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Iverson ENK, Criswell A, Havird JC. Stronger evidence for relaxed selection than adaptive evolution in high-elevation animal mtDNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576402. [PMID: 38328137 PMCID: PMC10849488 DOI: 10.1101/2024.01.20.576402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Mitochondrial (mt) genes are the subject of many adaptive hypotheses due to the key role of mitochondria in energy production and metabolism. One widespread adaptive hypothesis is that selection imposed by life at high elevation leads to the rapid fixation of beneficial alleles in mtDNA, reflected in the increased rates of mtDNA evolution documented in many high-elevation species. However, the assumption that fast mtDNA evolution is caused by positive, rather than relaxed purifying selection has rarely been tested. Here, we calculated the dN/dS ratio, a metric of nonsynonymous substitution bias, and explicitly tested for relaxed selection in the mtDNA of over 700 species of terrestrial vertebrates, freshwater fishes, and arthropods, with information on elevation and latitudinal range limits, range sizes, and body sizes. We confirmed that mitochondrial genomes of high-elevation taxa have slightly higher dN/dS ratios compared to low-elevation relatives. High-elevation species tend to have smaller ranges, which predict higher dN/dS ratios and more relaxed selection across species and clades, while absolute elevation and latitude do not predict higher dN/dS. We also find a positive relationship between body mass and dN/dS, supporting a role for small effective population size leading to relaxed selection. We conclude that higher mt dN/dS among high-elevation species is more likely to reflect relaxed selection due to smaller ranges and reduced effective population size than adaptation to the environment. Our results highlight the importance of rigorously testing adaptive stories against non-adaptive alternative hypotheses, especially in mt genomes.
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Affiliation(s)
- Erik N K Iverson
- Department of Integrative Biology, the University of Texas at Austin, Austin, TX, United States
| | - Abby Criswell
- Department of Integrative Biology, the University of Texas at Austin, Austin, TX, United States
| | - Justin C Havird
- Department of Integrative Biology, the University of Texas at Austin, Austin, TX, United States
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2
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Voss PA, Gornik SG, Jacobovitz MR, Rupp S, Dörr M, Maegele I, Guse A. Host nutrient sensing is mediated by mTOR signaling in cnidarian-dinoflagellate symbiosis. Curr Biol 2023; 33:3634-3647.e5. [PMID: 37572664 DOI: 10.1016/j.cub.2023.07.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/31/2023] [Accepted: 07/20/2023] [Indexed: 08/14/2023]
Abstract
To survive in the nutrient-poor waters of the tropics, reef-building corals rely on intracellular, photosynthetic dinoflagellate symbionts. Photosynthates produced by the symbiont are translocated to the host, and this enables corals to form the structural foundation of the most biodiverse of all marine ecosystems. Although the regulation of nutrient exchange between partners is critical for ecosystem stability and health, the mechanisms governing how nutrients are sensed, transferred, and integrated into host cell processes are largely unknown. Ubiquitous among eukaryotes, the mechanistic target of the rapamycin (mTOR) signaling pathway integrates intracellular and extracellular stimuli to influence cell growth and cell-cycle progression and to balance metabolic processes. A functional role of mTOR in the integration of host and symbiont was demonstrated in various nutritional symbioses, and a similar role of mTOR was proposed for coral-algal symbioses. Using the endosymbiosis model Aiptasia, we examined the role of mTOR signaling in both larvae and adult polyps across various stages of symbiosis. We found that symbiosis enhances cell proliferation, and using an Aiptasia-specific antibody, we localized mTOR to symbiosome membranes. We found that mTOR signaling is activated by symbiosis, while inhibition of mTOR signaling disrupts intracellular niche establishment and symbiosis altogether. Additionally, we observed that dysbiosis was a conserved response to mTOR inhibition in the larvae of a reef-building coral species. Our data confim that mTOR signaling plays a pivotal role in integrating symbiont-derived nutrients into host metabolism and symbiosis stability, ultimately allowing symbiotic cnidarians to thrive in challenging environments.
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Affiliation(s)
- Philipp A Voss
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Sebastian G Gornik
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Marie R Jacobovitz
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Sebastian Rupp
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Melanie Dörr
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Ira Maegele
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Annika Guse
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany.
