Abstract
The comparative induction of non-symbiotic hemoglobins (Hbs) by nitrate, nitrite, and nitric oxide in cultured rice cells were investigated. Rice possesses two Hb genes, ORYsaGLB1a and ORYsaGLB1b. RT-PCR analysis using gene specific primers showed that the transcription of ORYsaGLB1a and ORYsaGLB1b was induced in nitrate treated cells. Maximal induction of ORYsaGLB1a and ORYsaGLB1b mRNA occurred after 8h of treatment with nitrate. In nitrite-supplied cells, the induction of ORYsaGLB1a and ORYsaGLB1b mRNA was more rapid than nitrate treated cells, where ORYsaGLB1a and ORYsaGLB1b was detected 0.5-1 h after the addition of nitrite and increased to a maximum at 4 h. The treatment of rice cells with S-nitroso-N-acetylpenicillamine (SNAP), a nitric oxide donor, also resulted in an accumulation of ORYsaGLB1a and ORYsaGLB1b mRNA with a maximum induction at 2-4 h after treatment. The present experiments indicate that nitrate, nitrite, and nitric oxide is an effective inducer for Hbs in cultured rice cells.
