PAP-SAL1 chloroplast retrograde pathway involved in iron homeostasis regulation in Arabidopsis.

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

Mar del Plata

Congreso; LI Reunión de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2015

SAIB

Iron (Fe) is an essentialelement for human nutrition and vegetables represent a major dietary source ofthe nutrient. Plant Fe metabolism is a subject of active research; some of itskey components are yet to be deciphered, including signals and sensorsregulating Fe nutritional status. New plastid retrograde signals, from thechloroplast and mitochondria to the nucleus, have been recently identified, suchas 3´-phosphoadenosine 5´-phosphate (PAP). Transcriptomeanalysis of Arabidopsis mutant plantsin PAP-SAL1 pathway revealed that the ferritin genes AtFer1, AtFer3, and AtFer4 are upregulated in these geneticbackgrounds, thus establishing a link between the PAP retrograde signalingpathway and the regulation of Fe homeostasis.Inthis work, we focused in the relationship between Fe metabolism and thePAP-SAL1 retrograde signaling pathway. Four mutants in this route -alx8,fry1-6, xrn4, and xrn2/xrn3-showed altered gene expression and modified activities of proteins involved inFe uptake, transport and storage. In addition, these plants grown in high Femedia exhibited different levels of oxidative stress damage compared with thewild type. These preliminary results suggest that the PAP-SAL1 retrogradesignaling pathway could play important roles in Fe homeostasis andbioavailability, possibly communicating the high Fe demand organelles with thenucleus.