Allocation of Carbon from an Arbuscular Mycorrhizal Fungus, Gigaspora margarita, to Its Gram-Negative and Positive Endobacteria Revealed by High-Resolution Secondary Ion Mass Spectrometry

Microorganisms

Hisayoshi Yurimoto¹  Yukari Kuga²  Chie Katsuyama²  Ting-Di Wu³  Naoya Sakamoto⁴ 

[1] Department of Natural History Sciences, Hokkaido University, Kita-21 Nishi-11, Kita-ku, Sapporo 001-0021, Hokkaido, Japan;Graduate School of Integrated Sciences for Life, Hiroshima University, 1-7-1 Kagamiyama, Higashi-Hiroshima 739-8521, Hiroshima, Japan;Institut Curie, Université PSL, CNRS UMS2016, Inserm US43, Université Paris-Saclay, Multimodal Imaging Center, 91400 Orsay, France;Isotope Imaging Laboratory, Creative Research Institution, Hokkaido University, Kita-21 Nishi-11, Kita-ku, Sapporo 001-0021, Hokkaido, Japan;

关键词: arbuscular mycorrhiza;    endobacteria;    stable isotope labelling;    secondary ion mass spectrometry;   

DOI  :  10.3390/microorganisms9122597

来源: DOAJ

【 摘 要 】

Arbuscular mycorrhizal fungi are obligate symbionts of land plants; furthermore, some of the species harbor endobacteria. Although the molecular approach increased our knowledge of the diversity and origin of the endosymbiosis and its metabolic possibilities, experiments to address the functions of the fungal host have been limited. In this study, a C flow of the fungus to the bacteria was investigated. Onion seedlings colonized with Gigaspora margarita, possessing Candidatus Glomeribacter gigasporarum (CaGg, Gram-negative, resides in vacuole) and Candidatus Moeniiplasma glomeromycotorum (CaMg, Gram-positive, resides in the cytoplasm,) were labelled with ¹³CO₂. The ¹³C localization within the mycorrhiza was analyzed using high-resolution secondary ion mass spectrometry (SIMS). Correlative TEM-SIMS analysis of the fungal cells revealed that the ¹³C/¹²C ratio of CaGg was the lowest among CaMg and mitochondria and was the highest in the cytoplasm. By contrast, the plant cells, mitochondria, plastids, and fungal cytoplasm, which are contributors to the host, showed significantly higher ¹³C enrichment than the host cytoplasm. The C allocation patterns implied that CaMg has a greater impact than CaGg on G. margarita, but both seemed to be less burdensome to the host fungus in terms of C cost.

【 授权许可】

Unknown