Arsenate as a potential negative selection agent for deficiency variants in cultured plant cells

Sodium arsenate is toxic to cultured soybean [Glycine max (L.) Merr.] cells, killing virtually 100% of the cells during a 24-h exposure at a 1-2 mM concentration. However, when growth is previously halted by nitrogen deprivation 50-100% of the cells survive arsenate treatment. Because of this growthdependent toxicity, arsenate has promise as a negative selection agent for cultured plant cells. Using arsenate (2 mM) I was able to select from among 2×10(7) cells a cell line with a growth requirement for an amino acid mixture. This trait was maintained through 9 months of passage but then was lost.