Red flower apple in the collection of the National University of Life and Environmental Sciences of Ukraine

Apple trees with red flowers are especially attractive during the flowering period, making ones a desirable component of ornamental plantings. 30 samples of apple trees with anthocyanin organ coloring in the collection of Scientific Laboratory "Genetic resources, introduction, and breeding of unusual fruit and ornamental crops", located in Agronomic Research Station of the National University of Life and Environmental Sciences of Ukraine have been studied. In 2001 phenological observations during blooming and morphometric analysis of flowers and leaves were carried out, also decorativeness was evaluated. The dominant gene that controls the anthocyanin pigmentation of organs in the apple tree comes from Malus niedzwetzkyana. Now the rank of this taxon is reduced to a variety – M. domestica var. niedzwetzkyana. Niedzvetzky’s apple was involved in crossing with small-fruited apple species to develop ornamental hybrids, some of which received nothospecies names, and in the breeding of fruit varieties and rootstocks of M. domestica. According to the International Code of Nomenclature for Cultivated Plants, varieties with anthocyanin-colored petals having in the pedigree M. domestica var. niedzwetzkyana can be distinguished as Malus Niedzwetzkyana Group. If the Malus Niedzwetzkyana Group is supplemented with varieties with anthocyanin color of petals that originate from other species of apple trees, e.g., M. halliana and M. spectabilis, then the expanded Group can be called Malus Purpurea Group. At the same time, some varieties may belong to other Groups, in particular, Malus Pendula Group, Malus Redflesh Group, etc. The highest decorativeness (5 points) during blooming is inherent for the samples Nos. 2332 'Makamik', 2947, 3100 'Aldenhamensis', 3157 'Pionerka', 3305, 3382, 3540, 3592, 3601, 3603, 3656, 3691, 3692, 4292 and hybrids '17-279', '17-316', '18-275', '18-293', '18-325'. The samples No. 1723 'Lawn Krasnolepestnaya', 3314 'Royalty', 3375 'Black Pearl' are slightly inferior to them in decorativeness, but they have a special habitus or intense anthocyanin color of the leaves, which gives them certain advantages. The use of these samples allows you to establish a conveyor of elongated flowering of red-flowered apple trees at green construction sites.

Molecular labeling of Vrn, Ppd genes and vernalization response of the ultra-early lines of spring bread wheat Triticum aestivum L.

Background. The knowledge of genetic control of vernalization response in the ultra-early accessions can facilitate bread wheat breeding for a high adaptive capacity. Materials and methods. The study involved the ultra-early lines Rico (k-65588) and Rimax (k-67257) as the earliest maturing lines in the VIR bread wheat collection, as well as 10 Rifor lines (k-67120, k-67121, k-67250-67256) with a high rate of development before heading. A late ripening accession ‘Forlani Roberto’ (k-42641) and ‘Leningradskaya 6’ variety (k-64900), regionally adapted to Northwestern Russia, were also studied. The alleles of the Vrn and Ppd genes were identified by the PCR analysis using the allele-specific primers published in literature sources. The response to vernalization (30 days at 3°C) and a short 12-hour day were determined using a methodology accepted at VIR. Results. The ultra-early lines respond to a short 12-hour day and 30-day vernalization very poorly. The genotype of ultra-early wheat lines is mainly represented by three genes, Vrn-A1, Vrn-B1a, and Vrn-D1, which ensure insensitivity to vernalization alongside with the expression of Ppd-D1a, which controls the response to photoperiod. The ultra-early lines Rifor 4 and Rifor 5 have a recessive allele vrn-A1a, like the original ‘Forlani Roberto’ accession. The lines Rifor 4 and Rifor 5 are vernalization-insensitive under the long day and have a very weak response under the short day (3.5±0.42 days and 4.0±0.61 days, respectively). However, ‘Forlani Roberto’ with the vrn-A1a gene responds to vernalization in the same way under any photoperiod (12.3±1.58 days and 12.2±0.74 days). Conclusion The ultra-early lines of bread wheat Rifor 4 and Rifor 5 with the vrn-A1a gene can have no response to vernalization or have a low level response. This effect can be a reason for the formation of a complex of modifier genes along with the dominant gene Vrn-D1, which forms during the hybridization of F7-8 Rico × Forlani Roberto. The ultra-early lines of bread wheat Rico, Rimax and Rifor (k-67120, k-67121, k-67250-67256) can serve as effective sources of genes for earliness in common wheat breeding.

