期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2020
卷号：117
期号：35
页码：20994-20996
DOI：10.1073/pnas.2014598117
出版社：The National Academy of Sciences of the United States of America
摘要：Symbiotic microorganisms are essential for the lives of many multicellular eukaryotes (1). In insects, decades of symbiosis and—more recently—microbiome research have shown that microbial symbionts can supplement limiting nutrients, aid in digestion or detoxification, and defend their host against antagonists, thereby expanding the ecological and evolutionary potential of their hosts (2). In order to ensure that their offspring are endowed with the beneficial symbionts, insects have evolved a range of transmission routes to pass the symbionts vertically from parents to offspring or acquire them horizontally from unrelated host individuals or from the environment (3, 4). However, while, at first glance, the transmission from one host individual to another might seem like the most intricate problem for a symbiotic partnership, maintaining the symbiosis throughout the host’s development may be no less of a challenge (5). In particular, holometabolous insects like beetles, butterflies and moths, flies, ants, bees, and wasps experience a complete restructuring of the body during metamorphosis from the larva to the adult individual. While gut microbes can be maintained throughout the reorganization of the gut (6), and other extracellular symbionts can persist outside of the host’s body (7), how intracellular mutualists located in special organs (bacteriomes) are maintained and sometimes even translocated during metamorphosis remained poorly understood (but see ref. 8). Maire et al., in PNAS (9), now elucidate the complex journey of the symbiont-bearing organs and their inhabitants in the rice weevil Sitophilus oryzae (Fig. 1), an organism with a long history of study of its symbiotic interaction with the Gammaproteobacteria Sodalis pierantonius (10). These symbionts were previously found to supply limiting nutrients including aromatic amino acids to their host and thereby support cuticle sclerotization and melanization (11).
