以拉氏拟柱胞藻和浮丝藻为主的蓝藻水华对中华绒螯蟹肠道和鳃及其养殖环境微生物群落结构的影响

Influence of cyanobacterial bloom dominated by Planktothrix sp.and Cylindrospermopsis raciborskii on microflora structure of intestine,gill and culture enviroment of cultured Eriocheir sinensis

通过运用16S rDNA高通量测序技术,研究了蓝藻水华的发生对中华绒螯蟹(Eriocheir sinensis)体内及其养殖环境中微生物群落结构的影响。结果显示,蓝藻水华以蓝藻门的浮丝藻(Planktothrix sp.)和拉氏拟柱胞藻(Cylindrospermopsis raciborskii)为优势种。总体来看,蓝藻池中的群落丰富度高于对照池,微生物多样性低于对照池。蓝藻池和对照池中伊乐藻中的细菌种类很少,而底泥中的细菌种类很丰富。基于门水平下的菌群分类,在蓝藻池水中优势菌群为蓝细菌门(Cyanobacteria)、放线菌门(Actinobacteria)、变形菌门(Proteobacteria)和疣微菌门(Verrucomicrobia),对照池水中则为变形菌门、放线菌门和拟杆菌门(Bacteroidetes)。中华绒螯蟹鳃中均以放线菌门、拟杆菌门和变形菌门为优势菌,但在物种相对丰度上存在差异;中华绒螯蟹肠道均以拟杆菌门、柔膜菌门(Tenericutes)、变形菌门、厚壁菌门(Firmicutes)为优势菌。基于属水平下的菌群分类,蓝藻池池水的优势菌群为浮丝藻属(Planktothrix)、CL500-29_marine_group属和hgcI_clade属,对照池池水中以不动杆菌属(Acinetobacter)、Candidatus_Aquiluna属和hgcI_clade属为优势菌属。中华绒螯蟹鳃中优势属为Ilumatobacter属,且蓝藻池中Ilumatobacter属生物相对丰度更高;中华绒螯蟹肠道样品中Candidatus_Bacilloplasma属和Prolixiibacter属生物相对丰度较高。基于NMDS分析,中华绒螯蟹肠道的菌群结构较为稳定,样本层级聚类分析的结果也映证了这一点。研究结果表明,蓝藻水华的发生会影响养殖环境和中华绒螯蟹肠道及鳃的菌群结构。

Eriocheir sinensis is one of the most important economic crabs in China.However,cyanobacterial bloom often occurs in culture ponds of Eriocheir sinensis,which threatens the normal growth of crab.With the natural fishing output decreasing,the culture technology of Eriocheir sinensis has been developed greatly,and pond culture is one of the main culture methods for Eriocheir sinensis.In order to evaluate the effect of cyanobacterial bloom dominated by Planktothrix sp.and Cylindrospermopsis raciborskii on the microecological health of Eriocheir sinensis,we studied the microbial community structure of gills and intestines of Eriocheir sinensis.To find the relationship between environmental microorganisms and microorganisms in Eriocheir sinensis,we also studied the microflora of water,Elodea nuttallii and sediment in the culture environment.A cyanobacteria outbreak pond and a control pond of the same farm were selected as sampling points.The water,sediment,Elodea nuttallii,intestines and gills of Eriocheir sinensis were collected for low-temperature storage.Using the high-throughput sequencing,we obtained microflora of samples from the cyanobacterial bloom pond and the control pond.In this paper,based on 16S rDNA high-throughput sequencing technology,we analyzed the influence of cyanobacteria bloom on the microbial community in Eriocheir sinensis and its culture environment.Results showed that Planktothrix sp.and Cylindrospermopsis raciborskii were the dominant species in cyanobacteria bloom.In general,the community richness in the cyanobacteria pond was higher than that in the control pond,and the community diversity was lower than that in the control pond.There were few bacteria in the cyanobacteria pond and the control pond,on the contrary,the bacteria in the bottom mud were abundant.Based on phylum level analysis,Cyanobacteria,Actinobacteria,Proteobacteria and Verrucomicrobia were found in the water of cyanobacteria bloom ponds,and the dominant bacteria in the control pond water were Proteobacteria,Actinobacteria and Bacteroidetes.The gills of Eriocheir sinensis were dominated by Actinomycetes,Bacteroides and Proteobacteria,but there were differences in the relative abundance of species.The intestines of Eriocheir sinensis were dominated by Bacteroides,Tenericutes,Proteobacteria and Firmicutes.Based on the classification of the flora at the genus level,the dominant floras of the cyanobacteria pond water were Planktothrix,CL500-29_marine_group and hgcI_clade,and the control pool water was Acinetobacter,Candidatus_Aquiluna and hgcI_clade.The dominant species in the gills of Eriocheir sinensis was Ilumatobacter,and the relative abundance of Ilumatobacter in the cyanobacteria pond was higher;the organisms of Candidatus_Bacilloplasma and Prolixiibacter were relatively abundant in the intestinal samples of cultured Eriocheir sinensis.Based on NMDS analysis,the structure of the intestinal flora of Eriocheir sinensis was relatively stable,and the results of the sample-level cluster analysis also reflected this.In summary,the occurrence of cyanobacterial blooms will affect the culture environment and the microbial structure of Eriocheir sinensis intestines and gills.