The Unstable Restorer-of-Fertility Locus in Pepper (Capsicum Annuum. L) is Delimited to a Genomic Region Containing PPR Genes

The use of cytoplasmic-genic male sterility (CGMS) systems greatly increases the efficiency of hybrid seed production. Although marker development and candidate gene isolation have been performed for the Restorer-of-fertility (Rf) gene in pepper (Capsicum annuum L.), the broad use of CGMS systems has been hampered by the instability of fertility restoration among pepper accessions, especially sweet peppers, due to the widespread presence of the Unstable Restorer-of-fertility (Rfu) locus. Therefore, to investigate the genetic factors controlling unstable fertility restoration in sweet peppers, we developed a segregation population from a cross between a male-sterile line and an Rfu-containing line to examine the inheritance of Rfu. Individuals with unstable restoration vs. sterility segregated at a 3:1 ratio, indicating that a single dominant gene controls unstable fertility restoration. Genetic mapping delimited the Rfu locus to a 479 kb genomic region on chromosome 6 flanked by two markers, which is close to but different from the previously identified Rf-containing region. The Rfu-containing region harbors a pentatricopeptide repeat (PPR) gene, along with 13 other candidate genes. In addition, this region is syntenic to the genomic region containing the largest number of Rf-like PPR genes in tomato. Therefore, the dynamic evolution of PPR genes might be responsible for both the restoration and instability of fertility in pepper. During genetic mapping, we developed various molecular markers, including one that co-segregated with Rfu. These markers showed higher accuracy for genotyping than previously developed markers, pointing to their possible use in marker-assisted breeding of sweet peppers.

Novel Fusarium Wilt Resistance Genes Uncovered in the Wild Progenitors and Heirloom Cultivars of Strawberry

Fusarium wilt, a soilborne disease caused by Fusarium oxysporum f. sp. fragariae, poses a significant threat to strawberry (Fragaria × ananassa) production in many parts of the world. This pathogen causes wilting, collapse, and death in susceptible genotypes. We previously identified a dominant gene (FW1) on chromosome 2B that confers resistance to race 1 of the pathogen and hypothesized that gene-for-gene resistance to Fusarium wilt was widespread in strawberry. To explore this, a genetically diverse collection of heirloom and modern cultivars and wild octoploid ecotypes were screened for resistance to Fusarium wilt races 1 and 2. Here we show that resistance to both races is widespread and that resistance to race 1 is mediated by dominant genes (FW1, FW2, FW3, FW4, and FW5) on three non-homoeologous chromosomes (1A, 2B, and 6B). The resistance proteins encoded by these genes are not yet known; however, plausible candidates were identified that encode pattern recognition receptor or other proteins known to mediate gene-for-gene resistance in plants. High-throughput genotyping assays for SNPs in linkage disequilibrium with FW1-FW5 were developed to facilitate marker-assisted selection and accelerate the development of race 1 resistant cultivars. This study laid the foundation for identifying the genes encoded by FW1-FW5, in addition to exploring the genetics of resistance to race 2 and other races of the pathogen, as a precaution to averting a Fusarium wilt pandemic.

Bulked Segregant RNA-Seq Provides Distinctive Expression Profile Against Powdery Mildew in the Wheat Genotype YD588

Wheat powdery mildew, caused by the fungal pathogen Blumeria graminis f. sp. tritici (Bgt), is a destructive disease leading to huge yield losses in production. Host resistance can greatly contribute to the control of the disease. To explore potential genes related to the powdery mildew (Pm) resistance, in this study, we used a resistant genotype YD588 to investigate the potential resistance components and profiled its expression in response to powdery mildew infection. Genetic analysis showed that a single dominant gene, tentatively designated PmYD588, conferred resistance to powdery mildew in YD588. Using bulked segregant RNA-Seq (BSR-Seq) and single nucleotide polymorphism (SNP) association analysis, two high-confidence candidate regions were detected in the chromosome arm 2B, spanning 453,752,054-506,356,791 and 584,117,809-664,221,850 bp, respectively. To confirm the candidate region, molecular markers were developed using the BSR-Seq data and mapped PmYD588 to an interval of 4.2 cM by using the markers YTU588-004 and YTU588-008. The physical position was subsequently locked into the interval of 647.1–656.0 Mb, which was different from those of Pm6, Pm33, Pm51, Pm52, Pm63, Pm64, PmQ, PmKN0816, MlZec1, and MlAB10 on the same chromosome arm in its position, suggesting that it is most likely a new Pm gene. To explore the potential regulatory genes of the R gene, 2,973 differentially expressed genes (DEGs) between the parents and bulks were analyzed using gene ontology (GO), clusters of orthologous group (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Based on the data, we selected 23 potential regulated genes in the enriched pathway of plant-pathogen interaction and detected their temporal expression patterns using an additional set of wheat samples and time-course analysis postinoculation with Bgt. As a result, six disease-related genes showed distinctive expression profiles after Bgt invasion and can serve as key candidates for the dissection of resistance mechanisms and improvement of durable resistance to wheat powdery mildew.

