Genetic diversity and genetic structure of Corydalis tomentella Franch. (Papaveraceae), an endangered herb species from Central China

Abstract Corydalis tomentella Franch. (Papaveraceae), a species endemic to Central China, occurs within specialized habitats of limestone cliffs. To date, extensive harvesting by local people for medical use has led to a sharp decline in wild populations of this plant. To investigate the genetic diversity and genetic structure of the species, differences in the composition of one nuclear DNA (nDNA) locus (NADPH) and two chloroplast DNA (cpDNA) fragments ( trnH-psbA and trnG introns) from wild populations of this plant were analysed. Six chlorotypes and 17 nuclear genotypes were identified in a survey of 8 populations distributed in the current geographic regions of C. tomentella . Two cpDNA haplotypes were shared in two present distribution regions, Shennongjia and Nanchuan in Central China, while there were no similar nDNA genotypes in these regions. As a whole, Shennongjia's populations had greater gene diversity than found in Nanchuan's population of C. tomentella. Greater population differentiation was also detected along with low gene flow in the distribution regions. This may result from the plants predominantly self-mating system, the short-distance dispersal system associated with the plant, and the specific habitat requirements for growth. These data suggest that Shennongjia region should be regarded as the priority area for conservation of C. tomentella due to its greater diversity of this plant found there.