莆田近海孔烂病海带微生物群落结构及其与环境因子的关系

Microbial community structure and its relationship with environmental factors on Hole-Rotten disease of Saccharina japonica in coastal Putian

摘要:

为探究莆田近海孔烂病海带微生物群落结构及其与环境因子的关系，采用16S rRNA扩增子测序技术对健康海带(HT)、孔烂病海带(DT)、健康海带养殖区海水(HS)和孔烂病海带养殖区海水(DS)样本进行测序分析，利用冗余分析研究了海水微生物群落与环境因子的关系。结果显示，HT和DT样本的Ace、Shannon和Heip指数均具有显著差异，HS和DS样本的Ace和Shannon指数具有显著差异，Heip指数则无显著差异，各样本的微生物群落分区明显。微生物群落组成分析显示，盐单胞菌科在HT和DT样本中的相对丰度分别为1.63%和49.01%，蓝细菌门在HS和DS样本中的相对丰度分别为74.45%和3.89%，假交替单胞菌科在DS样本中的相对丰度为30.87%，在HS样本中却不足1%。环境因子关联分析显示，HS和DS样本中盐度和温度指标差异显著，对海水微生物群落变异的解释度分别为46.75%和42.42%。海水优势细菌群落中的蓝细菌与盐度呈正相关，与温度呈负相关。优势细菌群落中的黄杆菌科、红杆菌科、假交替单胞菌科和弧菌科与盐度呈负相关，与温度呈正相关。研究表明，孔烂病的发生可能与海带微生物中的盐单胞菌和海水微生物中的蓝细菌、假交替单胞菌有密切的联系，盐度和温度可能是导致海水微生物群落发生变化的关键环境因子。

Abstract:

In order to explore microbial community structure and the correlation between environmental factors and community structure on Hole-Rotten disease of kelp Saccharina japonica in coastal regions of Putian, in this study, 16S rRNA gene amplicon sequencing technology was used to analyze the samples of healthy (HT) S. japonica, S. japonica with Hole-Rotten disease (DT), seawater from area of cultivated healthy S. japonica (HS) and seawater from area of cultivated S. japonica with Hole-Rotten disease (DS). The interactions between seawater microbial and environmental factors were analyzed by redundancy analysis (RDA) as well. The results showed that the Ace index, Shannon index and Heip index were significantly different between HT and DT samples (P<0.05), the Ace index and Shannon indes were significantly different between HS and DS samples (P<0.05), while the Heip index was not significantly different (P>0.05). The results of principal co-ordinate analysis showed that the microbial community of each sample was obviously partitioned. Microbial community composition analysis showed the relative abundance of Halomonadaceae in the HT and DT samples were 1.63% and 49.01%, the relative abundance of Cyanobacteria in the HS and DS samples were 74.45% and 3.89%, respectively. The relative abundance of Pseudoalteromonadaceae in DS samples is 30.87%, nevertheless, less than 1% in HS samples. The results of correlation analysis of environmental factors showed the salinity and temperature were significantly different in the association between HS and DS samples (P<0.05), and the explanations for the variation of seawater microbial communities were 46.75% and 42.42%, respectively. The dominant Cyanobacteria in seawater was positively correlated with salinity and negatively correlated with temperature; the dominant Flavobacteriaceae, Rhodobacteraceae, Pseudoalteromonadaceae and Vibrionaceae, were negatively correlated with salinity and positively correlated with temperature. In summary, the occurrence of Hole-Rotten disease may be intimately related to the Halomonas in S. japonica epiphytes and the Cyanobacteria and Pseudoalteromonadaceae in seawater microorganisms. Salinity and temperature might be the key environmental factors leading to the change of seawater microflora.