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Kanturski M, Yeh HT, Lee Y. Morphology, taxonomy, and systematic position of the enigmatic aphid genus Sinolachnus (Hemiptera: Aphididae, Lachninae). THE EUROPEAN ZOOLOGICAL JOURNAL 2023. [DOI: 10.1080/24750263.2022.2157897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- M. Kanturski
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - H.-T. Yeh
- The Experimental Forest, College of Bioresources and Agriculture, National Taiwan University, Zhushan Township, Nantou County, Taiwan
| | - Y. Lee
- Insect Biosystematics Laboratory, Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
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Kett S, Pathak A, Turillazzi S, Cavalieri D, Marvasi M. Antifungals, arthropods and antifungal resistance prevention: lessons from ecological interactions. Proc Biol Sci 2021; 288:20202716. [PMID: 33529557 DOI: 10.1098/rspb.2020.2716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Arthropods can produce a wide range of antifungal compounds, including specialist proteins, cuticular products, venoms and haemolymphs. In spite of this, many arthropod taxa, particularly eusocial insects, make use of additional antifungal compounds derived from their mutualistic association with microbes. Because multiple taxa have evolved such mutualisms, it must be assumed that, under certain ecological circumstances, natural selection has favoured them over those relying upon endogenous antifungal compound production. Further, such associations have been shown to persist versus specific pathogenic fungal antagonists for more than 50 million years, suggesting that compounds employed have retained efficacy in spite of the pathogens' capacity to develop resistance. We provide a brief overview of antifungal compounds in the arthropods' armoury, proposing a conceptual model to suggest why their use remains so successful. Fundamental concepts embedded within such a model may suggest strategies by which to reduce the rise of antifungal resistance within the clinical milieu.
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Affiliation(s)
- Steve Kett
- Department of Natural Sciences, Middlesex University London, London, UK
| | - Ayush Pathak
- Institute of Integrative Biology, Department of Environmental Systems Science, ETH Zürich, Zurich, Switzerland
| | - Stefano Turillazzi
- Department of Biology, University of Florence, Sesto Fiorentino, Florence, Italy.,Insect Pharma Entomotherapy S.r.l, Sesto Fiorentino, Florence, Italy
| | - Duccio Cavalieri
- Department of Biology, University of Florence, Sesto Fiorentino, Florence, Italy
| | - Massimiliano Marvasi
- Department of Biology, University of Florence, Sesto Fiorentino, Florence, Italy
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Ding H, Yeo H, Puniamoorthy N. Wolbachia infection in wild mosquitoes (Diptera: Culicidae): implications for transmission modes and host-endosymbiont associations in Singapore. Parasit Vectors 2020; 13:612. [PMID: 33298138 PMCID: PMC7724734 DOI: 10.1186/s13071-020-04466-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/05/2020] [Indexed: 12/31/2022] Open
Abstract
Background Wolbachia are intracellular bacterial endosymbionts found in most insect lineages. In mosquitoes, the influence of these endosymbionts on host reproduction and arboviral transmission has spurred numerous studies aimed at using Wolbachia infection as a vector control technique. However, there are several knowledge gaps in the literature and little is known about natural Wolbachia infection across species, their transmission modes, or associations between various Wolbachia lineages and their hosts. This study aims to address these gaps by exploring mosquito-Wolbachia associations and their evolutionary implications. Methods We conducted tissue-specific polymerase chain reaction screening for Wolbachia infection in the leg, gut and reproductive tissues of wild mosquitoes from Singapore using the Wolbachia surface protein gene (wsp) molecular marker. Mosquito-Wolbachia associations were explored using three methods—tanglegram, distance-based, and event-based methods—and by inferred instances of vertical transmission and host shifts. Results Adult mosquitoes (271 specimens) representing 14 genera and 40 species were screened for Wolbachia. Overall, 21 species (51.2%) were found positive for Wolbachia, including five in the genus Aedes and five in the genus Culex. To our knowledge, Wolbachia infections have not been previously reported in seven of these 21 species: Aedes nr. fumidus, Aedes annandalei, Uranotaenia obscura, Uranotaenia trilineata, Verrallina butleri, Verrallina sp. and Zeugnomyia gracilis. Wolbachia were predominantly detected in the reproductive tissues, which is an indication of vertical transmission. However, Wolbachia infection rates varied widely within a mosquito host species. There was no clear signal of cophylogeny between the mosquito hosts and the 12 putative Wolbachia strains observed in this study. Host shift events were also observed. Conclusions Our results suggest that the mosquito-Wolbachia relationship is complex and that combinations of transmission modes and multiple evolutionary events likely explain the observed distribution of Wolbachia diversity across mosquito hosts. These findings have implications for a better understanding of the diversity and ecology of Wolbachia and for their utility as biocontrol agents.
