Scientific Projects
Development and evolution of lateral meristems in kalanchoe
The genus Kalanchoe comprises ~150 species, some of which develop lateral meristems along the border of flattened leaf-like organs. These particular species have lost the ability to produce viable seeds. In these cases, their major means of reproduction is through budding, when these lateral meristems lead to the development of plantlets. Some species within Kalanchoe, however, are still capable of reproducing sexually and only produce clones in special conditions, while other species are incapable of budding.
In species restricted to asexual reproduction plantlets grow specifically in each indent of leaf-like organs. Older plantlets fall off from the mother plant and grow into new genetically identical adult plants (i.e., clones).
This project aims at understanding the evolution of asexual reproduction within the genus Kalanchoe. We would like to understand the molecular mechanisms leading to the formation of meristems in the genus, and the processes that lead to an asexual-only reproduction in some species. In particular, we would like to understand how the mother plant is capable of regulating the precise location of the various meristems without leading to abnormal growth or meristem misplacement.
Some of the questions we would like to answer with this project are:
- What are the genes involved in lateral meristem specification in the leaf-like organs?
- Are the molecular mechanisms of lateral meristem specification in the leaf-like organ similar to those acting at the shoot apical meristem?
- What are the processes leading to loss of seed viability in some Kalanchoe species?
- Which evolutionary processes may be taking place in species reproducing exclusively asexually?
- How does the environment influence the production of plantlets? how does drought stress influence the production of plantlets?
COMPARATIVE GENOMICS OF CONVERGENT EVOLUTION
Convergent Evolution of Pollination Syndromes within Neotropical Costus
In nature, convergent evolution often occurs due to correlations between adaptive phenotypes and environmental or functional factors, and examples of convergent evolution abound in almost every lineage of the tree of life. Phenotypic convergence provides evidence that ecological circumstances can select for similar solutions on an evolutionary time scale. In particular, pollination syndromes - suites of floral traits evolving in response to different biotic or abiotic pollen vectors - have been considered a hallmark of ecological convergence. Although ecological studies on pollination syndrome abound in the literature, studies of the genetic basis of pollination syndrome are much less common. Genome-wide studies of pollination syndrome convergence have yet to be undertaken, however such detailed studies are essential to provide mechanistic explanations for the convergent evolution of pollination syndromes, especially within a phylogenetically circumscribed scenario.
This research project aims to characterize the genome-wide signatures of convergent evolution of pollination syndromes, using independent evolution of pollination syndromes in closely related species as a model system. This proposal will generate genome and transcriptome sequences for a variety of species within the tropical genus Costus, in which multiple independent events of bee-to-bird pollination shifts occurred in closely related species. By using numerous sister-pair comparisons the proposed research will allow us to address the diversity of processes underlying adaptive evolution and tease apart the factors contributing to floral phenotypic plasticity within this lineage.
Some of the research questions this project will answer are:
- Are there genome-specific changes associated with pollination shifts across Costus species?
- Are there signatures of selection associated with shifts in pollination syndrome?
- What genes are associated with these shifts across Costus spicies? Are these genes conserved?
This project is a collaboration between the Almeida Lab (CSUEB) and the Specht Lab (Cornell University).
PLANT MORPHOLOGICAL EVOLUTION
Evolution of the Abaxial-Adaxial Gene Regulatory Network in Land Plants
This project aims at uncovering the evolution of the abaxial-adaxial gene regulatory network (ab-ad GRN) in land plants. Within a comparative framework, we apply next-generation sequencing technologies combined with classical microscopy techniques in developing plant organs of distinct evolutionary lineages in order to understand the contributions of the ad-ab GRN in shaping plant form.
We would also like to model gene regulatory networks underlying basic developmental processes involved in plant development, particularly the ab-ad GRN, to understand how changes in these gene regulatory networks might have lead to changes in plant morphology through evolution.
The main questions we would like to answer with this project are:
- Do similar changes in gene regulatory networks lead to changes in plant morphology in independent evolutionary lineages?
- How conserved are the gene regulatory networks involved in plant development, particularly when we compare different lineages?
- How do gene regulatory networks involved in plant development evolve through time?
