Detection of Transport Activity in Barley and Rice Aquaporins with Newly Developed Yeast System

抄録

Some aquaporins showed CO₂ transport activities, many aquaporin species have not yet been analyzed. NtAQP1 already reported the activity of CO₂ transport but the method has technical restrictions. Therefore, we have developed the new yeast system to detect CO₂ permeability of aquaporins from barley and rice. CO₂ induced intracellular acidification was measured in yeast cells with fluorescein fluoresce. Double transformants containing the carbonic anhydrase and pH-sensitive EGFP in addition to the aquaporin constructs were selected. Transport of CO₂ resulted in an intracellular acidification and a decrease of fluorescein fluoresces. We have screened aquaporins from barley and rice. Previously, our research had reported barley aquaporins, HvPIP2;1 can transport CO₂. We have confirmed such results using our new yeast system. In addition, other two HvPIP1;1 and HvPIP2;3 are detected to have CO₂ transport activities. In rice aquaporins, it was revealed that OsPIP2;1 and OsTIP2;2 could transport CO₂. Our investigation of using new yeast system in the aquapoirns gives more easy and simple method for examination of CO₂ transport activity.