Sel’skokhozyaistvennaya Biologiya [Agricultural Biology], 2012, № 6, p. 92-99 UDK 633.366:575.17:577.21 MOLECULAR ANALYSIS OF THE GENETIC DIVERSITY OF POPULATIONS OF SWEET CLOVER (Melilotus dentatus Pers.) А. <...> N. Muntyan, V.S. Belova, E.P. Chizhevskaya, M.L. Rumyantseva, B.V. Simarov, E.E. Andronov All-Russia Research and Development Institute for Agricultural Microbiology, RAAS, St. Petersburg-Pushkin 196608, Russia e-mail: eeandr@gmail.com Received May 25, 2012 S u m m a r y In the studies of Melilotus dentatus Pers. populations from different geographically remote areas (North Caucasus and Kazakhstan), a compex approach of intra- and inter-population analysis of taxonomically important molecular markers (ITS) was used. <...> The analysis of receptor gene nfr5 was also made. <...> It is shown that the Melilotus dentatus Pers. plants differ at both intra- and inter-population levels. <...> A consolidation of sweet clover's populations to clusters is observed according to their geographic location. <...> An independent distribution of populations on receptor part of nfr5 gene concerning cluster structure of ITS region is determined. <...> These genes encode LysM-containing receptor kinase, and they have domain structure typical for plants: extracellular LysM-domains – probable participants in the reception of Nod-factor, a transmembrane domain, and an intracellular domain of serine / threonine kinase. <...> Phylogenetic analysis has shown that some sequences of bacterial LysM-motifs have common roots with nucleotide sequences of fungi, plants, insects and animals. <...> A structural resemblance of LysM-containing protein kinase and the peptidogycan component of bacterial cell wall confirms the involvement of receptor proteins NFR1 and NFR5 in the recognition of Nod-factor and its transfer to following links of a signaling cascade leading to nodulation (7). <...> The purpose of this research was molecular analysis of genetic variation in sweet clover (Melilotus dentatus Pers.) samples collected in different geographically remote areas (Sub-Aral region and the Northern Caucasus). <...> Genomic DNA was isolated from 2-day-old seedlings by chloroform extraction with CTAB-buffer (9). <...> The plant material was thoroughly homogenized, then suspended in CTAB and incubated at 65 C for 60 min. After the chloroform extraction, a supernatant containing DNA was precipitated with an equal volume of isopropanol and then washed with 70% ethanol <...>