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Affiliation(s)
- Huicong Ding
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore, 117558, Singapore
| | - Huiqing Yeo
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore, 117558, Singapore
| | - Nalini Puniamoorthy
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore, 117558, Singapore.
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De Cock M, Virgilio M, Vandamme P, Bourtzis K, De Meyer M, Willems A. Comparative Microbiomics of Tephritid Frugivorous Pests (Diptera: Tephritidae) From the Field: A Tale of High Variability Across and Within Species. Front Microbiol 2020; 11:1890. [PMID: 32849469 PMCID: PMC7431611 DOI: 10.3389/fmicb.2020.01890] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 07/20/2020] [Indexed: 01/04/2023] Open
Abstract
The family Tephritidae includes some of the most notorious insect pests of agricultural and horticultural crops in tropical and sub-tropical regions. Despite the interest in the study of their gut microbiome, our present knowledge is largely based on the analysis of laboratory strains. In this study, we present a first comparative analysis of the gut microbiome profiles of field populations of ten African and Mediterranean tephritid pests. For each species, third instar larvae were sampled from different locations and host fruits and compared using 16S rRNA amplicon sequencing and a multi-factorial sampling design. We observed considerable variation in gut microbiome diversity and composition both between and within fruit fly species. A “core” microbiome, shared across all targeted species, could only be identified at most at family level (Enterobacteriaceae). At genus level only a few bacterial genera (Klebsiella, Enterobacter, and Bacillus) were present in most, but not all, samples, with high variability in their relative abundance. Higher relative abundances were found for seven bacterial genera in five of the fruit fly species considered. These were Erwinia in Bactrocera oleae, Lactococcus in B. zonata, Providencia in Ceratitis flexuosa, Klebsiella, and Rahnella in C. podocarpi and Acetobacter and Serratia in C. rosa. With the possible exception of C. capitata and B. dorsalis (the two most polyphagous species considered) we could not detect obvious relationships between fruit fly dietary breadth and microbiome diversity or abundance patterns. Similarly, our results did not suggest straightforward differences between the microbiome profiles of species belonging to Ceratitis and the closely related Bactrocera/Zeugodacus. These results provide a first comparative analysis of the gut microbiomes of field populations of multiple economically relevant tephritids and provide base line information for future studies that will further investigate the possible functional role of the observed associations.
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Affiliation(s)
- Maarten De Cock
- Royal Museum for Central Africa, Tervuren, Belgium.,Laboratory of Microbiology, Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | | | - Peter Vandamme
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint Food and Agriculture Organization of the UnitedNations/International Atomic Energy Agency (FAO/IAEA) Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | | | - Anne Willems
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, Belgium
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Odden JP, Eng W, Lee K, Donelick H, Hiefield M, Steach J, Chan L. Novel Host-Bacterial Symbioses Revealed: Characterization of Wolbachia in Arthropods of Western North America. WEST N AM NATURALIST 2019. [DOI: 10.3398/064.079.0407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Joanne P. Odden
- Pacific University, Department of Biology, Forest Grove, OR 97116
| | - Wyatt Eng
- Pacific University, Department of Biology, Forest Grove, OR 97116
| | - Kelsey Lee
- Pacific University, Department of Biology, Forest Grove, OR 97116
| | - Helen Donelick
- Pacific University, Department of Biology, Forest Grove, OR 97116
| | - Mallory Hiefield
- Pacific University, Department of Biology, Forest Grove, OR 97116
| | - Jamie Steach
- Pacific University, Department of Biology, Forest Grove, OR 97116
| | - Lauren Chan
- Pacific University, Department of Biology, Forest Grove, OR 97116
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Wang A, Peng Y, Harder LD, Huang J, Yang D, Zhang D, Liao W. The nature of interspecific interactions and co-diversification patterns, as illustrated by the fig microcosm. THE NEW PHYTOLOGIST 2019; 224:1304-1315. [PMID: 31494940 PMCID: PMC6856861 DOI: 10.1111/nph.16176] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 09/02/2019] [Indexed: 05/05/2023]
Abstract
Interactions between mutualists, competitors, and antagonists have contrasting ecological effects that, sustained over generations, can influence micro- and macroevolution. Dissimilar benefits and costs for these interactions should cause contrasting co-diversification patterns between interacting clades, with prevalent co-speciation by mutualists, association loss by competitors, and host switching by antagonists. We assessed these expectations for a local assemblage of 26 fig species (Moraceae: Ficus), 26 species of mutualistic (pollinating), and 33 species of parasitic (galling) wasps (Chalcidoidea). Using newly acquired gene sequences, we inferred the phylogenies for all three clades. We then compared the three possible pairs of phylogenies to assess phylogenetic congruence and the relative frequencies of co-speciation, association duplication, switching, and loss. The paired phylogenies of pollinators with their mutualists and competitors were significantly congruent, unlike that of figs and their parasites. The distributions of macroevolutionary events largely agreed with expectations for mutualists and antagonists. By contrast, that for competitors involved relatively frequent association switching, as expected, but also unexpectedly frequent co-speciation. The latter result likely reflects the heterogeneous nature of competition among fig wasps. These results illustrate the influence of different interspecific interactions on co-diversification, while also revealing its dependence on specific characteristics of those interactions.
