RT Journal Article
SR Electronic
T1 Sugars dominate the seagrass rhizosphere
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 797522
DO 10.1101/797522
A1 E. Maggie Sogin
A1 Dolma Michellod
A1 Harald Gruber-Vodicka
A1 Patric Bourceau
A1 Benedikt Geier
A1 Dimitri V. Meier
A1 Michael Seidel
A1 Soeren Ahmerkamp
A1 Sina Schorn
A1 Grace D’Angelo
A1 Gabriele Procaccini
A1 Nicole Dubilier
A1 Manuel Liebeke
YR 2021
UL http://biorxiv.org/content/early/2021/03/17/797522.abstract
AB Seagrasses are one of the most efficient sinks of carbon dioxide on Earth1: They bury carbon 35 times faster than tropical rainforests on a per unit area basis2. While we know that carbon sequestration in terrestrial plants is intimately linked to the microorganisms living in their soils3–6, the interactions of seagrasses with their rhizospheres are poorly understood. We show that three seagrass species from two oceans excrete simple sugars, mainly sucrose, into their rhizosphere that accumulate to over 200 µM. Such high concentrations are at least 80 times higher than previously observed in the ocean, and surprising, as sugars are quickly consumed by microorganisms. In situ analyses and incubation experiments indicated that phenolic compounds from the seagrass inhibited microbial consumption of sucrose. Metagenomic and metatranscriptomic analyses of the microbial communities in the seagrass rhizosphere revealed that many members had the genes for degrading sucrose, but these were only expressed by a few specialists that also expressed genes for degrading phenolics. Our results explain why sucrose accumulates under seagrass meadows, where it comprises as much as 40% of the dissolved organic carbon. Destruction of extant seagrass canopies would allow sediment microorganisms to consume the tremendous deposits of sucrose buried underneath their meadows, thereby releasing large amounts of CO2 into the oceans and atmosphere.Competing Interest StatementThe authors have declared no competing interest.