSECT SCIENCE 2019; 35:20-26. [PMID: 31302355 DOI: 10.1016/j.cois.2019.06.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/29/2019] [Accepted: 06/20/2019] [Indexed: 06/10/2023]
Abstract
Climate change is altering the abundance and distribution of millions of insect species around the world and is a major contributor to the decline of numerous species. Many insect species may be indirectly affected through their nutritional dependence on mutualistic bacteria. Indeed, these bacterial partners generally have a highly reduced and static genome, resulting from millions of years of coevolution and isolation in insect cells, and have limited adaptive capacity. The dependence of insects on bacterial partners with narrow environmental tolerance also restricts their ability to adapt, potentially increasing the risk of their extinction, particularly in a world characterized by increasing and fluctuating temperatures. In this review, we examine how climate change can affect the evolutionary trajectories of bacterial mutualism in insects by considering the possible alternatives that may compensate for the dependence on bacterial partners that have become 'Achilles' heels'. We also discuss the beneficial and compensatory effects, as well as the antagonistic effects associated with so-called facultative symbionts in the context of an increased incidence of transient extreme temperatures.
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Affiliation(s)
- François Renoz
- Université catholique de Louvain, Earth and Life Institute, Biodiversity Research Center, Croix de Sud 4-5, bte L7.07.04, 1348 Louvain-la-Neuve, Belgium.
| | - Inès Pons
- Université catholique de Louvain, Earth and Life Institute, Biodiversity Research Center, Croix de Sud 4-5, bte L7.07.04, 1348 Louvain-la-Neuve, Belgium
| | - Thierry Hance
- Université catholique de Louvain, Earth and Life Institute, Biodiversity Research Center, Croix de Sud 4-5, bte L7.07.04, 1348 Louvain-la-Neuve, Belgium
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16
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Chomicki G, Weber M, Antonelli A, Bascompte J, Kiers ET. The Impact of Mutualisms on Species Richness. Trends Ecol Evol 2019; 34:698-711. [DOI: 10.1016/j.tree.2019.03.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/11/2019] [Accepted: 03/18/2019] [Indexed: 11/28/2022]
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17
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Ye S, Badhiwala KN, Robinson JT, Cho WH, Siemann E. Thermal plasticity of a freshwater cnidarian holobiont: detection of trans-generational effects in asexually reproducing hosts and symbionts. THE ISME JOURNAL 2019; 13:2058-2067. [PMID: 31015561 PMCID: PMC6775974 DOI: 10.1038/s41396-019-0413-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/16/2019] [Accepted: 03/15/2019] [Indexed: 11/08/2022]
Abstract
Understanding factors affecting the susceptibility of organisms to thermal stress is of enormous interest in light of our rapidly changing climate. When adaptation is limited, thermal acclimation and deacclimation abilities of organisms are critical for population persistence through a period of thermal stress. Holobionts (hosts plus associated symbionts) are key components of various ecosystems, such as coral reefs, yet the contributions of their two partners to holobiont thermal plasticity are poorly understood. Here, we tested thermal plasticity of the freshwater cnidarian Hydra viridissima (green hydra) using individual behavior and population responses. We found that algal presence initially reduced hydra thermal tolerance. Hydra with algae (symbiotic hydra) had comparable acclimation rates, deacclimation rates, and thermal tolerance after acclimation to those without algae (aposymbiotic hydra) but they had higher acclimation capacity. Acclimation of the host (hydra) and/or symbiont (algae) to elevated temperatures increased holobiont thermal tolerance and these effects persisted for multiple asexual generations. In addition, acclimated algae presence enhanced hydra fitness under prolonged sublethal thermal stress, especially when food was limited. Our study indicates while less intense but sublethal stress may favor symbiotic organisms by allowing them to acclimate, sudden large, potentially lethal fluctuations in climate stress likely favor aposymbiotic organisms. It also suggests that thermally stressed colonies of holobionts could disperse acclimated hosts and/or symbionts to other colonies, thereby reducing their vulnerability to climate change.
