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Black spot in roses caused by the hemibiotrophic ascomycete Diplocarpon rosae (Wolf) (anamorph Marssonina rosae) is the most devastating disease of field grown roses and, therefore, affects both consumers of ornamental roses and commercial production. Chemical control of the disease is restricted by regulations, and consumers increasingly demand resistant varieties. As breeding black spot resistant rose varieties is complicated by its polyploid nature and the regular emergence of new pathogenic races of the pathogen, a deeper understanding of the biological characteristics of the interaction between the fungal parasite and its host is urgently needed. This review summarizes some investigations of the parasite and its interactions from early descriptions of the pathogen to recent molecular analyses of the fungus. [ABSTRACT FROM AUTHOR]

Different flowering and closing times within a diurnal period play a significant role in reproductive isolation. However, few studies focused on the genetics of flower opening and closing times within a day for the lack of suitable plant materials. Iris dichotoma opens in the afternoon and closes in the evening, while I. domestica opens in the early morning and closes at dusk. Moreover, they have overlapping flowering phenology and produce fertile hybrids, providing an extraordinary opportunity to study the genetics of flower opening and closing times within a day. To illuminate the genetic mechanism regulating flower opening and closing times, the flowering processes of I. dichotoma (Y), I. domestica (S), and their hybrids: F1, F2, F1 × S, Y × F1, (F1 × S) × F1 and F1 × (F1 × S) were observed. The results indicated that flower opening and closing times are controlled by different polygenes. For flower opening time, opening in the early morning as I. domestica is partial dominant to opening in the afternoon as I. dichotoma. For flower closing time, flower closure at dusk is dominant to closure in the evening. [ABSTRACT FROM AUTHOR]

Gibberellin 20‐oxidase (GA20ox) is a multifunctional enzyme that is involved in the regulation of GA biosynthesis and the control of plant growth. We identified and characterized a GA20ox gene (CrGA20ox1) in Camellia reticulata 'Hentiangao'; subsequently, expression levels of CrGA20ox1 in four phenotypically different camellias were analysed using fluorescent quantitative real‐time PCR (qRT‐PCR). The results demonstrated that the CrGA20ox1 gene was expressed in all four camellias at various levels, indicating that the gene's expression intensity was positively associated with camellia height. In addition, phenotypic comparison among transgenic tobacco plants saw a nearly 3.6‐fold increase in height of sense CrGA20ox1 lines as contrasted with wild‐type tobacco. Interestingly and contrarily, the height of the transgenic plants expressing antisense CrGA20ox1 copies decreased by only around 0.5‐fold of the controls' height. Endogenous hormone measurements illustrated that bioactive GA4 predominantly increased in sense transgenic plants, whereas an obvious drop was observed in the antisense lines. Hence, overexpression of the CrGA20ox1 gene could accelerate vegetative growth; however, silent expression of the CrGA20ox1 gene impelled plants towards dwarfism. [ABSTRACT FROM AUTHOR]

Roses produced or grown in the field, as well as pot-grown and cut roses, are attacked by different fungal pathogens causing leaf spot diseases. The incorrect identification and scoring of these pathogens and the lack of information about their genetic and pathotype diversity hamper resistance breeding. This is especially true for the hemibiotrophic ascomycete Sphaceloma rosarum, which is often confused with other fungi. Here for the first time, the genetic variability between isolates at both the molecular and morphological level is analysed. Eighty leaf spot samples were collected from different rose genotypes at five different locations, and 15 single conidial isolates established. All of the samples showed high morphological similarities to the reference isolate CBS 213.33 that was obtained from a public repository. By sequencing a part of the large subunit ( LSU) of the 28S ribosomal RNA and phylogenetic analysis, high sequence similarities were shown to other Sphaceloma species for 13 of the isolates and the CBS reference. One of the isolates clustered with Septoria species and another clustered with Seimatosporium species. UPGMA clustering with 145 polymorphic AFLP markers resulted in five distinct groups in the majority rule consensus tree for the 14 S. rosarum isolates, including the CBS reference. Jaccard similarities ranged from 0·31 to 0·91. A detached leaf assay using a differential set of five rose genotypes led to the classification of the five tested isolates as five distinct pathotypes. Therefore, grouping depending on the avirulence gene diversity was clearly different from clustering using selectively neutral AFLP markers that were evenly distributed throughout the genome. [ABSTRACT FROM AUTHOR]

