Broussonetia × hanjiana (Moraceae) microsatellite markers for species and ploidy determination developed using...

Broussonetia × hanjiana has been considered a hybrid owing to its morphology, which is intermediate between that of B. papyrifera (L.) L'Her. ex Vent. and B. kazinoki Siebold. A recent study demonstrated the hybrid origin of B. × hanjiana in Korea using molecular markers. In this study, we developed microsatellite markers for B. × hanjiana using next-generation sequencing and cross-species transferability analysis.

A total of 432 primers were designed from 205,819 contigs. Among them, 24 microsatellite markers showing polymorphisms were used to evaluate the population genetic characteristics. The observed heterozygosity (H_O) and expected heterozygosity (H_E) were 0.835 and 0.628, respectively. The cross-species transferability of these markers was evaluated in two closely related species of Broussonetia; all 24 markers showed cross-species amplification. Using flow cytometry, diploid and triploid individuals were identified in B. × hanjiana. In particular, the BR137 marker showed evidence of two parent species (B. papyripera and B. kazinoki), with a hybrid pattern observed in B. × hanjiana, demonstrating its utility for species identification and ploidy assessment.

The new B. × hanjiana microsatellite markers can be useful in genetic studies of closely related B. papyripera, B. kazinoki, and B. × hanjiana.