RESUMEN

Wheat stem rust, caused by Puccinia graminis f. sp. tritici, which used to be a harmful disease of winter wheat in the southern part of Russia, has been largely affecting the yield of spring bread wheat in the territories of the temperate climate zone since 2009. In total, 222 P. graminis f. sp. tritici isolates were obtained from samples of susceptible cultivars of spring bread wheat in Central and Volga regions and Omsk and Novosibirsk provinces in 2019. Genotyping of the isolates was carried out at 16 simple-sequence repeat (SSR) loci. Number of alleles, proportion of heterozygotes, and deviation from Hardy-Weinberg equilibrium were determined at each SSR locus. Based on genetic variability of SSR genotypes, it was shown that the P. graminis f. sp. tritici population is subdivided into two large clusters in the territory of the Russian temperate climate zone: the "European" population (the Central region) and the "Asian" one (the Volga region and two main wheat provinces of Western Siberia). Both of the P. graminis f. sp. tritici populations are characterized by a mixed mode of reproduction (sexual and clonal) but different sources of inoculum seem to shape a genotype structure within them. A group of P. graminis f. sp. tritici genotypes with high variability, the inbreeding coefficient closed to zero, and low observed heterozygosity was revealed among samples from Omsk. Moreover, two singular SSR genotypes identified among the Asian samples of P. graminis f. sp. tritici isolates should attract special attention in the monitoring of stem rust in order to disclose unexpected rapid changes of the pathogen in the corresponding regions and to prevent disease outbreak.

Asunto(s)

Basidiomycota , Pan , Enfermedades de las Plantas , Basidiomycota/genética , Genotipo , Federación de Rusia

RESUMEN

Tan spot caused by Pyrenophora tritici-repentis (Died.) Drechsler, in recent years, occupies an increasingly large area on the territory of Russia. Due to the wide distribution and economic significance of this disease, the search for resistant plants to the pathogen is relevant. This paper presents the results of a field assessment for 2017-2019 of 34 regionally distributed winter wheat varieties of Russian selection for resistance to P. tritici-repentis in the North Caucasus region of Russia. Field resistance - the development of the disease up to 30% against the background of artificial infection for three years was shown by 20.5% of the studied varieties. Wheat varieties were assessed for resistance to isolates of tan spot identified as races 1, 3, and 4 in the greenhouse at the seedling stage. The number of resistant accessions for each race was different and ranged from 12 to 20. The 12 varieties showed resistance to race 1, 14 varieties to race 3, 20 varieties to race 4. This research showed that the resistance to tan spot of studied varieties was race-specific. A functional allele of the susceptibility gene Tsn1 to P. tritici-repentis isolates, producing the toxin Ptr ToxA, was diagnosed by PCR method. Of the analyzed 34 varieties, 13 had a dominant allele of the Tsn1 (Tsn1+), and 21 had a recessive allele in the tsn1tsn1 homozygous state. All Tsn1+ varieties, and most varieties with recessive alleles tsn1tsn1, were susceptible to tan spot in the field. Varieties Dolya, Gurt, Lebed and Sila, which showed field resistance, had the tsn1tsn1 genotype. The expected reaction of varieties with different allelic composition of the Tsn1 gene to inoculation with the isolate of race 1, according to the generally accepted model of "gene-to-gene" interaction, did not coincide with that observed in reality, which confirms the results obtained by other authors. Research results demonstrate the effect of weather conditions on the susceptibility of wheat varieties to tan spot. In years with higher humidity and higher average air temperatures, the susceptibility response to the disease was observed in more varieties than in drier years. The studies show that the main part (79.5%) of winter wheat varieties of Russian selection widely zoned in the North Caucasus region of Russia are susceptible to P. tritici-repentis. Varieties that have been resistant to the pathogen in the adult phase in the field for three years and to the pathogen races in which the recessive allele of the tsn1 gene has been identified may be of interest as sources of resistance for developing new disease-resistant varieties.

RESUMEN

Three fractions with different molecular weights were isolated from pig skin. Fraction 1 (F1) and fraction 3 (F3) stimulated human keratinocyte proliferation in primary and regenerating cultures, but didn't affect their differentiation. Fraction 2 (F2) inhibited keratinocyte proliferation and stimulated their differentiation. The content of the proteins, carbohydrates, ribonucleic acids (RNA) and total lipids were determined in the fractions. The content of proteins and total lipids decreased from F1 to F3, but the content of carbohydrates and RNA increased. Physico-chemical properties of the fractions were studied by the methods of isoelectric focusing and vertical electrophoresis in polyacrilamide gel with sodium dodecyl sulphate and 7 M urea. The authors found that F1 contained 2-3 main proteins with molecular weight of 58 kDa and pI from 4.9 to 5.1 and RNA with molecular weight of 44 kDa. F2 was more heterogeneous. It contained a few main proteins with molecular weights from 6.9 to 61 kDa and pI from 4.4 to 8.3 and RNA with approximate molecular weights from 5.0 to 7.5 kDa. F3 contained a few main proteins with molecular weights from 3.5 to 59 kDa and pI from 4.8 to 5.1 and RNA with approximate molecular weights from 4.8 to 7.0 kDa.