* In this study, using positional cloning and transgenic strategies, heavy metal ATPase 3 (OsHMA3) was identified as the gene that controls root-to-shoot Cd translocation rates. The subcellular localization and Cdtransporting activity of the gene products were also investigated. * The allele of OsHMA3 that confers high root-to-shoot Cd translocation rates (OsHMA3mc) encodes a defective P1B-ATPase transporter. OsHMA3 fused to green fluorescent protein was localized to vacuolar membranes in plants and yeast. An OsHMA3 transgene complemented Cd sensitivity in a yeast mutant that lacks the ability to transport Cd into vacuoles. By contrast, OsHMA3mc did not complement the Cd sensitivity of this yeast mutant, indicating that the OsHMA3mc transport function was lost. * We propose that the root cell cytoplasm of Cd-overaccumulating rice plants has more Cd available for loading into the xylem as a result of the lack of OsHMA3-mediated transportation of Cd to the vacuoles. This defect results in Cd translocation to the shoots in higher concentrations. These data demonstrate the importance of vacuolar sequestration for Cd accumulation in rice. Notes: TY - JOUR URL: http://dx.doi.org/10.1111/j.1469-8137.2010.03459.x Author Address: 1) Laboratory of Plant Genetics and Breeding, Department of Biological Production, Faculty of Bioresource Sciences, Akita Prefectural University, Kaidoubata-Nishi 241-438, Shimoshinjyo-Nakano, Akita 010-0195, Japan 2) Laboratory of Brewing Microbiology, Department of Applied Biology, Faculty of Bioresource Sciences, Akita Prefectural University, Kaidoubata-Nishi 241-438, Shimoshinjyo-Nakano, Akita 010-0195, Japan 3) Akita Agricultural Experiment Station, Genpachizawa 34-1, Aikawa, Yuwa, Akita 010-1231, Japan 4) Graduate School of Life and Environmental Sciences, University of Tsukuba, Tennoudai 1-1-1, Tsukuba, 305-8572 Ibaraki, Japan XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Author: Mlotshwa S, Pruss GJ, Gao Z, Mgutshini NL, Li J, Chen X, Bowman LH, Vance V, Year: 2010 Title: * Transcriptional Silencing Induced by Arabidopsis T-DNA Mutants is Associated with 35S Promoter siRNAs and Requires Genes Involved in siRNA-mediated Chromatin Silencing. Journal: The Plant Journal - Received Date : 15-Jun-2010 - Revised Date : 27-Aug-2010 - Accepted Date : 07Sep-2010. Pages: no Label: Bioengineering Expression Keywords: transcriptional silencing DCL3 35S promoter siRNA T-DNA insertion mutant SALK line Abstract: The utility of many T-DNA insertion mutant lines of Arabidopsis is compromised by their propensity to trigger transcriptional silencing of transgenes expressed from the cauliflower mosaic virus 35S promoter. To try to circumvent this problem, we characterized the genetic requirements for maintaining 35S promoter homology-dependent transcriptional gene silencing (TGS) induced by the dcl3-1 (SALK_005512) T-DNA insertion mutant line. Surprisingly, even though DCL3 and RDR2 are known components of the siRNAdependent TGS pathway, TGS of a 35S promoter-driven GUS hairpin transgene occurred in plants homozygous for the dcl3-1 T-DNA insertion and was unaffected by loss of function of RDR2. However, the TGS was alleviated in dcl2 dcl3 dcl4 triply mutant plants and also by mutations in AGO4, NRPD2, HEN1, and MOM1. Thus, at least some T-DNA insertion mutant lines induce 35S promoter homology-dependent transcriptional silencing that requires neither DCL3 nor RDR2, but involves other genes known to function in siRNAdependent transcriptional silencing. Consistent with these results, we detected 35S promoter siRNAs in dcl3-1 SALK line plants, suggesting that 35S promoter homology-dependent silencing induced by some T-DNA insertion mutant lines is siRNA-mediated. URL: http://dx.doi.org/10.1111/j.1365-313X.2010.04358.x Author Address: 1Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA 2Department of Botany and Plant Sciences and Institute of Integrative Genome Biology, University of California Riverside, Riverside, California, USA XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX Author: Mocali S
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