NITRATE TRANSPORT - A KEY STEP IN NITRATE ASSIMILATION

The nitrate assimilation pathway has been the matter of intensive rese arch during the past decade. Many genes involved in low and high affin ity nitrate uptake have been identified in fungi, algae and, more rece ntly, in plants. The plant genes so far isolated are transcriptionally regulated, their inducibility by nitrate seems to be a common feature , shared by their homologs in fungi and algae. A number of questions r emain to be elucidated regarding the physiological roles of these tran sporters and the regulation of their expression.