Ecological diamics of marine birnavirus in marine organisms and the environments in the Uwa Sea

本研究旨在阐明海洋双RNA病毒（marine birnavirus，MABV）在日本珍珠牡蛎（Japanese Pearl Oyster）和自然宿主体内的生态学，以及MABV在宇和海的季节性发生。病毒在夏季以少量基因组和蛋白质侵入血细胞，在冬季向实质细胞扩散。冬季养殖牡蛎的PCR病毒检出率明显升高。冬季海水中的病毒检出率也有所上升，乌波海浮游植物中含有大量的菱形藻，牡蛎无法消化的食物本研究揭示了MABV的生态学特征、MABV在珠母贝中的感染状况、MABV在不同宿主中的变异情况，以及MABV在珠母贝中的传播途径。

This project has aimed to clarify the ecology of marine birnavirus (MABV) in Japanese Pearl Oyster and natural hosts, and the seasonal occurrence of MABV in the Uwa Sea.The infection status of MABV in Japanese Pearl Oyster was found to change between summer and winter. The virus infected in haemocytes in summer with small amount of genome and protein, and then spread in winter into the parenchymal cells. Virus detection rate by PCR in the cultured oyster appeared to be increased in winter. Also the virus detection rate in seawater increased in winter season.The phytoplankton in the Uwa Sea contained much amount of Nitzchia spp., which could not be digested by the oyster. This suggests that the feed plankton of the oyster might be deficient.MABV was firstly detected in Ayu, fresh water fish, whereas Amago salmon in close area possessed another birnavirus, IPNV.This suggests seawater is a carrier of MABV in Ayu.This project revealed ecology of MABV, infective state in the pearl oyster, mutation in various hosts.