Gills as the respiratory tissue of crustacean encounter various threats in the environment. The immune defense in gills is essential to the health of shrimp. In the present study, we identified a novel gill-abundant crustin, LvCrustin Ⅱ-1, from the shrimp Litopenaeus vannamei. The full-length open reading frame of LvCrustin Ⅱ-1 is 522 bp, which encodes 173 amino acid residues. The amino acid sequence of LvCrustin Ⅱ-1 contained a signal peptide, a glycine rich region, a cysteine rich region and a whey acidic protein (WAP) domain. The expression level of LvCrustin Ⅱ-1 was significantly up-regulated at different time points after Vibrio parahaemolyticus immersion. When LvCrustin Ⅱ-1 was silenced by dsRNA interference, the count of bacteria colonies increased significantly in the hepatopancreas of shrimp after V. parahaemolyticus immersion, which indicated that the infection progress of pathogenic bacteria was accelerated after LvCrustin Ⅱ-1 knockdown. Compared with the microbiota of seawater, the lower proportion of aquatic bacteria and higher proportion of symbiont in the gills microbiota of shrimp indicated the bacterial colonization was modulated by the host. Knockdown of LvCrustin Ⅱ-1 changed the proportion of some potential pathogens and aquatic bacteria, which supported the idea that the new identified crustin in the gills played important roles in modulation of the microbiota community in shrimp. The present data provided new insights into the multiple functions of crustin in the immunity of shrimp.

作为甲壳类动物呼吸组织的在环境中遇到各种威胁。g的免疫防御对虾的健康至关重要。在本研究中，我们从虾对虾凡纳滨对虾中鉴定了一种新型的g g丰富的LustCrustinⅡ -1。LvCrustinⅡ-1的全长开放阅读框为522 bp，编码173个氨基酸残基。LvCrustinⅡ-1的氨基酸序列包含一个信号肽，一个富含甘氨酸的区域，一个富含半胱氨酸的区域和一个乳清酸性蛋白（WAP）结构域。副溶血性弧菌浸没后不同时间点，LvCrustinⅡ-1的表达水平明显上调。什么时候LvCrustinⅡ-1被dsRNA干扰沉默，副溶血弧菌浸泡后虾肝胰脏中细菌菌​​落数量显着增加，表明LvCrustinⅡ-1敲低后病原菌的感染进程加快。与海水微生物区系相比，虾the微生物区系中水生细菌的比例较低，共生菌的比例较高，这表明细菌的定殖受到宿主的调节。LvCrustinⅡ-1的敲低改变了一些潜在病原体和水生细菌的比例，这支持了这样一种观点，即identified中新鉴定出的硬质蛋白在调节虾的微生物群落中起着重要作用。目前的数据提供了新的见解，在虾的免疫中的甲壳素。