Send to:

Choose Destination
See comment in PubMed Commons below
Plant Physiol. 2013 Oct;163(2):1047-58. doi: 10.1104/pp.113.221895. Epub 2013 Aug 8.

Abscisic acid regulates axillary bud outgrowth responses to the ratio of red to far-red light.

Author information

  • 1Department of Soil and Crop Sciences, Texas A&M University and Texas A&M AgriLife Research, College Station, Texas 77843.


Low red light/far-red light ratio (R:FR) serves as an indicator of impending competition and has been demonstrated to suppress branch development. The regulation of Arabidopsis (Arabidopsis thaliana) rosette bud outgrowth by the R:FR and the associated mechanisms were investigated at several levels. Growth under low R:FR suppressed outgrowth of the third from topmost bud (bud n-2) but not that of the topmost bud. Subsequently increasing the R:FR near the time of anthesis promoted bud n-2 outgrowth and reduced topmost bud growth. Buds from specific rosette positions, exhibiting divergent fates to increased R:FR, were harvested 3 h after modifying the R:FR and were used to conduct ATH1 microarray-based transcriptome profiling. Differentially expressed genes showed enrichment of light signaling and hormone-related Gene Ontology terms and promoter motifs, most notably those associated with abscisic acid (ABA). Genes associated with ABA biosynthesis, including the key biosynthetic gene NINE-CIS-EPOXYCAROTENOID DIOXYGENASE3 (NCED3), and with ABA signaling were expressed at higher levels in the responsive bud n-2, and increasing the R:FR decreased their expression only in bud n-2. ABA abundance in responsive buds decreased within 12 h of increasing the R:FR, while indole-3-acetic acid levels did not change. A role for ABA in repressing bud outgrowth from lower positions under low R:FR was demonstrated using the nced3-2 and aba2-1 ABA biosynthesis mutants, which showed enhanced branching and a defective bud n-2 outgrowth response to low R:FR. The results provide evidence that ABA regulates bud outgrowth responses to the R:FR and thus extend the known hormonal pathways associated with the regulation of branching and shade avoidance.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk