Project description:The plant pathogenic fungus Verticillium dahliae has homologs of the clock genes [Cascant-Lopez et al., 2020], which are well described in Neurospora crassa [Diernfellner et al., 2020]. In N. crassa, frequency (Frq) and the Frq-interacting RNA helicase (Frh) interact and form the Frq-Frh complex [Cheng et al., 2005]. Formation of this complex was described to be still possible but weakened by a single amino acid exchange of arginine 806 of Frh to histidine (Frh^R806H) [Shi et al., 2010; Conrad et al., 2016]. We found that both FRQ and wild-type FRH were required for enhanced conidiation and the light-dependent repression of microsclerotia formation in V. dahliae, but were dispensable for disease induction in tomato plants. Strikingly, the FRH^R806H mutant strain grew similar to the FRQ deletion strain, although transcript and protein levels of Frq were not significantly affected by the FRH^R806H mutation when compared with the wild-type. Therefore, we hypothesized that V. dahliae Frq and Frh form the Frq-Frh complex to regulate V. dahliae development, and that this complex formation is abolished upon the amino acid exchange in the Frh. By the use of protein pull-downs, potential interactions of Frh-GFP or Frh^R806H-GFP with Frq were investigated. While we found evidence for a direct interaction of Frh-GFP and Frq, no proteins were significantly co-enriched with Frh^R806H-GFP. References: Cascant-Lopez, E.; Crosthwaite, S.K.; Johnson, L.J.; Harrison, R.J. No evidence that homologs of key circadian clock genes direct circadian programs of development or mRNA abundance in Verticillium dahliae. Front Microbiol 2020, 11, 1977, doi:10.3389/fmicb.2020.01977. Diernfellner, A.C.R.; Brunner, M. Phosphorylation timers in the Neurospora crassa circadian clock. J Mol Biol 2020, 432, 3449–3465, doi:10.1016/j.jmb.2020.04.004. Cheng, P.; He, Q.; He, Q.; Wang, L.; Liu, Y. Regulation of the Neurospora circadian clock by an RNA helicase. Genes Dev 2005, 19, 234–241, doi:10.1101/gad.1266805. Shi, M.; Collett, M.; Loros, J.J.; Dunlap, J.C. FRQ-interacting RNA helicase mediates negative and positive feedback in the Neurospora circadian clock. Genetics 2010, 184, 351–361, doi:10.1534/genetics.109.111393. Conrad, K.S.; Hurley, J.M.; Widom, J.; Ringelberg, C.S.; Loros, J.J.; Dunlap, J.C.; Crane, B.R. Structure of the frequency‐interacting RNA helicase: a protein interaction hub for the circadian clock. EMBO J 2016, 35, 1707–1719, doi:10.15252/embj.201694327.
2023-07-12 | PXD041716 | Pride
Manfred Heller 