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Affiliation(s)
- Ai‐Ying Wang
- State Key Laboratory of Earth Surface Processes and Resource EcologyMinistry of Education Key Laboratory for Biodiversity Science and Ecological EngineeringBeijing Normal UniversityBeijingChina
| | - Yan‐Qiong Peng
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesKunmingChina
| | - Lawrence D. Harder
- Department of Biological SciencesUniversity of Calgary2500 University Drive NWCalgaryABCanada
| | - Jian‐Feng Huang
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesKunmingChina
| | - Da‐Rong Yang
- CAS Key Laboratory of Tropical Forest EcologyXishuangbanna Tropical Botanical GardenChinese Academy of SciencesKunmingChina
| | - Da‐Yong Zhang
- State Key Laboratory of Earth Surface Processes and Resource EcologyMinistry of Education Key Laboratory for Biodiversity Science and Ecological EngineeringBeijing Normal UniversityBeijingChina
| | - Wan‐Jin Liao
- State Key Laboratory of Earth Surface Processes and Resource EcologyMinistry of Education Key Laboratory for Biodiversity Science and Ecological EngineeringBeijing Normal UniversityBeijingChina
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Andongma AA, Wan L, Dong XP, Akami M, He J, Clarke AR, Niu CY. The impact of nutritional quality and gut bacteria on the fitness of Bactrocera minax (Diptera: Tephritidae). ROYAL SOCIETY OPEN SCIENCE 2018; 5:180237. [PMID: 30109079 PMCID: PMC6083673 DOI: 10.1098/rsos.180237] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
To examine how nutritional quality and resident gut bacteria interplay in improving the fitness of an oligophagous fruit fly, Bactrocera minax, artificial sucrose diets and full diets (sucrose, tryptone and yeast extract) were fed to flies with and without antibiotic supplementation. Furthermore, Klebsiella oxytoca and Citrobacter freundii were supplemented to sucrose-only diets. Flies were maintained in the laboratory and the fitness parameters, male and female longevity, number of copulations and female fecundity, were recorded. Full diet without bacterial depletion significantly increased fecundity and copulation. In the absence of gut bacteria, flies fed with full diets had significantly decreased mean fecundity and copulation rate. Flies that were fed with sucrose diet had a very low copulation rate and produced no eggs. Diet type and the presence of bacteria did not have any effect on the average longevity of male and female flies. Bacterial supplementation in sucrose diets did not improve any of the measured parameters. The results demonstrate that gut bacteria interact with diet to influence mating and reproduction in B. minax. Symbiotic bacteria significantly and positively impact reproduction in B. minax; however, their impact can only be fully realized when the flies are fed with a nutritionally complete diet.
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Affiliation(s)
- Awawing A. Andongma
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Lun Wan
- Hubei Center for Disease Control and Prevention, Zhuodaoquanbei Road 6, Wuhan, 430079, People's Republic of China
| | - Xue-ping Dong
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Mazarin Akami
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Anthony R. Clarke
- School of Earth, Environmental, and Biological Sciences, Queensland University of Technology, Brisbane, 4001 Queensland, Australia
| | - Chang-Ying Niu
- College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
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