Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia; Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.
Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia.
Water Res. 2018 Jun 1;136:34-40. doi: 10.1016/j.watres.2018.02.041. Epub 2018 Feb 19.
Production of taste and odour (T/O) compounds, principally geosmin, by complex cyanobacterial blooms is a major water quality issue globally. Control of these cyanobacteria imposes a significant cost on water producing and dependent industries, and requires routine monitoring and management. Classic monitoring methods, including microscopy and direct chemical analysis, lack sensitivity, are laborious, expensive or cannot reliably identify the source of geosmin production. Polymerase Chain Reaction (PCR) based tools targeting the geosmin synthase gene (geoA) provide a novel tool for routine monitoring. However, geoA is variable at the nucleotide level and potential geosmin producers represent a broad taxonomic distribution, such that multiple PCR primers with distinct amplification protocols are needed to target all potential sources of this important T/O compound. Development of novel primers is hindered by a lack of sequence data and limited field and laboratory data on geosmin producers prevents prioritizing taxa for PCR testing. Here we performed a genetic screen of 253 bloom samples from Victoria, Australia using each existing PCR protocol targeting geoA. We detected Dolichospermum ucrainicum as the major geosmin producer (87% of sequenced samples) along with 3 unknown geoA sequence types. Using these data, we designed a novel, short amplicon, PCR protocol utilising a single standardised primer pair, capable of amplifying all geoA positive samples in our study, as well as a Nostoc punctiforme positive control. This single protocol geoA PCR can further be tested on other geosmin producers and will simplify routine monitoring of T/O producing cyanobacteria.
产生活性和气味（T/O）化合物，主要是土臭素，由复杂的蓝藻水华产生，是一个全球性的主要水质问题。这些蓝藻的控制对水生产和依赖水生产的行业造成了重大成本，并需要进行常规监测和管理。经典的监测方法，包括显微镜检查和直接化学分析，缺乏敏感性，繁琐，昂贵，或者不能可靠地识别土臭素产生的来源。针对土臭素合酶基因（geoA）的聚合酶链反应（PCR）工具提供了一种常规监测的新工具。然而，geoA 在核苷酸水平上是可变的，潜在的土臭素生产者代表了广泛的分类分布，因此需要具有不同扩增方案的多个 PCR 引物来针对这种重要的 T/O 化合物的所有潜在来源。新引物的开发受到缺乏序列数据和有限的现场和实验室土臭素生产者数据的阻碍，这阻碍了针对 PCR 测试对分类群进行优先级排序。在这里，我们使用针对 geoA 的每种现有 PCR 方案对来自澳大利亚维多利亚州的 253 个水华样本进行了遗传筛选。我们检测到乌克兰念珠藻是主要的土臭素生产者（87%的测序样本），同时还有 3 种未知的 geoA 序列类型。利用这些数据，我们设计了一种新的、短的扩增子、PCR 方案，使用一对单一的标准化引物，能够扩增我们研究中的所有 geoA 阳性样本，以及一个鱼腥藻阳性对照。这种单一方案的 geoA PCR 可以进一步在其他土臭素生产者上进行测试，并将简化 T/O 产生的蓝藻的常规监测。
