Abstract
Animals endemic to deep-sea hydrothermal vents often form obligatory symbioses with bacteria, maintained by intricate host-symbiont interactions. Most genomic studies on holobionts have not investigated both sides to similar depths. Here, we report dual symbiosis in the peltospirid snail Gigantopelta aegis with two gammaproteobacterial endosymbionts: a sulfur oxidiser and a methane oxidiser. We assemble high-quality genomes for all three parties, including a chromosome-level host genome. Hologenomic analyses reveal mutualism with nutritional complementarity and metabolic co-dependency, highly versatile in transporting and using chemical energy. Gigantopelta aegis likely remodels its immune system to facilitate dual symbiosis. Comparisons with Chrysomallon squamiferum, a confamilial snail with a single sulfur-oxidising gammaproteobacterial endosymbiont, show that their sulfur-oxidising endosymbionts are phylogenetically distant. This is consistent with previous findings that they evolved endosymbiosis convergently. Notably, the two sulfur-oxidisers share the same capabilities in biosynthesising nutrients lacking in the host genomes, potentially a key criterion in symbiont selection.
Original language | English (US) |
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Journal | Nature communications |
Volume | 12 |
Issue number | 1 |
DOIs | |
State | Published - Feb 20 2021 |
Bibliographical note
KAUST Repository Item: Exported on 2021-02-23Acknowledgements: We thank the captain and crew of the R/V Xiangyanghong 9 and pilots of HOV Jiaolong for their great support during the research cruise DY35th-II, the captain and crew of the R/V Dayang Yihao as well as the operation team of the ROV Sea Dragon III during the third leg of the China Ocean Mineral Resources Research and Development Association DY52nd cruise. Dr. Jack C.H. Ip and Dr. Ting Xu from Hong Kong Baptist University, as well as Dr. Ken Takai and Dr. Shinsuke Kawagucci from JAMSTEC are gratefully acknowledged for their helpful comments. Katsuyuki Uematsu (Marine Works Japan Ltd.) is thanked for his help during the TEM observations. This work was supported by grants from the National Key R&D Program of China (2018YFC0309904), China Ocean Mineral Resources Research and Development Association (DY135-E2-1-03), the Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (SMSEGL20SC01), Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2019ZD0409), and Major Project of Basic and Applied Basic Research of Guangdong Province (2019B030302004-04).