Post-Transcriptional Coordination of the Arabidopsis Iron Deficiency Response is Partially Dependent on the E3 Ligases RING DOMAIN LIGASE1 (RGLG1) and RING DOMAIN LIGASE2 (RGLG2).

Acclimation to changing environmental conditions is mediated by proteins, the abundance of which is carefully tuned by an elaborate interplay of DNA-templated and post-transcriptional processes. 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. A total of 13,706 and 12,124 proteins was identified with a quadrupole-Orbitrap hybrid mass spectrometer in roots and leaves, respectively.

Vacuolar-Iron-Transporter1-Like proteins mediate iron homeostasis in Arabidopsis.

Iron deficiency is a nutritional problem in plants and reduces crop productivity, quality and yield. With the goal of improving the iron (Fe) storage properties of plants, we have investigated the function of three Arabidopsis proteins with homology to Vacuolar Iron Transporter1 (AtVIT1). Heterologous expression of Vacuolar Iron Transporter-Like1 (AtVTL1; At1g21140), AtVTL2 (At1g76800) or AtVTL5 (At3g25190) in the yeast vacuolar Fe transport mutant, Δccc1, restored growth in the presence of 4 mM Fe.

The transcriptional response of Arabidopsis leaves to Fe deficiency.

Due to its ease to donate or accept electrons, iron (Fe) plays a crucial role in respiration and metabolism, including tetrapyrrole synthesis, in virtually all organisms. In plants, Fe is a component of the photosystems and thus essential for photosynthesis. Fe deficiency compromises chlorophyll (Chl) synthesis, leading to interveinal chlorosis in developing leaves and decreased photosynthetic activity.

Disrupting the bimolecular binding of the haem-binding protein 5 (AtHBP5) to haem oxygenase 1 (HY1) leads to oxidative stress in Arabidopsis.

The Arabidopsis thaliana L. SOUL/haem-binding proteins, AtHBPs belong to a family of five members. The Arabidopsis cytosolic AtHBP1 (At1g17100) and AtHBP2 (At2g37970) have been shown to bind porphyrins and metalloporphyrins including haem.

Phosphate deficiency-induced cell wall remodeling: linking gene networks with polysaccharide meshworks.

The formation of root hairs is a unique developmental process that requires the concerted action of a multitude of proteins. Root hair development is controlled by intrinsic programs, but fine-tuning of these programs occurs in response to environmental signals, dictating the shape and function of epidermal cells. In particular, low availability of soil-immobile mineral nutrients such as phosphate (Pi) affects the density and length of root hairs, resulting in an increased absorptive surface area.

Members of a small family of nodulin-like genes are regulated under iron deficiency in roots of Arabidopsis thaliana.

The analysis of rapid responses in the transcriptome of Arabidopsis roots to a decreased iron (Fe) supply was studied using DNA microarrays and revealed candidate genes with putative roles in Fe homeostasis. In addition to the frequently reported induction of gene activity in response to Fe deficiency, the expression of a number of putative cationic metal transporters was found to rapidly decrease in response to Fe deficiency. In this report we have investigated a small family of five nodulin-like genes that show protein sequence similarity to AtVIT1 and likely have a function in regulation of Fe homeostasis.

Coexpression-based clustering of Arabidopsis root genes predicts functional modules in early phosphate deficiency signaling.

Phosphate (Pi) deficiency triggers the differential expression of a large set of genes, which communally adapt the plant to low Pi bioavailability. To infer functional modules in early transcriptional responses to Pi deficiency, we conducted time-course microarray experiments and subsequent coexpression-based clustering of Pi-responsive genes by pairwise comparison of genes against a customized database. Three major clusters, enriched in genes putatively functioning in transcriptional regulation, root hair formation, and developmental adaptations, were predicted from this analysis.

A hitchhiker's guide to the Arabidopsis ferrome.

Unraveling the mysteries behind the perception and response to iron deficiency has resulted in a vast collection of data that is summarized under the topic "ferromics". The analysis of the immediate effects induced by iron deficiency has been facilitated and in most cases greatly accelerated by the development of analytical and computational tools. These tools permit on the one hand the collection of information from a large number of sources and on the other the analysis of this collection to detect patterns in the re-ordering homeostatic processes at the genomic, transcriptomic, and proteomic levels.

Early iron-deficiency-induced transcriptional changes in Arabidopsis roots as revealed by microarray analyses.

Background: Iron (Fe) is an essential nutrient in plants and animals, and Fe deficiency results in decreased vitality and performance. Due to limited bio-availability of Fe, plants have evolved sophisticated adaptive alterations in development, biochemistry and metabolism that are mainly regulated at the transcriptional level. We have investigated the early transcriptional response to Fe deficiency in roots of the model plant Arabidopsis, using a hydroponic system that permitted removal of Fe from the nutrient solution within seconds and transferring large numbers of plants with little or no mechanical damage to the root systems.

Insights into metabolism obtained from microarray analysis.

The regulation of plant metabolic processes in response to environmental and developmental signals is a complex interaction between optimization of enzyme activity and transcriptional regulation of gene expression. Through painstaking efforts over more than 50 years, many metabolic pathways in plants have been characterized and their regulation investigated, often in detail. Widely available cDNA and oligonucleotide arrays can now be used to analyze the expression profiles of a large number of genes in parallel.

The involvement of a multicopper oxidase in iron uptake by the green algae Chlamydomonas reinhardtii.

In the unicellular green algae Chlamydomonas reinhardtii, high-affinity uptake of iron (Fe) requires an Fe(3+)-chelate reductase and an Fe transporter. Neither of these proteins nor their corresponding genes have been isolated. We previously identified, by analysis of differentially expressed plasma membrane proteins, an approximately 150-kD protein whose synthesis was induced under conditions of Fe-deficient growth.