Separation of the up-regulated genes under nitrogen starvation from Phaeodactylum tricornutum by suppression subtractive hybridization technology

Sixteen cDNA fragments of Phaeodactylum tricornutum were isolated and identified to be up-regulated under nitrogen starvation by suppression subtractive hybridization (SSH) technology in order to elucidate the molecular mechanism of the diatom nitrogen utilization. Seven of them have high similarity with the functional genes related to the utilization of nitrogen. Northern blotting analysis indicated that 5 genes, nitrate transporter gene (nrt), nitrite reductase gene (nir), ammonium transporter gene (amt), ATP-binding cassette transporter gene (abc), and purine permease gene (pup), were significantly up-regulated under nitrogen starvation