Sulfate permease (SulP) and hydrogenase (HydA) in the green alga Tetraspora sp. CU2551: Dependence of gene expression on sulfur status in the medium

The newly identified chloroplast envelope-localized sulfate permease gene (sulP) and the hydrogenase gene (hydA) from the green alga Tetraspora sp. CU2551 are reported in this study. The sulP showed an open reading frame of 1014 bp with the 5′- and 3′-UTR being 285 and 225 bp, respectively. The deduced amino acid sequence of SulP revealed an extended N-terminus where the putative chloroplast transit peptide was identified. This suggests a close relationship between Tetraspora and Chlamydomonas reinhardtii SulPs, as confirmed by phylogenetic tree analysis. In addition, the Tetraspora hydA was identified. The cDNA sequence showed an 878 bp encoding 292 amino acid residues. The deduced amino acid sequence of Tetraspora HydA is closely related to HydA of Chlorella fusca. The transcript levels of both sulP and hydA of Tetraspora showed an up-regulation of about 2.3 times after sulfur deprivation, whereas upon sulfur repletion the expression of both genes decreased. The production of H2 and PSII activity decreased in cells grown under sulfur-deprived condition. These two activities could be restored when the cells were transferred to the medium supplemented with sulfur. Our results demonstrate a different response to sulfur deprivation between C. reinhardtii and Tetraspora sp. CU 2551.