title: Early transcriptomic response to Fe supply in Fe-deficient tomato plants is strongly influenced by the nature of the chelating agent.
abstract: BACKGROUND
  It is well known that in the rhizosphere soluble Fe sources available for plants are mainly represented by a mixture of complexes between the micronutrient and organic ligands such as carboxylates and phytosiderophores (PS) released by roots, as well as fractions of humified organic matter. The use by roots of these three natural Fe sources (Fe-citrate, Fe-PS and Fe complexed to water-extractable humic substances, Fe-WEHS) have been already studied at physiological level but the knowledge about the transcriptomic aspects is still lacking.
  
  
  RESULTS
  The (59)Fe concentration recorded after 24 h in tissues of tomato Fe-deficient plants supplied with (59)Fe complexed to WEHS reached values about 2 times higher than those measured in response to the supply with Fe-citrate and Fe-PS. However, after 1 h no differences among the three Fe-chelates were observed considering the (59)Fe concentration and the root Fe(III) reduction activity. A large-scale transcriptional analysis of root tissue after 1 h of Fe supply showed that Fe-WEHS modulated only two transcripts leaving the transcriptome substantially identical to Fe-deficient plants. On the other hand, Fe-citrate and Fe-PS affected 728 and 408 transcripts, respectively, having 289 a similar transcriptional behaviour in response to both Fe sources.
  
  
  CONCLUSIONS
  The root transcriptional response to the Fe supply depends on the nature of chelating agents (WEHS, citrate and PS). The supply of Fe-citrate and Fe-PS showed not only a fast back regulation of molecular mechanisms modulated by Fe deficiency but also specific responses due to the uptake of the chelating molecule. Plants fed with Fe-WEHS did not show relevant changes in the root transcriptome with respect to the Fe-deficient plants, indicating that roots did not sense the restored cellular Fe accumulation.
authors.affiliation: Department of Biotechnology, University of Verona, via delle Grazie 15, 37134, Verona, Italy. anita.zamboni@univr.it.
authors.forename: Anita
authors.initials: A
authors.lastname: Zamboni
authors.affiliation: Department of Agriculture and Environmental Sciences, University of Udine, via delle Scienze 208, 33100, Udine, Italy. laura.zanin@uniud.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Zanin
authors.affiliation: Department of Agriculture and Environmental Sciences, University of Udine, via delle Scienze 208, 33100, Udine, Italy. nicola.tomasi@uniud.it.
authors.forename: Nicola
authors.initials: N
authors.lastname: Tomasi
authors.affiliation: Department of Biotechnology, University of Verona, via delle Grazie 15, 37134, Verona, Italy. linda.avesani@univr.it.
authors.forename: Linda
authors.initials: L
authors.lastname: Avesani
authors.affiliation: Department of Agriculture and Environmental Sciences, University of Udine, via delle Scienze 208, 33100, Udine, Italy. roberto.pinton@uniud.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Pinton
authors.affiliation: Department of Biotechnology, University of Verona, via delle Grazie 15, 37134, Verona, Italy. zeno.varanini@univr.it.
authors.forename: Zeno
authors.initials: Z
authors.lastname: Varanini
authors.affiliation: Faculty of Science and Technology, Free University of Bolzano, piazza Università 5, 39100, Bolzano, Italy. stefano.cesco@unibz.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Cesco
mesh_terms: D002614:Chelating Agents / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry / Q000494:pharmacology*; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D008024:Ligands; D018551:Solanum lycopersicum / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics*; D017262:Siderophores / Q000737:chemistry
chemical_list: D002614:Chelating Agents; D005290:Ferric Compounds; D008024:Ligands; D010940:Plant Proteins; D017262:Siderophores; D007501:Iron