Francisellosis of Yesso scallops Mizuhopecten yessoensis in Japan is caused by a novel type of Francisella halioticida
Francisellosis of Yesso scallops Mizuhopecten yessoensis in Japan is caused by a novel type of Francisella halioticida
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DOI：
10.3354/dao03574
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发表时间：
2021-01-01
影响因子：
1.4
通讯作者：
Itoh, Naoki
中科院分区：
文献类型：
--
作者：
Kawahara, Miku;Yoshitake, Kazutoshi;Itoh, Naoki
也从虾夷扇贝（Mizuhopecten yessoensis）中分离出了杀盐弗朗西斯菌（Francisella halioticida），其是巨型鲍鱼（Halotis hallotea）弗朗西斯菌病的病原体，虾夷扇贝在闭壳肌中呈现出橙子/粉红色病变，并且经历了高死亡率。然而，目前尚不清楚F。从大鲍鱼和Yesso扇贝分离的嗜盐菌在表型和遗传上彼此相同。目前的研究表明，从巨大的鲍鱼和Yesso扇贝的菌株是表型不同的，与缓慢的增长，在改良的优贡肉汤和缺乏脯氨酰氨肽酶和苯丙氨酸氨肽酶Yesso扇贝菌株。此外，我们发现8个管家基因中有3个在它们之间是不同的。基于这些表型和遗传差异，我们建议F。分离自日本Yesso扇贝的嗜盐菌被命名为“J-扇贝型”，以区别于来自鲍鱼的菌株（“鲍鱼型”）。对一株J-扇贝型菌株的全基因组序列分析表明，J-扇贝型菌株与鲍鱼型菌株的相似性为99.84%。根据缺乏脯氨酰氨肽酶活性，一般来说，所有的J-扇贝型菌株检查有一个1 bp的缺失，在负责基因编码脯氨酰氨肽酶。这种缺失在所有F中得到证实。结果表明，在日本，虾夷扇贝弗朗西斯菌病是由一种新的F.而不是鲍鱼型。
Francisella halioticida, the causative agent of francisellosis of the giant abalone Hallotis gigantea, has also been isolated from Yesso scallops Mizuhopecten yessoensis, which presented with orange/pinkish lesions in the adductor muscle and experienced high mortality. However, it is not clear whether the F. halioticida isolated from the giant abalone and Yesso scallops are phenotypically and genetically identical to each other. The present study revealed that isolates from the giant abalone and Yesso scallops were phenotypically different, with slower growth in modified eugon broth and a lack of prolyl aminopeptidase and phenylalanine aminopeptidase in Yesso scallop isolates. Additionally, we found that 3 of 8 housekeeping genes were different between them. Based on these phenotypic and genetic differences, we propose that F. halioticida isolated from Yesso scallops in Japan be designated as the 'J-scallop type' to distinguish it from strains from abalone ('abalone type'). Whole-genome sequencing analysis of a strain belonging to the J-scallop type showed that the overall similarity between the J-scallop and abalone type strains was estimated to be 99.84 %. In accordance with a lack of prolyl aminopeptidase activity, in general, all of the J-scallop type strains examined have a 1 bp deletion in the responsible gene encoding prolyl aminopeptidase. This deletion was confirmed in all F. halioticida in diseased Yesso scallops examined, suggesting that in Japan, francisellosis of Yesso scallops is caused by a novel type of F. halioticida and not by the abalone type.