Abstract
Rubisco is the key enzyme responsible for photosynthesis and its amount is increased with increasing N supply. In this study, changes in the mRNA levels of rbcS nuclear multigene family (genes coding for the small subunit of Rubisco) in response to N supply were examined in rice. Rice plants were grown hydroponically with different levels of N supply and the mRNA levels in tenth leaf blade were determined. There are five rbcS genes (designated as OsRBCS1 to OsRBCS5) and the mRNAs of OsRBCS2 to OsRBCS5 were highly accumulated irrespective of N supply, The maximum levels of these mRNAs were increased with high N supply. The maximum mRNA levels of OsRBCS2 and OsRBCS4 were decreased with low N supply, whereas these of OsRBCS3 and OsRBCS5 were increased. Therefore, it is concluded that the mRNA levels of rbcS multigene family were differentially regulated in response to N supply in rice.
