Mycorrhizal Fungi and Rhizobial Bacteria Evolutionarily Divergent Organisms Utilizing Convergent Signaling Mechanisms
Date of Award
2011
Document Type
Thesis
Degree Name
Bachelors
Department
Natural Sciences
First Advisor
Clore, Amy
Keywords
Mycorrizae, Rhizobia, Signaling, Simbiont (sim) Pathway
Area of Concentration
Biology
Abstract
Rhizobial and mycorrhizal symbioses are both plant root associations that involve bidirectional nutrient exchange. These associations can confer selective advantages to their hosts and therefore have the potential to act in driving community ecology. Several mechanisms by which symbionts can drive successional patterns have been recently set forth. Depending on ecological conditions, these symbionts have the potential to drive plants towards coexistance or towards monodominance. Though the participants in these symbioses are taxonomically divided as prokaryotes and eukaryotes, similarities are seen in both interactions, most notably utilization of a common signaling pathway involved in allowing accommodation of both symbionts. Though this so-called symbiotic (Sym) the pathway is commonly utilized, varied downstream responses between the two associations are exhibited. How these varied responses are elicited using the same signaling molecules is discussed. A discussion of the common utilization of this pathway also raises an evolutionary question, that is, what led to the common exploitation of this pathway by such divergent organisms? Results of a computational analysis addressing the possibility of the acquisition of fungal genes necessary for establishment of this pathway in rhizobia from a fungal source are presented. This analysis identified several possible orthologues to the Nod genes in the mycorrhiza, most notably three fungal chitin synthases with similarity to NodC. More refined alignments revealed alignment similarities between the two possible orthologues in a conserved potential ligand binding domain. All in all, this warrants further research into the origins of the bacterial Nod genes.
Recommended Citation
Tisdale, Ryan, "Mycorrhizal Fungi and Rhizobial Bacteria Evolutionarily Divergent Organisms Utilizing Convergent Signaling Mechanisms" (2011). Theses & ETDs. 4471.
https://digitalcommons.ncf.edu/theses_etds/4471
Rights
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