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Affiliation(s)
- Siao Ye
- Department of Biosciences, Rice University, Houston, TX, 77005, USA.
| | | | - Jacob T Robinson
- Bioengineering Department, Rice University, Houston, TX, 77005, USA
- Electrical and Computer Engineering Department, Rice University, Houston, TX, 77005, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Won Hee Cho
- Department of Biosciences, Rice University, Houston, TX, 77005, USA
| | - Evan Siemann
- Department of Biosciences, Rice University, Houston, TX, 77005, USA
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18
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Ye S, Bhattacharjee M, Siemann E. Thermal Tolerance in Green Hydra: Identifying the Roles of Algal Endosymbionts and Hosts in a Freshwater Holobiont Under Stress. MICROBIAL ECOLOGY 2019; 77:537-545. [PMID: 30613848 DOI: 10.1007/s00248-018-01315-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 12/25/2018] [Indexed: 05/23/2023]
Abstract
It has been proposed that holobionts (host-symbiont units) could swap endosymbionts, rapidly alter the hologenome (host plus symbiont genome), and increase their stress tolerance. However, experimental tests of individual and combined contributions of hosts and endosymbionts to holobiont stress tolerance are needed to test this hypothesis. Here, we used six green hydra (Hydra viridissima) strains to tease apart host (hydra) and symbiont (algae) contributions to thermal tolerance. Heat shock experiments with (1) hydra with their original symbionts, (2) aposymbiotic hydra (algae removed), (3) novel associations (a single hydra strain hosting different algae individually), and (4) control hydra (aposymbiotic hydra re-associated with their original algae) showed high variation in thermal tolerance in each group. Relative tolerances of strains were the same within original, aposymbiotic, and control treatments, but reversed in the novel associations group. Aposymbiotic hydra had similar or higher thermal tolerance than hydra with algal symbionts. Selection on the holobiont appears to be stronger than on either partner alone, suggesting endosymbiosis could become an evolutionary trap under climate change. Our results suggest that green hydra thermal tolerance is strongly determined by the host, with a smaller, non-positive role for the algal symbiont. Once temperatures exceed host tolerance limits, swapping symbionts is unlikely to allow these holobionts to persist. Rather, increases in host tolerance through in situ adaptation or migration of pre-adapted host strains appear more likely to increase local thermal tolerance. Overall, our results indicate green hydra is a valuable system for studying aquatic endosymbiosis under changing environmental conditions, and demonstrate how the host and the endosymbiont contribute to holobiont stress tolerance.
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Affiliation(s)
- Siao Ye
- Department of Biosciences, Rice University, 6100 S. Main St., Houston, TX, 77005, USA.
| | | | - Evan Siemann
- Department of Biosciences, Rice University, 6100 S. Main St., Houston, TX, 77005, USA
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19
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Rukke BA, Sivasubramaniam R, Birkemoe T, Aak A. Temperature stress deteriorates bed bug (Cimex lectularius) populations through decreased survival, fecundity and offspring success. PLoS One 2018. [PMID: 29538429 PMCID: PMC5851602 DOI: 10.1371/journal.pone.0193788] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Sublethal heat stress may weaken bed bug infestations to potentially ease control. In the present study, experimental populations exposed to 34, 36 or 38°C for 2 or 3 weeks suffered significant mortality during exposure. Among survivors, egg production, egg hatching, moulting success and offspring proliferation decreased significantly in the subsequent 7 week recovery period at 22°C. The overall population success was negatively impacted by increasing temperature and duration of the stress. Such heat stress is inadequate as a single tool for eradication, but may be included as a low cost part of an integrated pest management protocol. Depending on the time available and infestation conditions, the success of some treatments can improve if sublethal heat is implemented prior to the onset of more conventional pest control measures.
