Most plant development occurs post-embryonically, and is tied closely to environmental signals.  We use techniques of genetics, molecular biology, microscopy, physiology, and biochemistry to study how environmental and endogenous signals regulate plant development.  For these studies we use the model plant Arabidopsis thaliana, which has numerous technical advantages that facilitate experimental progress.  We hope in the long run to reconstruct how endogenous developmental programs and exogenous signals cooperate to determine plant form and the partitioning of growth among different organs.

The hormone auxin regulates multiple developmental processes in plants, including embryo and meristem patterning, organ growth, and flower maturation.   Auxin induces gene expression through a family of transcription factors called ARFs (Auxin Response Factors), whose activity is regulated by Aux/IAA proteins.  Auxin switches ARF proteins between gene repressing and gene activating states by promoting Aux/IAA protein turnover.  We are currently studying how this regulatory system controls seedling growth, ovule development, and flower opening and fertilization.

Among genes regulated by auxin are some (including those encoding Aux/IAA proteins) that feed back negatively on auxin response; and others encoding proteins that affect intercellular auxin transport.  We are interested in how feedback controls affect the dynamics of auxin response, and in how regulated intercellular auxin movement coordinates growth and differentiation of different cells during development.