Authors: Takeshi Nagata Hirofumi Morita Toshifumi Akizawa Hidemitsu PanHou
Publish Date: 2010/04/15
Volume: 87, Issue: 2, Pages: 781-786
Abstract
To develop the potential of plant for phytoremediation of methylmercury pollution a genetically engineered tobacco plant that coexpresses organomercurial lyase MerB with the ppkspecified polyphosphate polyP and merTencoding mercury transporter was constructed by integrating a bacterial merB gene into ppk/merTtransgenic tobacco A large number of independent transgenic tobaccos was obtained in some of which the merB gene was stably integrated in the plant genome and substantially translated to the expected MerB enzyme in the transgenic tobacco The ppk/merT/merBtransgenic tobacco callus showed more resistance to methylmercury CH3Hg+ and accumulated more mercury from CH3Hg+containing medium than the ppk/merTtransgenic and wildtype progenitors These results suggest that the MerB enzyme encoded by merB degraded the incorporated CH3Hg+ to Hg2+ which then accumulated as a less toxic HgpolyP complex in the tobacco cells Phytoremediation of CH3Hg+ and Hg2+ in the environment with this engineered ppk/merT/merBtransgenic plant which prevents the release mercury vapor Hg0 into the atmosphere in addition to generating potentially recyclable mercuryrich plant residues is believed to be more acceptable to the public than other competing technologies including phytovolatilizationWe are grateful to Dr M Kiyono of Kitasato University for her technical assistance in the cloning of pBMK01 and constructive suggestions concerning the manuscript We also thank A Kuwahara of this University for her technical assistance The wildtype tobacco N tabacum cv Samsun NN was a generous gift from Japan Tobacco Inc This work was supported in part by a grantinaid to HH from the Ministry of the Environment Japan
Keywords: