Plant Molecular Biology

, Volume 61, Issue 1–2, pp 63–78 | Cite as

Characterizations of a Hypomorphic Argonaute1 Mutant Reveal Novel AGO1 Functions in Arabidopsis Lateral Organ Development

  • Li Yang
  • Weihua Huang
  • Hua Wang
  • Run Cai
  • Yuquan Xu
  • Hai Huang


Genes that encode the ARGONAUTE (AGO) proteins make up a highly conserved family, and several members in the family have been defined to function in posttranscriptional gene silencing (PTGS) in plants, quelling in fungi and RNAi in animals. The Arabidopsis AGO1 gene has been demonstrated to be crucial in multiple RNA silencing pathways (PTGS, microRNA and trans-acting siRNA pathways); however, its biological functions do not seem to be fully addressed. Here we report characterizations of a new hypomorphic ago1 allele, ago1-37, and show novel AGO1 functions important in lateral organ development. We found that double mutants combining ago1-37 with asymmetric leaves1 (as1) or asymmetric leaves2 (as2) produced more severe phenotypes than the single mutants, indicating that AGO1 genetically interacts with AS1 and AS2 for plant development. Similar to the previously characterized mutants rdr6, sgs3 and zippy, which are deficient in the trans-acting siRNA activity, ago1-37 also showed an earlier phase transition from juvenile to adult leaves. Moreover, based on the detailed phenotypic analyses of single and double mutant plants, we found that the AGO1 functions are required for repressing several class I KNOTTED1-like homeobox (KNOX) genes in leaves, and for specifying both adaxial and abaxial identities of the leaf and petal. Our results demonstrate several important AGO1 functions in plant lateral organ development.


Arabidopsis ARGONAUTE1 KNOX genes leaf polarity posttranscriptional gene silencing 



posttranscriptional gene silencing


RNA-dependent RNA polymerase


RNA induced silencing complex


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Copyright information

© Springer 2006

Authors and Affiliations

  • Li Yang
    • 1
    • 2
  • Weihua Huang
    • 1
    • 3
  • Hua Wang
    • 1
  • Run Cai
    • 3
  • Yuquan Xu
    • 2
  • Hai Huang
    • 1
  1. 1.National Laboratory of Plant Molecular Genetics, Shanghai Institute of Plant Physiology and Ecology, Shanghai Institute for Biological SciencesChinese Academy of SciencesShanghaiChina
  2. 2.College of Life Science and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
  3. 3.School of Agriculture and BiologyShanghai Jiao Tong UniversityShanghaiChina

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