Ben Field - An unusual nucleotide is a potent controller of chloroplast function that regulates plant growth and development

  • Date: Mar 1, 2017
  • Time: 02:00 PM - 03:30 PM (Local Time Germany)
  • Speaker: Ben Field
  • BIOTECHNOLOGY AND BIOSCIENCE INSTITUTE OF AIX-MARSEILLE
  • Location: Central Building
  • Room: Seminar Room
  • Host: Salma Balazadeh
The chloroplast originated from the endosymbiosis of an ancient photosynthetic bacterium by a eukaryotic cell. Remarkably, the chloroplast has retained elements of a bacterial stress response pathway that is mediated by the signaling nucleotides guanosine penta- and tetraphosphate (ppGpp). However, an understanding of the mechanism and outcomes of ppGpp signaling in the photosynthetic eukaryotes has remained surprisingly elusive. I will present our findings in the model plant Arabidopsis thaliana where we recently showed that ppGpp is a potent regulator of chloroplast gene expression in vivo that directly reduces the quantity of chloroplast transcripts and chloroplast-encoded proteins. We were also able to demonstrate that the antagonistic functions of different plant RelA SpoT homologs (RSHs) together modulates ppGpp levels to regulate chloroplast function, and RSHs are required for optimal plant growth, chloroplast volume, and chloroplast breakdown during dark-induced and developmental senescence. Together our results strongly suggest that ppGpp signaling is not only linked to stress responses in plants but is also an important mediator of cooperation between the chloroplast and the nucleocytoplasmic compartment during plant growth and development.

Sugliani M, Abdelkefi H, Ke H, Bouveret E, Robaglia C, Caffarri S, Field B (2016) An Ancient Bacterial Signaling Pathway Regulates Chloroplast Function to Influence Growth and Development in Arabidopsis. Plant Cell. 28:661-79

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