Currently: PERT postdoctoral fellow, University of Arizona
In plants, chitinases commonly act as pathogenesis-related proteins, which are either induced in response to insect herbivory and fungal elicitors, or constitutively expressed in tissues vulnerable to attack. Interestingly, class I chitinases are among the various enzymes identified to be important in plant carnivory. Depending on subclass, these chitinases can be secreted from specialized digestive glands and found within morphologically diverse traps. The degree of homology among these proteins and the method by which these enzymes have been adapted for the carnivorous habit has yet to be elucidated. Tanya Renner’s dissertation research is focused on understanding the evolution of carnivory and chitinase genes in one of the major groups of plants that has evolved the carnivorous habit: the Caryophyllales. The proposed research is driven by two hypotheses: (1) During the evolution of carnivory within the Caryophyalles, chitinase genes that were primarily utilized for pathogenesis response by ancestral non-carnivorous plants duplicated and diverged, allowing for subfunctionalization of class Ia (for pathogensis) and Ib chitinases (for carnivory), (2) After class I chitinase gene duplication into subclasses Ia and Ib, selection on class Ib chitinases shifted from positive to purifying selection, as functional pathogenesis response gave way to a role specific to carnivory. Tanya tests her two hypotheses using a combination of phylogenetic reconstruction, protein-specific divergence and selection studies, as well as analyses of gene expression in Dionaea muscipula.
Tanya was an NSF Dissertation Research Fellow (2008) and received an NSF Doctoral Dissertation Improvement Grant in 2010. She completed her dissertation in December 2011 and is now a PERT postdoctoral fellow at the University of Arizona.
Renner, T and Specht CD (2012) Evolution of class I chitinases in the carnivorous Caryophyllales. Molecular Biology and Evolution.
Renner T, Specht CD (2011). A sticky situation: assessing adaptations for plant carnivory in the Caryophyllales utilizing stochastic character mapping. International Journal of Plant Science.
Renner T, Bragg J, Driscoll HE, Cho J, Jackson A & Specht CD (2009). Viral Induced Gene Silencing as a tool for investigating floral developmental genetics in the Zingiberales. Molecular Plant 3:1-11.
Rensing S, et al. (2008) The genome of the moss Physcomitrella patens reveals evolutionary insights into the conquest of land by plants. Science 319(5859): 64-69.
Renner T, Waters ER (2007) Comparative genomic analysis of the Hsp70s from five diverse photosynthetic eukaryotes. Cell Stress & Chaperones 12(2):172–185.