Neither Glutamate nor Alanine but Arginine Sensitizes BY-2 Cells to Arsenate.

Arsenic is toxic for plants. Our previous results showed that the application of proline enhanced the sensitivity of tobacco BY-2 cells to arsenate. In order to clarify the enhancement mechanism, we investigated the effects of other amino acids on the arsenate-stressed BY-2 cells. Glutamate at up to 10 mm did not affect the cell growth in the absence or presence of arsenate. Arginine at up to 10 mm did not affect the growth in the absence of arsenate but arginine at 10 mm enhanced the inhibition of the cell growth by arsenate. Alanine at up to 10 mm did not affect the cell growth under nonstressed condition but alanine at 10 mm significantly improved the cell growth under arsenate stress. These results suggest that alanine mitigates arsenate stress in BY-2 cells and that arginine like proline enhances the sensitivity of BY-2 cells to arsenate.