Advertisement

Molecular and General Genetics MGG

, Volume 259, Issue 4, pp 414–423 | Cite as

Symbiotic mutants deficient in nodule establishment identified after T-DNA transformation of Lotus japonicus

  • L. Schauser
  • K. Handberg
  • N. Sandal
  • J. Stiller
  • T. Thykjær
  • E. Pajuelo
  • A. Nielsen
  • J. Stougaard
ORIGINAL PAPER

Abstract

Nitrogen-fixing root nodules develop on legumes as a result of an interaction between host plants and soil bacteria collectively referred to as rhizobia. The organogenic process resulting in nodule development is triggered by the bacterial microsymbiont, but genetically controlled by the host plant genome. Using T-DNA insertion as a tool to identify novel plant genes that regulate nodule ontogeny, we have identified two putatively tagged symbiotic loci, Ljsym8 and Ljsym13, in the diploid legume Lotus japonicus. The sym8 mutants are arrested during infection by the bacteria early in the developmental process. The sym13 mutants are arrested in the final stages of infection, and ineffective nodules are formed. These two plant mutant lines were identified in progeny from 1112 primary transformants obtained after Agrobacterium tumefaciens T-DNA-mediated transformation of L. japonicus and subsequent screening for defects in the symbiosis with Mesorhizobium loti. Additional nontagged mutants arrested at different developmental stages were also identified and genetic complementation tests assigned all the mutations to 16 monogenic symbiotic loci segregating recessive mutant alleles. In the screen reported here independent symbiotic loci thus appeared with a frequency of ∼1.5%, suggesting that a relatively large set of genes is required for the symbiotic interaction.

Key words Root nodule development T-DNA tagging Legume genetics Symbiotic loci Plant-microbe interaction 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • L. Schauser
    • 1
  • K. Handberg
    • 1
  • N. Sandal
    • 1
  • J. Stiller
    • 1
  • T. Thykjær
    • 1
  • E. Pajuelo
    • 1
  • A. Nielsen
    • 1
  • J. Stougaard
    • 1
  1. 1.Laboratory of Gene Expression, Department of Molecular and Structural Biology, University of Aarhus Gustav Wieds Vej 10, DK-8000 Aarhus C, Denmark Fax: +45-86-201222; e-mail: stougard@biobase.dkDK

Personalised recommendations