Paenibacillus encodes a membrane-localized Spo0B.

Area of Science:

• Microbiology
• Bacterial genetics
• Cellular differentiation

Background:

• Bacterial sporulation is crucial for survival in harsh environments.
• The genus Paenibacillus contains species significant in agriculture, food spoilage, and human opportunistic infections.
• Sporulation initiation involves a conserved phosphorelay, but knowledge of non-model organisms like Paenibacillus is limited.

Purpose of the Study:

• To conduct a comprehensive survey of sporulation genes in Paenibacillus.
• To investigate the conservation and function of the sporulation-initiating phosphorelay in Paenibacillus.
• To identify novel variants within conserved bacterial pathways.

Main Methods:

• Genome-wide analysis of 1,460 Paenibacillus genomes.
• Bioinformatic prediction and experimental validation of protein localization (Spo0B-TM).
• Sequence identity comparisons across Bacillota.

Main Results:

• All essential components of the sporulation-initiating phosphorelay are conserved in Paenibacillus.
• A novel variant, Spo0B-TM, with a transmembrane domain localizing it to the cell membrane, is present in 92% of surveyed genomes.
• Spo0B-TM's transmembrane domain is critical for its interaction with Spo0A and Spo0F, and Spo0B shows low sequence identity compared to other phosphorelay members across Bacillota.

Conclusions:

• A unique, membrane-localized Spo0B variant (Spo0B-TM) is highly conserved across Paenibacillus, impacting sporulation initiation.
• This discovery highlights significant diversity within the generally conserved bacterial phosphorelay system.
• The findings contribute to understanding bacterial adaptation and pathogenesis in the Paenibacillaceae family and related taxa.