Abstract

Plants can modulate their developmental program depending on the prevailing environmental conditions. A good example of this plasticity is the degree of shoot branching in which both developmental and environmental inputs are integrated by a network of hormonal signals. This network systemically transmits the information, which is locally interpreted to regulate axillary bud outgrowth.

To understand the molecular basis for dynamic variation in branch number, we examined quantitatively different versions of the shoot branching regulatory network. Branching data were collected from Arabidopsis Multiparent Advanced Generation Intercross (MAGIC) lines grown under low or high nitrogen conditions and used to identify Quantitative Trait Loci (QTL) for branch number and branching plasticity. Currently, we are working to identify the genes that underlie these QTL by combining the results with an association mapping approach. Therefore we also collected branching data from genotyped natural Arabidopsis accessions. Comparing these data sets revealed interesting trait correlations between branch number and branch number plasticity. Furthermore comparison of vernalized and unvernalized natural accessions showed that plasticity is under seasonal control.