Abstract: This study aimed to reveal the structure of bacterial flora and dominant spoilage bacteria in adductors of the scallop Patinopecten yessoensis. The total bacterial flora of fresh and spoiled scallop adductors were analyzed via high-throughput sequencing of metagenomic DNA, as well as the culturable bacterial flora via high-throughput sequencing of total cultured colonies’ genomic DNA. The results based on metagenomic DNA showed that the diversity of bacterial flora in fresh samples was relatively high, among which, the genera with high relative abundance were Candidatus kuenenia (10.73%), Vibrio (8.15%), Aliivibrio (7.38%), Bacillus (7.20%) and unclassified (16.08%). The dominant spoilage bacteria at 4 ℃ were Photobacterium (46.91%), Aliivibrio (36.82%) and Pseudoalteromonas (11.01%). The dominant spoilage bacteria at 15 ℃ were Photobacterium (46.97%) and Aliivibrio (43.33%). The dominant spoilage bacteria at 25 ℃ were Photobacterium (41.94%), Aliivibrio (23.10%), Fusobacterium (18.61%) and Lactobacillus (10.60%). The results from cultured colonies’ genomic DNA sequencing revealed that the diversity of culturable bacteria flora in fresh samples, which was dominated by Pseudoalteromonas (89.46%), was significantly decreased. The culturable dominant spoilage bacteria during storage at 25 ℃ were Vibrio (50.98%), Shewanella (17.43%) and Lactobacillus (10.68%). The findings of this study can provide a basis for further investigating the mechanism of microbial quality?deterioration in adductors of P. yessoensis.

Key words: adductor of Patinopecten yessoensis, high-throughput sequencing, diversity of bacterial flora, dominant spoilage bacteria