PT  - JOURNAL ARTICLE
AU  - Ingrid Richter
AU  - Zerrin Uzum
AU  - Claire E. Stanley
AU  - Nadine Moebius
AU  - Timothy P. Stinear
AU  - Sacha J. Pidot
AU  - Iuliia Ferling
AU  - Falk Hillmann
AU  - Christian Hertweck
TI  - Secreted TAL effectors protect symbiotic bacteria from entrapment within fungal hyphae
AID  - 10.1101/2020.03.28.013177
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.03.28.013177
4099  - http://biorxiv.org/content/early/2020/03/29/2020.03.28.013177.short
4100  - http://biorxiv.org/content/early/2020/03/29/2020.03.28.013177.full
AB  - The association of the agriculturally significant phytopathogenic fungus Rhizopus microsporus with the bacterial endosymbiont Burkholderia rhizoxinica is a remarkable example of bacteria controlling host physiology and reproduction. Here, we show that a group of transcription activator-like effectors (TALEs) called Burkholderia TALE-like proteins (BATs) from B. rhizoxinica are essential for the establishment of the symbiosis. Mutants lacking BAT proteins are unable to induce host sporulation. Utilising novel microfluidic devices in combination with fluorescence microscopy we observed the accumulation of BAT-deficient mutants in specific fungal side-hyphae with accompanying increased fungal re-infection. High-resolution live imaging revealed septa biogenesis at the base of infected hyphae leading to compartmental trapping of BATdeficient endobacteria. Trapped endosymbionts showed reduced intracellular survival, suggesting a protective response from the fungal host against bacteria lacking specific effectors. These findings underscore the involvement of BAT proteins in maintaining a balance between mutualism and antagonism in bacterial-fungal interactions and provide deeper insights into the dynamic interactions between bacteria and eukaryotes.