Effect of Drought on Expression of Nitrate Transporter Genes in Apple

Nitrogen transporters are members of a large superfamily, the Major Facilitator Superfamily (MFS). This family is ubiquitous and diverse and includes proteins that facilitate the transport of a wide range of substrates across the cytoplasmic or intracellular membranes. Among the proteins encoded by this group of genes are those specifically associated with transport of nitrates into the cell. In a recent analysis of genes responding to simulated drought, a High Affinity Nitrate Transporter from apple roots was identified. Bioinformatic tools were then utilized to identify the apple gene family of nitrate transporters and to compare it to Arabidopsis and peach. The promoters regulating expression of these genes have been identified, and the expression of these genes in apples subjected to a simulated severe drought was determined. Implications for the transport of nitrogen in plants under abiotic stress are presented.