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Affiliation(s)
- Bjørn Arne Rukke
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
| | - Ranjeni Sivasubramaniam
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Tone Birkemoe
- Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Anders Aak
- Department of Pest Control, Norwegian Institute of Public Health, Oslo, Norway
- * E-mail:
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20
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Shan HW, Deng WH, Luan JB, Zhang MJ, Zhang Z, Liu SS, Liu YQ. Thermal sensitivity of bacteriocytes constrains the persistence of intracellular bacteria in whitefly symbiosis under heat stress. ENVIRONMENTAL MICROBIOLOGY REPORTS 2017; 9:706-716. [PMID: 28585771 DOI: 10.1111/1758-2229.12554] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/29/2017] [Indexed: 06/07/2023]
Abstract
Temperature affects the persistence of diverse symbionts of insects. Our previous study indicates that the whitefly symbionts confined within bacteriocytes or scattered throughout the body cavity outside bacteriocytes may have differential thermal sensitivity. However, the underlying mechanisms remain largely unknown. Here, we report that following continuous heat stress, Portiera and Hamiltonella were almost completely depleted in two species of Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) of the Bemisia tabaci whitefly cryptic species complex. Meanwhile, proliferation of bacteriocytes was severely inhibited and approximately 50% of the nymphs had lost one of the two bacteriomes. While cell size of bacteriocytes was increased, cell number was severely decreased leading to reduction of total volume of bacteriocytes. Moreover, bacteriocyte organelles and associated symbionts were lysed, and huge amount of electron-dense inclusions accumulated. Eventually, Portiera and Hamiltonella failed to be transmitted to the next generation. In contrast, Rickettsia could be detected although at a reduced level, and successfully transmitted to eggs. The results suggest that the thermal sensitivity of bacteriocytes may limit thermal tolerance and vertical transmission of the associated symbionts, and consequently different patterns of distribution of symbionts may affect their capacity to tolerate unfavourable temperatures and persistence in the host.
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Affiliation(s)
- Hong-Wei Shan
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wen-Hao Deng
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jun-Bo Luan
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
| | - Min-Jing Zhang
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhen Zhang
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Shu-Sheng Liu
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yin-Quan Liu
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China
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21
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Wernegreen JJ. In it for the long haul: evolutionary consequences of persistent endosymbiosis. Curr Opin Genet Dev 2017; 47:83-90. [PMID: 28934627 DOI: 10.1016/j.gde.2017.08.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 08/27/2017] [Accepted: 08/31/2017] [Indexed: 11/30/2022]
Abstract
Phylogenetically independent bacterial lineages have undergone a profound lifestyle shift: from a free-living to obligately host-associated existence. Among these lineages, intracellular bacterial mutualists of insects are among the most intimate, constrained symbioses known. These obligate endosymbionts exhibit severe gene loss and apparent genome deterioration. Evolutionary theory provides a basis to link their unusual genomic features with shifts in fundamental mechanisms - selection, genetic drift, mutation, and recombination. This mini-review highlights recent comparative and experimental research of processes shaping ongoing diversification within these ancient associations. Recent work supports clear contributions of stochastic processes, including genetic drift and exceptionally strong mutational pressure, toward degenerative evolution. Despite possible compensatory mechanisms, genome degradation may constrain how persistent endosymbionts (and their hosts) respond to environmental fluctuations.
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Affiliation(s)
- Jennifer J Wernegreen
- Nicholas School of the Environment, Duke University, Durham, NC, United States; Center for Genomic and Computational Biology, Duke University, Durham, NC, United States.