In cucumber, low temperatures can result in chilling injuries and can lead to significant yield decreases in open field production. The lack of a cold-tolerant cucumber germplasm has limited classical breeding. Recent progress in understanding plant response to cold stress has allowed to develop transgenic approaches to improving cold tolerance in chilling sensitive crop species. The pGT:: Dhn24 gene construct containing an anthocyanidine glucosyltransferase promoter and the DHN24 dehydrin-encoding gene originating from cold-acclimated species Solanum sogarandinum was developed, and preliminary study showed that its expression could increase cucumber chilling tolerance. In this study, a set of transgenic cucumber lines was developed and tested for cold tolerance. Expression of pGT:: Dhn24 was confirmed in the transgenic cucumber lines at both the transcript and protein level. At the protein level, chilling-induced pGT:: Dhn24 transgene expression was observed in the leaves; however, it was constitutive in the roots. Cold stress-related physiological parameters, germination ability and severity of chilling injury were measured for the transgenic lines at the phytotron conditions. No evidence for increased cold tolerance of the transgenic cucumber lines was found. [ABSTRACT FROM AUTHOR]

Variegated leaf colour is an important agronomic trait that affects the market value of ornamental kale ( Brassica oleracea L. var. acephala). The red leaf phenotype in kale is due to anthocyanin accumulation. To investigate the pattern of inheritance of this trait, we constructed an F2 population by crossing 'Y005-15', a double haploid with red leaves, with a white-leaved double haploid, 'Y011-13-38', followed by self-pollination. An F2 population consisting of 4284 individuals was used to study the inheritance of this trait, which showed that the character was controlled by a dominate gene. All of the 1050 white leaf trait plants in the F2 were used for mapping and developing markers linked to Re gene. Results showed that Re was mapped to a locus on linkage group C09 of Brassica oleracea, and the locus was mapped between six SSR markers (C9Z1, C9Z16-1, C9Z90, C9Z94, C9Z96 and C9Z99), with a genetic distance of 6.7, 1.0, 0.3, 2.0, 2.1 and 0.4 cM from Re gene, respectively. These results may facilitate marker-assisted selection of the red leaf trait in kale breeding as well as map-based cloning of the red leaf trait gene. [ABSTRACT FROM AUTHOR]

To integrate the gene pool of a wild species (primarily diploid) into a cultivated pool (primarily tetraploid), a crossing between a dihaploid cultivated rose and a hybrid of Rosa wichurana allowed to obtain interspecific diploid hybrids that produced 2n pollen grains. A return to a tetraploid level sought by breeders can then be considered using sexual polyploidization, obtained by crossing a tetraploid cultivated rose with these hybrids. Application of a high-temperature regime led to a small but significant increase in the percentage of 2n pollen grains in these hybrids of up to 4.6%. This result was obtained by applying high temperatures close to 32°C during the day to plants cultivated in a glasshouse during recurrent cycles of bloom. Crosses were made between an unreleased tetraploid hybrid tea rose, as a female, and the diploid hybrid that produces the most 2n pollen grains. Tetraploid (42.1%) and triploid (57.9%) offspring were obtained. The use of these 2n pollen grains of the first division restitution type should facilitate the introgression of complex traits of interest. [ABSTRACT FROM AUTHOR]

The objectives of the study were to (i) demonstrate that the hybridization data from microarrays can yield information on sequence variation between two inbred lines, an introgression line 'Mogeor' and its genetic background 'Moneymaker'; (ii) characterize, by means of the identified SFPs, the introgressed genomic segments of 'Mogeor', carrying resistance genes; and (iii) deliver a set of genetically anchored SFPs potentially useful for breeding. In this work, the GeSNP software was used to identify SFPs in tomato using Affymetrix data from a previous experiment. Sequencing of 12 putative polymorphism-containing amplicons yielded a SFP probe set validation rate of 90%. In total, 92 Gene Models putatively harbouring SFPs were identified, distributed as following: 61 Gene Models on chromosome 9, and one to eight on the remaining tomato chromosomes apart from chromosomes 7, 8 and 12. Newly discovered SFPs from microarray data can thus provide not only useful information for definition of introgressed genomic regions, but also identification of candidate genes and new markers for MAS. [ABSTRACT FROM AUTHOR]

We report on the identification of phenotypic and molecular markers for genes introgressed into oilseed pumpkin Cucurbita pepo from C. moschata germplasm originating in Nigeria, Portugal and Puerto Rico, which provide resistance against zucchini yellow mosaic virus ( ZYMV) and on pyramiding these genes for improved and long-lasting field protection of oilseed pumpkins. One SCAR and two SSR markers have been found for three dominant resistance genes, Zym-0, Zym-1 and Zym-2. Characteristic reactions to ZYMV inoculation of plants carrying the recessive genes for resistance zym-4* and zym-6 have been defined. Described are procedures and results of pyramiding various combinations of these genes in oilseed pumpkin using the three markers and the specific phenotypic reactions to infection of some of these genes. The putative combination of all six resistance genes in one genotype resulted in a resistance that appeared to be at least as strong as or even stronger than that of the resistance source germplasm in C. moschata. [ABSTRACT FROM AUTHOR]

