Faculty of Agricultural, Environmental and Food Sciences, Free University of Bozen-Bolzano , Bolzano, Italy.
UMR 1345, Université d'Angers, Institut Agro, INRAE, IRHS, SFR Quasav , Beaucouzé, France.
mSystems. 2023 Oct 26;8(5):e0057823. doi: 10.1128/msystems.00578-23. Epub 2023 Sep 28.
Heritable beneficial bacterial endosymbionts have been crucial for the evolutionary success of numerous insects by enabling the exploitation of nutritionally limited food sources. Herein, we describe a previously unknown dual endosymbiosis in the psyllid genus , consisting of the primary endosymbiont " Carsonella ruddii" and a co-occurring Enterobacteriaceae bacterium for which we propose the name " Psyllophila symbiotica." Its localization within the bacteriome and its small genome size confirm that is a co-primary endosymbiont widespread within the genus . Despite its highly eroded genome, perfectly complements the tryptophan biosynthesis pathway that is incomplete in the co-occurring . Moreover, the genome of is almost as small as 's, suggesting an ancient dual endosymbiosis that has now reached a precarious stage where any additional gene loss would make the system collapse. Hence, our results shed light on the dynamic interactions of psyllids and their endosymbionts over evolutionary time.
遗传性有益细菌共生体通过使昆虫能够利用营养有限的食物来源，对许多昆虫的进化成功至关重要。在此，我们描述了一种以前未知的双共生现象，存在于沫蝉属中，包括主要共生体“Carsonella ruddii”和一种共同存在的肠杆菌科细菌，我们将其命名为“Psyllophila symbiotica”。它在菌体内的定位及其较小的基因组大小证实，是该属内广泛存在的共主要共生体。尽管其基因组高度退化，但它却完美地补充了共同存在的共生体中不完全的色氨酸生物合成途径。此外，的基因组几乎与“Carsonella ruddii”一样小，这表明这是一种古老的双共生现象，现在已经达到了一个危险的阶段，任何额外的基因丢失都会使系统崩溃。因此，我们的研究结果揭示了沫蝉及其共生体在进化过程中的动态相互作用。
