Molecular-cytogenetic analysis of diploid wheatgrass Thinopyrum bessarabicum (Savul. and Rayss) A. Löve

Ekaterina D Badaeva; Sergei A Surzhikov; Alexander V Agafonov

doi:10.3897/CompCytogen.v13i4.36879

Molecular-cytogenetic analysis of diploid wheatgrass Thinopyrum bessarabicum (Savul. and Rayss) A. Löve

Comp Cytogenet. 2019 Dec 3;13(4):389-402. doi: 10.3897/CompCytogen.v13i4.36879. eCollection 2019.

Authors

Ekaterina D Badaeva^{1

2}, Sergei A Surzhikov², Alexander V Agafonov³

Affiliations

¹ N.I. Vavilov Institute of General Genetics, Russian Academy of Sciences. Gubkina str. 3, Moscow 117333, Russia Engelhardt Institute of Molecular Biology, Russian Academy of Sciences Moscow Russia.
² Engelhardt Institute of Molecular Biology, Russian Academy of Sciences. Vavilova str. 34, Moscow 117334, Russia N.I. Vavilov Institute of General Genetics, Russian Academy of Sciences Moscow Russia.
³ Central Siberian Botanical Garden, Russian Academy of Sciences, Siberian Branch, Zolotodolinskaya st., 101, Novosibirsk 630090, Russia Central Siberian Botanical Garden, Russian Academy of Sciences Novosibirsk Russia.

Abstract

Thinopyrum bessarabicum (T. Săvulescu & T. Rayss, 1923) A. Löve, 1980 is diploid (2n=2x=14, JJ or E^bE^b), perennial self-fertilizing rhizomatous maritime beach grass, which is phylogenetically close to another diploid wheatgrass species, Agropyron elongatum (N. Host, 1797) P. de Beauvois, 1812. The detailed karyotype of Th. bessarabicum was constructed based on FISH with six DNA probes representing 5S and 45S rRNA gene families and four tandem repeats. We found that the combination of pAesp_SAT86 (= pTa-713) probe with pSc119.2 or pAs1/ pTa-535 allows the precise identification of all J-genome chromosomes. Comparison of our data with the results of other authors showed that karyotypically Th. bessarabicum is distinct from A. elongatum. On the other hand, differences between the J-genome chromosomes of Th. bessarabicum and the chromosomes of hexaploid Th. intermedium (N. Host, 1797) M. Barkworth & D.R. Dewey, 1985 and decaploid Th. ponticum (J. Podpěra, 1902) Z.-W. Liu & R.-C. Wang, 1993 in the distribution of rDNA loci and hybridization patterns of pSc119.2 and pAs1 probes could be an indicative of (1) this diploid species was probably not involved in the origin of these polyploids or (2) it could has contributed the J-genome to Th. intermedium and Th. ponticum, but it was substantially modified over the course of speciation.

Keywords: Chromosome; FISH-karyotyping; J genome; Thinopyrum bessarabicum; evolution; rRNA gene distribution.

Ekaterina D. Badaeva, Sergei A. Surzhikov, Alexander V. Agafonov.