Aspartate aminotransferase-P2 is implicated in the assimilation of recently fixed nitrogen in the Rhizobium-legume symbiosis. AAT-P2 protein and enzyme activity have been shown to increase strongly during nodule development and the protein is localised to the proplastid fraction of the nodule (Reynolds, Farnden, 1979; Boland et al., 1982). cDNAs have been cloned from a number of plants including lupin (Reynolds et al. 1992), alfalfa (Gantt et al. 1992), soybean (Wadsworth et al., 1993) as well as carrot (Turano et al., 1992) and Arabadopsis (Wilkie et al., 1995).