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Tomato Solanum lycopersicum L. is one of the main vegetable crops, accessions and cultivars of which are characterized by a low level of genomic polymorphism. Introgressive tomato breeding uses related wild Solanum species to improve cultivars for stress tolerance and fruit quality traits. The aim of this work was to evaluate the genome variability of 59 cultivars and perspective breeding lines of S. lycopersicum and 11 wild tomato species using the AFLP method. According to the AFLP analysis, four combinations of primers E32/M59, E32/M57, E38/M57, and E41/M59, which had the highest PIC (polymorphism information content) values, were selected. In the process of genotyping a collection of 59 cultivars/lines of S. lycopersicum and 11 wild tomato accessions, the selected primers revealed 391 fragments ranging in size from 80 to 450 bp, of which 114 fragments turned out to be polymorphic and 25 were unique. Analysis of the amplification spectra placed wild tomato accessions into separate clades. Sister clades included cultivars of FSCV breeding resistant to drought and/or cold and, in part, to late blight, Alternaria, Septoria, tobacco mosaic virus and blossom end rot, as well as tomato accessions not characterized according to these traits, which suggests that they have resistance to stress factors. In accessions of distant clades, there was clustering on the basis of resistance to Verticillium, cladosporiosis, Fusarium, tobacco mosaic virus, gray rot, and blossom end rot. The combination of accessions according to their origin from the originating organization was shown. The primer combinations E32/M59, E32/M57, E38/M57 and E41/M59 were shown to be perspective for genotyping tomato cultivars to select donors of resistance to various stress factors. The clade-specific fragments identified in this work can become the basis for the development of AFLP markers for traits of resistance to stress factors.

At all stages of flowering, a decisive role is played by the family of MADS-domain transcription factors, the combinatorial action of which is described by the ABCDE-model of flower development. The current volume of data suggests a high conservatism of ABCDE genes in angiosperms. The E-proteins SEPALLATA are the central hub of the MADS-complexes, which determine the identity of the floral organs. The only representative of the SEPALLATA3 clade in tomato Solanum lycopersicum L., SlMADS5, is involved in determining the identity of petals, stamens, and carpels; however, data on the functions of the gene are limited. The study was focused on the SlMADS5 functional characterization. Structural and phylogenetic analyses of SlMADS5 confirmed its belonging to the SEP3 clade. An in silico expression analysis revealed the absence of gene transcripts in roots, leaves, and shoot apical meristem, and their presence in flowers, fruits, and seeds at different stages of development. Two-hybrid analysis showed the ability of SlMADS5 to activate transcription of the target gene and interact with TAGL1. Transgenic plants Nicotiana tabacum L. with constitutive overexpression of SlMADS5 cDNA flowered 2.2 times later than the control; plants formed thickened leaves, 2.5–3.0 times thicker stems, 1.5–2.7 times shortened internodes, and 1.9 times fewer flowers and capsules than non-transgenic plants. The flower structure did not differ from the control; however, the corolla petals changed color from light pink to magenta. Analysis of the expression of SlMADS5 and the tobacco genes NtLFY, NtAP1, NtWUS, NtAG, NtPLE, NtSEP1, NtSEP2, and NtSEP3 in leaves and apexes of transgenic and control plants showed that SlMADS5 mRNA is present only in tissues of transgenic lines. The other genes analyzed were highly expressed in the reproductive meristem of control plants. Gene transcripts were absent or were imperceptibly present in the leaves and vegetative apex of the control, as well as in the leaves and apexes of transgenic lines. The results obtained indicate the possible involvement of SlMADS5 in the regulation of flower meristem development and the pathway of anthocyanin biosynthesis in petals.

