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Zhan C, Chen L, Guo D, Sun J, Duan Y, Zhang P, Li P, Ma L, Xu M, Wang Y, Bao H, Gao G, Liu L, Zhang K. An Intestinal Symbiotic Bacterial Strain of Oscheius chongmingensis Modulates Host Viability at Both Global and Post-Transcriptional Levels. Int J Mol Sci 2022; 23:ijms232314692. [PMID: 36499019 PMCID: PMC9739912 DOI: 10.3390/ijms232314692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/08/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
A rhabditid entomopathogenic nematode (EPN), Oscheius chongmingensis, has a stable symbiotic relationship with the bacterial strain Serratia nematodiphila S1 harbored in its intestines and drastically reduced viability when associated with a non-native strain (186) of the same bacterial species. This nematode is thus a good model for understanding the molecular mechanisms and interactions involved between a nematode host and a member of its intestinal microbiome. Transcriptome analysis and RNA-seq data indicated that expression levels of the majority (8797, 87.59%) of mRNAs in the non-native combination of O. chongmingensis and S. nematodiphila 186 were downregulated compared with the native combination, including strain S1. Accordingly, 88.84% of the total uniq-sRNAs mapped in the O. chongmingensis transcriptome were specific between the two combinations. Six DEGs, including two transcription factors (oc-daf-16 and oc-goa-1) and four kinases (oc-pdk-1, oc-akt-1, oc-rtk, and oc-fak), as well as an up-regulated micro-RNA, oc-miR-71, were found to demonstrate the regulatory mechanisms underlying diminished host viability induced by a non-native bacterial strain. Oc-rtk and oc-fak play key roles in the viability regulation of O. chongmingensis by positively mediating the expression of oc-daf-16 to indirectly impact its longevity and stress tolerances and by negatively regulating the expression of oc-goa-1 to affect the olfactory chemotaxis and fecundity. In response to the stress of invasion by the non-native strain, the expression of oc-miR-71 in the non-native combination was upregulated to downregulate the expression of its targeting oc-pdk-1, which might improve the localization and activation of the transcription factor DAF-16 in the nucleus to induce longevity extension and stress resistance enhancement to some extent. Our findings provide novel insight into comprehension of how nematodes deal with the stress of encountering novel potential bacterial symbionts at the physiological and molecular genetic levels and contribute to improved understanding of host-symbiont relationships generally.
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Affiliation(s)
- Chengxiu Zhan
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Long Chen
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Dandan Guo
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Jing Sun
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yunbin Duan
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Panjie Zhang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Pengpeng Li
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Lijun Ma
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Man Xu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Ying Wang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Haoran Bao
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Guofu Gao
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Liwang Liu
- National Key Laboratory of Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Germplasm Enhancement of Horticultural Crop (East China), Ministry of Agriculture and Rural Affairs, College of Horiticulture, Nanjing Agricultural University, Nanjing 210095, China
- Correspondence: (L.L.); (K.Z.)
| | - Keyun Zhang
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
- Correspondence: (L.L.); (K.Z.)
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Cao M, Goodrich-Blair H. Xenorhabdus nematophila bacteria shift from mutualistic to virulent Lrp-dependent phenotypes within the receptacles of Steinernema carpocapsae insect-infective stage nematodes. Environ Microbiol 2020; 22:5433-5449. [PMID: 33078552 DOI: 10.1111/1462-2920.15286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/03/2020] [Accepted: 10/18/2020] [Indexed: 01/06/2023]
Abstract
Xenorhabdus nematophila bacteria are mutualists of Steinernema carpocapsae nematodes and pathogens of insects. Xenorhabdus nematophila exhibits phenotypic variation between insect virulence (V) and the mutualistic (M) support of nematode reproduction and colonization initiation in the infective juvenile (IJ) stage nematode that carries X. nematophila between insect hosts. The V and M phenotypes occur reciprocally depending on levels of the transcription factor Lrp: high-Lrp expressors are M+V- while low-Lrp expressors are V+M-. We report here that variable (wild type) or fixed high-Lrp expressors also are optimized, relative to low- or no-Lrp expressors, for colonization of additional nematode stages: juvenile, adult and pre-transmission infective juvenile (IJ). In contrast, we found that after the bacterial population had undergone outgrowth in mature IJs, the advantage for colonization shifted to low-Lrp expressors: fixed low-Lrp expressors (M-V+) and wild type (M+V+) exhibited higher average bacterial CFU per IJ than did high-Lrp (M+V-) or no-Lrp (M-V-) strains. Further, the bacterial population becomes increasingly low-Lrp expressing, based on expression of an Lrp-dependent fluorescent reporter, as IJs age. These data support a model that virulent X. nematophila have a selective advantage and accumulate in aging IJs in advance of exposure to insect hosts in which this phenotype is necessary.
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Affiliation(s)
- Mengyi Cao
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Heidi Goodrich-Blair
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, 53706, USA.,Department of Microbiology, University of Tennessee, Knoxville, TN, 37996, USA
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Roder AC, Wang Y, Butcher RA, Stock SP. Influence of symbiotic and non-symbiotic bacteria on pheromone production in Steinernema nematodes (Nematoda, Steinernematidae). ACTA ACUST UNITED AC 2019; 222:jeb.212068. [PMID: 31511342 DOI: 10.1242/jeb.212068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 09/04/2019] [Indexed: 11/20/2022]
Abstract
In this study, we assessed the effect of symbiotic (cognate and non-cognate) and non-symbiotic bacteria on ascaroside production of first-generation adults in two Steinernema spp.: S. carpocapsae All strain and S. feltiae SN strain. Each nematode species was reared under three bacterial scenarios: (1) cognate symbiotic, (2) non-cognate symbiotic strain and (3) non-cognate symbiotic species. Our results showed S. carpocapsae produced four quantifiable ascaroside molecules: asc-C5, asc-C6, asc-C7 and asc-C11, whereas in S. feltiae only three molecules were detected: asc-C5, asc-C7 and asc-C11. Bacterial conditions did not significantly affect the quantity of the secreted ascarosides in first-generation adults of S. carpocapsae However, in S. feltiae, Xenorhabdus nematophila All strain influenced the production of two ascaroside molecules: asc-C5 and asc-C11.
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Affiliation(s)
- Alexandra C Roder
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Yuting Wang
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - Rebecca A Butcher
- Department of Chemistry, University of Florida, Gainesville, FL 32611, USA
| | - S Patricia Stock
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, AZ 85721, USA .,Department of Entomology, University of Arizona, Forbes Building Rm 410, 1140 E. South Campus Drive, Tucson, AZ 85721, USA
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