[Organization of rRNA genes in various tribes of plants in the cereal family (Poaceae barnh.)].

The organization of 18S and 26S rRNA in 14 plant species, belonging to 8 tribes of the cereal family was studied. In rDNA of all the cereals studied, except maize and reed, the similar character of localization of nucleotide sequences, recognized by restrictases BamHI and EcoRI in 18S and 26S rRNA genes was revealed. The structural organization of rDNA of sainfoin (Papilionaceae) was shown to differ from genes, coding for high molecular rRNA in cereals. The primary structure of subrepeat of non-transcribed rDNA spacer of diploid wheat Tr. urartu, consisting of 132 base pairs was determined. The given subrepeat was hybridized with BamHI-fragments of DNA from cereals and sainfoin. It is shown to hybridize with rDNA of all the cereals studied, and it hardly hybridizes with rDNA of maize and sorghum, but doesn't hybridize with rDNA of sainfoin. The conclusion is made that the size polymorphism of restriction fragments in the coding rDNA region and the level of similarity of subrepeats of rDNA of the non-transcribed spacer may help to reveal the phylogenetic affinity of plants, belonging to different tribes within one family.