Genetic characterisation of sexually and parthenogenetically reproductive populations of Chara canescens (Charophyceae) using AFLP, rbcL, and SNP markers

Parthenogenetically reproducing Chara canescens (Charophyceae) populations have been described from several European locations. Sexually reproducing populations with female and male individuals are known only from the Neusiedler See located in Seewinkel National Park, Austria. Sexual and parthenogenetic populations probably coexist in this area, but no morphological attribute is known to differentiate between females of the two reproductive modes. To find markers associated with parthenogenesis, DNA samples from individuals of both reproductive modes were screened via amplified fragment length polymorphism (AFLP) analysis. Although no unique monomorphic loci for the reproduction systems could be identified, neighbour-joining analysis separated the individuals into two groups representing the two reproductive modes. The rbcL gene sequence analysis also revealed two nucleotide differences among these groups. Sequence characterization of the flanking region of one microsatellite locus from C. canescens individuals identified one insertion/deletion (indel) between the reproductive modes. This indel was converted via polymerase chain reaction into a marker associated with sexual reproduction. Further analysis of the AFLP data showed a high level of polymorphism and genetic diversity between and within populations of the reproductive modes. A larger sample size is needed to confirm the gene pool cluster and the degree of genetic diversity between the reproductive modes finally, but the successful development of a promising marker system for the reproduction mode provides a tool for future research to characterise geographical parthenogenesis of C. canescens in detail.