Isoenzyme variation and genetic affinities among five Festuca species of section Aulaxyper Dumort.

Abstract

Despite a considerable number of taxonomical and biosystematic studies of genus Festuca L. in Europe , there are few papers discussing phylogeny and systematic of genus Festuca as well the evolution of its different groups. The most important among them are the studies of N. Tzvelev , who proposed three sections within type subgenus Festuca : Variae Hack., Aulaxyper Dumort. and Festuca . There are many studies on species belonging to section Festuca , including chemosystematic ones , but the species of section Aulaxyper are rather neglected. For this reason we choose F. rubra L., F. nigrescens Lam., F. picturata Pils., F. amethystina L. and F. heterophylla Lam. , which belong to section Aulaxyper . The aim of the study was to examine the isoenzyme variation and to evaluate the genetic affinities among the above-listed species of genus Festuca . Ten natural Bulgarian populations were examined . The isoforms of enzymes glutamate-oxaloacetate transaminase, malate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase were resolved by polyacrylamide gel electrophoresis. Based on mean allelic frequencies/locus/taxon, genetic identities (I) values for all pair-wise comparisons among the studied species were calculated . The group of F. rubra s.l. is more primitive compared to F. ovina s.l. and has sheaths closed nearly to the mouth while the sheaths of species of section Festuca are closed to the base. Festuca amethystina occupies an intermediate position as its sheaths are closed for 1/3-1/2 of their length. This character indicates for its specific position within section Aulaxyper and isolates it from the rest taxa of the group. Our results confirmed its peculiar position within section Aulaxyper. Festuca heterophylla at the same time includes both primitive traits which are specific for the ancient species of genus Festuca , and the number of highly-specialized characters. The obtained molecular data confirm a peculiar position of F. heterophylla within genus Festuca . On the contrary, the closely related to F. rubra polyploids, namely F. nigrescens and F. picturata should be considered as more recent “new” species. Festuca amethystina showed the greatest divergence and should be considered also as an ancient species. Despite a considerable number of taxonomical and biosystematic studies of genus Festuca L. in Europe, there are few papers discussing phylogeny and systematic of genus Festuca as well the evolution of its different groups. The most important among them are the studies of N. Tzvelev, who proposed three sections within type subgenus Festuca: Variae Hack., Aulaxyper Dumort. and Festuca. There are many studies on species belonging to section Festuca, including chemosystematic ones, but the species of section Aulaxyper are rather neglected. For this reason we choose F. rubra L., F. nigrescens Lam., F. picturata Pils., F. amethystina L. and F. heterophylla Lam., which belong to section Aulaxyper. The aim of the study was to examine the isoenzyme variation and to evaluate the genetic affinities among the above-listed species of genus Festuca. Ten natural Bulgarian populations were examined. The isoforms of enzymes glutamate-oxaloacetate transaminase, malate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase were resolved by polyacrylamide gel electrophoresis. Based on mean allelic frequencies/locus/taxon, genetic identities (I) values for all pair-wise comparisons among the studied species were calculated. The group of F. rubra s.l. is more primitive compared to F. ovina s.l. and has sheaths closed nearly to the mouth while the sheaths of species of section Festuca are closed to the base. Festuca amethystina occupies an intermediate position as its sheaths are closed for 1/3-1/2 of their length. This character indicates for its specific position within section Aulaxyper and isolates it from the rest taxa of the group. Our results confirmed its peculiar position within section Aulaxyper. Festuca heterophylla at the same time includes both primitive traits which are specific for the ancient species of genus Festuca, and the number of highly-specialized characters. The obtained molecular data confirm a peculiar position of F. heterophylla within genus Festuca. On the contrary, the closely related to F. rubra polyploids, namely F. nigrescens and F. picturata should be considered as more recent “new” species. Festuca amethystina showed the greatest divergence and should be considered also as an ancient species.