Project Number: 5358-12220-004-09
Project Type: Reimbursable

Start Date: Jan 01, 2011
End Date: Dec 31, 2013

Objective:
1. Determine the influence of purified antibiotics on the transcriptome of P. fluorescens Pf-5. 2. Determine the influence of antibiotic-mediated cell to cell signaling on the expression of antibiotic-biosynthesis genes and biocontrol activity of P. fluorescens.

Approach:
1. Characterize the transcriptome of P. fluorescens Pf-5 by strand-specific direct RNA sequencing, employing bioinformatic and computational tools to identify the genome-wide distribution of transcripts and small RNAs. 2. Focusing on antibiotics produced by Pf-5 and other biocontrol strains of Pseudomonas sp. (examples: 2,4-diacetylphloroglucinol, pyoluteorin, pyrrolnitrin, orfamide A, rhizoxin analogs, phenazine-1-carboxylate), evaluate the influence of purified compounds on a) the transcriptome and b) antibiotic production profiles of Pf-5 grown in culture. 3. Evaluate the influence of purified antibiotics on the transcriptome of Pf-5 on seed surfaces. 4. Determine the influence of antibiotic-producing bacterial co-inhabitants on a) the expression of biocontrol genes by Pf-5 in the rhizosphere or spermosphere of plants grown in soil, and b) biological control of Pythium damping-off. These experiments will employ a combination of well-characterized mutants and reporter gene constructs to assess gene expression and biocontrol in natural field soils.