Skip to main content
padlock icon - secure page this page is secure

Free Content The Arabidopsis Myb genes MYR1 and MYR2 are redundant negative regulators of flowering time under decreased light intensity

Download Article:

You have access to the full text article on a website external to Ingenta Connect.

Please click here to view this article on Wiley Online Library.

You may be required to register and activate access on Wiley Online Library before you can obtain the full text. If you have any queries please visit Wiley Online Library


Changes in the duration, quality and intensity of light affect flowering time. Compared with the effects of light duration and quality, less is known about the effects of light intensity on flowering. Here we describe two paralogous single Myb domain genes, MYB-RELATED PROTEIN 1 (MYR1) and MYB-RELATED PROTEIN 2 (MYR2), and their roles as repressors of responses to decreased light intensity in Arabidopsis. Homozygous myr1 myr2 double mutants flowered early under low light intensities. Additionally, myr1 myr2 mutants exhibited increases in petiole length, leaf angle and apical dominance. Genetic analyses involving mutants in the long-day, gibberellin (GA) and phyB flowering pathways indicated that all aspects of the myr1 myr2 phenotype required GA biosynthesis. The early-flowering phenotype of myr1 myr2 also required FLOWERING LOCUS T, and myr1 myr2 mutants showed an epistatic interaction with the phyB-9 mutant. Over-expression of MYR1 or MYR2 produced GA-deficiency symptoms that were rescued by application of gibberellic acid (GA3). Loss of MYR1 and MYR2 function was associated with a twofold increase in GA20ox2 expression and a 30% increase in GA4 levels, while over-expression of MYR2 led to a threefold decrease in GA20ox2 expression and a 50% decrease in GA4 levels. Considered together, these results suggest that the ability of MYR1 and MYR2 to repress flowering and organ elongation is at least partly due to their negative effect on levels of bioactive GA.
No References
No Citations
No Supplementary Data
No Article Media
No Metrics

Keywords: Myb transcription factor; apical dominance; flowering time; gibberellin; organ elongation; phloem

Document Type: Research Article

Affiliations: 1: Department of Horticulture, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA 2: Growth Regulation Research Group, RIKEN Plant Science Center, Suehirocho 1-7-22, Tsurumi-ku, Yokohama 230-0045, Japan

Publication date: May 1, 2011

  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more