Powdery mildew resistance of apple clonal rootstocks from the collection of the Michurinsk State Agrarian University.

Apple clonal rootstocks are the basis of modern intensive horticulture, providing a rapid increase in yield and convenience of fruit trees cultivation. Production of clonal rootstocks under high humidity often causes powdery mildew infection caused by the pathogenic fungus Podosphaera leucotricha Salm., which significantly reduces the productivity of stoolbed. Growing powdery mildew resistant genotypes is the most appropriate way to combat this disease and allows reducing the use of fungicides. To accelerate the search for resistant forms, molecular markers associated with resistance genes have been developed. However, these markers have not been used to study clonal rootstocks. The aims of the work were the field assessment of powdery mildew resistance of apple clonal rootstocks from the collection of the Michurinsk State Agrarian University and the screening of the collection for Pl-1, Pl-2, Pl-w and Pl-d resistance genes. The results of a three-year field evaluation of powdery mildew resistance of 80 rootstocks allowed us to distinguish five main groups ranging from very low to highly resistant. A group of 57 accessions was classified as powdery mildew resistant. The search for resistance genes was performed using the AT20 SCAR (Pl-1 gene), OPU02 SCAR (Pl- 2 gene), EM DM01 (Pl-d gene), and EM M02 (Pl-w gene) markers. The Pl-d and Pl-1 genes identified in 33 (41.25 %) and 31 (38.75 %) accessions, respectively, were the most common in the collection. The Pl-w gene was detected only in two accessions. Identification of the Pl-2 gene with the OPU02 SCAR marker did not reveal a fragment of the expected size. Thirty accessions with different powdery mildew resistance scores had two genes, Pl-1 and Pl-d, and highly resistant forms G16 and 14-1 had a combination of the Pl-d and Pl-w genes. These accessions can be used as donors of powdery mildew resistance for breeding new apple clonal rootstocks.

Safe Use of Genetic Technologies.

The prospects and problems of the development of modern genetic technologies are analyzed, and pressing issues of updating the regulatory framework for the safe use of their products are posed in this article, which is based on the materials of reports at the RAS Presidium meeting on December 7, 2021. At the end of 2018, by Presidential Decree no. 680 On the Development of Genetic Technologies in the Russian Federation, this R&D area was declared a priority. According to the authors, to expand genetic technologies in Russia, it is necessary to change the concept of their legal regulation and to bring the legislative norms in line with the current level of the development of science in this area, including the adjustment of the genetic engineering nomenclature.

[Analysis of microsatellite loci variability in rare and endemic species Allium regelianum A.K. Becker ex Iljin].

SSR analysis of rare and endemic species Allium regelianum, which grows in the south of Russia, was performed for the first time. Variability analysis of 88 accessions of A. regelianum was carried out using four highly polymorphic microsatellite loci (PIC value ranged from 0.55 to 0.72). SSR-analysis made it possible to revealed polymorphism within and among the populations of A. regelianum from Volgograd region. Analysis of Wright's F-statistics and the analysis of molecular variance showed that more than 90% of total genetic variation of the species was attributed to the differences within the populations and less than 10% of the differences were found among the populations. Cluster analysis of 46 accessions of A. regelianum from three populations of Volgograd region and principal coordinate analysis of all accessions did not reveal differentiation among the populations.

[Analysis of the ITS1/ITS2 nuclear spacers and the secondary structure of 5.8S rRNA gene in endemic species Bellevalia sarmatica (Pall. ex Georgi) Woronow and related species of the subfamily scilloideae].

Sequence variability of the ITS spacers and 5.8S rRNA gene was examined in 11 accessions of the subfamily Scilloideae, including seven accessions of rare and endangered species Bellevalia sarmatica from Volgograd region. The intraspecific polymorphism level of the examined ITS1­5.8S­ITS2 sequence of B. sarmatica accessions constituted 1.3%. The phylogenetic position of B. sarmatica within the genus Bellevalia was determined. It was demonstrated that B. sarmatica belonged to the section Nutantes, and the most closely related species were B. webbiana and B. dubia. Nucleotide substitutions in the 5.8S rRNA gene sequence of the analyzed Scilloideae accessions were identified and studied. The predicted secondary structure of 5.8S rRNA gene was constructed. It was demonstrated that in the examined accessions, mutations in the 5.8S rRNA gene were mainly localized in the third hairpin region and had no effect on the secondary structure of the 5.8S rRNA molecule.

