Abstract
A new gene induced by aluminum (Al) was isolated from root apices of Al-tolerant wheat cultivar (Atlas66) by the differential display method. The deduced amino acid sequence exhibited high homology to the multidrug resistance (MDR) proteins, thus this gene was named TaMDR1 (Triticum aestivum MDR). The induction of TaMDR1 was observed both in Atlas66 and Scout66 (Al-sensitive cultivar). The induction of TaMDR1 and inhibition of root elongation were observed at lower Al concentration in Scout66 than in Atlas66, suggesting that the gene induction was caused by the Al injury in the roots. Expression of the TaMDR1 was significantly stimulated when plants were exposed to the inhibitors of calcium channels, and to low calcium concentration in growth medium. These results suggested that the induction of TaMDR1 is caused by the breaking of calcium homeostasis which occurred at early stage of Al toxicity.
