An obligately endosymbiotic mycorrhizal fungus itself harbors obligately intracellular bacteria
An obligately endosymbiotic mycorrhizal fungus itself harbors obligately intracellular bacteria
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DOI：
10.1128/aem.62.8.3005-3010.1996
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发表时间：
1996-08-01
影响因子：
4.4
通讯作者：
Bonfante, P
中科院分区：
文献类型：
--
作者：
Bianciotto, V;Bandi, C;Bonfante, P
丛枝菌根真菌是一种专性内共生菌，在近80%的陆生植物根部定植。本文介绍了就业相结合的形态学和分子生物学的方法来证明，细胞质的丛枝菌根真菌Gigaspora margarita港口进一步细菌endosgmbiont。在其孢子、萌发和共生菌丝体中检测到胞质内细菌样生物（BLO）。荧光染色的形态学观察显示，每个孢子内约有25万个活细菌。对芽孢BLOs的小亚基rRNA基因序列与代表性的细菌谱系的序列进行了比较，分子系统发育分析明确表明，G.玛格丽塔是rRNA组II假单胞菌（Burkholderia属）。使用具有专门设计的寡核苷酸的PCR测定来检查来自BLO的序列驯服。当使用来自孢子和共生菌丝体的模板时，获得了成功的扩增。从盾孢菌属的孢子中也获得了预期长度的条带。阴性对照品未给出条带。这些发现表明菌根系统包括植物、真菌和细菌细胞。
Arbuscular-mycorrhizal fungi are obligate endosymbionts that colonize the roots of almost 80% of land plants. This paper describes the employment of a combined morphological and molecular approach to demonstrate that the cytoplasm of the arbuscular-mycorrhizal fungus Gigaspora margarita harbors a further bacterial endosgmbiont. Intracytoplasmic bacterium-like organisms (BLOs) were detected ultrastructurally in its spores and germinating and symbiotic mycelia Morphological observations with a fluorescent stain revealed about 250,000 live bacteria inside each spore. The sequence for the small-subunit rRNA gene obtained for the BLOs from the spores was compared with those for representatives of the enbacterial lineages, Molecular phylogenetic analysis uambiguously sheaved that the endosymbiont of G. margarita was an rRNA group II pseudomonad (genus Burkholderia). PCR assays with specifically designed oligonucleotides were used to check that the sequence tame from the BLOs. Successful amplification was obtained when templates from both the spores and the symbiotic mycelia were used. A band of the expected length was also obtained from spores of a Scutellospora sp. No bands were given by the negative controls. These findings indicate that mycorrhizal systems ran include plant, fungal, and bacterial cells.