Background and aims: Expected increases in world population will continue to make demands on agricultural productivity and food supply. These challenges will only be met by increasing the land under cultivation and by improving the yields obtained on existing farms. Genetic engineering can target key traits to improve crop yields and to increase production on marginal soils. Soil acidity is a major abiotic stress that limits plant production worldwide. The goal of this study was to enhance the acid soil tolerance of wheat by increasing its resistance to Al(3+) toxicity.
Methods: Particle bombardment was used to transform wheat with TaALMT1, the Al(3+) resistance gene from wheat, using the maize ubiquitin promoter to drive expression. TaALMT1 expression, malate efflux and Al(3+) resistance were measured in the T(1) and T(2) lines and compared with the parental line and an Al(3+)-resistant reference genotype, ET8.
Key results: Nine T(2) lines showed increased TaALMT1 expression, malate efflux and Al(3+) resistance when compared with untransformed controls and null segregant lines. Some T(2) lines displayed greater Al(3+) resistance than ET8 in both hydroponic and soil experiments.
Conclusions: The Al(3+) resistance of wheat was increased by enhancing TaALMT1 expression with biotechnology. This is the first report of a major food crop being stably transformed for greater Al(3+) resistance. Transgenic strategies provide options for increasing food supply on acid soils.