Project description:To dissect the mechanisms that control and mediate cellular iron homeostasis, we conducted quantitative high-resolution iTRAQ proteomics and microarray-based transcriptomic profiling of iron-deficient Arabidopsis thaliana plants. Proteomic and transcriptomic profiling of Arabidopsis Col and RING DOMAIN LIGASE1 (RGLG1) and RING DOMAIN LIGASE2 (RGLG2) double mutation in response to iron deficiency were conducted. This integrative analysis provides a detailed catalog of post-transcriptionally regulated proteins and allows the concept of a chiefly transcriptionally regulated iron deficiency response to be revisited.
Project description:Iron and copper are important environmental nutrients for plant growth. However, the molecular mechanisms of both iron and copper signaling that integrate the two pathways remain poorly understood. The Arabidopsis thaliana high affinity copper transporter COPT5, is a tonoplast localized permease involved in copper remobilization. Here, a global expression microarray analysis of the copt5 mutant points out the induction of iron deficiency responses, including NATURAL RESISTANCE-ASSOCIATED MACROPHAGE PROTEIN 4 (NRAMP4), a tonoplast-localized iron transporter. The copper requirement in iron perception and uptake from the media becomes more evident in the double nramp3nramp4 mutant, unable to remobilize iron from vacuoles, that is highly sensitive to copper deficiency. Furthermore, COPT5 expression is altered under iron deficiency and the copt5 mutant is sensitive to iron deficiency and is unable to perceive iron in the media under copper deficiency. Noteworthy, iron deficiency post-transcriptionally restraints the copper-dependent superoxide dismutase protein levels and the subsequent activity. As a consequence of its increased iron deficiency responses, the copt5 mutant present lower levels of both copper- and iron-dependent superoxide dismutase activities. Moreover, the copt5 mutant mobilizes faster its iron storage pools and presents higher levels of iron in cotyledons and seeds. These results underline the importance of internal metal pools in the understanding of copper and iron deficiency responses and their crosstalk that are critical for governing proper plant development in response to combined metal scarcities in soils.
Project description:The study examined the proteins that were specifically carbonylated in the wild-type seedlings exposed to iron-deficiency conditions. The results indicated that proteins were differentially carbonylated between the wild type and the triple ferritin mutant Fer1-3-4 in the leaves, stem, and flowers in either control or heat stress conditions. A change in the iron availability in the growth medium greatly influenced the carbonylation of certain proteins involved in the intracellular signal transduction, translation, and iron-deficiency response. Overall, the study underlined the importance of iron homeostasis in the occurrence of protein carbonylation in vivo.