Nitrogen isotopes reveal independent origins of N2-fixing symbiosis in extant cycad lineages

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00023272%3A_____%2F24%3A10136270" target="_blank" >RIV/00023272:_____/24:10136270 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.nature.com/articles/s41559-023-02251-1" target="_blank" >https://www.nature.com/articles/s41559-023-02251-1</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1038/s41559-023-02251-1" target="_blank" >10.1038/s41559-023-02251-1</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Nitrogen isotopes reveal independent origins of N2-fixing symbiosis in extant cycad lineages

Popis výsledku v původním jazyce

Cycads are ancient seed plants (gymnosperms) that emerged by the early Permian. Although they were common understory fora and food for dinosaurs in the Mesozoic, their abundance declined markedly in the Cenozoic. Extant cycads persist in restricted populations in tropical and subtropical habitats and, with their conserved morphology, are often called &apos;living fossils.&apos; All surviving taxa receive nitrogen from symbiotic N2-fxing cyanobacteria living in modifed roots, suggesting an ancestral origin of this symbiosis. However, such an ancient acquisition is discordant with the abundance of cycads in Mesozoic fossil assemblages, as modern N2-fxing symbioses typically occur only in nutrient-poor habitats where advantageous for survival. Here, we use foliar nitrogen isotope ratios-a proxy for N2 fxation in modern plants-to probe the antiquity of the cycad-cyanobacterial symbiosis. We fnd that fossilized cycad leaves from two Cenozoic representatives of extant genera have nitrogen isotopic compositions consistent with microbial N2 fxation. In contrast, all extinct cycad genera have nitrogen isotope ratios that are indistinguishable from co-existing non-cycad plants and generally inconsistent with microbial N2 fxation, pointing to nitrogen assimilation from soils and not through symbiosis. This pattern indicates that, rather than being ancestral within cycads, N2-fxing symbiosis arose independently in the lineages leading to living cycads during or after the Jurassic. The preferential survival of these lineages may therefore refect the efects of competition with angiosperms and Cenozoic climatic change.

Název v anglickém jazyce

Nitrogen isotopes reveal independent origins of N2-fixing symbiosis in extant cycad lineages

Popis výsledku anglicky

Cycads are ancient seed plants (gymnosperms) that emerged by the early Permian. Although they were common understory fora and food for dinosaurs in the Mesozoic, their abundance declined markedly in the Cenozoic. Extant cycads persist in restricted populations in tropical and subtropical habitats and, with their conserved morphology, are often called &apos;living fossils.&apos; All surviving taxa receive nitrogen from symbiotic N2-fxing cyanobacteria living in modifed roots, suggesting an ancestral origin of this symbiosis. However, such an ancient acquisition is discordant with the abundance of cycads in Mesozoic fossil assemblages, as modern N2-fxing symbioses typically occur only in nutrient-poor habitats where advantageous for survival. Here, we use foliar nitrogen isotope ratios-a proxy for N2 fxation in modern plants-to probe the antiquity of the cycad-cyanobacterial symbiosis. We fnd that fossilized cycad leaves from two Cenozoic representatives of extant genera have nitrogen isotopic compositions consistent with microbial N2 fxation. In contrast, all extinct cycad genera have nitrogen isotope ratios that are indistinguishable from co-existing non-cycad plants and generally inconsistent with microbial N2 fxation, pointing to nitrogen assimilation from soils and not through symbiosis. This pattern indicates that, rather than being ancestral within cycads, N2-fxing symbiosis arose independently in the lineages leading to living cycads during or after the Jurassic. The preferential survival of these lineages may therefore refect the efects of competition with angiosperms and Cenozoic climatic change.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10506 - Paleontology

Projekt

—

Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Nature ecology &amp; evolution

ISSN

2397-334X

e-ISSN

—

Svazek periodika

8

Číslo periodika v rámci svazku

2251

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

13

Strana od-do

57-69

Kód UT WoS článku

001106164400002

EID výsledku v databázi Scopus

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