我国沿海多环旋沟藻的形态与分子遗传特征及其分布研究

In this project, samples of Cochlodinium polykrikoides and cysts from water column and sediments will be collected in China seas. Special attention will be paid to the typical bloom area in the East China Sea. The targeted species and strains will be isolated and cultured in lab condition. Various means such as normal light microcopy, laser scanning confocal microscopy, SEM and TEM will be employed for morphological study. The molecular identification will be also performed by amplification and sequencing specific genes (such as LSU rDNA, SSU rDNA, ITS rDNA) and using AFLP ，microsatellite technology. The phylogenetic relation between Cochlodinium polykrikoides and other relative species will be clarified and different ribotypes of the targeted species will be identified. Then, the geographic distribution pattern could be determined. The information of cell density of different ribotypes and Cochlodinium polykrikoidescyst will be obtained from field data by using microscopic counting and FQ-PCR method. On the basis of this data, the distribution pattern of targeted species and long term trend will be determined. The expected finding from this project will be significant for understanding the long term variation pattern of HABs in China and expending mechanism in global sense. And it will also be helpful and beneficial for monitoring and early warning of harmful blooms caused by this species in the near future.

本项目将在我国沿海尤其是东海典型藻华发生区，采集水体和沉积样品，分离纯化多环旋沟藻目标藻株，运用传统的光学显微镜、共聚焦激光显微镜、扫描电镜和透射电镜形态学方法结合多种分子生物学手段如特定基因测序分析（如核糖体大亚基、核糖体小亚基、ITS rDNA ）、AFLP以及微卫星（microsatellite）技术等分析方法，对分布于我国海区的多环旋沟藻进行形态及分子鉴定，搞清多环旋沟藻与相关旋沟藻的亲缘关系，并进一步区分多环旋沟藻种內不同的核糖体型(ribotype),确定其在中国沿海的地理分布特征,建立我国海区多环旋沟藻不同核糖体型的荧光实时定量PCR检测技术，结合经典显微镜定量分析，获取研究海区多环旋沟藻营养细胞及沉积物孢囊的丰度信息，以期揭示他们的时空分布及长期变化特征。项目的开展对于阐释有害藻华的长期演变及旋沟藻的扩张态势及机制具有重要科学意义，并可望为此类藻华的监测与预警提供科学依据。

本项目通过分离纯化多环旋沟藻目标藻株，运用传统的光学显微镜、共聚焦激光显微镜、扫描电镜和透射电镜形态学方法，结合大亚基核糖体（LSU rDNA）等分析方法，对分布于我国海区的多环旋沟藻进行形态及分子鉴定，运用大亚基核糖体（LSU rDNA）测序分析对分布于我国海区的多环旋沟藻进行分子鉴定并结合形态分析，发现迄今为止我国海域的多环旋沟藻属于东亚核糖体型（East Asian ribotype），通过研究表明多环旋沟藻分布范围呈现明显的扩展态势，先前只在我国南部海域出现，近年来分布范围明显扩展至渤海，并可发生规模性藻华，与此同时，我国近海的海水表面温度在过去的半个世纪上升趋势相当显著, 多环旋沟藻在我国沿海的分布扩张态势是否与气候变化及日益加剧的富营养化趋势有关?值得引起关注和进一步深入研究。项目研究结果将对目标藻的赤潮监测策略具有重要参考意义。