长江刀鲚体内菌群PCR-DGGE指纹图谱及多样性比较分析

PCR-DGGE FINGERPRINTING AND DIVERSITY ANALYSIS OF THE PREDOMINANT BACTERIAL COMMUNITY IN COILIA NASUS

以长江刀鲚(Coilia nasus)洄游前幼鱼和洄游后成鱼为对象,通过PCR-DGGE指纹技术探讨长江刀鲚菌群多样性及受洄游路径周围环境影响之后的稳定性。结果显示,PCR-DGGE指纹谱带丰富,共显示出70条可鉴别条带,其中长江水体谱带数(28)高于洄游后刀鲚鳃(26)、胃(26)、肠道壁(20)、肠道内容物(21)和洄游前刀鲚鳃(21)、胃(20)、肠道壁(11)、肠道内容物(13),洄游后刀鲚成鱼体内各对应部位菌群数显著高于洄游前刀鲚幼鱼。UPGMA聚类和PCA结果显示不同样品之间差异显著,虽长江水体与洄游后刀鲚鳃、胃及肠道内容物样品在聚类图上聚为一簇,但其菌群结构的相似度较低,分别为43%、35%和28%。成功克隆测序其中43条条带,主要包含α-变形菌(25.6%)、β-变形菌(7%)、γ-变形菌(16.3%)、放线菌(25.6%)、厚菌门(9.3%)、拟杆菌(7%)、柔膜菌门(4.6%)、绿弯菌(2.3%)和未定义菌(2.3%)。以上结果表明长江刀鲚体内不同部位及其在洄游前后不同阶段,菌群结构存在显著差异,并受环境和宿主双层因素影响。

In this study we investigated the diversity and stability of the bacterial community structure in the juvenile （before the migration） and adult （after the migration） Coilia nasus using PCR-DGGE. The DGGE fingerprint bands were abundant and there were 70 detectable bands with different signal intensities. The number of bands in the water （28） was higher than that in the gill, the stomach, the intestinal wall, and the intestinal contents of Coilia nasus before and after the migration. And the numbers of the bands in the tested organs in adult Coilia nasus were higher than those in juvenile Coilia nasus. The UPGMA clustering and PCA analysis of the DGGE fingerprint showed significant differences be- tween samples. Between the water sample and the post-migration Coilia nasus, the similarities of the bacteria structures in the fish gill, the stomach and the intestinal contents were only 43%, 35% and 28% respectively. Forty-three DGGE bands were successfully cloned including α-Proteobacteria （25.6%）, β-Proteobacteria （7%）,γ-Proteobacteria （16.3%）, Actinobacteria （25.6%）, Firmicutes （9.3%）, Bacteroidetes （7%）, Tenericutes （4.6%）, Chloroflexi （2.3%）, and some un- classified bacteria （2.3%）. These results revealed that the bacterial community varied significantly at different migration stages, and in different bacterial parasitic parts of Coilia nasus. Therefore the external environment and the host should be the main factors affecting the composition of a bacterial community.