Genetic diversity and population structure of Lamiophlomis rotata (Lamiaceae), an endemic species of Qinghai-Tibet Plateau.

Lamiophlomis rotata (Lamiaceae), a perennial medicinal herb, is endemic to the Qinghai-Tibet Plateau. A total of 188 individuals from eight natural populations of L. rotata in Qinghai-Tibet Plateau (four from Tibet, two from Yunnan, and two from Qinghai) were analyzed using intersimple sequence repeats (ISSR) and randomly amplified polymorphic DNA (RAPD) techniques. Our results revealed that the level of genetic variation in L. rotata was relatively high (P = 94.85%, I = 0.440 +/- 0.220, H(T) = 0.289 +/- 0.028). Three genetic groups corresponding to the three geographic regions were detected, suggesting significant geographic structure. Our results suggest that the highly structured geographic pattern found in L. rotata might represent diverging evolutionary processes associated with the uplifting of the Qinghai-Tibet Plateau and Quaternary climatic oscillations. These findings imply that as many populations as possible should be preserved in situ for the conservation of this species. Given their genetic variability and peripheral distribution, Qinghai and Yunnan populations should be assigned priority for conservation. Optimal harvesting strategies, domestication and tissue culture of L. rotata should be developed as soon as possible to guarantee its sustainable use.