Abstract
The fern Athyrium yokoscense is known as a hyperaccumulator of cadmium(Cd). Although the tolerance to Cd and lead are reported, the mechanism of tolerance is not enough become cleared. Cd sets the upper-part of the plant in a state of Fe-deficiency in a usual plant. Recent molecular aspects in Arabidopsis indicated that Fe-transporters play a major role in Cd-uptake. Here, we isolated the three types of iron transporters from Athyrium yokoscense (AyIRT, AyYSL and AyNramp).
AyIRT and AyNramp showed differences in a specific amino acids, which are highly conserved between plants and considered to be important for the Cd tolerance. Furthermore, AyIRT is different from the major IRTs (AtIRT1) in number of transmembrane domain. When those genes were expressed in yeast cells, cells could grow well on 30μM Cd than the control. It is possible that these specific amino acids relate to the hyper Cd-tolerance in Athyrium yokoscense.