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22
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Kikuchi Y, Tada A, Musolin DL, Hari N, Hosokawa T, Fujisaki K, Fukatsu T. Collapse of Insect Gut Symbiosis under Simulated Climate Change. mBio 2016; 7:e01578-16. [PMID: 27703075 PMCID: PMC5050343 DOI: 10.1128/mbio.01578-16] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 09/07/2016] [Indexed: 11/29/2022] Open
Abstract
Global warming impacts diverse organisms not only directly but also indirectly via other organisms with which they interact. Recently, the possibility that elevated temperatures resulting from global warming may substantially affect biodiversity through disrupting mutualistic/parasitic associations has been highlighted. Here we report an experimental demonstration that global warming can affect a pest insect via suppression of its obligate bacterial symbiont. The southern green stinkbug Nezara viridula depends on a specific gut bacterium for its normal growth and survival. When the insects were reared inside or outside a simulated warming incubator wherein temperature was controlled at 2.5°C higher than outside, the insects reared in the incubator exhibited severe fitness defects (i.e., retarded growth, reduced size, yellowish body color, etc.) and significant reduction of symbiont population, particularly in the midsummer season, whereas the insects reared outside did not. Rearing at 30°C or 32.5°C resulted in similar defective phenotypes of the insects, whereas no adult insects emerged at 35°C. Notably, experimental symbiont suppression by an antibiotic treatment also induced similar defective phenotypes of the insects, indicating that the host's defective phenotypes are attributable not to the heat stress itself but to the suppression of the symbiont population induced by elevated temperature. These results strongly suggest that high temperature in the midsummer season negatively affects the insects not directly but indirectly via the heat-vulnerable obligate bacterial symbiont, which highlights the practical relevance of mutualism collapse in this warming world. IMPORTANCE Climate change is among the biggest environmental issues in the contemporary world, and its impact on the biodiversity and ecosystem is not only of scientific interest but also of practical concern for the general public. On the basis of our laboratory data obtained under strictly controlled environmental conditions and our simulated warming data obtained in seminatural settings (elevated 2.5°C above the normal temperature), we demonstrate here that Nezara viridula, the notorious stinkbug pest, suffers serious fitness defects in the summer season under the simulated warming conditions, wherein high temperature acts on the insect not directly but indirectly via suppression of its obligate gut bacterium. Our finding highlights that heat-susceptible symbionts can be the "Achilles' heel" of symbiont-dependent organisms under climate change conditions.
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Affiliation(s)
- Yoshitomo Kikuchi
- National Institute of Advanced Industrial Science and Technology (AIST) Hokkaido, Sapporo, Japan
| | - Akiyo Tada
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Dmitry L Musolin
- Saint Petersburg State Forest Technical University, Saint Petersburg, Russia
| | - Nobuhiro Hari
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | | | - Kenji Fujisaki
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takema Fukatsu
- National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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23
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Silva FWS, Elliot SL. Temperature and population density: interactional effects of environmental factors on phenotypic plasticity, immune defenses, and disease resistance in an insect pest. Ecol Evol 2016; 6:3672-3683. [PMID: 27195105 PMCID: PMC4851648 DOI: 10.1002/ece3.2158] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/01/2016] [Accepted: 04/06/2016] [Indexed: 01/06/2023] Open
Abstract
Temperature and crowding are key environmental factors mediating the transmission and epizooty of infectious disease in ectotherm animals. The host physiology may be altered in a temperature‐dependent manner and thus affects the pathogen development and course of diseases within an individual and host population, or the transmission rates (or infectivity) of pathogens shift linearly with the host population density. To our understanding, the knowledge of interactive and synergistic effects of temperature and population density on the host–pathogen system is limited. Here, we tested the interactional effects of these environmental factors on phenotypic plasticity, immune defenses, and disease resistance in the velvetbean caterpillar Anticarsia gemmatalis. Upon egg hatching, caterpillars were reared in thermostat‐controlled chambers in a 2 × 4 factorial design: density (1 or 8 caterpillars/pot) and temperature (20, 24, 28, or 32°C). Of the immune defenses assessed, encapsulation response was directly affected by none of the environmental factors; capsule melanization increased with temperature in both lone‐ and group‐reared caterpillars, although the lone‐reared ones presented the most evident response, and hemocyte numbers decreased with temperature regardless of the population density. Temperature, but not population density, affected considerably the time from inoculation to death of velvetbean caterpillar. Thus, velvetbean caterpillars succumbed to Anticarsia gemmatalis multiple nucleopolyhedrovirus (AgMNPV) more quickly at higher temperatures than at lower temperatures. As hypothesized, temperature likely affected caterpillars' movement rates, and thus the contact between conspecifics, which in turn affected the phenotypic expression of group‐reared caterpillars. Our results suggest that environmental factors, mainly temperature, strongly affect both the course of disease in velvetbean caterpillar population and its defenses against pathogens. As a soybean pest, velvetbean caterpillar may increase its damage on soybean fields under a scenario of global warming as caterpillars may reach the developmental resistance faster, and thus decrease their susceptibility to biological control by AgMNPV.
