@article{93e1c57c62a04897a55e2d1c9a6bf50e,
title = "Endosymbiont population genomics sheds light on transmission mode, partner specificity, and stability of the scaly-foot snail holobiont",
abstract = "The scaly-foot snail (Chrysomallon squamiferum) inhabiting deep-sea hydrothermal vents in the Indian Ocean relies on its sulphur-oxidising gammaproteobacterial endosymbionts for nutrition and energy. In this study, we investigate the specificity, transmission mode, and stability of multiple scaly-foot snail populations dwelling in five vent fields with considerably disparate geological, physical and chemical environmental conditions. Results of population genomics analyses reveal an incongruent phylogeny between the endosymbiont and mitochondrial genomes of the scaly-foot snails in the five vent fields sampled, indicating that the hosts obtain endosymbionts via horizontal transmission in each generation. However, the genetic homogeneity of many symbiont populations implies that vertical transmission cannot be ruled out either. Fluorescence in situ hybridisation of ovarian tissue yields symbiont signals around the oocytes, suggesting that vertical transmission co-occurs with horizontal transmission. Results of in situ environmental measurements and gene expression analyses from in situ fixed samples show that the snail host buffers the differences in environmental conditions to provide the endosymbionts with a stable intracellular micro-environment, where the symbionts serve key metabolic functions and benefit from the host{\textquoteright}s cushion. The mixed transmission mode, symbiont specificity at the species level, and stable intracellular environment provided by the host support the evolutionary, ecological, and physiological success of scaly-foot snail holobionts in different vents with unique environmental parameters.",
author = "Yi Lan and Jin Sun and Chong Chen and Hao Wang and Yao Xiao and Maeva Perez and Yi Yang and Kwan, {Yick Hang} and Yanan Sun and Yadong Zhou and Xiqiu Han and Junichi Miyazaki and Watsuji, {Tomo O} and Dass Bissessur and Qiu, {Jian Wen} and Ken Takai and Qian, {Pei Yuan}",
note = "Funding Information: We thank the great support from the captain and crew of the R/V Xiangyanghong 9 and pilots of HOV Jiaolong during the cruise COMRA DY38 Leg 1 (principal scientist: Xiqiu Han); the captain and crew of the R/V Dayang Yihao and the operation team of the ROV Sea Dragon III during the cruise COMRA DY52 Leg 3; the captain and crew of R/V YOKOSUKA during cruises YK09-13 Leg 2 (principal scientists: Kentaro Nakamura and Satoshi Nakagawa), YK13-02 (principal scientist: Manabu Nishizawa), YK13-03 (principal scientist: Kentaro Nakamura) and YK16-02E (principal scientist: Ken Takai); and the pilots of the DSV SHINKAI 6500 during these cruises. We thank Norio Miyamoto and Hiromi Kayama Watanabe from X-STAR of Japan Agency for Marine-Earth Science and Technology (JAMSTEC) for collecting scaly-foot snails from the Solitaire vent and fixing them in PFA for FISH experiments. We thank Chenggang Liu from the Second Institute of Oceanography in the Ministry of Natural Resources for taking photos of scaly-foot snails collected from the Tiancheng vent. We thank Ting Xu from the Hong Kong University of Science and Technology for her suggestions on the colour code of the figures. We also thank the editors{\textquoteright} and reviewers{\textquoteright} constructive comments that helped us improve an earlier version of the present paper. This work was supported by grants from the Key Special Project for Introduced Talents Team of the Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2019ZD0409), the Major Project of Basic and Applied Basic Research of Guangdong Province (2019B030302004), the Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (SMSEGL20SC01), the General Research Fund of Hong Kong SAR (16101219, 12101021), and the China Ocean Mineral Resources Research and Development Association (DY135-E2-1-03). JS was supported by the National Natural Science Foundation of China (42176110). CC was supported by the Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research ({\textquoteleft}KAKENHI{\textquoteright}, grant code 18K06401). The authors wish to acknowledge the Mauritian Government for allowing the sampling of deep-sea animals in the Mauritian EEZ (Ref. 29/2014; 50/38/24 V2). Publisher Copyright: {\textcopyright} The Author(s) 2022 ",
year = "2022",
month = sep,
doi = "10.1038/s41396-022-01261-4",
language = "English",
volume = "16",
pages = "2132--2143",
journal = "ISME Journal",
issn = "1751-7362",
publisher = "Nature Publishing Group",
number = "9",
}