Development and characterization of EST-SSR markers for Catalpa bungei (Bignoniaceae).

PREMISE OF THE STUDY: Catalpa bungei (Bignoniaceae) is a deciduous tree native to China. We developed microsatellite markers for C. bungei to investigate its population genetics.

METHODS AND RESULTS: One hundred seventy-seven expressed sequence tag (EST)-simple sequence repeat (SSR) primer pairs were isolated and characterized using next-generation sequencing. Thirty of these primer pairs were polymorphic loci in 52 individuals of C. bungei. The number of alleles ranged from two to 18 with observed and expected heterozygosity values of 0.05-1.00 and 0.18-0.95, respectively. The fixation index ranged from -1.00 to 1.00 with an average of 0.32. No linkage disequilibrium was detected in any pair of loci. All markers showed good amplification results in four species (C. bungei, C. fargesii, C. duclouxii, and C. ovata) except three loci.

CONCLUSIONS: These polymorphic markers are expected to be helpful in further studies on the systematics and phylogeography of C. bungei and related species.