Abstract
Graminaceous plants secrete mugineic acid family phytosiderophores (MAs) in response to iron deficiency. Deoxymugineic acid (DMA) is the initial member of the MAs and serves as a precursor for the synthesis of other MAs.
We have cloned DMAS(s) genes from barley (HvDNAS1) maize (ZmDNAS1) and wheat (TaDNAS1). These genes belong to aldo-keto reductase super family and sequence of DMAS(s) is highly conserved among graminaceous plants. Based on nucleotide sequence all these genes were predicted to encode polypeptides of 314 amino acids and are highly homologous (82-96%) to each other. Fusion proteins, expressed in E. coli., showed the in-vitro enzymatic activity to synthesize DMA. Northern blot analysis revealed that DMAS(s) genes were up regulated in response to iron deficiency in root tissue, while no expression was detected in iron deficient or sufficient shoots. Subcellular localization of these genes will be characterized.
