Genome Size Diversity in Rare, Endangered, and Protected Orchids in Poland.

Monika Rewers,Anna Jakubska-Busse,Iwona Jedrzejczyk,Agnieszka Rewicz

doi:10.3390/genes12040563

Abstract

Orchidaceae is one of the largest and the most widespread plant families with many species threatened with extinction. However, only about 1.5% of orchids’ genome sizes have been known so far. The aim of this study was to estimate the genome size of 15 species and one infraspecific taxon of endangered and protected orchids growing wild in Poland to assess their variability and develop additional criterion useful in orchid species identification and characterization. Flow cytometric genome size estimation revealed that investigated orchid species possessed intermediate, large, and very large genomes. The smallest 2C DNA content possessed Liparis loeselii (14.15 pg), while the largest Cypripedium calceolus (82.10 pg). It was confirmed that the genome size is characteristic to the subfamily. Additionally, for four species Epipactis albensis, Ophrys insectifera, Orchis mascula, Orchis militaris and one infraspecific taxon, Epipactis purpurata f. chlorophylla the 2C DNA content has been estimated for the first time. Genome size estimation by flow cytometry proved to be a useful auxiliary method for quick orchid species identification and characterization.

Highlights

The orchid family (Orchidaceae) is one of the largest and the most diverse group of flowering plants with both epiphytic and terrestrial perennial members [1,2,3]
Nearly 800 species are listed as threatened on the International Union for Conservation of Nature (IUCN) [11] Red List and their number is constantly increasing
Variation in nuclear DNA content for the selected orchid species growing wild in Poland is discussed

Summary

Introduction

The orchid family (Orchidaceae) is one of the largest and the most diverse group of flowering plants with both epiphytic and terrestrial perennial members [1,2,3]. The genome size is used in forecasting changes and the evolution of these species that grow in a polluted environment, and in the protection of species with large genomes, whose adaptation to changing climatic conditions is smaller, and more vulnerable to extinction [19,20,21]. This was confirmed by studies of Temsch et al [22] and Vidic et al [23], where only plants with smaller genome sizes survived in polluted conditions. The genome size (2C DNA content) of 15 species and one infraspecific taxon of the Orchidaceae family, being valuable for Polish flora diversity, were determined using flow cytometry. Variation in nuclear DNA content for the selected orchid species growing wild in Poland is discussed

Plant Material

Estimation of 2C DNA Content

Results and Discussion