Oksana Borisovna Polivanova

Rice is a staple food for nearly one-half of the world’s population. Rice is a thermophilic crop and temperature conditions is an important factor that restricts the area of its cultivation. The south of the European part of Russia is one of the most northern regions of rice cultivation in the world. Therefore, studies of specimens cultivated in this region can play an important role in understanding the mechanisms responsible for adaptation to temperature conditions and other abiotic and biotic environmental factors, improving the breeding process and expanding the boundaries of cultivation of the crop. However, no systematic research on the genetic diversity of Russian rice varieties using modern methods has been performed so far. The analysis of whole-plastome sequences is an important source of data on plant phylogeny and evolution. In the present study, we analyzed the complete sequences of chloroplast genomes of 56 rice accessions, including Russian and European varieties, varieties from the former Soviet Union countries, and some other varieties and lines of different origins. It was shown that all the studied samples could be classified into only three out of five previously identified groups of chloroplast genomes of cultivated rice. The most represented group of all was group 1 (Or-wj-I). A significantly large part of the analysed samples had identical haplotypes. Thus, our data lead to the conclusion about the low genetic diversity of the studied sample. This may be explained by the limited set of parental forms used to create genotypes adapted to cultivation at the northern border of the cropping area.

   Relevance. Late blight is a disease associated with significant economic losses in potatoes. Losses from this disease in Russia average over 4 million tons annually. The optimal strategy for containing and combating the spread of the pathogen is the development of resistant potato varieties carrying one or more Rpi genes combined with a high level of horizontal resistance.    The aim of research. To identify late blight-resistant genotypes among hybrids of different genetic origins and correlate their resistance level with the presence of Rpi genes.    Materials and methods.  The study involved potato hybrids of different genetic origins, selected for their agronomic and biological traits from 45 crosses. Resistance to late blight was assessed using a laboratory method, artificially infecting leaves and tubers. The presence of molecular markers was assessed using PCR methods using previously published SCAR markers for five Rpi genes (R1, R2, R3a, R3b, and Rpi-blb1 = Rpi-sto1).    Results.  The screening identified 24 hybrids with high and very high foliar resistance, most of which carried at least one Rpi gene. The R2 gene was predominant among the very highly resistant and resistant samples. The R1 gene was more common in the group of hybrids with moderate resistance and without leaf resistance. Tuber resistance level does not depend on the number and combination of Rpi genes and is likely controlled by a different set of genes. These results reflect the complexity of genotype-phenotype interactions in the potato plant-Phytophthora infestans system. To increase the efficiency of using molecular markers in breeding for the production and selection of late blight-resistant potato genotypes, it is necessary to expand the range of tested markers of known R-genes and conduct an analysis of the original parental forms, on the basis of which to evaluate the hybrid offspring.

Starch is the most important component of potato tubers, the content and structure of which play a decisive role in its use during processing and storage. In this work, a comprehensive assessment of potato samples from the collection Russian Potato Research Centre and hybrids was carried out to determine the starch content during 2021-2024. The assessment was carried out using materials from the genetic collection, including forms of wild and cultivated species, varieties and interspecific hybrids of various origins. In addition to the traditional method of quantitative assessment of starch content based on determining the specific gravity followed by calculation using the empirical formula, a comprehensive assessment was proposed that takes into account the average weight of tubers in the records. About 250 samples of the collection were assessed each year. Based on the results of 2021 and previous studies, 12 samples with a consistently high starch content were identified. The 2022 studies also identified 16 accessions with high starch content, including accessions with complex interspecific origin and interspecific hybrids of species such as S. stoloniferum, S. pinnatisectum, and S. alandiae. In 2023, 10 accessions promising in terms of starch content were identified, including two accessions from the dihaploid collection with a starch content of more than 26%. In 2024, 16 hybrids with high starch content and 3 accessions with a starch content of more than 23% were identified in the analyzed sample. Despite the fact that high starch content requires confirmation of the stability of the trait in subsequent years, as part of the work done, accessions promising for further use in breeding programs were identified, including both varieties and complex interspecific hybrids.

The study of potato genetic diversity using traditional and modern molecular genetic methods for identifying valuable genes allows for faster selection of desired genotypes with a set of economically important traits for use in breeding programs. In this research, based on the results of a long-term study of 200 nursery samples of late blight-resistant hybrids from the genetic collection, 31 samples with a consistently high manifestation of the trait over the years were selected. The assessment was carried out in the field and by the method of artificial infection of tubers and leaves. The presence of markers of resistance genes was determined by PCR. According to the results of the tests, these samples were characterized by a high level of stability of leaves and tubers, and are characterized by a high level of a number of other selection-significant features. At the same time, the selected samples had up to 4 markers of Rpi genes, which determine the vertical resistance of genotypes. The identified samples can be used in the breeding process as donors of a high level of resistance to late blight.

