Gerald Lackner

Personal Data:
Country of Origin: Germany
Start of PhD: November 2006

PhD Project:
The genome of the endofungal bacterium Burkholderia rhizoxinca

Project Leader: Prof. Dr. Christian Hertweck

Abstract:
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:

• Lackner G, Partida-Martinez LP, Hertweck C (2009) Endofungal bacteria as producers of mycotoxins. Trends Microbiol 17(12), 570-576.
• Lackner G, Moebius N, Scherlach K, Partida-Martinez LP, Winkler R, Schmitt I, Hertweck C (2009) Global Distribution and Evolution of a Toxinogenic Burkholderia-Rhizopus Symbiosis. Appl Environ Microbiol 75(9), 2982–2986.
• Lackner G, Schenk A, Xu Z, Reinhardt K, Yunt ZS, Piel J, Hertweck C (2007) Biosynthesis of pentangular polyphenols: deductions from the benastatin and griseorhodin pathways. J Am Chem Soc 129(30), 9306-9312.