Could somaclonal variation play advantageous role in ex situ endangered species conservation?- case study on Viola stagnina

In vitro regeneration of Viola stagnina Kit., an endangered species, was successfully obtained based on the newly developed protocol using organogenesis and rooting of shoots. Regenerated plantlets had the same genome size estimated by flow cytometry as initial material and plants from natural populations. Obtained in tissue cultures plants developed chasmogamous flowers with highly viable pollen grains, cleistogamous flowers, and set seeds from both flower types during cultivation at experimental plots. ISSR markers revealed among in vitro recovered plants, individuals ‘true-to-type’ and plants genetically distant from initial plant. It was also showed that somaclonal variation is present at some degree in nearly all of the regenerated plant groups but with relatively small number of punctual mutations in most cases. Genetic indices (number of genotypes, polymorphic markers, gene diversity, total gene diversity, mean gene diversity) were lower in all groups of clones than in natural populations of this species. We conclude that producing genetically identical somaclones as ex situ conservation technique might have a negative impact on population genetic structure. Uniform genotypes reduce genetic diversity of population. Introduction into the natural habitats diverse genetic micropropagated plantlets of V. stagnina, covering natural genetic diversity, will maintain the genetic variation of this species population. Regenerated in vitro plants are a good source of material for re-introdution. This is the first report of a successfully developed micropropagation protocol of V. stagnina, and the first detailed genetic analysis of recovered plants with the use of ISSR markers and genome size measurements.