Page 25 - Plant-Based Remediation Processes

12 S. Chatterjee et al.

Fig. 1.4 Schematic representation of phytostimulation where plant exudates stimulate the micro-
flora of root zone to degrade contaminants

phytostimulation. In the past decades, many successful attempts have been made
with transgenic plants. Some of which are listed below:
• Mammalian cytochrome P450 gene inserted into the plants as Nicotiana
tabacum, Solanum tuberosum, Oryza sativa, and Arabidopsis thaliana exhibited
increased tolerance to herbicides mainly atrazine and simazine and showed a
marked increase in the capability of metabolism of various xenobiotics (Doty
et al. 2000; Eapen et al. 2007).
• Transgenic Indian mustard (B. juncea) expressing glutathione transferase
(GSTs), a phase II cellular detoxification gene, shows increased tolerance to
atrazine, metachlor, phenanthrene, and 1-chloro-2,4, dinitrobenzene (Flocco
et al. 2004). Overexpression of GST genes enhances the potential for
phytodegradation of herbicides (Kawahigashi 2009).
• Rhizodegradation of pollutant bisphenol A and PCB was efficiently carried out
by transgenic tobacco plants inoculated with the gene coding laccase obtained
from a fungus Coriolus versicolor (Sonoki et al. 2005).