Transcriptome analysis documents induced competence of Bacillus subtilis during nitrogen limiting conditions

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Understanding gene expression regulation in Bacillus subtilis is crucial for microbial biotechnology.
• Nitrogen availability significantly impacts bacterial physiology and gene expression.
• Bacillus subtilis is a model organism for studying Gram-positive bacterial development and genetic manipulation.

Purpose of the Study:

• To investigate the differential gene expression in Bacillus subtilis strain 168 under varying nitrogen conditions.
• To identify genes induced during nitrogen starvation.
• To evaluate the impact of nitrogen availability on bacterial competence and optimize transformation protocols.

Main Methods:

• DNA microarrays were employed to compare gene expression profiles.
• Bacillus subtilis strain 168 was cultured in defined media with controlled nitrogen levels (limiting vs. excess).
• Competence assays were performed on cells grown in minimal medium with glutamate.

Main Results:

• Over 100 genes showed significant induction during nitrogen starvation.
• Key gene clusters including comG, comF, comE, nin-nucA, and comK, along with recA, were identified as upregulated.
• Bacillus subtilis cells grown with glutamate as the sole nitrogen source demonstrated competence.

Conclusions:

• Nitrogen limitation triggers a specific set of gene expression changes in Bacillus subtilis.
• The identified gene expression patterns correlate with the induction of competence.
• These findings facilitate a simplified one-step transformation procedure for Bacillus subtilis strain 168.