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Betaproteobacteria L imnohabitans strains increase fecundity in the crustacean D aphnia magna : symbiotic relationship between major bacterioplankton and zooplankton in freshwater ecosystem
Author(s) -
Peerakietkhajorn Saranya,
Kato Yasuhiko,
Kasalický Vojtěch,
Matsuura Tomoaki,
Watanabe Hajime
Publication year - 2016
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.12919
Subject(s) - biology , daphnia , zooplankton , daphnia magna , fecundity , population , symbiotic bacteria , ecology , zoology , symbiosis , bacteria , chemistry , genetics , demography , organic chemistry , toxicity , sociology
Summary How symbioses between bacteria and aquatic animals influence food webs in freshwater ecosystems is a fundamental question in ecology. We investigated symbiosis between a crustacean zooplankton D aphnia magna and its dominant bacterial symbiont L imnohabitans , an abundant and globally distributed freshwater B etaproteobacteria . Aposymbiotic juvenile D aphnia were prepared and exposed to any of four L imnohabitans sp. – L imnohabitans strains DM 1, 2 KL ‐3, 2 KL ‐7 and L imnohabitans planktonicus strain II ‐ D 5, all previously found in D . magna digestive tract or culture. Re‐infected D aphnia were cultured until they produced the first clutch of juveniles. L imnohabitans strain DM 1 and L . planktonicus strain II ‐ D 5 successfully re‐infected D aphnia through single exposure at the first instar juvenile stage. In contrast to aposymbiotic D aphnia that produced non‐viable juveniles, re‐infected D aphnia produced viable juveniles and increased fecundity to levels of that of symbiotic D aphnia . Re‐infected D aphnia did not increase their number of eggs nor growth rates. L imnohabitans strains 2 KL ‐7 and 2 KL ‐3 could not recover fecundity even in multiple exposures during culture. This study shows the functional evidence demonstrating that a single bacterium L imnohabitans regulates fecundity of the consumer D aphnia through symbiosis. Our results indicated that symbiotic relationship between major bacterioplankton and zooplankton is important for maintaining the population of zooplankton in freshwater ecosystems.