INTER‐ AND INTRASPECIFIC COMMUNITY STRUCTURE WITHIN THE DIATOM GENUS PSEUDO‐NITZSCHIA (BACILLARIOPHYCEAE) 1
INTER‐ AND INTRASPECIFIC COMMUNITY STRUCTURE WITHIN THE DIATOM GENUS PSEUDO‐NITZSCHIA (BACILLARIOPHYCEAE) 1
复制标题
硅藻属伪菱形藻（硅藻纲）内的种间和种内群落结构1
作者：
Katherine A Hubbard;G. Rocap;E. Armbrust
拟菱形藻特异性 PCR 引物 (PnAll F/R) 设计用于扩增至少 11 个拟菱形藻物种的内部转录间隔区 1 (ITS1) 的多态性区域。这些引物用于生成来自华盛顿州普吉特湾和不列颠哥伦比亚省温哥华岛的环境克隆文库，以确认引物对拟菱形藻具有特异性，并确定各个物种内 ITS1 序列多样性的程度。使用 PnAll 引物生成的所有环境 ITS1 序列与已知的伪菱形藻 ITS1 序列显示出最大的相似性。克隆的 ITS1 片段的长度因物种而异，但在物种内是保守的。在克隆文库中检测到的 10 个物种中，有 7 个物种的种内基因型表现出 <3% 的序列差异。在环境样本中鉴定出太平洋西北地区特有的几种 ITS1 基因型，其他基因型分布更广泛。伪菱形藻引物还用于开发自动核糖体基因间间隔区分析 (ARISA)，以根据目标 ITS1 区域长度的物种特异性变化快速识别环境样品中的伪菱形藻物种。然后将 ARISA 峰与拟菱形藻物种的环境克隆序列相关联。在种间和种内水平上调查群落的遗传组成将增强我们对拟菱形藻水华动力学的理解。
Pseudo‐nitzschia‐specific PCR primers (PnAll F/R) were designed to amplify a polymorphic region of the internal transcribed spacer 1 (ITS1) from at least 11 Pseudo‐nitzschia species. The primers were used to generate environmental clone libraries from Puget Sound, Washington, and Vancouver Island, British Columbia, to confirm that the primers were specific for Pseudo‐nitzschia and to determine the extent of ITS1 sequence diversity within individual species. All environmental ITS1 sequences generated with PnAll primers displayed the greatest similarity to known Pseudo‐nitzschia ITS1 sequences. The length of cloned ITS1 fragments differed among species but was conserved within a species. Intraspecific genotypes exhibited <3% sequence divergence for seven of the 10 species detected in clone libraries. Several ITS1 genotypes unique to the Pacific Northwest were identified in environmental samples, and other genotypes were more broadly distributed. The Pseudo‐nitzschia primers were also used to develop an automated ribosomal intergenic spacer analysis (ARISA) to rapidly identify Pseudo‐nitzschia species in environmental samples based on species‐specific variation in the length of the targeted ITS1 region. The ARISA peaks were then associated with the environmental clone sequences for Pseudo‐nitzschia species. Surveying the genetic composition of communities at both the inter‐ and intraspecific levels will enhance our understanding of Pseudo‐nitzschia bloom dynamics.