Abstract
Boron (B) is essential in higher plants and B deficiency hampers crop yields in over 80 countries. Transgenic Arabidopsis overexprssing BOR1, a borate exporter for xylem loading, exhibited improved fertility under B limitation (Miwa et al, 2006). In this study, we aimed to further improve B-deficiency tolerance through overexpression of NIP5;1, a boric acid channel for B uptake in roots.
An NIP5;1 activation tag line showed improved root elongation under B limitation. We introduced a construct that mimics the NIP5;1 locus of this activation line into transgenic Arabidopsis overexpressing BOR1. Several independent transgenic lines showed improved root elongation under B deficiency and one of them exhibited elevated short- and long-term B uptake and improved fertility under B limitation. This study demonstrated that it is possible to generate nutrient-deficiency tolerant plants through overexpression of a channel for an essential mineral nutrient.
