Biology subjects

Dmitriev, A. A.

Publications and source records attributed to Dmitriev, A. A..

2 recordsLinked to original sources

bioRxiv2026

A Unique Type V CRISPR-Cas System Encoded by a Group of Thermus Viruses

CRISPR-Cas are widespread adaptive immune systems that protect bacteria and archaea from mobile genetic elements such as bacteriophages. Metagenomic sequencing identified CRISPR-Cas systems in phage genomes; however, their functions remain largely unknown. Here, we present Cas12r-CRISPR, a novel type V CRISPR-Cas system encoded by Lalka phages infecting thermophilic Thermus bacteria. We determined Cas12r-CRISPR PAM consensus sequence and crRNA structure and showed, that when provided with appropriate spacers and expressed in Thermus thermophilus, Cas12r-CRISPR efficiently interferes with plasmid transformation as well as infection by diverse Thermus phages. In the course of Lalka phage infection, the Cas12r-CRISPR locus is expressed with middle phage genes and its transcripts are among the most abundant phage RNAs. Notably, most Cas12r-CRISPR spacers target integrative mobile elements widespread in Thermus genomes. Both Lalka phages and targeted integrative mobile elements use host tRNA genes as attachment sites. We therefore propose that Cas12r-CRISPR participates in an inter-MGEs conflict. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/719267v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@f90c35org.highwire.dtl.DTLVardef@90a063org.highwire.dtl.DTLVardef@111f936org.highwire.dtl.DTLVardef@1008132_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2024

Genetic Diversity of Hippophae rhamnoides Varieties with Different Fruit Characteristics

Hippophae rhamnoides is a valuable crop whose fruits are rich in bioactive compounds with health benefits. To date, there is a lack of genetic data for varieties of sea buckthorn. This fact hinders the identification of genetic determinants of valuable traits and limits the efficiency of breeding. In the present study, we analyzed a representative set of 55 valuable H. rhamnoides varieties of Russian breeding with different fruit characteristics and diverse lineages. Whole-genome sequencing was performed on the Illumina platform and at least 25x genome coverage was obtained for each accession. Based on the sequencing data, DNA polymorphisms were identified in genome regions corresponding to genes. These polymorphisms were used to evaluate the genetic relationships of the studied sea buckthorn varieties. We revealed genetically distinct groups of accessions that mostly corresponded to the lineages of the genotypes. Our data are important for assessing the effect of selection on sea buckthorn diversity and for evaluating the genetic relationship of different varieties, which is useful for breeders when selecting parental forms for crosses. The obtained information on DNA polymorphisms is also necessary to study the diversity of genes, including those that may determine valuable sea buckthorn traits, including fruit characteristics. Thus, our data can benefit both basic and applied research on sea buckthorn.

genetics↗