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Gross M, Dunthorn M, Mauvisseau Q, Stoeck T. Using digital PCR to predict ciliate abundance from ribosomal RNA gene copy numbers. Environ Microbiol 2024; 26:e16619. [PMID: 38649189 DOI: 10.1111/1462-2920.16619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 03/16/2024] [Indexed: 04/25/2024]
Abstract
Ciliates play a key role in most ecosystems. Their abundance in natural samples is crucial for answering many ecological questions. Traditional methods of quantifying individual species, which rely on microscopy, are often labour-intensive, time-consuming and can be highly biassed. As a result, we investigated the potential of digital polymerase chain reaction (dPCR) for quantifying ciliates. A significant challenge in this process is the high variation in the copy number of the taxonomic marker gene (ribosomal RNA [rRNA]). We first quantified the rRNA gene copy numbers (GCN) of the model ciliate, Paramecium tetraurelia, during different stages of the cell cycle and growth phases. The per-cell rRNA GCN varied between approximately 11,000 and 130,000, averaging around 50,000 copies per cell. Despite these variations in per-cell rRNA GCN, we found a highly significant correlation between GCN and cell numbers. This is likely due to the coexistence of different cellular stages in an uncontrolled (environmental) ciliate population. Thanks to the high sensitivity of dPCR, we were able to detect the target gene in a sample that contained only a single cell. The dPCR approach presented here is a valuable addition to the molecular toolbox in protistan ecology. It may guide future studies in quantifying and monitoring the abundance of targeted (even rare) ciliates in natural samples.
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Affiliation(s)
- Megan Gross
- Ecology Group, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, Kaiserslautern, Germany
| | - Micah Dunthorn
- Natural History Museum, University of Oslo, Oslo, Norway
| | | | - Thorsten Stoeck
- Ecology Group, Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, Kaiserslautern, Germany
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Li H, Liu Y, Wei X, Pan H, Zhang Y, Zhou X, Chu D. Heterogeneous distribution of Cardinium in whitefly populations is associated with host nuclear genetic background. INSECT SCIENCE 2023; 30:1701-1712. [PMID: 37147785 DOI: 10.1111/1744-7917.13199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/28/2023] [Accepted: 03/15/2023] [Indexed: 05/07/2023]
Abstract
Inherited bacterial symbionts are very common in arthropods, but infection frequency can vary widely among populations. Experiments and interpopulation comparisons suggest that host genetic background might be important in explaining this variation. Our extensive field investigation showed that the infection pattern of the facultative symbiont Cardinium was heterogeneous across geographical populations of the invasive whitefly Bemisia tabaci Mediterranean (MED) in China, with genetic nuclear differences evident in 2 of the populations: 1 with a low infection rate (SD line) and 1 with a high infection rate (HaN line). However, whether the heterogeneous frequency of Cardinium is associated with the host genetic background remains poorly understood. Here, we compared the fitness of the Cardinium-infected and uninfected sublines with similar nuclear genetic backgrounds from SD and HaN lines, respectively, and further determine whether host extranuclear or nuclear genotype influenced the Cardinium-host phenotype by performing 2 new introgression series of 6 generations between SD and HaN lines (i.e., Cardinium-infected females of SD were backcrossed with uninfected males of HaN, and vice versa). The results showed that Cardinium provides marginal fitness benefits in the SD line, whereas Cardinium provides strong fitness benefits in the HaN line. Further, both Cardinium and the Cardinium-host nuclear interaction influence the fecundity and pre-adult survival rate of B. tabaci, whereas the extranuclear genotype does not. In conclusion, our results provide evidence that Cardinium-mediated fitness effects were closely associated with the host genetic background, which provides a fundamental basis for understanding the mechanism underlying the heterogeneous distribution of Cardinium in B. tabaci MED populations across China.
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Affiliation(s)
- Hongran Li
- Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shangdong Province, China
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Gene Editing Technologies (Hainan), Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong Province, China
| | - Ying Liu
- Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shangdong Province, China
| | - Xiaoying Wei
- Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shangdong Province, China
| | - Huipeng Pan
- Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, South China Agricultural University, Guangzhou, China
| | - Youjun Zhang
- Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xuguo Zhou
- Department of Entomology, University of Kentucky, Lexington, Kentucky, USA
| | - Dong Chu
- Shandong Engineering Research Center for Environment-Friendly Agricultural Pest Management, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, Shangdong Province, China
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Hiillos AL, Rony I, Rueckert S, Knott KE. Coinfection patterns of two marine apicomplexans are not associated with genetic diversity of their polychaete host. J Eukaryot Microbiol 2023; 70:e12932. [PMID: 35711085 PMCID: PMC10084031 DOI: 10.1111/jeu.12932] [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: 03/24/2022] [Revised: 04/21/2022] [Accepted: 05/08/2022] [Indexed: 01/13/2023]
Abstract
Coinfections of two or more parasites within one host are more of a rule than an exception in nature. Interactions between coinfecting parasites can greatly affect their abundance and prevalence. Characteristics of the host, such as genetic diversity, can also affect the infection dynamics of coinfecting parasites. Here, we investigate for the first time the association of coinfection patterns of two marine apicomplexans, Rhytidocystis sp. and Selenidium pygospionis, with the genetic diversity of their host, the polychaete Pygospio elegans, from natural populations. Host genetic diversity was determined with seven microsatellite loci and summarized as allelic richness, inbreeding coefficient, and individual heterozygosity. We detected nonsignificant correlations between infection loads and both individual host heterozygosity and population genetic diversity. Prevalence and infection load of Rhytidocystis sp. were higher than those of S. pygospionis, and both varied spatially. Coinfections were common, and almost all hosts infected by S. pygospionis were also infected by Rhytidocystis sp. Rhytidocystis sp. infection load was significantly higher in dual infections. Our results suggest that factors other than host genetic diversity might be more important in marine apicomplexan infection patterns and experimental approaches would be needed to further determine how interactions between the apicomplexans and their host influence infection.
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Affiliation(s)
- Anna-Lotta Hiillos
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Irin Rony
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Sonja Rueckert
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, UK.,Centre for Conservation and Restoration Science, Edinburgh Napier University, Edinburgh, UK
| | - K Emily Knott
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
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