Abstract: A <i>Bacillus</i> Strain Isolated by Undergraduate Students at UCLA Promotes Plant Growth by Procuring Soil Nutrients and May Also Serve as a Biological Control Agent (2011 SACNAS National Conference)

Friday, October 28, 2011

Hall 1-2 (San Jose Convention Center)

Irma Ortiz , Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA

Allison R. Schwartz , Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA

Erin R. Sanders , Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA

Andrew C. Diener , Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA

Darleen A. DeMason , Botany and Plant Sciences, University of California, Riverside, Riverside, CA

Ann M. Hirsch, PhD , Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA

The plant microbiome in the rhizosphere consists of both bacteria and fungi that exhibit many beneficial effects on plant growth. The Plant-Growth Promoting Bacteria (PGPB) offer an important solution to the negative consequences of adding chemical fertilizers and pesticides by enhancing plant yield, producing phytohormones such as auxin or interfering with ethylene synthesis, controlling plant pathogens, and obtaining critical nutrients such as iron, nitrogen, and phosphorous. In this study, we analyzed the mechanisms whereby a Bacillus strain, isolated from the Mildred E. Mathias Botanical Garden and investigated by two undergraduate courses, could mediate a positive growth response on legume Pisum sativum. From various assays, we determined that the improvements in plant growth are likely to be the result of a combination of bacterial factors including IAA synthesis, siderophore production, and phosphate solubilization. Because PGPB are also known to protect plants from pathogenic fungi and bacteria, a co-culture assay was established on potato dextrose agar (PDA) plates. The plates were either left uninoculated or spotted with a number of different fungal pathogens, and then co-inoculated with the new Bacillus strain or B. subtilis, a well-known biocontrol agent. Our results so far suggest that the newly isolated Bacillus strain is a weaker biological control agent than B. subtilis.

A Bacillus Strain Isolated by Undergraduate Students at UCLA Promotes Plant Growth by Procuring Soil Nutrients and May Also Serve as a Biological Control Agent