Exploring Genetic Diversity and Inter-/Intraspecific Polymorphism in Rheum sp. (Polygonaceae) Using the iPBS Retrotransposon Marker System

This study investigated interspecific and intraspecific polymorphism in <i>Rheum</i> (Polygonaceae) from Kazakhstan using the inter-primer binding site (iPBS) retrotransposon marker system. The results revealed considerable variation in the level and nature of genetic polymorphism both within and among <i>Rheum</i> species and ecopopulations across different regions of Kazakhstan. <i>Rh. compactum</i> and the ecopopulation <i>Rh. tataricum</i> from the Zhambyl Region (ZH) exhibited the lowest levels of polymorphism, supporting their designation as conservation priorities. Genetic differentiation analysis among species and ecopopulations identified clear distinctions, resulting in the formation of well-defined clusters with high bootstrap support. Minimal genetic distances were observed between the two ecopopulations of <i>Rh. tataricum</i>, along with a high degree of intraspecific genetic homogeneity in <i>Rh. compactum</i> and <i>Rh. nanum</i>. A distinct genetic divergence between <i>Rh. compactum</i> and the other taxa was detected, reinforcing its status as a separate species rather than a synonym of <i>Rh. altaicum</i>. The iPBS markers proved effective for investigating genetic variation in <i>Rheum</i>, offering valuable insights for future studies aimed at understanding the evolutionary history of the genus.