暂养期健康海带和患病海带附生菌群落结构及多样性分析

Community structure and diversity of epiphytic bacteria in healthy and diseased Saccharina japonica seedlings during a temporary rearing period

为探究暂养期健康海带(Saccharina japonica)和患病海带附生菌群落结构差异及其与海水之间的关系,本研究采用高通量测序技术,分析了暂养期健康海带(HS)、患病海带(DS)、健康海带养殖区海水(HW)和患病海带养殖区海水(DW) 4个样本中微生物的16S rRNA序列。结果显示,共识别出32个门, 77个纲, 398个科, 797个属, 1772个OTUs。从门分类上来说,海带样本的优势细菌门为变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)、放线菌门(Actinobacteria)和厚壁菌门(Firmicutes),其中拟杆菌门、放线菌门和厚壁菌门在HS和DS样本中的相对丰度分别为19.91%、10.79%、15.52%和37.31%、1.65%、5.92%,差异较大;从科分类上来说,黄杆菌科(Flavobacteriaceae)和红杆菌科(Rhodobacteraceae)在HS样本中的相对丰度分别为10.7%和12.55%,均低于DS样本(33.47%和21.17%)。多样性分析显示, HS与DS样本之间的Ace和Chao指数无显著性差异(P>0.05), Shannon和Simpson指数具有显著性差异(P<0.05)。SIMPER分析显示,患病海带中3个细菌科的4个OTUs (OTU1169、OTU1111、OTU1351和OTU1353)共提供35.88%的差异率。综上所述,健康海带和患病海带优势附生菌的相对丰度具有较大差异,种间分布具有显著性差异(P<0.05),但物种丰富度无显著性差异,属于黄杆菌科的OTU1169和OTU1111是诊断海带是否感染疾病的主要指示菌。本研究从群落结构和多样性的角度分析附生菌与暂养期海带病害的互作关系,为今后揭示暂养期海带病害发生的机制提供科学参考。

To explore the bacterial community structure on the surface of healthy and diseased seedlings of Saccharina japonica during a temporary rearing period and their relationships with seawater,in this study,sequences of 16 S rRNA from healthy kelp(HS),diseased kelp(DS),seawater from healthy kelp breeding areas(HW),and seawater from diseased kelp breeding areas(DW)were analyzed using Illumina sequencing technology.The results showed that 32 phyla,77 classes,398 families,797 genera,and 1772 operational taxonomic units(OTUs)were identified.At the phylum level,the dominant bacteria in the kelp samples were Proteobacteria,Bacteroidetes,Actinobacteria,and Firmicutes.The relative abundances of Bacteroides,Actinobacteria,and Firmicutes in the HS and DS samples were 19.91%,10.79%,15.52%,37.31%,1.65%,and 5.92%,respectively,showing substantial differences.At the family level,the relative abundances of Flavobacteriaceae and Rhodobacteraceae in the HS samples were 10.7%and 12.55%,respectively,which was lower than those in the DS samples(33.47%and 21.17%,respectively).The diversity analysis showed that the Ace and Chao indexes between HS and DS samples showed no significant differences(P>0.05),whereas the Shannon and Simpson indexes showed significant differences(P<0.05).The SIMPER analysis showed that the four OTUs(OTU1169,OTU1111,OTU1351,and OTU1353)from the three bacterial families in the diseased kelp provided a difference rate of 35.88%.In summary,the relative abundances of dominant epiphytes in healthy and diseased kelp were significantly different,as was the distribution between species(P<0.05),but there was no significant difference in species richness.OTU1169 and OTU1111,belonging to the flavobacteria,were the main indicators for the diagnosis of diseases in kelp.This study analyzed the interaction between epiphytes and vegetative kelp diseases from the perspective of community structure and diversity and provided a scientific reference for revealing the mechanism of vegetative kelp diseases in the future.