基于细胞分裂基因表达量研究太湖微囊藻原位生长率的时空变化及环境影响因子

In-situ growth rate is an important parameter to study the formation mechanism, distribution, and forecasting of cyanobacteria bloom. However, currently methods for in-situ growth rate determination have defect of time consuming and operates troublesomely, when it is used at high frequency and large-scale regional study for cyanobacteria bloom. ftsZ is a key protein to regulate cell division. The expression of ftsZ gene showed positive correlation with growth rate of Microcystis. This program plan to create an effective and precise method to determine the in-situ growth rate of Microcystis, after assaying the ftsZ gene expression of Microcystis with different growth rate and constructing regression equation between the expression and the growth rate. To obtain the growth potential of Microcystis in different district and season and assay the relation between the environmental factors and in-situ growth rate in Taihu Lake, the new method will be used to investigate the time-space change of in-situ growth rate of Microcystis in this program. Furthermore, we plan to reveal the starting time and environmental threshold of recruitment and dormant of cyanobacteria, and establish in-situ growth rate of Microcystis in different weather condition by high frequent observation in Taihu Lake. The results of this program will improve efficiency and precision of in-situ growth rate of Microcystis, and help us command the occurrence and distribution regularity and predict the development tendency accurately.

原位生长率是研究蓝藻水华形成机理和分布特征，以及进行水华预测的必要参数，现有的一些浮游植物原位生长率测定方法在开展高频或大水域蓝藻水华研究时，存在着操作繁琐、耗时长的局限性。FtsZ是一种调控细胞分裂的关键蛋白，微囊藻ftsZ基因表达量与生长率有着很好的相关性。本项目通过分析不同生长率微囊藻ftsZ基因的转录水平，构建一种高效且准确的微囊藻原位生长率估算方法。然后利用该方法对太湖的微囊藻原位生长率进行周年的时空调查，分析环境因子与微囊藻原位生长率的相关关系，比较微囊藻在各湖区不同季节的生长潜力。另外，通过微囊藻复苏期、休眠期和水华高发期原位生长率的高频观测，确定太湖水华蓝藻复苏和休眠的时间节点和环境条件阈值，获得水华高发期不同气象条件下的微囊藻原位生长率。研究结果有助于提高微囊藻原位生长率检测效率和精度，掌握太湖蓝藻水华的发生规律和分布特征，准确预判蓝藻水华的发展趋势。

目前对于太湖各湖区微囊藻不同季节的生长潜力还缺乏研究，也没有合适的研究方法，而现有的一些浮游植物原位生长率测定方法在开展高频或大水域蓝藻水华研究时，存在着操作繁琐、耗时长的局限性。通过本项目研究，课题人员构建了ftsZ基因和16S rRNA基因的标准曲线，并初步建立了微囊藻生长率μ与ftsZ基因相对表达量的线性回归方程；调查了微囊藻关键功能基因在太湖不同湖区与季节表达量的时空变化，确定了主要环境因子对微囊藻关键功能基因表达量的影响，以及微囊藻在各湖区、不同季节的生长潜力；通过室内模拟实验研究了不同温度环境下，微囊藻关键功能基因表达量、光合活性以及生长率的变化，获得了微囊藻复苏与越冬的温度阈值，以及最佳生长温度范围。研究结果有助于掌握太湖蓝藻水华的发生规律和分布特征，准确预判蓝藻水华的发展趋势。