Cloning and screening of differentially expressed genes from the male gametophytes of Laminaria japonica Aresch

Differentially expressed cDNAs subtracted female from male gametophytes of Laminaria japonica were obtained by suppression subtractive hybridization （SSH）. The differentially expressed cDNAs from the male gametophytes were ligated into the pGEM-T vector and the latter was consequentially transformed into Escherichia coli JM109 competent cells. The subtracted cDNA libraries of male gametophytes were constructed. One hundred randomly selected clones were amplified by PCR using T7 and SP6 primers for primary screening. The length of inserted fragments assayed by PCR amplification was mostly from 200 to 1000 base pairs. Ten clones obtained after dot-blot Southem hybridization were sequenced and analyzed for homology comparison using BLAST. Seven of the ten clones showed no sequence homology in the GenBank database, suggesting that they or at least some of them with longer base pairs might represent novel gene sequences. The other three clones shared 88% and 98% sequence homologies with understood Fop and Lhcfs genes, respectively.