Molecular Detection of blaOXA-type Carbapenemase Genes and Antimicrobial Resistance Patterns among Clinical Isolates of Acinetobacter baumannii

Acinetobacter baumannii is a bacterium found in most places, especially in clinics and hospitals, and an important agent of nosocomial infections. The presence of class D enzymes such as OXA-type carbapenemases in A. baumannii is proven to have a key function in resistance to carbapenem. The aim of the current study is to determine the blaOXA-type carbapenemase genes and antimicrobial resistance among clinically isolated samples of A. baumannii. We assessed 100 clinically isolated specimens of A. baumannii from patients in intensive care units of educational hospitals of Hamadan, West of Iran. The A. baumannii isolates' susceptibility to antibiotics was performed employing disk diffusion method. Multiplex polymerase chain reaction was used to identify the blaOXA-24-like , blaOXA-23-like , blaOXA-58-like , and blaOXA-51-like genes. The blaOXA-23-like , blaOXA-24-like , and blaOXA-58-like genes' prevalence were found to be 84, 58, and 3%, respectively. The highest coexistence of the genes was for blaOXA-51/23 (84%) followed by blaOXA-51/24-like (58%). The blaOXA-51/23- like pattern of genes is a sort of dominant gene in resistance in A. baumannii from Hamadan hospitals. The highest resistance to piperacillin (83%) and ciprofloxacin (81%) has been observed in positive isolates of blaOXA-23-like . The A. baumannii isolates with blaOXA-58-like genes did not show much resistance to antibiotics. Based on the results of the phylogenetic tree analysis, all isolates have shown a high degree of similarity. This study showed the high frequency of OXA-type carbapenemase genes among A. baumannii isolates from Hamadan hospitals, Iran. Thus, applying an appropriate strategy to limit the spreading of these strains and also performing new treatment regimens are necessary.

A Novel Pear Scab (Venturia nashicola) Resistance Gene, Rvn3, from Interspecific Hybrid Pear (Pyrus pyrifolia × P. communis)

Asian pear scab is a fungal disease caused by Venturia nashicola. The identification of genes conferring scab resistance could facilitate the breeding of disease-resistant cultivars. Therefore, the present study aimed to identify a scab-resistance gene using an interspecific hybrid population ((Pyrus pyrifolia × P. communis) × P. pyrifolia). Artificial inoculation of V. nashicola was carried out for two years. The segregation ratio (1:1) of resistant to susceptible individuals indicated that resistance to V. nashicola was inherited from P. communis and controlled by a single dominant gene. Based on two years phenotypic data with the Kruskal–Wallis test and interval mapping, 12 common markers were significantly associated with scab resistance. A novel scab resistance gene, Rvn3, was mapped in linkage group 6 of the interspecific hybrid pear, and co-linearity between Rvn3 and one of the apple scab resistance genes, Rvi14, was confirmed. Notably, an insertion in pseudo-chromosome 6 of the interspecific hybrid cultivar showed homology with apple scab resistance genes. Hence, the newly discovered Rvn3 was considered an ortholog of the apple scab resistance gene. Since the mapping population used in the present study is a pseudo-BC1 population, pyramiding of multiple resistance genes to pseudo-BC1 could facilitate the breeding of pear cultivars with durable resistance.

