Cloning and identification of ammonium transporter ApAMT1;3 from the aquatic weed Alternanthera philoxeroides

Alligatorweed (Alternanthera philoxeroides) has been recently investigated for its potential capability of phytoremediation of water eutrophication, especially for the accumulation of ammonium (NH4+) nutrient pollutes. However, molecular studies towards NH4+ uptake is largely unclear in this plant. In this study, we successfully isolated an NH4+ transporter cDNA, named ApAMT1;3, using degenerated primers and rapid amplification of cDNA end（RACE）techniques. Quantitative realtime PCR（qRTPCR）showed that ApAMT1;3 was majorly expressed in shoots, and the transcript levels were significantly enhanced in all tested organs, including roots, stems and leaves by NH4+ starvation of ApAMT1;3. Functional complementation of yeast mutant showed that ApAMT1;3 can mediate external NH4+ uptake. This study directly provide new gene resource to reveal NH4+ uptake and utilization of alligatorweed, and favorably help to investigate the mechanisms underlying NH4+ uptake and transport in aquatic plants.