Development and significance of RAPD-SCAR markers for the identification of Litchi chinensis Sonn: by improved RAPD amplification and molecular cloning
Background Analysis of genetic diversity is important for the authentication of a species. Litchi (Litchi chinensis Sonn.) is a subtropical evergreen tree. Recently, L. chinensis has been characterized by an improved random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) analysis. The goal of this study was to develop sequence-characterized amplified region (SCAR) markers from the improved RAPD fragments for the genetic analysis of L. chinensis. Results The improved RAPD fragments from L. chinensis were cloned, sequenced and converted into stable SCAR markers. Sequencing of three cloned RAPD fragments revealed that the clone L7-16 consisted of 222 nucleotides (GenBank accession number KM235222), clone L9-6 consisted of 648 nucleotides (GenBank accession number KM235223), and clone L11-26 consisted of 369 nucleotides (GenBank accession number KM235224). Then, specific primers for SCAR markers L7-16, L9-6, and L11-26 were designed and synthesized. PCR amplification was performed using DNA templates from 24 different samples, including 6 samples of L. chinensis and other plants. The SCAR marker L9-6 was specific for all of the L. chinensis samples, the SCAR marker L11-26 specific for five L. chinensis samples, and the SCAR marker L7-16 only specific for the samples from Luzhou. Conclusions This study developed stable SCAR markers for the identification of L. chinensis by the cloning of the improved RAPD fragments. Combining RAPD and SCAR markers provides a simple and reliable tool for the genetic characterization of plant species.