Bonfante Paola, Desirò Alessandro
Department of Life Science and Systems Biology, University of Torino, Torino, Italy.
Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, USA.
ISME J. 2017 Aug;11(8):1727-1735. doi: 10.1038/ismej.2017.21. Epub 2017 Apr 7.
Bacterial interactions with plants and animals have been examined for many years; differently, only with the new millennium the study of bacterial-fungal interactions blossomed, becoming a new field of microbiology with relevance to microbial ecology, human health and biotechnology. Bacteria and fungi interact at different levels and bacterial endosymbionts, which dwell inside fungal cells, provide the most intimate example. Bacterial endosymbionts mostly occur in fungi of the phylum Mucoromycota and include Betaproteobacteria (Burkhoderia-related) and Mollicutes (Mycoplasma-related). Based on phylogenomics and estimations of divergence time, we hypothesized two different scenarios for the origin of these interactions (early vs late bacterial invasion). Sequencing of the genomes of fungal endobacteria revealed a significant reduction in genome size, particularly in endosymbionts of Glomeromycotina, as expected by their uncultivability and host dependency. Similar to endobacteria of insects, the endobacteria of fungi show a range of behaviours from mutualism to antagonism. Emerging results suggest that some benefits given by the endobacteria to their plant-associated fungal host may propagate to the interacting plant, giving rise to a three-level inter-domain interaction.
多年来，人们一直在研究细菌与动植物之间的相互作用；不同的是，直到新千年，细菌与真菌相互作用的研究才蓬勃发展，成为微生物学的一个新领域，与微生物生态学、人类健康和生物技术相关。细菌和真菌在不同层面相互作用，而生活在真菌细胞内的细菌内共生体就是最密切的例子。细菌内共生体大多存在于毛霉门真菌中，包括β-变形菌纲（与伯克霍尔德菌属相关）和柔膜菌纲（与支原体属相关）。基于系统发育基因组学和分歧时间估计，我们对这些相互作用的起源提出了两种不同的设想（细菌早期入侵与晚期入侵）。真菌内细菌基因组测序显示基因组大小显著减小，尤其是球囊菌纲的内共生体，这与其不可培养性和对宿主的依赖性相符。与昆虫的内细菌类似，真菌的内细菌表现出从共生到拮抗的一系列行为。新出现的结果表明，内细菌给予与其共生的植物相关真菌宿主的一些益处可能会传递给与之相互作用的植物，从而产生一种三级跨域相互作用。
