Acetic acid bacteria encode two levansucrase types of different ecological relationship

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Acetic acid bacteria (AAB) inhabit diverse environments like plants and insects.
• The mechanisms enabling AAB to colonize these varied ecological niches remain unclear.
• Plant-derived sucrose metabolism via levansucrases (LS) is linked to biofilm formation in some AAB.

Purpose of the Study:

• To investigate the role of two distinct levansucrase (LS) types as determinants for habitat selection in acetic acid bacteria (AAB).
• To analyze the evolutionary origins, genetic organization, structural features, and secretion mechanisms of these LS types.
• To explore the distribution of these LS types across different proteobacteria groups.

Main Methods:

• Comparative genomic analysis of levansucrase (LS) genes in acetic acid bacteria (AAB).
• Phylogenetic analysis to determine evolutionary trajectories (vertical T1 vs. horizontal T2).
• Characterization of genetic organization, structural features, and secretion pathways for each LS type.

Main Results:

• Two distinct levansucrase (LS) types (T1 and T2) were identified in acetic acid bacteria (AAB) as potential habitat determinants.
• T1-LS are secreted by plant-pathogenic α- and γ-proteobacteria, suggesting a role in plant pathogenicity.
• T2-LS genes are prevalent in diazotrophic, plant-growth-promoting α-, β-, and γ-proteobacteria, indicating a role in plant symbiosis.

Conclusions:

• Levansucrase (LS) types represent key evolutionary determinants for acetic acid bacteria (AAB) habitat specialization.
• Understanding LS diversity aids in comprehending microbial ecology and plant-microbe interactions.
• This research offers insights into biofilm formation and potential applications in plant health management.