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Affiliation(s)
- Farley W S Silva
- Post-graduate Program in Entomology Department of Entomology Universida de Federal de Viçosa (UFV) Av. PH Rolfs 36570-900 Viçosa Minas Gerais Brazil
| | - Simon L Elliot
- Post-graduate Program in Entomology Department of Entomology Universida de Federal de Viçosa (UFV) Av. PH Rolfs 36570-900 Viçosa Minas Gerais Brazil
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24
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Bazazi S, Arganda S, Moreau M, Jeanson R, Dussutour A. Responses to nutritional challenges in ant colonies. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2015.10.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Cass BN, Himler AG, Bondy EC, Bergen JE, Fung SK, Kelly SE, Hunter MS. Conditional fitness benefits of the Rickettsia bacterial symbiont in an insect pest. Oecologia 2015; 180:169-79. [PMID: 26376661 DOI: 10.1007/s00442-015-3436-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 08/25/2015] [Indexed: 11/25/2022]
Abstract
Inherited bacterial symbionts are common in arthropods and can have strong effects on the biology of their hosts. These effects are often mediated by host ecology. The Rickettsia symbiont can provide strong fitness benefits to its insect host, Bemisia tabaci, under laboratory and field conditions. However, the frequency of the symbiont is heterogeneous among field collection sites across the USA, suggesting that the benefits of the symbiont are contingent on additional factors. In two whitefly genetic lines collected from the same location, we tested the effect of Rickettsia on whitefly survival after heat shock, on whitefly competitiveness at different temperatures, and on whitefly competitiveness at different starting frequencies of Rickettsia. Rickettsia did not provide protection against heat shock nor affect the competitiveness of whiteflies at different temperatures or starting frequencies. However, there was a strong interaction between Rickettsia infection and whitefly genetic line. Performance measures indicated that Rickettsia was associated with significant female bias in both whitefly genetic lines, but in the second whitefly genetic line it conferred no significant fitness benefits nor conferred any competitive advantage to its host over uninfected whiteflies in population cages. These results help to explain other reports of variation in the phenotype of the symbiosis. Furthermore, they demonstrate the complex nature of these close symbiotic associations and the need to consider these interactions in the context of host population structure.
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Affiliation(s)
- Bodil N Cass
- Graduate Interdisciplinary Program in Entomology and Insect Science, University of Arizona, 410 Forbes, Tucson, AZ, 85721, USA
| | - Anna G Himler
- Department of Entomology, University of Arizona, 410 Forbes, Tucson, AZ, 85721, USA
- Department of Biology, The College of Idaho, 2112 Cleveland Blvd., Box 44, Caldwell, ID, 83605, USA
| | - Elizabeth C Bondy
- Department of Entomology, University of Arizona, 410 Forbes, Tucson, AZ, 85721, USA
| | - Jacquelyn E Bergen
- Department of Entomology, University of Arizona, 410 Forbes, Tucson, AZ, 85721, USA
| | - Sierra K Fung
- Department of Entomology, University of Arizona, 410 Forbes, Tucson, AZ, 85721, USA
| | - Suzanne E Kelly
- Department of Entomology, University of Arizona, 410 Forbes, Tucson, AZ, 85721, USA
| | - Martha S Hunter
- Department of Entomology, University of Arizona, 410 Forbes, Tucson, AZ, 85721, USA.
