Date of Award


Degree Type

Honors College Thesis

Academic Program

Biological Sciences BS


Biological Sciences

First Advisor

Dmitri Mavrodi, Ph.D.

Advisor Department

Biological Sciences


Gynuella sunshinyii is a newly characterized bacterium with a remarkable ability to produce multiple secondary metabolites that act as potential antibiotics for medical applications. Currently, little is known about gene regulation in this unusual microorganism. In 2018, studies conducted of rhizosphere microbiomes of tidal marsh grasses on Deer Island, MS, resulted in multiple isolates of halophilic, aerobic, Gram-negative bacteria with antagonistic properties. One of the most active antagonists was identified as Gynuella sunshinyii 449. The genome of strain 449 was sequenced with Illumina MiSeq, assembled with Unicycler and SPAdes, and annotated with RASTtk. The annotation revealed a 6.09 Mb genome that encodes 52 RNAs and 5,608 proteins, 2,822 of which had functional assignments. The analysis also revealed that the strain harbored genes for the production of numerous polyketides with potential cytotoxic and antibacterial activities. In many Gammaproteobacteria, the production of secondary metabolites, surface motility, and biofilm formation are regulated by the GacS/GacA system. The G. sunshinyii 449 genome encodes well-conserved homologs of GacA and GacS, and we hypothesized that these genes might be involved in the motility and ability to produce bioactive metabolites. To test this hypothesis, we constructed a knockout plasmid by cloning the gacA gene of strain 449. This plasmid will be used in the future to create an isogenic mutant that will be tested for alterations in the motility and ability to produce polyketides. This study provides insights into pathways conferring the regulatory and metabolic flexibility in a species that serves as a rich source of bioactive metabolites.

Included in

Microbiology Commons