A detoxification gene in transgenic Nicotiana tabacum confers 2,4-D tolerance

Transgenic Nicotiana tabacum with tolerance to 2,4-D has previously been pr oduced using a bacterial 2,4-D-dioxygenase gene (tfdA) driven by the 35S pr omoter of cauliflower mosaic virus. Using promoters from the Pisum sativum plastocyanin gene (petE) and an Arabidopsis thaliana histone gene (H4A), we demonstrate that similar protection from 2,4-D can be obtained in transgen ic N. tabacum by targeting expression of tfdA to either meristematic tissue s or chloroplast-containing tissues. As with the 35S promoter constructs, t he plants are tolerant but not completely resistant; very young seedlings i n particular are only slightly protected. However, the revels of tolerance observed could offer a useful degree of protection from accidental spray dr ift.