The genome of the endofungal bacterium Burkholderia rhizoxinica
Symbiosis – the close association of two biological species – is a common survival strategy found in nature. The bacterium Burkholderia rhizoxinica is an endosymbiont of the phytopathogenic fungus Rhizopus microsporus, living within the hyphae of its host. It serves its host as intracellular toxin factory providing the fungus with the antimitotic compound rhizoxin. Rhizoxin is a pathogenicity factor against plants and causes symptoms of a severe plant disease called ‘rice seedling blight’. Furthermore, rhizoxin was in clinical trials as an antitumor agent. Consequently, the Burkholderia-Rhizopus alliance has numerous implications for natural product research and drug development. In addition, since B. rhizoxinica is the first symbiont of fungi that could be grown in pure culture, it has become a model system for bacterial-fungal interaction. I conducted experiments aiming at the elucidation of molecular mechanisms underlying fungal-bacterial interaction like infection and vertical transmission of symbionts. First, the whole genome of B. rhizoxinica was sequenced by shotgun technology and closed by finishing reactions. After automated annotation of the genome, I identified candidate genes that might be essential for endofungal lifestyle. The establishment of a gene inactivation strategy and a new bioassay allowed the generation and testing of mutant endosymbionts for defects in fungal-bacterial symbiosis. We expect that a better understanding of microbial communication might open new ways for efficient control of microorganisms with applications in biotechnology or agriculture.
Publications
(2015) Genome Sequence of Mushroom Soft-Rot Pathogen Janthinobacterium agaricidamnosum. Genome Announc 3(2), Details PubMed
(2015) Structure, genetics and function of an exopolysaccharide produced by a bacterium living within fungal hyphae. Chembiochem 16(3), 387-392. Details PubMed
(2014) Biosynthesis of the halogenated mycotoxin aspirochlorine in koji mold involves a cryptic amino acid conversion. Angew Chem Int Ed Engl 53(49), 13409-13413. Details PubMed
(2014) Active invasion of bacteria into living fungal cells. Elife 3, e03007. Details PubMed
(2013) Biosynthesis and mass spectrometric imaging of tolaasin, the virulence factor of brown blotch mushroom disease. Chembiochem 14(18), 2439-2443. Details PubMed
(2012) Imaging mass spectrometry and genome mining reveal highly antifungal virulence factor of mushroom soft rot pathogen. Angew Chem Int Ed Engl 51(52), 13173-13177. Details PubMed
(2012) Symbiotic cooperation in the biosynthesis of a phytotoxin. Angew Chem Int Ed Engl 51(38), 9615-9618. Details PubMed
(2012) Structural characterization of two lipopolysaccharide O-antigens produced by the endofungal bacterium Burkholderia sp. HKI-402 (B4). Carbohydr Res 347(1), 95-98. Details PubMed
(2011) Characterization of Burkholderia rhizoxinica and B. endofungorum isolated from clinical specimens. PLoS One 6(1), e15731. Details PubMed
(2011) Impact of endofungal bacteria on infection biology, food safety, and drug development. PLoS Pathog 7(6), e1002096. Details PubMed
(2011) Endofungal bacterium controls its host by an hrp type III secretion system. ISME J 5(2), 252-261. Details PubMed
(2011) Complete genome sequence of Burkholderia rhizoxinica, an Endosymbiont of Rhizopus microsporus. J Bacteriol 193(3), 783-784. Details PubMed
(2011) Evolution of an endofungal lifestyle: Deductions from the Burkholderia rhizoxinica genome. BMC Genomics 12, 210. Details PubMed
(2010) An unusual galactofuranose lipopolysaccharide that ensures the intracellular survival of toxin-producing bacteria in their fungal host. Angew Chem Int Ed Engl 49(41), 7476-7480. Details PubMed
(2009) Global distribution and evolution of a toxinogenic Burkholderia-Rhizopus symbiosis. Appl Environ Microbiol 75(9), 2982-2986. Details PubMed
(2009) Endofungal bacteria as producers of mycotoxins. Trends Microbiol 17(12), 570-576. Details PubMed
(2007) Biosynthesis of pentangular polyphenols: deductions from the benastatin and griseorhodin pathways. J Am Chem Soc 129(30), 9306-9312. Details PubMed
Supervisor
Co-Supervisors
Start of PhD
November 1, 2006
Doctoral Disputation
February 1, 2011
