Evaluation of genetic diversity of toxicodendron vernicifluum planted in Japan using est-ssr and genetic SSR markers

Genetic diversity of Toxicodendron vernicifluum trees planted in Japan was evaluated using two types of simple sequence repeat (SSR) markers: expressed sequenced tag (EST)-SSRs and genomic SSRs. ESTs were isolated from two T. vernicifluum clones using nextgeneration sequencing. Twenty-one primer pairs were designed to amplify ESTs with an SSR region, which is a 2-3 bp repeat motif, and eight EST-SSR markers were developed. These eight EST-SSR markers and seven genomic SSR markers were used to characterize genetic diversity and genetic structure among nine stands of T. vernicifluum planted in Japan. This species was introduced into Japan from wild populations in ancient times. It is easy to clone this species using root cuttings, and the loss of genetic diversity within the T. vernicifluum stands had become a concern. However, some analyses indicated that most of the stands in Japan retained genetic diversity, slightly higher than that of T. succedaneum, a closely related species. Moreover, genetic structure among stands was caused by transfer of seedlings. The risk of genetic bottleneck, resulting in reduced genetic diversity among the T. vernicifluum stands planted in Japan, is low. If the T. vernicifluum trees stands in Japan are suitably managed at present, this valuable genetic resource may not be at risk for extinction.