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.

[Prevention of thromboembolic and hemorrhagic events in patients with atrial fibrillation undergoing elective surgery]. / Profilaktika tromboémbolicheskikh i gemorragicheskikh oslozhnenii u patsientov s fibrilliatsiei predserdii pri provedenii planovogo khirurgicheskogo lecheniia.

OBJECTIVE: To compare incidence of thromboembolic and hemorrhagic complications in patients with atrial fibrillation (AF) undergoing elective surgery on different schemes of perioperative anticoagulant therapy (ACT). MATERIAL AND METHODS: There were 86 patients (56 (65.1%) men and 30 (34.9%) women, mean age was 69 (64; 78) years) with non-valvular AF who underwent elective interventions. Forty (46.5%) patients underwent abdominal surgery, 34 (39.5%) - cardiovascular procedures, 12 (14.0%) patients underwent surgery for malignant diseases. We have analyzed incidence of thromboembolic and hemorrhagic events and compliance of perioperative ACT modes with current international guidelines. RESULTS: Thromboembolic and hemorrhagic events developed in 14 (16.3%) patients. Thromboembolic complications were noted in 6 (7.0%) patients, hemorrhagic events - in 8 (9.3%) cases. Maximum complication rate was observed in case of bridge-therapy (n=12, 20.0%). Cancellation of ACT was followed by 2 (9.5%) complications, bridge-therapy - by 4 (6.7%) thromboembolic complications. Hemorrhagic events were 2 times more common in case of this therapy (n=8, 13.3%). It was found that ESC guidelines for perioperative ACT were applied in less than half of patients (41, 47.7% patients with AF undergoing elective surgery). Half of complications (8 out of 16) occurred if unapproved modes of ACT were used (including 7 cases of bridge-therapy was not necessary). The causes of these complications were inadequate assessment of perioperative risk of thromboembolic and hemorrhagic events; unreasonable administration of bridge therapy. CONCLUSION: An unambiguous clinical effect of bridge therapy has not been confirmed in patients with high risk of thromboembolic complications. Cancer patients have higher risk of complications compared with others. These events occur mainly due to non-compliance with clinical guidelines and insufficient prevention of thromboembolic events.

[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.