As a plant’s shoot apical meristem ages, the morphology and chemistry of the organs it produces change to match the selection pressures that are reliably associated with the different phases of growth. These developmental shifts in adaptive phenotypes are often most pronounced in woody perennials where the environment experienced by a small seedling is radically different than that of a mature tree. Two of the most common traits that shift over a tree’s life span are changes in the morphology of juvenile and adult leaves, and the duration of a juvenile reproductive phase (juvenility). In the Leichty lab, we use a number of woody systems (Acacia, Populus, and Citrus) to examine the developmental basis of these shifts using comparative evolutionary analysis. Some of the questions we are investigating include:
How do trees delay flowering for many years?
How are changes in vegetative morphology coupled with changes in reproductive maturity, and can these shifts be decoupled?
What role do evolutionary shifts in developmental timing (heterochrony) play in explaining morphological differences between species?
What is the genetic basis of juvenile and adult differences in leaf morphogenesis and how do timing pathways integrate with these genetic regulatory networks
How do developmental pathways constrain the observed and potential morphological diversity of a species?
Selected Publications
Leichty A.R. and Poethig R.S. (2025) Heterochronic shifts in a time-keeping microRNA are associated with neoteny in plants. PNAS in press.
Massaro I., Thomson J., Leichty A.R. (2025) Diploid genome of Mexican lime. G3: Genes, Genomes, Genetics in press.
Massaro I., Poethig R.S., Sinha N.R. & Leichty A.R. (2024). Chromosome-level genome of the transformable northern wattle, Acacia crassicarpa. G3: Genes, Genomes, Genetics, 14(3), jkad284.
Nakayama H., Leichty A.R. & Sinha N.R. (2022). Molecular mechanisms underlying leaf development, morphological diversification, and beyond. The Plant Cell 34, 2534-2548.
Leichty A.R. & Sinha N.R. (2022). A grand challenge in development and evodevo: quantifying the role of development in evolution. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2021.752344.
Leichty A.R. & Sinha N.R. (2021). Development: How competing modes of growth coexist in close proximity. Current Biology, 31, R472-474.
Lawrence E.H., Leichty A.R., Ma C., Strauss S.H. & Poethig R.S. (2021). Vegetative phase change in Populus tremula x alba. New Phytologist, 231, 351-364.
Leichty A.R., & Poethig R.S. (2019). Development and evolution of age-dependent defenses in ant-acacias. PNAS, 116, 15596-15601.
Xu M., Leichty A.R., Hu T. & Poethig R.S. (2018). H2A.Z promotes the transcription of MIR156A and MIR156C in Arabidopsis by facilitating the deposition of H3K4me3. Development, 145, dev152868.
Leichty A.R. & Brisson D. (2014). Selective whole genome amplification for resequencing target microbial species from complex natural samples. Genetics, 198, 473-81.
Leichty, A.R., Pfennig, D.W., Jones, C., & Pfennig, K.S. (2012). Relaxed genetic constraint is ancestral to the evolution of phenotypic plasticity. Integrative and Comparative Biology, 52, 16-30.
Rice, A.M., Leichty, A.R., & Pfennig, D.W. (2009). Parallel evolution and ecological selection: replicate character displacement in spadefoot toads. Proceedings of the Royal Society of London Series B, 276, 4189-4196.
For the most updated publication list, see Aaron's Google scholar.
Plant morphology, leaf morphogenesis, developmental timing and regulation of phase transitions, heterochrony