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26
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Moore ML, Six DL. Effects of Temperature on Growth, Sporulation, and Competition of Mountain Pine Beetle Fungal Symbionts. MICROBIAL ECOLOGY 2015; 70:336-347. [PMID: 25773718 DOI: 10.1007/s00248-015-0593-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/26/2015] [Indexed: 06/04/2023]
Abstract
The mountain pine beetle, Dendroctonus ponderosae, depends on two fungi, Grosmannia clavigera and Ophiostoma montium, to augment a nutrient-poor woody food resource. Because the two fungi exert differential effects on the host beetle, temperature-driven differences in fungal growth and competition outcomes have a strong potential to influence host population dynamics. Weisolated fungi from beetles and wood from three locations in Montana and Utah, USA, and measured their growth rates and sporulation between 5 and 35 °C on artificial media. We also measured growth rates and percent resource capture for each fungus at 10, 15, 21, and 25 °C during inter- and intra-specific competition. G. clavigera excelled at resource capture at most temperatures. Its optimal growth temperature occurs around 20 °C while that of O. montium occurs near 30 °C. There was no effect of collection site on growth or sporulation; however, O. montium exhibited greater variability in response to temperature than did G. clavigera. Sporulation of G. clavigera was greatest at 30 °C while O. montium sporulated at low levels across all temperatures. During competition experiments, G. clavigera captured more resources than O. montium at most temperatures and captured a greater percentage of resources at a greater rate during inter-specific competition than during intra-specific competition. In contrast, O. montium captured a greater percentage of resources during intra-specific competition. These results demonstrate that temperature can differentially affect growth, sporulation, and resource capture of the two symbionts, indicating that it may be an important factor influencing the composition and dynamics of the symbiosis.
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Affiliation(s)
- Melissa L Moore
- Department of Ecosystem and Conservation Sciences, The University of Montana, Missoula, MT, 59812, USA
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27
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Abstract
The development, existence, and functioning of numerous animals and plants depend on their symbiotic interactions with other organisms, mainly microorganisms. In return, the symbionts benefit from safe habitats and nutrient-rich environments provided by their hosts. In these interactions, genetic changes in either of the partners may provide fitness advantages and become subjects to natural selection. Recent findings suggest that epigenetic changes, heritable or within the organism's life time, in either of the partners play significant roles in the establishment of symbiotic relationships. In this review, a variety of epigenetic effects underlying the most common host-symbiont interactions will be examined to determine to what extent these effects are shared in various interactions and how the epigenetic pathways could possibly be manipulated to benefit the interacting symbionts.
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Affiliation(s)
- Sassan Asgari
- Australian Infectious Disease Research Centre, School of Biological Sciences, The University of Queensland, Brisbane, QLD, Australia
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Heritable symbiosis: The advantages and perils of an evolutionary rabbit hole. Proc Natl Acad Sci U S A 2015; 112:10169-76. [PMID: 25713367 DOI: 10.1073/pnas.1421388112] [Citation(s) in RCA: 311] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. A model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and Buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. Symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritable symbiosis. Receiving less attention are potential negative ramifications of symbiotic alliances. In the short run, symbionts impose metabolic costs. Over evolutionary time, hosts evolve dependence beyond the original benefits of the symbiosis. Symbiotic partners enter into an evolutionary spiral that leads to irreversible codependence and associated risks. Host adaptations to symbiosis (e.g., immune-system modification) may impose vulnerabilities. Symbiont genomes also continuously accumulate deleterious mutations, limiting their beneficial contributions and environmental tolerance. Finally, the fitness interests of obligate heritable symbionts are distinct from those of their hosts, leading to selfish tendencies. Thus, genes underlying the host-symbiont interface are predicted to follow a coevolutionary arms race, as observed for genes governing host-pathogen interactions. On the macroevolutionary scale, the rapid evolution of interacting symbiont and host genes is predicted to accelerate host speciation rates by generating genetic incompatibilities. However, degeneration of symbiont genomes may ultimately limit the ecological range of host species, potentially increasing extinction risk. Recent results for the aphid-Buchnera symbiosis and related systems illustrate that, whereas heritable symbiosis can expand ecological range and spur diversification, it also presents potential perils.
