文摘
Garlic (Allium sativum L.) is an economically important crop and has significant value as a food, spice, and medicine. The lack of simple sequence repeat (SSR) markers is a major obstacle in genetic studies of garlic. In order to develop SSR markers on a large scale, we performed transcriptome analysis using Illumina pair-end sequencing. Approximately 69.7 million clean sequence reads were generated, and these reads were eventually assembled into 135,360 unigenes. Of these, 56,953 (42.1 %) unigenes were annotated for their function. Examination of SSR loci in these 135,360 ESTs identified 2446 SSRs. Because 940 of the loci were located on the end of the EST, only the residual 1506 SSRs were flanked by designing primer pairs complementary to regions, and these regions were designated as SSR markers. Within these markers, the trinucleotide repeat motif was the most abundant type (66.1 %), with the AGA/TCT and GAA/TTC motifs occurring most frequently. Using 200 randomly selected EST-SSRs, 194 markers were successfully amplified in garlic and 155-86 SSRs in five other Allium species. This suggests that the markers were good quality and had high cross-species transferability. The EST-SSRs developed in this study represent the first large-scale development of SSR markers for garlic. These SSRs could be used for the development of genetic and physical maps, quantitative trait loci mapping, genetic diversity studies, association mapping, and cultivar fingerprinting. Keywords Garlic Transcriptome Illumina sequencing SSR marker Transferability