Theses and Dissertations - UTB/UTPA

Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Anita Baines

Second Advisor

Dr. Kristine Lowe

Third Advisor

Dr. Jonathan Lieman


Streptomyces are Gram-positive, filamentous bacteria that are readily isolated from soil and produce diverse secondary metabolites such as pigments and antibiotics. A survey of indigenous soil microbes from Rio Grande Valley agricultural soils revealed several isolates with broad inhibitory abilities against a range of soil-borne plant pathogens. The goal of this study was to characterize eleven of these potential biocontrol isolates both biochemically and genetically. Nutrient utilization profiles, 16S rDNA sequencing, and the presence of genes involved in antibiotic biosynthesis pathways (strBl, strR, strF, strN, strS and KS) on plasmids or the chromosome were investigated. Nutrient utilization profiling revealed that 31 of 95 available carbon sources were utilized by all 11 isolates. Plasmids were located in 6 of the 11 isolates and it was determined that different combinations of the strN, strR, and strS genes were found on them. 16S rDNA sequencing has confirmed that 5 out of the 11 isolates are in fact Streptomyces species. Identifying differences in nutrient utilization and genetic composition among the isolates may enhance their efficacy as potential biocontrol agents by understanding their ecological niches and evolutionary trajectories.


Copyright 2009 Uylissa A. Rodriguez. All Rights Reserved.

Granting Institution

University of Texas-Pan American