title: Approach to engineer tomato by expression of AtHMA4 to enhance Zn in the aerial parts.
abstract: The aim of this work was to assess the potential for using AtHMA4 to engineer enhanced efficiency of Zn translocation to shoots, and to increase the Zn concentration in aerial tissues of tomato. AtHMA4, a P1B-ATPase, encodes a Zn export protein known to be involved in the control of Zn root-to-shoot translocation. In this work, 35S::AtHMA4 was expressed in tomato (Lycopersicon esculentum var. Beta). Wild-type and transgenic plants were tested for Zn and Cd tolerance; Zn, Fe and Cd accumulation patterns, and for the expression of endogenous Zn/Fe-homeostasis genes. At 10μM Zn exposure, a higher Zn concentration was observed in leaves of AtHMA4-expressing lines compared to wild-type, which is promising in terms of Zn biofortification. AtHMA4 also transports Cd and at 0.25μM Cd the transgenic plants showed similar levels of this element in leaves to wild-type but lower levels in roots, therefore indicating a reduction of Cd uptake due to AtHMA4 expression. Expression of this transgene AtHMA4 also resulted in distinct changes in Fe accumulation in Zn-exposed plants, and Fe/Zn-accumulation in Cd-exposed plants, even though Fe is not a substrate for AtHMA4. Analysis of the transcript abundance of key Zn/Fe-homeostasis genes showed that the pattern was distinct for transgenic and wild-type plants. The reduction of Fe accumulation observed in AtHMA4-transformants was accompanied by up-regulation of Fe-deficiency marker genes (LeFER, LeFRO1, LeIRT1), whereas down-regulation was detected in plants with the status of Fe-sufficiency. Furthermore, results strongly suggest the importance of the up-regulation of LeCHLN in the roots of AtHMA4-expressing plants for efficient translocation of Zn to the shoots. Thus, the modifications of Zn/Fe/Cd translocation to aerial plant parts due to AtHMA4 expression are closely related to the alteration of the endogenous Zn-Fe-Cd cross-homeostasis network of tomato.
authors.affiliation: University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland.
authors.forename: Maria
authors.initials: M
authors.lastname: Kendziorek
authors.affiliation: University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Barabasz
authors.affiliation: University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Rudzka
authors.affiliation: University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Tracz
authors.affiliation: University of Southampton, Centre for Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom.
authors.forename: Rebecca F
authors.initials: RF
authors.lastname: Mills
authors.affiliation: University of Southampton, Centre for Biological Sciences, Building 85, Highfield, Southampton SO17 1BJ, United Kingdom.
authors.forename: Lorraine E
authors.initials: LE
authors.lastname: Williams
authors.affiliation: University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa Str. 1, 02-096 Warszawa, Poland. Electronic address: dma@biol.uw.edu.pl.
authors.forename: Danuta Maria
authors.initials: DM
authors.lastname: Antosiewicz
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005818:Genetic Engineering; D006706:Homeostasis; D017136:Ion Transport; D007501:Iron / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics / Q000502:physiology*; D035261:Plant Components, Aerial / Q000235:genetics / Q000502:physiology; D018517:Plant Roots / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D013312:Stress, Physiological; D019076:Transgenes; D015032:Zinc / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D002104:Cadmium; D007501:Iron; D000251:Adenosine Triphosphatases; C477864:HMA4 protein, Arabidopsis; D015032:Zinc
keywords: AtHMA4; Biofortification; Cadmium; Tomato; Zinc