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Shan HW, Lu YH, Bing XL, Liu SS, Liu YQ. Differential responses of the whitefly Bemisia tabaci symbionts to unfavorable low and high temperatures. MICROBIAL ECOLOGY 2014; 68:472-482. [PMID: 24788211 DOI: 10.1007/s00248-014-0424-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 04/15/2014] [Indexed: 06/03/2023]
Abstract
The whitefly Bemisia tabaci complex contains many cryptic species, of which the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) are notorious invasive pests. In our field-collected whitefly samples, MEAM1 harbors an obligate primary symbiont "Candidatus Portiera aleyrodidarum" and two secondary symbionts, "Candidatus Hamiltonella defensa" and Rickettsia sp., whereas MED has only "Ca. Portiera aleyrodidarum" and "Ca. Hamiltonella defensa." Both "Ca. Portiera aleyrodidarum" and "Ca. Hamiltonella defensa" are intracellular endosymbionts residing in the bacteriomes, whereas Rickettsia sp. has a scattered distribution throughout the host body cavity. We examined responses of these symbionts to adverse temperatures as well as survival of the host insects. After cold treatment at 5 or 10 °C or heat treatment at 35 or 40 °C for 24 h, respectively, the infection rates of all symbionts were not significantly decreased based on diagnosis PCR. However, quantitative PCR assays indicated significant reduction of "Ca. Hamiltonella defensa" at 40 °C, and the reduction became greater as the duration increased. Compared with "Ca. Hamiltonella defensa," "Ca. Portiera aleyrodidarum" was initially less affected in the first day but then showed more rapid reduction at days 3-5. The density of Rickettsia sp. fluctuated but was not reduced significantly at 40 °C. Meanwhile, the mortality rates of the host whiteflies elevated rapidly as the duration of exposure to heat treatment increased. The differential responses of various symbionts to adverse temperatures imply complex interactions among the symbionts inside the same host insect and highlight the importance of taking the whole bacterial community into account in studies of symbioses.
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Affiliation(s)
- Hong-Wei Shan
- Ministry of Agriculture Key Laboratory of Agricultural Entomology, Institute of Insect Sciences, Zhejiang University, 866 Yuhangtang Street, Hangzhou, 310058, China
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Affiliation(s)
- Nancy A. Moran
- Department of Integrative Biology, University of Texas at Austin, Texas 78712; ,
| | - Gordon M. Bennett
- Department of Integrative Biology, University of Texas at Austin, Texas 78712; ,
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Kupper M, Gupta SK, Feldhaar H, Gross R. Versatile roles of the chaperonin GroEL in microorganism-insect interactions. FEMS Microbiol Lett 2014; 353:1-10. [DOI: 10.1111/1574-6968.12390] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 01/20/2014] [Accepted: 01/22/2014] [Indexed: 11/28/2022] Open
Affiliation(s)
- Maria Kupper
- Chair of Microbiology; Biocenter; University of Würzburg; Würzburg Germany
| | - Shishir K. Gupta
- Chair of Microbiology; Biocenter; University of Würzburg; Würzburg Germany
- Chair of Bioinformatics; Biocenter; University of Würzburg; Würzburg Germany
| | - Heike Feldhaar
- Animal Ecology I; Bayreuth Center for Environment and Ecology Research (BayCEER); University of Bayreuth; Bayreuth Germany
| | - Roy Gross
- Chair of Microbiology; Biocenter; University of Würzburg; Würzburg Germany
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