健康与患病凡纳滨对虾肠道菌群结构及功能差异研究

为探究病害发生后健康与患病凡纳滨对虾肠道菌群结构和功能的差异,并筛选肠道指示菌群来评估宿主健康状况,评价凡纳滨对虾肠道菌落的功能冗余性。实验采集健康和患病凡纳滨对虾样品,通过Illumina高通量测序技术测定肠道菌群组成,并利用PICRUSt进行功能预测,以此比较健康与患病凡纳滨对虾肠道微生物的群落结构和功能差异,并预测功能与群落组成的相关性。结果显示,病害的发生伴随着肠道菌群结构的显著变化,而多样性无显著差异。与健康凡纳滨对虾肠道细菌组成相比,患病凡纳滨对虾肠道中放线菌门(Actinobacteria)、浮霉菌门(Planctomycetes)和疣微菌门(Verrucomicrobia)相对丰度降低,而γ-变形菌纲(Gammaproteobacteria)和拟杆菌门(Bacteroidetes)增加。同时,筛选出16个指示细菌科,能够很好地指示宿主健康状况。与健康组相比,患病凡纳滨对虾中参与弧菌侵染的过程显著增加,而溶酶体和过氧化物酶等免疫功能代谢过程显著减弱。此外,肠道微生物群落结构与功能组成呈显著正相关,表明凡纳滨对虾肠道菌群组成具有较低的功能冗余性。研究表明,健康与患病凡纳滨对虾肠道菌群结构存在显著差异,并且由细菌介导的功能随之发生改变,能够用指示微生物评估宿主健康状况。

Characterizing the compositional and functional structures of intestinal microflora between healthy and diseased Litopenaeus vannamei

The aim of this study was to investigate the difference of the compositional and functional structures between healthy and diseased shrimp gut bacterial community, and to screen the intestinal bio-indicators for evaluating the host health status, to assess the functional redundancy of shrimp gut bacterial community in response to disease. Using an Illumina sequencing based analysis of 16S rRNA gene, we compared the gut bacterial community composition between healthy and diseased shrimps, and analyzed functional profiles by Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). In addition, we estimated the correlation between the gut bacterial community structures and predicted functional compositions. The results showed that the occurrence of disease was associated with significant changes in the bacterial community structures and functional compositions of the shrimp gut microbiota, with no significant changes in bacterial diversity. In compared with the gut microbiota in healthy shrimps, the relative abundances of Actinobacteria, Planctomycetes and Verrucomicrobia significantly decreased in the diseased shrimps, whereas those of Gammaproteobacteria and Bacteroidetes exhibited an appositive pattern. In addition, 16 sensitive indicator families were screened, their occurrences contributed a clear discriminative pattern according to the shrimp health status. Furthermore, the abundance of pathways involved in Vibrio infection significantly increased in the diseased shrimp; in contrast, the pathways for antibacterial and immunity, such as lysosome and peroxisome pathways, markedly decreased in diseased shrimp. Notably, there was a significant and positive association (r = 0.862, P < 0.001) compositional and functional composition between the gut microbiota community, indicating a low functional redundancy of the shrimp gut bacterial community. The occurrence of disease was associated with the change of the shrimp gut bacterial community composition, which subsequently disrupts the bacterial-mediated functions. Further, this study provides sensitive bio-indicators for evaluating the host health status.