Gene profiling by using cDNA microarray analysis of Dunaliella salina under salt and heat stress.

Abstract

Dunaliella is one of the most studied microalgae under laboratory and mass culture conditions, because of its commercial utilization. To investigate the molecular response to the varieties of environmental stress, such as light, heat and salt, cDNA library was created from irradiance-stressed D. salina. From the cDNA library, 1112 randomly selected expressed sequence tags (ESTs) were prepared and generated cDNA microarray to screen differentially expressed genes in D. salina under heat and salt-stressed culture conditions. Fabricated cDNA chip was used to compare gene expression profiling between cells growing under heat-stressed (42℃), salt -stressed (4.5M ) culture condition. Among the 608 genes in the cDNA array, there are 133 genes exhibiting differential expression (two-fold changes) under heat stress condition. In salt stress condition, there are 186 genes exhibiting differential expression (two-fold changes), where 130 genes showed up-regulation, but 57 genes showed down-regulation. A comparison of microarray and real-time PCR analysis showed that the differentially expressed genes showed a high correlation between the two methods. Our results indicated that the cDNA microarray constructed here is reliable and can be used to monitor gene expression profiles in D. salina.. Among 608 genes, carbonic anhydrase gene of D. salina was further analyzed