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Symbiosis refers to the partnership (usually long-term) that is established between two or more organisms. In microbiology, symbiotic relationships are often established between a microorganism and its host, and the partnership can be mutualistic or parasitic.
Observations of recent or dynamic transitions between parasitism and mutualism are scarce. Here, Flórez et al. provide evidence that Burkholderia gladioli bacteria can protect the eggs of herbivorous beetles by producing antimicrobial compounds, while retaining their ancestral ability to infect plants.
The respiratory tract spans from the nostrils to the lung alveoli and these distinct niches host a diverse microbiota. In this Review, Man, de Steenhuijsen Piters and Bogaert discuss the role of the respiratory microbiota in the maintenance of human health.
Two new studies provide insights into the close association between Wolbachia spp. and their hosts; one shows plant-mediated transmission and the other the bacterial origin of a new host sex chromosome.