Anna N Stepanova

Assistant Professor of Plant and Microbial


PhD, University of Pennsylvania

Postdoctoral, North Carolina State University

Jose M Alonso

Professor of Plant and Microbial Biology

PhD, Universitat de Valencia, Spain

Postdoctoral, University of Pennsylvania and The Salk Institute for Biological Studies

                        General interests

Molecular Genetics of the Ethylene-Auxin Interactions

    Our main interest is to understand the molecular circuits plants use to integrate environmental and developmental signals to produce specific responses. Towards this general goal we have been focusing on the identification of the molecular “signal integrators” or “logic gates” involved in the interaction between two plant hormones, ethylene and auxin, in the regulation of root growth. Using a multidisciplinary approach (genetics, molecular biology, genomics, metabolomics, cell biology, etc.), we have uncovered a complex multistep integration process with both spatial and temporal components. Our research has shown that ethylene activates the transcription of auxin biosynthetic genes in the root meristem (root tip) and then auxin is transported upwards to where it sensitizes the cells in the division zone enabling them to properly respond to ethylene. Our more recent findings suggest that translation regulation represents a key aspect of this “sensitizing” mechanism triggered by auxin. In addition, these studies have allowed us to decipher the first complete auxin biosynthetic pathway in plants and we continue to investigate the role of auxin biosynthesis in development. Finally, we combine our interests in basic biology with the development and implementation of new genetic technologies to accelerate discoveries in plant biology.

Inter-tissue cell growth coordination

    Unlike mobile animals, sessile plants spend their lives in a fixed place and, being unable to move away, have to endure and withstand harsh conditions of their environment. To cope with this challenge, plants have learned to adapt to their surroundings by modifying their metabolic activity, growth rates and patterns. Our earlier work has focused on the elucidation of the role of two key plant hormones, auxin and ethylene, in the phenotypic plasticity of root growth and has uncovered a previously unknown ethylene-mediated regulation of auxin biosynthesis. Adequate levels of auxin production, perception, signaling, and response were found to be required for the ethylene-triggered morphological changes. Current efforts of the lab are focused on another intriguing (yet poorly understood) aspect of plant phenotypic plasticity: the ability of plants to maintain tight coordination of cell division/expansion between individual tissues of an organ regardless of the overall growth rate dictated by the environment and the plantʼs genotype. While it is widely accepted that the synchronized growth of tissues involves some type of cell-to-cell communication, the respective contribution of different tissues to organ growth and the nature of the inter-tissue interaction mechanism are currently unresolved. To address these long-standing controversial questions, we are utilizing a combination of transgenic approaches, cell biology, computational methods, and chemical, classical, and systems genetics to systematically dissect the mechanisms underlying inter-tissue growth coordination in leaves using Arabidopsis as a model system.


  Currently, we are working on three main areas, gene modification in a chromosomal context using recombineering approaches, high-resolution whole-genome analysis of translation using next-generation-sequencing (NGS) -enabled ribosome footprinting, and implementation of metabolic biosensors, specifically a FRET (Fluorescence Resonance Energy Transfer) -based tryptophan biosensors.


A new outreach activity targeted at school-age kids (2nd to 5th grade) has been initiated. For the first pilot experiment, a local elementary school with a high ratio of Hispanic students has been approached. In conjunction with the Brier Creek Elementary School ESL teacher Natalia Kipfer, the PIs are developing a set of experimental modules in biology. The basic idea is to use very accessible materials to show how environment affects living organisms, specifically plants. For example, experiments to show how plants respond to different amounts of light, water, and pollutants (salts, detergents, etc.) will be carried out by the students. Importantly, by using Spanish and English both orally and in the small brochures describing the experiments, the PIs not only will provide Hispanic children with an easier path to a science experience, but also allow their parents (that often cannot read English) to reinforce the scientific methodology at home.

Best viewed with Safari or Firefox

-Auxin biosynthesisAlonso-Stepanova_Auxin_Biosynthesis.htmlAlonso-Stepanova_Auxin_Biosynthesis.htmlshapeimage_4_link_0
-Ethylene signalingAlonso-Stepanova_Ethylene_signaling.htmlAlonso-Stepanova_Ethylene_signaling.htmlshapeimage_5_link_0
-Current lab membersAlonso-Stepanova_People3.htmlAlonso-Stepanova_People3.htmlshapeimage_7_link_0
-Former lab membersAlonso-Stepanova_Former_lab_members.htmlAlonso-Stepanova_Former_lab_members.htmlshapeimage_8_link_0
-Arabidopsis localizomeAlonso-Stepanova_Arabidopsis_localizome.htmlAlonso-Stepanova_Arabidopsis_localizome.htmlshapeimage_14_link_0