<p>Strictly heritable endosymbiotic bacteria that provide limiting nutrients to sap-sucking hemipteran insects are known for their highly reduced genomes conserved in organization and function. Here, we show how in ancestral endosymbionts of planthoppers, <i>Sulcia</i> and <i>Vidania</i>, which have been gradually losing genes during ~263 my of co-diversification with hosts, co-infections by additional microbes and host ecological switches coincided with more dramatic genomic changes. At its extremes, this has resulted in the smallest non-organellar bacterial genomes known, at barely 50-52 kb. Such minuscule <i>Vidania</i> genomes evolved convergently in two planthopper superfamilies, and are strikingly similar in gene contents, including the ability to produce a single amino acid (phenylalanine) for the host. Losing many additional cell-function genes places them very close to organelles of symbiotic origin in the level of host dependence, further blurring the bacteria-organelle boundary.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Convergent extreme reductive evolution in ancient planthopper symbioses

  • Anna Michalik,
  • Diego C. Franco,
  • Junchen Deng,
  • Monika Prus-Frankowska,
  • Adam Stroiński,
  • Piotr Łukasik

摘要

Strictly heritable endosymbiotic bacteria that provide limiting nutrients to sap-sucking hemipteran insects are known for their highly reduced genomes conserved in organization and function. Here, we show how in ancestral endosymbionts of planthoppers, Sulcia and Vidania, which have been gradually losing genes during ~263 my of co-diversification with hosts, co-infections by additional microbes and host ecological switches coincided with more dramatic genomic changes. At its extremes, this has resulted in the smallest non-organellar bacterial genomes known, at barely 50-52 kb. Such minuscule Vidania genomes evolved convergently in two planthopper superfamilies, and are strikingly similar in gene contents, including the ability to produce a single amino acid (phenylalanine) for the host. Losing many additional cell-function genes places them very close to organelles of symbiotic origin in the level of host dependence, further blurring the bacteria-organelle boundary.