PAP-SAL1 chloroplast retrogade pathway that functions in iron homeostasis regulation in Arabidopsis

BALPARDA, MANUEL; ESTAVILLO, GONZALO; PAGANI M AYELEN; GOMEZ CASATI, DIEGO

Mar del Plata

Congreso; LI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2015

Iron (Fe) is an essential element for human nutrition. Plantsrepresent a major dietary source of Fe. The understanding of Fesensing was the identification of several transcription factor cascadesregulating Fe homeostasis. New plastid retrograde signals, from thechloroplast and mitochondria to the nucleus, have been recentlyidentified, such as 3´-phosphoadenosine 5´-phosphate (PAP).Transcriptome analysis of Arabidopsis mutant plants in PAP-SAL1pathway revealed that the ferritin genes AtFer1, AtFer3, and AtFer4 areupregulated in these genetic backgrounds, thus establishing a linkbetween the PAP retrograde signaling pathway and the regulation ofFe homeostasis genes.In this work, we focus in the relationship between the Fe homeostasisand the PAP-SAL1 retrograde signal. Recently, we indetified fivemutants, in this pathway: alx8, fry1-6, xrn4 and xrn2/xrn3 with modifiedgene expression and activities of enzymes involved in the Fe uptake,transport and storage. In addition, we measured the levels of oxidativestress damage, in incresing concentration of Fe, finding positivedifferences with the wild type. The preliminary results suggest thatthese mutants could play impotant roles in Fe homeostasis andbioavailability.