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Published on: September 27, 2018
Genome-sequence analysis of Acinetobacter johnsonii MB44 reveals potential nematode-virulent factors
Shijing Tian1, Muhammad Ali2, Li Xie1
1State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070 Hubei Province China.
Abstract:
Acinetobacter johnsonii is generally recognized as a nonpathogenic bacterium although it is often found in hospital environments. However, a newly identified isolate of this species from a frost-plant-tissue sample, namely, A. johnsonii MB44, showed significant nematicidal activity against the model organism Caenorhabditis elegans. To expand our understanding of this bacterial species, we generated a draft genome sequence of MB44 and analyzed its genomic features related to nematicidal attributes. The 3.36 Mb long genome contains 3636 predicted protein-coding genes and 95 RNA genes (including 14 rRNA genes), with a G + C content of 41.37 %. Genomic analysis of the prediction of nematicidal proteins using the software MP3 revealed a total of 108 potential virulence proteins. Some of these proteins were homologous to the known virulent proteins identified from Acinetobacter baumannii, a pathogenic species of the genus Acinetobacter. These virulent proteins included the outer membrane protein A, the phospholipase D, and penicillin-binding protein 7/8. Moreover, one siderophore biosynthesis gene cluster and one capsular polysaccharide gene cluster, which were predicted to be important virulence factors for C. elegans, were identified in the MB44 genome. The current study demonstrated that A. johnsonii MB44, with its nematicidal activity, could be an opportunistic pathogen to animals.
Insights
Acinetobacter johnsonii MB44, a bacterium typically considered nonpathogenic, exhibits significant nematicidal activity against Caenorhabditis elegans. Genomic analysis reveals potential virulence factors, suggesting it may act as an opportunistic pathogen.
Area of Science:
- Microbiology
- Genomics
- Nematology
Background:
- Acinetobacter johnsonii is generally recognized as a nonpathogenic bacterium.
- This species is frequently detected in hospital settings.
- A novel isolate, A. johnsonii MB44, from frost-plant tissue demonstrated potent nematicidal activity.
Purpose of the Study:
- To investigate the genomic features of A. johnsonii MB44.
- To identify potential nematicidal attributes within its genome.
- To understand the implications of its nematicidal activity.
Main Methods:
- Whole-genome sequencing of A. johnsonii MB44.
- Bioinformatic analysis to predict protein-coding genes and RNA genes.
- Utilizing MP3 software for the prediction of nematicidal and virulence proteins.
- Comparative genomics to identify homologous proteins with known virulence factors.
Main Results:
- The MB44 genome is 3.36 Mb with 3636 protein-coding and 95 RNA genes (41.37% G+C content).
- Genomic analysis identified 108 potential nematicidal proteins, including homologs of virulence proteins from Acinetobacter baumannii (e.g., OmpA, Pld, Pbp7/8).
- A siderophore biosynthesis gene cluster and a capsular polysaccharide gene cluster, potential virulence factors for Caenorhabditis elegans, were identified.
Conclusions:
- Acinetobacter johnsonii MB44 possesses genomic features associated with nematicidal activity.
- The presence of specific virulence proteins and gene clusters suggests a potential pathogenic role.
- This isolate could be an opportunistic pathogen affecting animals due to its nematicidal capabilities.
