“Woah! It's like Spotify but for academic articles.”

Instant Access to Thousands of Journals for just $40/month

The Gibberellin Pathway Mediates KNOTTED1-Type Homeobox Function in Plants with Different Body Plans

The Gibberellin Pathway Mediates KNOTTED1-Type Homeobox Function in Plants with Different Body Plans Background: The shoot apical meristem (SAM) is an indeterminate structure that gives rise to the aerial parts of higher plants. Leaves arise from the differentiation of cells at the flanks of the SAM. Current evidence suggests that the precise regulation of KNOTTED1-like homeobox (KNOX) transcription factors is central to the acquisition of leaf versus meristem identity in a wide spectrum of plant species. Factors required to repress KNOX gene expression in leaves have recently been identified. Additional factors such as the CHD3 chromatin remodeling factor PICKLE (PKL) act to restrict meristematic activity in Arabidopsis leaves without repressing KNOX gene expression. Less is known regarding downstream targets of KNOX function. Recent evidence, however, has suggested that growth regulators may mediate KNOX activity in a variety of plant species. Results: Here we show that reduced activity of the gibberellin (GA) growth regulator pathway promotes meristematic activity, both in the natural context of KNOX function in the SAM and upon ectopic KNOX expression in Arabidopsis leaves. We show that constitutive signaling through the GA pathway is detrimental to meristem maintenance. Furthermore, we provide evidence that one of the functions of the KNOX protein SHOOTMERISTEMLESS (STM) is to exclude transcription of the GA-biosynthesis gene AtGA20ox1 from the SAM. We also demonstrate that AtGA20ox1 transcript is reduced in the pkl mutant in a KNOX-independent manner. Moreover, we show a similar interaction between KNOX proteins and GA-biosynthesis gene expression in the tomato leaf and implicate this interaction in regulation of the dissected leaf form. Conclusions: We suggest that repression of GA activity by KNOX transcription factors is a key component of meristem function. Transfer of the KNOX/GA regulatory module from the meristem to the leaf may have contributed to the generation of the diverse leaf morphologies observed in higher plants. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Current Biology Elsevier
Loading next page...

You're reading a free preview. Subscribe to read the entire article.

And millions more from thousands of peer-reviewed journals, for just $40/month

To be the best researcher, you need access to the best research

  • With DeepDyve, you can stop worrying about how much articles cost, or if it's too much hassle to order — it's all at your fingertips. Your research is important and deserves the top content.
  • Read from thousands of the leading scholarly journals from Springer, Elsevier, Nature, IEEE, Wiley-Blackwell and more.
  • All the latest content is available, no embargo periods.

Stop missing out on the latest updates in your field

  • We’ll send you automatic email updates on the keywords and journals you tell us are most important to you.
  • There is a lot of content out there, so we help you sift through it and stay organized.