Sui Generis Development of Molecular Markers from Transcriptome of Crotalaria juncea, a Fabaceae Family Bast Fiber Crop

Abstract

Lack of genomic resources in sunn hemp (Crotalaria juncea L.), a leguminous bast fiber crop, is one of the major constraints for germplasm characterization and genetic analysis. We identified non-redundant sets of a variety of molecular markers from the de novo flower-bud transcriptome of sunn hemp. These molecular markers included 1683 simple sequence repeats, 4759 intron length polymorphism markers primarily from protein-coding genes, and 3309 single nucleotide polymorphism allele-specific markers. All of these marker resources have been integrated into a simple database for easy access. To evaluate marker efficiency and polymorphism information content of the sampled primers, a subset of SSR and intron length polymorphism markers were validated in sunn hemp germplasm accessions to obtain average PIC values of 0.26–0.32. The SSR genotyping profiles also aided in the genetic distance matrix-based clustering of sunn hemp germplasm accessions. The ability of these molecular markers to successfully amplify in cross-genera bast fiber crops further demonstrated their effectiveness in genotyping. Thus, the current study describes the identification of previously undisclosed endogenous molecular markers in sunn hemp, which have potential applications in genetic studies and breeding in sunn hemp for bast fiber improvement.

Keywords

• bast fiber
• molecular markers
• intron length polymorphism
• simple sequence repeat
• single nucleotide polymorphism
• sunn hemp