Introduction of the reconstructed yeast ferric reductase gene, refre1, into tobacco

Fe(III) reduction at the root surface is an obligatory step in Fe uptake us ed by Strategy-I plants. The genes FRE1 and FRE2 are responsible for a simi lar mechanism of Fe acquisition in the cell membrane of Saccharomyces cerev isiae. We introduced the FRE1 gene into tobacco plants (Nicotiana tabacum L . cv. SR1). However, the transgenic tobacco showed no additional reductase activity, because the FRE1 transcripts from this transgenic tobacco were sh orter than expected. Further investigation revealed that the coding region of the FRE1 gene was polyadenylated. We then reconstructed the whole sequen ce of the FRE1 gene and named it refre1 (reconstructed FRE1). The refre1 ge ne was introduced into tobacco plants. The transgenic plants carrying the r efre1 gene produced full length mRNA and had constitutive ferric reductase activity.