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Keywords:

  • Arabidopsis;
  • auxin;
  • cotyledon;
  • leaf;
  • SHORT INTERNODES ;
  • STYLISH ;
  • vein

Summary

  • Leaves depend on highly developed venation systems to collect fixed carbon for transport and to distribute water. We hypothesized that local regulation of auxin biosynthesis plays a role in vein development. To this effect, we assessed the role of the SHORT INTERNODES/STYLISH (SHI/STY) gene family, zinc-finger transcription factors linked to regulation of auxin biosynthesis, in Arabidopsis thaliana leaf vein development.
  • Gene functions were assessed by a combination of high-resolution spatio-temporal expression analysis of promoter-marker lines and phenotypic analysis of plants homozygous for single and multiple mutant combinations.
  • The SHI/STY genes showed expression patterns with variations on a common theme of activity in incipient and developing cotyledon and leaf primordia, narrowing to apices and hydathode regions. Mutant analysis of single to quintuple mutant combinations revealed dose-dependent defects in vein patterning affecting multiple vein traits, most notably in cotyledons.
  • Here we demonstrate that local regulation of auxin biosynthesis is an important aspect of leaf vein development. Our findings also support a model in which auxin synthesized at the periphery of primordia affects vein development.