Bean golden mosaic virus ( BGMV) is the causal agent of bean golden mosaic of common beans. A transgenic bean line that has been developed based on RNA interference to silence the BGMV rep gene showed immunity to the virus. Crosses were done between the transgenic line and six bean cultivars followed by four backcrosses to the commercial cultivars 'Pérola' and 'BRS Pontal'. The transgene locus was consistently inherited from the crosses analysed in a Mendelian fashion in the segregating populations. The disease resistance reaction co-inherited with the transgene. Nevertheless, the expression of disease resistance displayed a dosage effect phenomenon in the F1 generation. The analysis of the homozygous near-isogenic lines in field conditions, under high BGMV disease incidence, indicated that the transgenic lines were completely resistant. These results show the strength of the disease resistance obtained, the stability of the trait across generations and its usefulness in the management of a disease for which there is no reported Phaseolus germplasm with immunity. [ABSTRACT FROM AUTHOR]

Pollen viability and male meiosis in intraspecific hybrids of Hydrangea aspera subsp. aspera Kawakami group (2n = 2x = 36) and subsp. sargentiana (2n = 2x = 34) were investigated. Although it had been assumed that they were sterile, pollen viability was observed; it varied from 2.5% to 12.1%. The production of gametes with different chromosome numbers was implied by the analysis of the dispersion of the diameter distribution of pollen grains. Analysis of male meiosis made it possible to identify the origins with two major categories of meiotic aberrations: abnormal chromosome distribution (early chromosome migration at metaphase, lagging chromosomes at anaphase, micronuclei at telophase), leading to the formation of unbalanced tetrads and/or ones with supernumerary microspores; and abnormal spindle orientation in metaphase II (tripolar, fused and parallel spindles), leading to the formation of dyads or triads. The mode of 2n pollen formation is of the First Division Restitution type. The high level of parental heterozygosity that is normally associated with them should facilitate the transfer of a polygenic trait in breeding programme. [ABSTRACT FROM AUTHOR]

The effect of genotype factors, year and their interaction was assessed on six architectural variables of eight cultivars of rose bush. Plants were grown in pots in a greenhouse in the spring of 2011 and 2012, two highly contrasted years in terms of the quantity of cumulative radiation, with a relative deviation (for 2012 compared to 2011) ranging from −24.6% (April) to +13.7% (March). Their architecture was digitized at two observation scales, the plant and the axis. Highly significant genotype ( G) and year ( Y) effects were revealed for all of the variables measured, as well as a G × Y interaction. Concerning the year effect, it was significantly higher in 2012 and for all of the variables measured. The G × Y interaction was due to (i) different genotype groupings according to year, (ii) difference response amplitudes between years according to genotype. Broad-sense heritability was calculated for each of these variables. It was moderate to high, ranging from 48% for the length of long axes to 98% for the number of metamers on long axes. [ABSTRACT FROM AUTHOR]

A chicory genetic map of 1208 cM has been created using 247 F2 plants and 237 markers (170 AFLP, 28 SSR, 27 EST- SNP and 12 EST- SSR). This map covers 84% of the chicory genome. The chicory-genic-markers-associated sequences were used to find potential orthologs in mapped lettuce ESTs from the Compositae Genome Project Database. Twenty-seven putative orthologous pairs were retained, pinpointing seven putative blocks of synteny that covered 11% of the chicory genome and 13% of the lettuce genome, opening new perspectives for the analysis of these two species. [ABSTRACT FROM AUTHOR]

Most of the commercial varieties of coffee ( Coffea arabica L.) derived from the Timor hybrid ( TH) have been shown to contain major genes for coffee leaf rust ( CLR) resistance. To identify markers tightly linked to such genes, an F2 mapping population derived from a cross between 'Caturra' (susceptible variety) and the TH-derived DI.200 line (highly resistant) was generated. Using expressed sequence information and a bioinformatics approach, both targeted region amplified polymorphism ( TRAPs) markers and simple sequence repeat ( SSR) markers were identified. Phenotypic evaluations in the field and under controlled conditions confirmed the existence of one quantitative trait locus for CLR resistance. Four candidate SSR markers were associated with high CLR resistance. They spanning a region of 2.5 cM designated QCLR_4 located within chromosome 4 of the international C. canephora map. The presence of this region was confirmed in a set of elite lines and commercial varieties. The QCLR_4 region corresponds to a new and genetically independent S H locus that could potentially be useful in gene pyramiding with other genes to enhance rust resistance in TH derivatives. [ABSTRACT FROM AUTHOR]

