The objective of this study was to identify the parasite causing the formation of root hair galls on eelgrass (Zostera marina) in Puget Sound, WA. Microscopic and molecular analyses revealed that a novel protist formed plasmodia that developed into sporangia in root hair tip galls and released biflagellate swimming zoospores. Root hair galls were also observed in the basal section of root hairs, and contained plasmodia or formed thick-walled structures filled with cells (resting spores). Phylogenetic analyses of 18S rDNA sequence data obtained from cells in sporangia indicated that the closest relative of the parasite with a known taxonomic identification was Plasmodiophora diplantherae (86.9% sequence similarity), a phagomyxid parasite that infects the seagrass Halodule spp. To determine the local geographic distribution of the parasite, root and soil samples were taken from four eelgrass populations in Puget Sound and analyzed for root hair galls and parasite DNA using a newly designed qPCR protocol. The percent of root hairs with galls and amount of parasite DNA in roots and sediment varied among the four eelgrass populations. Future studies are needed to establish the taxonomy of the parasite, its effects on Z. marina, and the factors that determine its distribution and abundance.

这项研究的目的是确定在华盛顿州普吉特海湾的鳗gra（Zostera marina）上形成根发hair的寄生虫。显微镜和分子分析表明，一种新的原生生物形成了疟原虫，其在根毛尖胆中发展成孢子囊并释放了双鞭毛游动孢子。在根毛的基部也观察到根毛，并含有疟原虫或形成的厚壁结构，充满了细胞（静止的孢子）。从孢子囊中的细胞获得的18S rDNA序列数据的系统发育分析表明，该寄生虫的最亲近的亲缘关系是已知的分类学鉴定（Piasmodiophora diplantherae）（86.9％的序列相似性），它是一种感染海藻Halodule的吞噬性寄生虫。spp。为了确定该寄生虫的本地地理分布，从普吉特海湾的四个鳗草种群中采集了根和土壤样品，并使用新设计的qPCR方案分析了根发gall和寄生虫DNA。在四个鳗草种群中，根毛有胆汁的根毛百分比以及根和沉积物中的寄生虫DNA量各不相同。需要进一步的研究来确定该寄生虫的分类学，其对Z. marina的影响以及决定其分布和丰度的因素。