[Genetic diversity of common wheat varieties at the gliadin-coding loci].

One hundred and fifty Russian and foreign winter common wheat varieties were examined by the PAGE method. A total of 70 alleles were identified at seven gliadin-coding loci. It was demonstrated that 42% of varieties were heterogeneous, i.e., were represented by a number of genotypes, while 52% of varieties were homogeneous. A unique combination of gliadin alleles was typical of 91.3% of examined varieties, while 8.7% of varieties had identical alleles of all gliadin-coding loci and were indistinguishable. Frequent and rare alleles were identified, with the former accounting for 18.6% of all alleles. It was demonstrated that allelic diversity at the Gli-2 loci (47 alleles) was almost twice that at the Gli-1 loci (23 loci) and was determined by the number of rare alleles. New alleles for the winter common wheat, including three alleles of the GliA2 locus and two alleles of the Gli-B2 locus, were determined. A tendency toward a reduction of the genetic diversity level in modern varieties, which was due to the use of identical parental varieties in breeding programs, was identified.

[AFLP Analysis of Genetic Diversity in the Genus Mallus Mill. (Apple)].

The first molecular genetic analysis of the apple species and varieties from Russian collections with the AFLP marker system was performed in order to study the genetic diversity of the genus Malus, as well as to clarify the phylogeny and solve some systematic issues of the genus. Nienty-one apple accessions, including species from five sections of the genus Malus and hybrid species, were examined. The level of polymorphism constituted 90.2%. It was demonstrated that the classical taxonomy of the genus Malus, which identifies five sections based on differences in their morphological characters, is valid and may be used to classify apple species. The species assignment of the Antonovka landraces was established. All of them belonged to the species M. domestica. It was demonstrated that the Yakutskaya apple variety was a domesticated species of the section Gymnomeles, presumably, M. baccata. AFLP analysis confirmed the hybrid nature of many species. The relationships between apple varieties of the Golden group with American wild species were demonstrated. The data suggest that the species M. sieversii was the ancestor of not only the domestic apple but also of other species of the Malus sections.

[Sorbitol-6-Phosphate Dehydrogenase Gene Polymorhism in Malus Mill. (Rosaceae)].

The sorbitol-6-phosphate dehydrogenase gene (S6PDH) sequences of six representatives of the genus Malus, which belong to five different taxonomic sections, were examined for the first time. The exon-intron structure and polymorphism of the nucleotide and amino acid sequences of these genes was characterized. The intraspecific polymorphism of the S6PDH gene was assessed for the first time in 40 Russian and foreign apple (Malus domestica) cultivars. It was demonstrated that the interspecific polymorphism level of the S6PDH coding sequences in the studied. representatives of the genus Malus was 4%, and the intraspecific polymorphism level of M. domestica cultivars was very low, constituting 0.96%.

[Interspecific polymorphism of the glucosyltransferase domain of the sucrose synthase gene in the genus Malus and related species of Rosaceae].

The sequences that encode the main functional glucosyltransferase domain of sucrose synthase genes have been identified for the first time in 14 species of the genus Malus and related species of the family Rosaceae, and their polymorphism was investigated. Single nucleotide substitutions leading to amino acid substitutions in the protein sequence, including the conservative transmembrane motif sequence common to all sucrose synthase genes of higher plants, were detected in the studied sequences.

[Analysis of sequences of ITS1 internal transcribed spacer and 5.8S ribosome gene of Malus species].

The nucleotide sequence of the ITS1-5.8S ribosomal DNA spacer fragment was determined for 41 samples of the Malus species. The total length of compared sequences ranged from 389 to 392 bp. The nucleotide sequence of the 5.8S gene within the genus was highly conserved. The level of polymorphism of ITS 1 region comprised 14%. Both species- and group-specific substitutions were identified. The analysis of M. orientalis and M. turkmenorum sequences revealed their full identity, which indicates the need to perform more research with a larger number of samples of both species from other collections to clarify the taxonomic status of the M. turkmenorum species. The previous findings on the synonymy of species M. baccata, M. mandshurica, M. pallasiana, and M. sachalinensis were also confirmed.

Catalogue of alleles of gliadin-coding loci in durum wheat (Triticum durum Desf.).

