Adenosine 3´,5´-bisphosphate (PAP)-mediated inter-compartmental metabolite signalling and intracellular transport of 3´-phosphoadenosine 5´-phosphosulfate (PAPS) and PAP in Arabidopsis thaliana

• Applicant: Professor Dr. Ulf-Ingo Flügge
• Subject Area: Plant Biochemistry and Biophysics
• Term: from 2011 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 207585579

Because plant cells are highly compartmentalized, they rely on an extensive exchange of signals between the different compartments to coordinate responses to a variety of internal and external cues. Recently, adenosine 3‘,5‘-bisphosphate (PAP) has been suggested to serve as a metabolic signal between plastids, mitochondria and nuclei. The phosphatase FRY1/SAL1 cleaving PAP into AMP and Pi is present in all three compartments. The increased accumulation of PAP in fry1/sal1 Arabidopsis thaliana knock-out plants causes changes in the expression of many nuclear-localized genes resulting in increased resistance to abiotic and biotic stresses such as drought, salt, high light or virus infection. It is aimed to get new insights on the role of FRY1/SAL1 and of plastidic (cPAPST1) and of mitochondrial (mPAPST1) PAP/PAPS transporters in intercompartmental PAP signalling. The role of each of these proteins in the generation, transduction and neutralization of the PAP signal in various cell compartments will be unravelled. To this end, (i) the transport characteristics of the organellar PAPS proteins will be assessed; (ii) genetic complementation of fry1 will be performed in which the expression of FRY1 is directed to only one of these compartments; (iii) the mutant plants containing different levels of PAP in either plastids, the cytosol or mitochondria will be generated and analyzed with respect to changes in plant appearance and resistances to abiotic stresses; (iv) the metabolite complementation of fry1/sal1 by crossing with mutants having manipulated levels of PAP in chloroplasts (apk1xapk2xapk4xfry1, apk1xapk2xapk4xcpapst1xfry1), mitochondria (mpapst1xfry1) or the cytosol (apk3xcpapst1xfry1, apk1xapk2xapk3xfry1, apk1xapk2xapk3xcpapst1xfry1) will be performed. These studies will include the determination of subcellular PAP levels.

• DFG Programme: Research Grants
• Participating Person: Privatdozentin Dr. Tamara Gigolashvili