Development and Application of EST-SSR Markers Related to Lead Stress Responses in Kenaf Based on Transcriptome Sequencing Data

Kenaf is an important bast fiber crop. In order to diversify the available kenaf simple sequence repeat (SSR) molecular markers and generate markers potentially useful for kenaf breeding, we developed expression sequence tag simple sequence repeat (EST-SSR) molecular markers based on lead-stressed kenaf transcriptome sequencing data and spliced unigene sequences. Additionally, the distribution of the SSRs in the transcriptome and the potential functions of the SSR-containing genes were determined. Moreover, SSR markers in the differentially expressed genes (DEGs) of a protein-protein interaction (PPI) network were analyzed to screen for polymorphic markers, which were used to examine the genetic diversity and population structure of kenaf germplasm resources. The genetic diversity and population structure of 138 kenaf germplasm materials revealed that 22 EST-SSR markers could be used to distinguish the kenaf germplasms. The 22 EST-SSR markers enrich the kenaf molecular markers database and provide an important tool for future genetic improvement of kenaf resistance to lead stress.