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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.

Starch degradation in plants is mediated by amylases, the activity of which is post-translationally regulated by inhibitors. It is assumed that the SbAI amylase inhibitor activity is associated with potato cold stress resistance. The study of possible correlations of the SbAI variability with the cold resistance of potato species will improve the understanding of the starch metabolism regulation during plant development and stress response. In the present study, the genome sequences homologous to SbAI were identified in 12 potato species of section Petota. In total, 36 allelic variants of the gene and 31 variants of the protein were revealed. Comparison with data on S. tuberosum cultivars showed that the SbAI cultivar polymorphism is 1.4–1.7 times higher than the interspecific, but the species possess a larger number of allelic variants. Phylogenetic analysis revealed that, for S. demissum, S. acaule, and S. stoloniferum, each species SbAI allelic variants did not get into one clade. The SbAI gene expression pattern was determined in various organs of the species S. tuberosum (cv. Nadezhda), S. rybinii, S. chacoense, and S. kurtzianum. In leaves, S. chacoense SbAI expression level was 13, 50, and 250 times higher than in S. tuberosum, S. kurtzianum, and S. rybinii, respectively. Varied levels of SbAI expression in the species may be due to different initial contents of both synthesized starch and reducing sugars in the leaves. In tubers, S. tuberosum SbAI expression was 5.2, 8.6, and 430 times higher than in S. kurtzianum, S. chacoense, and S. rybinii. In roots, S. rybinii SbAI expression was 2.4 times higher than in S. chacoense and 42.3 times higher than in S. kurtzianum and S. tuberosum. The absence of correlation between the SbAI expression level and the species cold resistance was shown. The obtained expression data suggest that different potato species and cultivars may differently regulate tuber starch content.

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.

Genes homologous to PSY1 and PSY2 that encode phytoene synthase isoforms in Capsicum species C. baccatum, C. chinense, C. frutescens, C. tovarii, C. eximium, and C. chacoense were identified. High conservatism of functionally significant sites of phytoene synthases of the analyzed accessions was revealed. It was found that only PSY1-based clustering of pepper species corresponds to the traditional Capsicum phylogeny; C. eximium was a part of the Purple corolla complex, and C. chacoense was equidistant from Annuum and Baccatum clades. The absence of significant differences between PSY1 and PSY2 of yellow-fruited C. chinense and red-fruited pepper accessions was shown. The yellow color of C. chinense fruit may be the result of both decreased PSY1 expression and increased PSY2 transcription. Thus, it was demonstrated that the acquired fruit pigmentation retains strict phylogenetic limitations, which, however, can be overcome using artificial selection for the activity of phytoene synthase PSY1.

New TOMATO MADS 5 (TM5) homologous genes were identified in evolutionarily recent, red-fruited and more ancient, wild green-fruited tomato species. It was shown that the identified TM5 homologs belong to the SEPALLATA3 clade; thus, the SEP subfamily diversification was characterized. For the first time, the TM5 and RIN co-expression pattern was determined in flowers, immature green fruits, and ripe fruits of Solanum lycopersicum and in five wild tomato species. It was shown that, regardless of the species, the level of TM5 transcription in flowers was higher than that of RIN, whereas in fruits it was lower than the level of RIN transcription. The data obtained suggest that TM5, together with other transcription factors RIN and SlCMB1, is involved in the regulation of fruit development and ripening.

The sequences of the apoplastic invertase inhibitor gene INVINH1 were identified in 71 maize accessions from the collection of the Vavilov All-Russian Institute of Plant Genetic Resources (VIR). In total, 35 INVINH1 allelic variants were found. In 21 maize accessions, at position –95 from the start codon, INVINH1 contained an extended insertion (143, 190, 192, or 210 bp). In INVINH1 proteins, 21 amino acid substitutions were identified, six of which (A49V, A49G, A65P, S97I, C99R, and D108Y), predicted to be radical, were localized in the PMEI functional domain.

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.

The intron located between the first and the second nucleotide of the leucine tRNA anticodon is the only representative of the group I introns in higher plants. In this work, the intron sequence of the plastid trnL gene was for the first time described in 16 legumes species and putative secondary structures of the full-length intron and its functional domains were reconstructed. A high level of polymorphism was detected for this intron in the Fabaceae genera and in the species within a single genus. Single nucleotide polymorphisms, have been found in the sequences of the catalytic center which are considered to be highly conservative.

For the first time the sequences of b/c intron of mitochondrial gene Nad1 have been determined in representatives of 13 Vicia species. It is shown that the sequences of the intron of the gene in these species is highly conservative. In total 23 variable sites and 11 indels have been determined with the intron length 1421–1447 b. p. On the basis of the results of pre-m-RNA intron folding the main elements of its secondary structure have been determined as well as the sites of interdomain interactions. The peculiarities of primary and secondary structure of intron Nad1 in Vicia have been characterized.