Gliadins are seed storage proteins which are characterized by high intervarietal polymorphism and can be used as genetic markers. As a result of our work, a considerably extended catalogue of allelic variants of gliadin component blocks was compiled for durum wheat; 74 allelic variants for four gliadin-coding loci were identified for the first time. The extended catalogue includes a total of 131 allelic variants: 16 for locus Gli-A1(d), 19 for locus Gli-B1(d), 41 for locus Gli-A2(d), and 55 for locus Gli-B2(d). The electrophoretic pattern of the standard cultivar and a diagram are provided for every block identified. The number of alleles per family is quite small for loci Gli-A1(d) and Gli-B1(d) of durum wheat, as contrasted to loci Gli-A2(d) and Gli-B2(d) that are characterized by large families including many alleles. The presence of large block families determines a higher diversity of durum wheat for loci Gli-A2(d) and Gli-B2(d) as compared to Gli-A1(d) and Gli-B1(d). The catalogue of allelic variants of gliadin component blocks can be used by seed farmers to identify durum wheat cultivars and evaluate their purity; by breeders, to obtain homogenous cultivars and control the initial stages of selection; by gene bank experts, to preserve native varieties and the original biotypic composition of cultivars.

Antifungal activity of storage 2S albumins from seeds of the invasive weed dandelion Taraxacum officinale Wigg.

In this work, we isolated and characterized novel antifungal proteins from seeds of dandelion (Taraxacum officinale Wigg.). We showed that they are represented by five isoforms, each consisting of two disulphide-bonded large and small subunits. One of them, To-A1 was studied in detail, including N-terminal amino acid sequencing of both subunits, and shown to display sequence homology with the sunflower 2S albumin. Using different assays we demonstrated that dandelion 2S albumins possess inhibitory activity against phytopathogenic fungi and the oomycete Phytophtora infestans at micromolar concentrations with various isoforms differing in their antifungal activity. Thus, 2S albumins of dandelion seeds represent a novel example of storage proteins with defense functions.

Analysis of phylogenetic relations of durum, carthlicum and common wheats by means of comparison of alleles of gliadin-coding loci.

Polymorphism and inheritance of wheat storage protein, gliadin, of durum (macaroni) and carthlicum wheats have been studied. Analysis of gliadin in 78 cultivars and in F2 seeds of intercultivar crosses of durum wheat revealed three different chromosome 1A-encoded blocks of components similar to those found in common wheat (GLD1A2, GLD1A18, GLD1A19). Most of the durum cultivars studied had these three blocks; GLD1A2 was also frequent in common wheat. In contrast, all chromosome 1B-encoded blocks of durum clearly differed in component composition from those found in common wheat. Therefore, durum could not be an ancestor or a derivate of recent bread wheat. Analysis of gliadin in the collection of carthlicum wheat (14 accessions) revealed several suspected chromosome 1A, 1B, and 6A-controlled blocks, some of which were similar to those in common wheat, while others were different. Therefore, carthlicum is likely to be an ancestor or a derivate of some forms of bread wheat. There were also chromosome 1A and 6A-, but not 1B-encoded blocks which were identical in durum and carthlicum wheats. The results confirm that all three wheats share the same genome A, but emphasize the heterogeneity of genotypes among donors of this genome. Discovery of identical blocks in tetraploids and hexaploids indicates polyphyletic [from different genotypes of donor (s)] origin of these wheats.

Polymorphism and inheritance of gliadin components controlled by chromosome 6A of spring durum wheat.

The gliadin composition of 78 spring durum wheat varieties has been studied by one-dimensional (Al-lactate, pH 3.1) and two-dimensional (first dimension, Al-lactate, pH 3.1; second dimension, sodium dodecyl sulfate-polyacrylamide gel) electrophoresis. Analysis of hybrids has shown that all components of the alpha zone of gliadin spectra are inherited together as blocks and are, probably, coded for by a cluster of tightly linked genes located on chromosome 6A. Fourteen variants of gliadin blocks have been identified, which can be classified into five families on the basis of component composition. All families but one have analogues among chromosome 6A-controlled blocks of bread wheat. The results indicate that some of the genome A diploid genotypes that were ancestors of durum wheats were also ancestors of bread wheats and that polyploid wheats were produced by repeated allopolyploidization events, as has been suggested earlier.