Microbiome analysis in the gills of kuruma shrimp Penaeus japonicus infected with Fusarium disease

The causative agents of Fusarium disease in kuruma shrimp have traditionally been attributed to a single infection of fungi belonging to Fusarium spp. However, in recent years, cases have been reported where the tissue around the gills, in addition to blackening of the gills, undergoes dissolution and disintegration. Here, we show that a fungal-bacterial mixed infection is associated with the exacerbation of Fusarium disease. The gill lesions contained not only Fusarium sp. but also Tenacibaculum spp. Although a variety of bacterial species were identified from the gill lesions, and Tenacibaculum spp. represented only a small fraction of the total microbiome, their strict co-localization with Fusarium fungi invading gill lesions and their proteolytic activity in vitro strongly suggest that Tenacibaculum spp. play crucial roles in the aggravation of Fusarium disease.