PAP-SAL1 retrograde pathway is involved in iron homeostasis in Arabidopsis thaliana.

BALPARDA, M.; PAGANI M.A.; ESTAVILLO, G.; DIEGO FABIAN GOMEZ CASATI

Córdoba

Congreso; LII Reunión de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2016

SAIB

Nucleargene expression is regulated by a diversity of retrograde signals that travelfrom the organelles to the nucleus in a lineal or classical model. One suchsignal molecule is 3´-phosphoadenisine-5´-phosphate (PAP); the levels of PAP in vivo are regulated by a phosphataseenzyme SAL1/FRY1 located in chloroplast and mitochondria. This metaboliteinhibits the action of a group of enzymes called exoribonucleases (XRNs), whichparticipate in the regulation of the post-transcriptional gene expression. Transcriptomeanalysis of Arabidopsis mutant plantsin PAP-SAL1 pathway revealed that the ferritin genes AtFer1, AtFer3, and AtFer4 are up regulated in these geneticbackgrounds, thus establishing a link between the PAP retrograde signalingpathway and the regulation of Fe homeostasis genes.In thiswork, we studied Fe homeostasis in sal1and xrn mutants, showing differencesin the expression of genes implicated in Fe uptake and storage; we also observedivergences in the enzyme activities concerned in Fe uptake, comparing withwild type. In Fe deficiency conditions, sal1and xrn mutants grew well while wildtype plants were clearly affected. These mutants presented a miscommunicationbetween the root and the shoot, upregulating Fe acquisition genes even when thenutritional demands are fulfilled.