Development of an InDel polymorphism database for jute via comparative transcriptome analysis

Jute (Corchorus spp.) is one of the most commercially important bast fiber crops in the world. However, molecular markers and high-density genetic maps are still lacking on jute compared with other crops. Insertion/deletion (InDel) markers, one of the most abundant sources of DNA/RNA variations in plant genomes, can easily be distinguished among different accessions using high-throughput sequencing. Using three transcriptome datasets, we identified and developed InDel markers. Altogether, 51 172 InDel sites in 18 800 unigenes were discovered, and the number of InDel loci per unigene varied from 1 to 31. Further, we found 94 InDel types, varying from 1 to 159 bp; the most common were single-nucleotide (23 028), binucleotide (9824), and trinucleotide (9182). In total, 49 563 InDels in 18 445 transcripts were discovered in the comparison between TC and YG, followed by 48 934 InDels in 18 408 transcripts between NY and YG, and 3570 InDels in 2701 unigenes between NY and TC. Additionally, there were 1273 InDel sites in 1129 unigenes with polymorphisms between any two of the three accessions. Twenty-nine (58%) primer pairs represented polymorphisms when compared to the jute accessions, and PIC varied from 0.340 to 0.680, with an average of 0.491.