RESUMO
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.
RESUMO
The sorbitol-6-phosphate dehydrogenase gene (S6PDH) sequences of six representatives of the genus Malus, which belong to five different taxonomic sections, were examined for the first time. The exon-intron structure and polymorphism of the nucleotide and amino acid sequences of these genes was characterized. The intraspecific polymorphism of the S6PDH gene was assessed for the first time in 40 Russian and foreign apple (Malus domestica) cultivars. It was demonstrated that the interspecific polymorphism level of the S6PDH coding sequences in the studied. representatives of the genus Malus was 4%, and the intraspecific polymorphism level of M. domestica cultivars was very low, constituting 0.96%.
Assuntos
Malus/genética , Proteínas de Plantas/genética , Polimorfismo Genético , Desidrogenase do Álcool de Açúcar/genética , Malus/enzimologiaRESUMO
The sequences that encode the main functional glucosyltransferase domain of sucrose synthase genes have been identified for the first time in 14 species of the genus Malus and related species of the family Rosaceae, and their polymorphism was investigated. Single nucleotide substitutions leading to amino acid substitutions in the protein sequence, including the conservative transmembrane motif sequence common to all sucrose synthase genes of higher plants, were detected in the studied sequences.
Assuntos
Evolução Molecular , Glucosiltransferases/genética , Sistema da Enzima Desramificadora do Glicogênio/genética , Malus/genética , Sequência de Aminoácidos , Substituição de Aminoácidos/genética , Malus/enzimologia , Polimorfismo Genético , Estrutura Terciária de Proteína/genética , Especificidade da EspécieRESUMO
In 12 different Russian and Kazakhstan potato cultivars, the polymorphism of the glycosyltransferase domain of the sucrose synthase gene was first examined, as well as the polymorphism of the sucrose synthase domain fragment of the same gene in the potato cultivars of Kazakhstan breed. It was demonstrated that the examined sequences contained point mutations, as well as insertions and deletions, including those not described earlier. Amino acid substitutions specific to heat- and drought-tolerant varieties were also identified and could be associated with the development of abiotic stress resistance.
Assuntos
Glucosiltransferases/genética , Proteínas de Plantas/genética , Polimorfismo Genético , Solanum tuberosum/genética , Substituição de Aminoácidos , Deleção de Genes , Resposta ao Choque Térmico/genética , Cazaquistão , Mutagênese Insercional , Mutação Puntual , Federação RussaRESUMO
The nucleotide sequence of the ITS1-5.8S ribosomal DNA spacer fragment was determined for 41 samples of the Malus species. The total length of compared sequences ranged from 389 to 392 bp. The nucleotide sequence of the 5.8S gene within the genus was highly conserved. The level of polymorphism of ITS 1 region comprised 14%. Both species- and group-specific substitutions were identified. The analysis of M. orientalis and M. turkmenorum sequences revealed their full identity, which indicates the need to perform more research with a larger number of samples of both species from other collections to clarify the taxonomic status of the M. turkmenorum species. The previous findings on the synonymy of species M. baccata, M. mandshurica, M. pallasiana, and M. sachalinensis were also confirmed.
Assuntos
DNA Espaçador Ribossômico/genética , Malus/genética , RNA Ribossômico 5,8S/genética , Malus/classificação , Filogenia , Polimorfismo GenéticoRESUMO
In the present work NBS-ARC domain sequences of Rx1 homologues of ten accessions of cultivated and wild potato species which differ in susceptibility to potato virus X were obtained and studied. Within the NBS-ARC domain different indels and nucleotide/amino acid substitutions, including substitutions in the conservative motives of the domain were detected. There were no direct associations between the mutational changes found in the conservative motives of the NBS-ARC domain and the susceptibility of the studied accessions to X virus.
Assuntos
Proteínas de Plantas/genética , Estrutura Terciária de Proteína/genética , Solanum/genética , Solanum/virologia , Motivos de Aminoácidos/genética , Mutação , Filogenia , Potexvirus/genética , Homologia de Sequência de AminoácidosRESUMO
Nucleotide and amino acid variability of fragments of the Sus4 gene encoding the sucrose synthase enzyme was studied in 24 potato cultivars selected in Russia and other countries and differing in starch content in tubers. Both SNPs and indels were detected in a chosen Sus4 gene fragment including the sequence from exon 3 to exon 6 and corresponding to the main part of the sucrose synthase domain. Four types of Sus4 sequences were revealed depending on the presence of an insertion in introns 4 and 5 and of the mononucleotide octamer (T)8 in intron 5. Differentiation of these sequences was confirmed by statistical methods. Sixteen amino acid substitutions were identified in the translated sequence, of which eleven were nonsynonymous. Specific varietal nucleotide and amino acid substitutions were also revealed, which can be used in future for marking potato cultivars/genotypes. No direct associations between the mutational changes and the starch content were found in the potato cultivars studied by us.
