Pyrola japonica s.l. has at least three separate genetic lineages that have different leaf morphologies. The genetic lineages and their coexistence could have led to the variable leaf size and suggest the possibility that gene flow from partial to full mycoheterotrophs could reverse the evolutionary transition to full mycoheterotrophy.

Gastrodia is the most species-rich genus among mycoheterotrophic plants, and is thus an essential taxon to understand the mechanism of species diversification in mycoheterotrophs. In this study, we developed microsatellite markers with high transferability for four Gastrodia species to examine genetic differentiation and similarity among species, populations and individuals. The 12 microsatellite markers developed from a G. fontinalis library showed high transferability for the ramets that identified G. nipponica, G. kuroshimensis and G. takeshimensis. In addition to the high transferability of these markers, we observed low allele variation within a sampled population of each species and allele differences among the four species. The 12 markers described here will be useful for investigating the genetic differences among and within the Gastrodia species, which evolved by a limitation of gene flow.

We developed microsatellite markers to compare the genetic variation between the putatively cleistogamous Gastrodia takeshimensis (Orchidaceae) and its chasmogamous sister species G. nipponica. We expected low genetic variation in G. takeshimensis in view of its hypothesized cleistogamy. Eighteen primer pairs were developed from a G. takeshimensis genomic DNA library, and their characteristics were tested for G. takeshimensis and G. nipponica. Seven loci were polymorphic in G. nipponica, whereas all loci showed no polymorphism in G. takeshimensis. Genetic diversity was thus not detected in G. takeshimensis, and it seems to have been lost by repeated selfing in the completely closed flower. The 18 markers described here will be useful for investigating the genetic variation between a cleistogamous species and its chasmogamous sister species.