Polymorphism of ITS sequences in 35S rRNA genes in Elymus dahuricus aggregate species: two cryptic species?

• Published in: Vavilov Journal of Genetics and Breeding
• Main Authors: A. V. Rodionov, K. S. Dobryakova, N. N. Nosov, A. A. Gnutikov, E. O. Punina, A. A. Kriukov, V. S. Shneyer, А. В. Родионов, К. С. Добрякова, Н. Н. Носов, А. А. Гнутиков, Е. О. Пунина, А. А. Крюков, В. С. Шнеер
• Other Authors: We thank N.N. Tzvelev of the Komarov Botanical Institute and N.S. Probatova of the Federal Scientific Center of the East Asia Terrestrial Biodiversity, Far Eastern Branch of the Russian Academy of Sciences for their interest to the work and expert help in the taxonomic identification of Elymus species. The authors also would like to acknowledge the funding by the Russian Foundation for Basic Research Projects No. 15-04-06438 and 18-04-01040 as well as the Ministry of Education and Sciences of the Russian Federation (АААА-А18-118040290161-3, 0126-2016-0001, BIN RAS). The research was done using equipment of The Core Facilities Center “Cell and Molecular Technologies in Plant Science” at the Komarov Botanical Institute RAS (St. Petersburg, Russia).
• Format: Article in Journal/Newspaper
• Language: English
• Published: Institute of Cytology and Genetics of Siberian Branch of the RAS 2019
• Subjects: Triticeae; interspecific hybridization; rDNA; 35S rRNA; межвидовая гибридизация; 35S рРНК; Chukotka; Yakutia; Siberia
• Online Access: https://vavilov.elpub.ru/jour/article/view/2020; https://doi.org/10.18699/VJ19.493

Nuclear ribosomal internal transcribed spacer (ITS) sequences were sequenced for 23 species and subspecies of Elymus sensu lato collected in Russia. The Neighbor-Net analysis of ITS sequences suggested that there are four ribotypes called Core Northern St-rDNA, Core Southern St-rDNA, Northern dahuricus St-rDNA and Southern dahuricus St-rDNA. The Core Southern variant of St-rDNA is closely related to rDNA of diploid Pseudoroegneria stipifolia (PI 313960) and P. spicata (PI 547161). The Core Northern St-rDNA is closely related to rDNA of P. cognata (PI 531720), a diploid species of Kyrgyzstan carrying StY variant of the St genome. The Core Northern St-rDNA is widespread among the Elymus species of Siberia and the Far East, including Yakutia and Chukotka. The Core Southern St-ribotype is typical of southern Elymus and Pseudoroegneria of the South Caucasus, Primorye, Pakistan, and South Korea. The Northern dahuricus St-ribotype and Southern dahuricus St-ribotype are derivatives of the Core Northern and Core Southern St-ribotypes, correspondingly. Both of them were found in all four studied species of the E. dahuricus aggregate: E. dahuricus Turcz. ex Griseb., E. franchetii Kitag., E. excelsus Turcz. ex Griseb. and Himalayan E. tangutorum (Nevski) Hand.-Mazz. In other words, there are at least two population groups (two races) of the Elymus dahuricus aggregate species that consistently differ in their ITS-sequences in Siberia, the Far East and Northern China. Each contains all morphological forms, which taxonomists now attribute either to different species of E. dahuricus aggr. (E. dahuricus sensu stricto, E. franchetii, E. tangutorum, E. excelsus) or subspecies of Campeiostachys dahurica (Turcz. ex Griseb.) B.R. Baum, J.L. Yang et C.C. Yen. At the moment it is unknown if there are any morphological differences between plants carrying either Northern or Southern dahuricus rDNA. Probably, they are cryptic species, but it is certain that if differences in morphology between the two races exist, they are not associated ...