O.B. POLIVANOVA, S.V. GORYUNOVA, E.A. SIMAKOV, A.B. SIVOLAPOVA, S.V. ZHEVORA, E.M. GINS, and A.V. MITYUSHKIN Citation: Polivanova OB, Goryunova SV, Simakov EA, Sivolapova AB, Zhevora SV, Gins EM, Mityushkin AV (2024). Total phenolic, flavonoid, and anthocyanin content in Russian potato. SABRAO J. Breed. Genet. 56(2): 728-738. http://doi.org/10.54910/sabrao2024.56.2.24. Summary Potato (Solanum

Potatoes with pigmented tubers contain anthocyanins and other phenolic compounds that demonstrate antioxidant activity and have a beneficial effect on human health. The nutritional value and other consumer qualities of available potato varieties must be combined with resistance to various infections, primarily late blight, which leads to significant yield losses and considerable costs for chemical protection. The purpose of this work was to assess late blight resistance of 46 promising potato hybrids with different pigmentation patterns, both in the field and by laboratory methods, including molecular screening. The objectives of this study included obtaining promising hybrids of colored potatoes characterized by a set of economically importatnt traits, laboratory and field assessment of the resistance of leaves and tubers to the late blight pathogen Phytophthora infestans, as well as molecular screening of late blight resistance gene markers (Rpi genes). The production, cultivation and evaluation of the hybrid material was carried out using standard methods. Field and laboratory resistance of leaves and tubers was assessed on a 9-point scale. Molecular screening was carried out using PCR analysis. The scientific novelty of the work lies in the fact that for the first time a comprehensive assessment of the resistance to late blight of hybrid material of colored potatoes obtained on the territory of Russian Federation was carried out. According to the results obtained, the studied samples demonstrated a high level of resistance of tubers and leaves in field conditions and laboratory tests. However, the results of the study did not reveal a relationship between laboratory or field resistance and the presence of Rpi gene markers, which may be due to the influence of many independent factors that determine horizontal resistance.

The potato is one of the most important food crops in the world. Improving the efficiency of potato breeding is of great importance for solving the global food problem. Today, researchers distinguish between six potato cytoplasm types: A, M, P, T, W, D. In the current study, the complete chloroplast genomes of Solanum tuberosum accessions with five out of the six major cytoplasmic genome types were sequenced (T-, W-, D-, A-, and P-genomes). A comparative analysis of the plastomes in potato accessions with different cytoplasm types was carried out for the first time. The time of origin of the different cytoplasm types was estimated. The presence of two main groups of chloroplast genomes among cultivated potato was confirmed. Based on the phylogenetic analysis of the complete plastome sequences, five main evolutionary branches of chloroplast genomes can be distinguished within the Petota section. Samples with A- and P- cytoplasm formed isolated and distant groups within a large and polymorphic group of samples with M-type cytoplasm, suggesting that A and P genomes arose independently. The findings suggest that the diversity of the T-genome in S. tuberosum Group Tuberosum could be initially low due to a bottle neck already existing at the origin of the Chilean clade. Differences in the rbcL gene sequence may be one of the factors causing differences in economically important traits in species with A and T-type cytoplasm. The data obtained will contribute to the development of methods for molecular marking of cytoplasm types and increase knowledge about the evolution and diversity of potato.

The complete chloroplast genomes of red currant cultivar ‘Belaya Potapenko’ and gooseberry cultivar ‘Nekrasovskij’ were sequenced and assembled for the first time. The plastomes are 157,802 bp and 157,559 bp in length for Ribes rubrum and R. uva-crispa, respectively. The R. rubrum cp genome is 243 b.p. longer. It has one more protein-coding gene ycf1, which is pseudogenized in the R. uva-crispa cp genome. In total, 56 and 54 simple sequence repeats (SSRs) were identified within the assembled plastid genomes. The SSR content of plastid genomes was assessed for the 18 Saxifragales species. Phylogeny inference based on plastome data of 18 Saxifragales revealed that all Ribes species are clustered together on the phylogenetic tree, though R. fasciculatum seems to be the most distant from the other analyzed Ribes species. The position of taxa inside the Ribes genus clade does not support the concept of its division into five subgenera. All Ribes species share approximately the same set of protein-coding genes in their plastome sequences. There was multiple independent pseudogenization of the ycf1 gene within the Ribes genus as well as other Saxifragales taxa. Negative selection was observed for most of the genes in both the Ribes group and Saxifragales. A positive selection ratio was observed only inside the Ribes group for the ycf4 and clpP genes. Together with positive selection signatures, pseudogenization events of ycfs genes perhaps reflect that these genes’ evolution was important for Ribes’ adaptation. Thus, our study provides genomic resources and valuable reference for marker development, and makes some clarifications of the phylogenomics of the Ribes genus.

The antioxidant defense system can be stimulated by growth regulators in plants when they are under stress, such as exposure to pathogens. There are a lot of natural growth regulators on the market, but no research has been carried out yet to determine how effective they are. This field and laboratory study examines the impact of two commonly used Russian growth regulators, Crezacin and Zircon, along with artificial infection with Fusarium culmorum on the antioxidant system of naked oat. The results show that, compared to the control, Crezacin-treated plants had higher contents of low molecular weight fructose and nonenzymatic antioxidants like proline, phenolic compounds, and flavonoids. Zircon-treated plants had a lower content of proline, carbohydrates, and lower total antioxidant activity than the control plants. The obtained data show that Crezacin treatment mainly affected nonenzymatic systems of the antioxidant defense. This treatment was more successful than the Zircon application, which did not show any appreciable effectiveness and was typically associated with an improvement in oat productivity. The treatment with growth regulators and a fungal suspension performed at the flowering phase provided the best effect on the biochemical parameters and productivity of naked oats. Moreover, oat treatment with the pathogen promoted the reproductive capabilities of the plants, while growth regulators helped in avoiding infectious stress.