Accumulation of cadmium (Cd) in T1 transgenic tobacco seedlings expressing metallothionein gene from Eleusine indica

Cadmium (Cd) contamination of urban and agricultural soils is toxic to humans, animals and may cause negative effects on plant growth and crop production. The existing conventional methods are found to be not efficient to remove Cd from contaminated soil. The present experiment reports the analysis of nine T1 lines of transgenic tobacco carrying metallothionein gene (eiMT1) from Eleusine indica, with potential for high efficiency to remediate Cd in contaminated soils. Thirty-days old tobacco plants were treated with different concentrations of CdNO3 (0, 50, 100 and, 150 mumol) for seven days and the accumulation of Cd in the whole seedling was quantitatively determined by using atomic absorption spectrometer (AAS). All transgenic tobacco lines showed greater tolerance and accumulated higher level of Cd than the wild type with lines 18D, 20D1 and, 18C were among the highest (678.7, 623.0 and 611.9 mgkg-1 Cd, respectively). Meanwhile, transgenic tobacco lines 18B1 and 20D1 showed higher expression of eiMT1 gene. These results suggest that the cadmium accumulation in transgenic tobacco did not strictly associate with the expression level of eiMT1 gene. However, expression of eiMT1 greatly required for higher accumulation of Cd in transgenic tobacco seedling.