Current Microbiology

, Volume 38, Issue 5, pp 309–311

News & Notes: Buchnera Plasmid-Associated trpEG Probably Originated from a Chromosomal Location Between hsIU and fpr


  • Marta A.  Clark
    • Microbiology Section, University of California, Davis, CA 95616-8665, USA
  • Paul  Baumann
    • Microbiology Section, University of California, Davis, CA 95616-8665, USA
  • Nancy A.  Moran
    • Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA

DOI: 10.1007/PL00006807

Cite this article as:
Clark, M., Baumann, P. & Moran, N. Curr Microbiol (1999) 38: 309. doi:10.1007/PL00006807


Buchnera are prokaryotic endosymbionts found in most aphids. One of their functions is the synthesis of the essential amino acid tryptophan for the aphid host. In Buchnera from some aphids that have a long development time, trpEG, which encodes the first enzyme of the tryptophan biosynthetic pathway (anthranilate synthase), is found as one copy on the endosymbiont chromosome and is located between hsIU and fpr. In Buchnera from Schizaphis graminum, which has a short development time, trpEG is amplified on plasmids. We have cloned and sequenced a 4.1-kb DNA fragment from Buchnera of S. graminum and have found the gene order hsIU-ibp-fpr-yjeA-kdtB. The proximity of hsIU and fpr is consistent with the excision, in an endosymbiont ancestor, of trpEG from a location between these two genes, with the excision either followed or preceded by acquisition of ibp.

Copyright information

© Springer-Verlag New York Inc. 1999