Fe(III) reductase, the FRE genes, and FRE‐transformed tobacco

Abstract

The importance of Fe(III) reductases in Fe acquisition by Strategy I plants suggests that manipulation of genes encoding Fe(III) reductases could enhance Fe nutrition. In yeast, reduction is also an essential step in iron uptake and two putative Fe(III) reductase genes, FRE1 and FRE2, have been isolated from the yeast Saccharomyces cerevisiae. As yeast genes can be successfully expressed in plants, it is of interest to determine if FRE genes have a similar function in plants. Open reading frames of FRE1 and FRE2 under the control of the CaMV 35S promoter were introduced into Nicotiana tabacum L. cv. Wisconsin 38 via Agrobacterium‐mediated transformation and homozygous R₂ and R₃ families harboring FRE1, FRE2, and FRE1+FRE2 were recovered. In this report we summarize key features of Fe(III) reductases, the FRE genes, and FRE‐transformed plants. The most promising findings concerning the transformants are enhanced Fe(III) reduction in roots and shoot sections, higher leaf Fe levels, and lower susceptibility (chlorophyll retention) to Fe deficiency chlorosis.