Identification of the immune expressed sequence tags of pearl oyster (Pinctada martensii, Dunker 1850) responding to Vibrio alginolyticus challenge by suppression subtractive hybridization

One hemolymph subtracted cDNA library of pearl oyster (Pinctada martensii, Dunker 1837) was constructed using the suppression subtractive hybridization (SSH) in response to Vibrio alginolyticus. A total of 1089 clones were sequenced. All the consensuses were recognized based on the BLAST searches in NCBI, and revealed that 376 (58%) of them had no significant matches to reported sequences in the database. 267 ESTs were in significant matches after homologous sequence searches. Hypothesized genes inferred from EST sequences were categorized into six groups according to their putative biological functions: replication, transcription and translation; cellular processes; responded to stimuli; metabolism and biosynthesis; signal transduction genes; “other” category. The five genes, pearlin gene promoter PGPPm, serine/threonine kinase STKPm, limbic system-associated membrane protein LSAMPPm, nacrein gene intron 6 NGIPm6 and ferritin-like protein FLPPm, were analyzed using real-time PCR. All these genes were significantly expressed after V. alginolyticus challenge.