As a native in Southeast Asia, Sagittaria trifolia L. var. sinensis (arrowhead) is an aquatic perennial herb of Alismataceae family. For the aim of discovering genes and development molecular markers, high-throughput transcriptome sequencing is applied to generate enormous transcript sequences from arrowhead leaf generate. Through trimmed and assembled, 51, 836 contigs were obtained with mean length of 680 bp. Sequence similarity analyses against four public databases (NR, GO, KEGG, KOG) found 23, 595 contigs that could be annotated with gene descriptions, conserved protein domains, or gene ontology terms. In this study, 3, 861 simple sequence repeat (SSR) markers of arrowhead were identified in 3, 174 contigs of transcriptome data,and 2, 476 primer pairs were designed for marker development. Of these, 100 primers were randomly selected, synthesized and used for validation of the amplification and assessment of polymorphisms in 79 arrowhead accessions. 78 loci reliably amplified a clear single band of expexted size, and 68 loci were scoreable and polymorphic with 2 to 11 alleles per locus. The polymorphism information content valued ranged from 0.01 to 0.84. The SSR markers developed from arrowhead, could be successfully applied to Sagittaria pygmaea, with a transferability rate of 91.14% (72/79). The phylogenetic tree was also constructed to analyse the genetic diversity in arrowhead accessions. The large number of SSR markers developed in this study will be useful in the researches of population genetics, genetic diversity, and germplasm characterization in arrowhead.

中文翻译：

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箭叶（Sagittaria trifolia L. Var。Sinensis）叶片转录组分析及EST-SSR标记的建立

作为东南亚本地人，慈姑L.var。sinensis（箭头）是泽泻科的多年生水生草本植物。为了发现基因和开发分子标记，高通量转录组测序被用于从箭头叶生成中产生巨大的转录序列。通过修剪和组装，获得了51、836个重叠群，平均长度为680 bp。针对四个公共数据库（NR，GO，KEGG，KOG）进行序列相似性分析，发现有23、595个重叠群可以用基因描述，保守的蛋白结构域或基因本体术语进行注释。在这项研究中，在3,174个转录组数据重叠群中鉴定了3,861个箭头的简单重复序列（SSR）标记，并设计了2,476个引物对用于标记开发。其中，随机选择了100个引物，合成并用于验证79个箭头种的扩增和评估多态性。78个基因座可靠地扩增了一个清晰的单条带，并扩大了大小，并且68个基因座是可计分的，具有多态性，每个基因座有2至11个等位基因。多态信息含量的值范围为0.01至0.84。从箭头开发的SSR标记可以成功应用于箭竹（Sagittaria pygmaea），可转移率为91.14％（72/79）。还构建了系统进化树，以分析箭头种的遗传多样性。这项研究中开发的大量SSR标记将有助于研究箭头的种群遗传学，遗传多样性和种质特征。