Developing genomic resources for the toxic dinoflagellate Alexandrium tamarense

描述(由申请人提供)：塔玛亚历山大藻是一种单细胞甲藻原生生物，通过产生萨曲霉毒素而引起有害的藻华(HAB)和麻痹性贝类中毒。人们对影响赤潮形成的因素、它们最近传播到新的地区以及与毒素产生有关的基因知之甚少。我们的工作还表明，甲藻是理解内生共生(细胞器发生)和水平基因转移的优秀模型，因为它们具有无与伦比的能力，可以承载不同的叶绿体内共生生物，并通过水平基因转移积累基因。在这里，我们建议为亚历山大藻创造一个重要的基因组资源，以加速赤潮生物的生物学和控制以及甲藻核基因组进化的研究。我们的具体目标是使用高效的基因发现策略来生成亚历山大藻的全面表达序列标签(EST)Unigene集合。对亚历山大藻不同序列的系统发育学和详细的系统发育分析将产生有助于阐明来自内共生菌和其他来源的水平基因转移对甲藻核基因组进化的贡献的树。我们还将使用大规模并行签名测序分析为亚历山大菌在不同培养条件下生长的细胞创建转录组标签数据库，这些培养条件会影响营养生理、细胞和生命周期阶段以及毒素产生。这项工作将帮助我们确定与这些功能相关的目标基因，并将为未来的微阵列分析奠定基础。这一建议是一项综合的合作努力，依赖于分子进化、EST加工和系统基因组学(Bhattacharya，SCARES)、高质量cDNA文库构建(SCARES)以及亚历山大藻(Anderson)生态学和生理学方面的专业知识。这项研究的结果将为科学家了解亚历山大藻等赤潮生物的生态和毒性提供宝贵的分子资源，并将为这些迷人的原生生物提供第一个全面的基因组学资源。

DESCRIPTION (provided by applicant): Alexandrium tamarense is a unicellular dinoflagellate protist that causes harmful algal blooms (HABs) and paralytic shellfish poisoning through the production of saxitoxins. Very little is known about the factors that influence the formation of HABs, their recent spread to new areas, and the genes involved in toxin production. Our work also shows that dinoflagellates are outstanding models for understanding endosymbiosis (organelle genesis) and horizontal gene transfer because of their unparalleled ability to host different plastid endosymbionts and to accumulate genes through horizontal gene transfer. Here we propose to generate a significant genomics resource for Alexandrium to accelerate research on the biology and control of HABs and on nuclear genome evolution in dinoflagellates. Our specific aims are to use a highly efficient gene discovery strategy to generate a comprehensive expressed sequence tag (EST) unigene set for Alexandrium. Phylogenomic and detailed phylogenetic analysis of the different sequences in the Alexandrium unigene set will result in trees that help elucidate the contribution of horizontal gene transfer from endosymbionts and other sources to dinoflagellate nuclear genome evolution. We will also use massively parallel signature sequencing analysis to create a transcriptome tag database for Alexandrium cells grown in different culture conditions that affect nutrient physiology, cell and life cycle stages, and toxin production. This work will help us identify target genes involved in these functions and will form the basis for future microarray analyses. This proposal is an integrated, collaborative effort that relies on expertise in molecular evolution, EST processing, and phylogenomics (Bhattacharya, Scares), high quality cDNA library construction (Scares), and expertise in the ecology and physiology of Alexandrium (Anderson). The results of this study will result in a valuable molecular resource for scientists working to understand the ecology and toxicity of HAB species like Alexandrium and will provide the first comprehensive genomics resource for these fascinating protists.