海草と海洋バクテリアの地上型窒素固定シンビオシス

Wiebke Mohr¹, Nadine Lehnen², Soeren Ahmerkamp²

¹Max Planck Institute for Marine Microbiology, Bremen, Germany. wmohr@mpi-bremen.de.

Nature

|November 4, 2021

まとめ

最近発見された窒素を固定する共生生物カンディダトゥス・セレリアンティモナス・ネプチュナは海草の根に生息し重要な栄養素を供給していますこの共生は海草が窒素の少ない海洋環境で繁栄するのを助けます

科学分野:

海の微生物学
植物と微生物の相互作用
シンビオティックな窒素固定

背景:

窒素を固定する微生物は,特に窒素の限られた生態系では,真核生物の窒素吸収に不可欠です.
窒素を固定する微生物と植物の間の親密な共生関係は,陸上の系統では一般的ですが,海草ではあまり記述されていません.
海草は,約1億年前に海洋環境に戻った陸上の開花植物から進化した.

研究の目的:

海草に関連した新しい窒素固定シンビオントを記述する.
海草の健康に寄与する共生関係の性質を明らかにする.
この共生がもたらす生態学的,進化的影響を探求する.

主な方法:

海草の根組織を顕微鏡で調べる
シンビオティックな微生物の識別と特徴付け
メタボロミック分析主体とシンビオントの栄養交換を決定する

主要な成果:

"Candidatus Celerinatantimonas neptuna"の発見は,海草の根の中に細胞内N2固定シンビオントとして
証明するよ C.ネプチューナは糖分と引き換えにホストにアンモニアとアミノ酸を供給します
この共生は,窒素が限られた地中海のポシドニア・オセアニカの草原の生産性を支えています.

結論:

発見された共生は,陸上のN2固定植物共生に類似しています.
この共生は窒素が少ない海洋生息地への花の植物の適応に役割を果たし重要な青い炭素の生態系を形成しました
カリフォルニアの親戚 C. ネプチューナは広く広がり,世界中の他の海洋および沿岸植物と類似の共生関係にある可能性があります.

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