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Defensive bacteriome symbiont with a drastically reduced genome
Atsushi Nakabachi1, Reiko Ueoka, Kenshiro Oshima
1Electronics-Inspired Interdisciplinary Research Institute (EIIRIS), Toyohashi University of Technology, Toyohashi 441-8580, Japan. nakabachi@eiiris.tut.ac.jp
Current Biology : CB
|July 16, 2013
Summary
The Asian citrus psyllid harbors a defensive bacterium, "Candidatus Profftella armatura," which produces a novel toxin called diaphorin. This symbiosis is ancient and essential for the psyllid, aiding in its survival.
Area of Science:
- Microbiology and Entomology
- Insect-Microbe Interactions
- Genomics and Biochemistry
Background:
- Insect symbiotic bacteria provide essential functions like nutrition and defense.
- The Asian citrus psyllid (Diaphorina citri) transmits citrus greening disease and harbors two symbionts.
- One symbiont, "Candidatus Profftella armatura," has an unknown role.
Purpose of the Study:
- To investigate the function and genomic characteristics of "Candidatus Profftella armatura" in Diaphorina citri.
- To determine if Profftella plays a role in host defense.
- To characterize any novel compounds produced by Profftella.
Main Methods:
- Genome sequencing and analysis of Profftella and Carsonella_DC.
- Toxin extraction and characterization (pharmacological and structural).
- Comparative analysis of Profftella presence across global D. citri populations.
Main Results:
- Profftella possesses an extremely streamlined genome with horizontally acquired genes for toxin synthesis.
- A novel polyketide toxin, diaphorin, was identified and characterized.
- Profftella and its diaphorin-biosynthetic genes are conserved in all studied D. citri populations, suggesting an obligate defensive role.
Conclusions:
- Profftella functions as an obligate defensive symbiont for the Asian citrus psyllid.
- The ancient symbiosis is characterized by extreme genome reduction and the production of a unique toxin, diaphorin.
- This discovery sheds light on insect defense mechanisms and co-evolutionary strategies.
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