The fruits of various pepper cultivars are characterized by a different colour, which is determined by the pigment ratio; carotenoids dominate in ripe fruits, while chlorophylls, in immature fruits. A key regulator of carotenoid biosynthesis is the phytoene synthase encoded by the PSY gene. The Capsicum annuum genome contains two isoforms of this enzyme, localized in leaf (PSY2) and fruit (PSY1) plastids. In this work, the complete PSY1 and PSY2 genes were identified in nine C. annuum cultivars, which differ in ripe fruit colour. PSY1 and PSY2 sequence variability was 2.43 % (69 SNPs) and 1.21 % (36 SNPs). The most variable were PSY1 proteins of the cultivars ‘Maria’ (red-fruited) and ‘Sladkij shokolad’ (red-brown-fruited). All identified PSY1 and PSY2 homologs contained the phytoene synthase domain HH-IPPS and the transit peptide. In the PSY1 and PSY2 HH-IPPS domains, functionally significant sites were determined. For all accessions studied, the active sites (YAKTF and RAYV), aspartate-rich substrate-Mg2+-binding sites (DELVD and DVGED), and other functional residues were shown to be conserved. Transit peptides were more variable, and their similarity in the PSY1 and PSY2 proteins did not exceed 78.68 %. According to the biochemical data obtained, the largest amounts of chlorophylls and carotenoids across the cultivars studied were detected in immature and ripe fruits of the cv. ‘Sladkij shokolad’ and ‘Shokoladnyj’. Also, ripe fruits of the cv. ‘Nesozrevayuschij’ (green-fruited) were marked by significant chlorophyll content, but a minimum of carotenoids. The PSY1 and PSY2 expression patterns were determined in the fruit pericarp at three ripening stages in ‘Zheltyj buket’, ‘Sladkij shokolad’, ‘Karmin’ and ‘Nesozrevayuschij’, which have different ripe fruit colours: yellow, red-brown, dark red and green, respectively. In the leaves of the cultivars studied, PSY1 expression levels varied significantly. All cultivars were characterized by increased PSY1 transcription as the fruit ripened; the maximum transcription level was found in the ripe fruit of ‘Sladkij shokolad’, and the lowest, in ‘Nesozrevayuschij’. PSY2 transcripts were detected not only in the leaves and immature fruits, but also in ripe fruits. Assessment of a possible correlation of PSY1 and PSY2 transcription with carotenoid and chlorophyll content revealed a direct relationship between PSY1 expression level and carotenoid pigmentation during fruit ripening. It has been suggested that the absence of a typical pericarp pigmentation pattern in ‘Nesozrevayuschij’ may be associated with impaired chromoplast formation.

The genus Allium L. (Amaryllidaceae), the most numerous among monocotyledonous plants, includes such economically important vegetable crops as onion (A. cepa), garlic (A. sativum) and leek (A. porrum). Leek has a high taste and proven valuable dietary properties and is one of the most popular vegetable crops in Western Europe. Despite a high importance of leek as a vegetable, this species is rarely the subject of molecular genetic studies. The genetic diversity of leeks has never been studied before. Therefore, in this work, we studied the nuclear variability (AFLP) and the chloroplast (nucleotide sequence analysis) genomes using a broad sample. For this work, 65 leek accessions were selected from the collection of the Scientific Center of Vegetable Crops, which included varieties of domestic and foreign breeding. As a result of an AFLP analysis and processing of the DNA spectra obtained, 760 fragments were identified, of which 716 were polymorphic for the leek accessions being analyzed. The calculated genetic distances between the leek samples varied from 0.4 to 0.76, which is comparable to the intraspecific polymorphism of related Allium species (onions, garlic). Analysis of the genomic structure with STRUCTURE 2.3.4 divided the leek samples into seven groups, which generally coincides with the clustering of these samples. To assess the variability of the chloroplast genome, nine sites of the chloroplast genome were sequenced in the leek samples, both non-coding (intergenic spacers rpl32-trnL, ndhJ-trnL, and intron rps16 gene), and protein coding genes (psaA, psaB, psbA, psbB, psbE, petB). The analysis of the sites of the leek chloroplast genome revealed an extremely low level of their polymorphism, only six SNPs were detected in the studied sequences with a total length of about 10,500 bp. Thus, as a result of this work, a high level of polymorphism of the leek nuclear genome was revealed, while the polymorphism of the chloroplast genome was extremely low.

The pea Pisum sativum is widely cultivated in Russia as well as over the world. Pea productivity depends on the ability of the pea plant to get into a symbiosis with nodule bacteria. It was previously shown that the strength of the symbiotic activity depends on the activity of plant sucrose cleavage enzymes. Sucrose synthase Sus1 is one of the most important enzymes involved in carbohydrate metabolism. Sucrose synthase cleaves sucrose into UDP-glucose and fructose. This paper is devoted to characterization of Sus1 gene intraspecific variability in 14 Pisum sativum accessions. The length of the identified Sus1 gene varied from 3514 bp to 3532 bp. All identified genes had a similar structure and contained 13 exons and 12 introns. According to their structure, they were assigned to the SUS1-group of dicotyledonous plants. In nucleotide sequences, 125 SNPs were identified. In addition to SNPs, intron sequences contained six indels, thus their length varied from 1093 bp to 1111 bp. The most variable was the intron III. In coding sequences, 47 SNPs were found, wherein the most variable was the exon II. 16 exon SNPs led to amino acid substitutions. Six of them were deleterious and may potentially influence protein folding and stability. All the conservative motifs and active sites were detected in the translated amino acid sequences. It was shown that their sequences were invariable in all the tested accessions. Computational analysis of the amino acid sequences has predicted Sus1 tertiary structure. The protein is a tetramer and each subunit in its turn consists of three domains. The phylogenetic analysis using identified Pisum Sus1 sequences and homologous sucrose synthase genes revealed that the Sus1 and Sus3 genes are closer to each other than to Sus2. It was also proposed that the sucrose synthase family genes had diverged before legumes split into species.