Fine Mapping of qd1, a Dominant Gene that Regulates Stem Elongation in Bread Wheat

Stem elongation is a critical phase for yield determination and, as a major trait, is targeted for manipulation for improvement in bread wheat (Triticum aestivum L.). In a previous study, we characterized a mutant showing rapid stem elongation but with no effect on plant height at maturity. The present study aimed to finely map the underlying mutated gene, qd1, in this mutant. By analyzing an F2 segregating population consisting of 606 individuals, we found that the qd1 gene behaved in a dominant manner. Moreover, by using the bulked segregant RNA sequencing (BSR-seq)-based linkage analysis method, we initially mapped the qd1 gene to a 13.55 Mb region on chromosome 4B (from 15.41 to 28.96 Mb). This result was further confirmed in F2 and BC3F2 segregating populations. Furthermore, by using transcriptome sequencing data, we developed 14 Kompetitive Allele-Specific PCR (KASP) markers and then mapped the qd1 gene to a smaller and more precise 5.08 Mb interval from 26.80 to 31.88 Mb. To develop additional markers to finely map the qd1 gene, a total of 4,481 single-nucleotide polymorphisms (SNPs) within the 5.08 Mb interval were screened, and 25 KASP markers were developed based on 10x-depth genome resequencing data from both wild-type (WT) and mutant plants. The qd1 gene was finally mapped to a 1.33 Mb interval from 28.86 to 30.19 Mb on chromosome 4B. Four candidate genes were identified in this region. Among them, the expression pattern of only TraesCS4B02G042300 in the stems was concurrent with the stem development of the mutant and WT. The qd1 gene could be used in conjunction with molecular markers to manipulate stem development in the future.

Genetic Mapping of Powdery Mildew Resistance Genes in Wheat Landrace ‘Guizi 1’ Using Genotyping-By-Sequencing

Wheat powdery mildew (Pm), caused by Blumeria graminis f. sp. tritici (Bgt), is a destructive disease of wheat (Triticum aestivum L.) worldwide that causes severe yield losses. Resistant wheat cultivars easily lose effective resistance against newly emerged Bgt strains; therefore, identifying new resistance genes is necessary for breeding resistant cultivars. ‘Guizi 1’ is a Chinese wheat cultivar with effective moderate and stable resistance against powdery mildew. A genetic analysis indicated that powdery mildew resistance in ‘Guizi 1’ was controlled by a single dominant gene, designated PmGZ1. In total, 110 F2 individual plants and the 2 parents were used for genotyping-by-sequencing, which produced 23,134 high-quality single-nucleotide polymorphisms (SNPs). The SNP distributions on the 21 chromosomes ranged from 134 on chromosome 6D to 6,288 on chromosome 3B. Chromosome 6A has 1,866 SNPs, among which 16 are located in a physical region between positions 307,802,221 and 309,885,836 in an approximate 2.3-cM region, which possessed the greatest SNP density. The average map distance between SNP markers was 0.1 cM. A quantitative trait locus with a significant epistatic effect on powdery mildew resistance was mapped to Chromosome 6A. The LOD value of PmGZ1 reached 34.8, and PmGZ1 was located within the confidence interval marked by chr6a-307802221 and chr6a-309885836. The phenotypic variance explained by PmGZ1 was 74.7%. Four candidate genes (two each encoding TaAP2-A and actin proteins) were annotated as resistance genes. The present results provide valuable information for wheat genetic improvement, quantitative trait loci fine mapping, and candidate gene validation.

Genetics and Genomics of Fusarium Wilt of Chilies: A Review

Hot pepper (Capsicum annum L.) is a major spice crop and is used worldwide for its nutritional value. In the field, its plant is susceptible to various fungal diseases, including fusarium wilt, caused by soil-borne fungus Fusarium oxysporum f. sp. capsici, which can survive in the soil for several years. The infected plant can be recognized by the yellowing of older leaves and downward curling of apical shoots, followed by plant wilting and ultimately the death of the plant. The resistance mechanism in plants is controlled by a single dominant gene, and conventional plant breeding techniques are used to develop a wilt-resistant germplasm. Non-conventional techniques such as gene pyramiding and expression enhancement of antifungal genes could be used to shorten the time to develop resistance against fusarium wilt in hot peppers. In this review, we discuss different aspects of the disease and the molecular basis of resistance in chili/hot pepper plants. Furthermore, this review covers the scope of conventional and non-conventional breeding strategies and different management approaches used to tackle the disease.