Lagerstroemia (crape myrtle) are famous ornamental plants with large pyramidal racemes, long flower duration and diverse colours. Genetic maps provide an important genomic resource of basic and applied significance. A genetic linkage map was developed by genotyping 192 F1 progeny from a cross between L. caudata (female) and L. indica (' Xiang Xue Yun') (male) with a combination of amplification fragment length polymorphisms ( AFLP) and simple sequence repeats ( SSR) markers in a double pseudo-testcross mapping strategy. A total of 330 polymorphic loci consisting of 284 AFLPs and 46 SSRs showing Mendelian segregation were generated from 383 AFLP primer combinations and 150 SSR primers. The data were analysed using JoinMap 4.0 (evaluation version) to construct the linkage map. The map consisted of 20 linkage groups of 173 loci (160 AFLPs and 13 SSRs) covering 1162.1 cM with a mean distance of 10.69 cM between adjacent markers. The 20 linkage groups contained 2-49 loci and ranged in length from 7.38 to 163.57 cM. This map will serve as a framework for mapping QTLs and provide reference information for future molecular breeding work. [ABSTRACT FROM AUTHOR]

A total of 85 Chinese Cymbidiums and one Zygopetalum were collected and analysed using 29 simple sequence repeats ( SSRs) and 12 intersimple sequence repeats ( ISSRs). These Chinese Cymbidiums are some of the most popular cultivars in market. The pairwise genetic distance between these accessions averaged 0.897, ranging from 0.259 to 1.000. A model-based clustering analysis revealed five genetic groups with serious admixture ancestry, as indicated by a fixation index of 0.156 and only 10.67% genetic variation among groups. By analysing the cross-compatibility and pollen morphology, Chinese Cymbidiums are revealed to have high compatibility for intra- and interspecific crosses. Notably, Zygopetalum mackayi had high compatibility with Chinese Cymbidiums and shared similar morphologies in terms of pollinia and pollen grain. This study is the first to report a successful cross between Zygopetalum and Chinese Cymbidiums. The high compatibility offers the potential for introducing Zygopetalum mackayi's superior traits into Chinese Cymbidiums. The similar pollen morphology as well as the low genetic differentiation might be related to the high cross-compatibility among these accessions. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine quantitative trait loci ( QTL) underlying ten floral and related traits in Aquilegia. The traits assessed were calyx diameter, corolla diameter, petal length, petal blade length, sepal length, sepal width, spur length, spur width, plant height and flower number. These are important traits for ornamental value and reproductive isolation of Aquilegia. QTL analysis of these traits was conducted using single-marker analysis and composite interval mapping ( CIM). We used an F2 population consisting of 148 individuals derived from a cross between the Chinese wild species Aquilegia oxysepala and the cultivar Aquilegia flabellata 'pumila'. Resulting CIM analysis identified 39 QTLs associated with these traits, which were mapped on seven linkage groups. These QTLs could explain 1.22-53.28% of the phenotypic variance. Thirty-one QTLs, which explained more than 10% of the phenotypic variation, were classified as major QTLs. Graphical representations of the QTLs on seven linkage groups were made. Our research provides the potential for future molecular assisted selection breeding programmes and the cloning of target genes through fine mapping. [ABSTRACT FROM AUTHOR]

Carnation ( Dianthus caryophyllus L.) belongs to the family Caryophyllaceae in the order Caryophyllales. Plants in this order do not accumulate carotenoids in petals. To understand how carotenoid accumulation is controlled in carnation petals, we analysed the expression of genes related to carotenoid accumulation. Petals at an early stage of development accumulated small amounts of carotenoids. As petals matured, their carotenoid content decreased to extremely low levels. In contrast, carnation leaves contained substantial amounts of carotenoids that are essential for photosynthesis. Most of the carotenogenic genes were expressed in petals at levels similar to those in leaves, and the expression levels of these genes increased during petal development. Genes encoding phytoene synthase and lycopene ε-cyclase were exceptions. Their expression levels in petals were very low compared with those in leaves. Expression of the gene encoding carotenoid cleavage dioxygenase 4 was detected in neither leaves nor petals. These data suggest that the low levels of carotenoids in carnation petals are caused not by enzymatic degradation but rather by low rates of carotenoid biosynthesis. [ABSTRACT FROM AUTHOR]

Eustoma grandiflorum is one of the leading cut-flowers in Japan. There are market demands for cultivars with deep-yellow flowers, but they have never been bred successfully. By investigating the carotenoid accumulation and carotenogenic gene expressions, this study attempted to explore the reasons that block the formation of deep-yellow colour in Eustoma. High performance liquid chromatography analysis showed that the carotenoid compositions in petals were similar to those in leaves, accumulating mainly lutein, violaxanthin and β-carotene. The total carotenoid contents decreased as the petals matured in all the cultivars tested. Quantitative real-time PCR analysis showed that the expression levels of PSY, LCYB, ZDS and LCYE showed significant differences between white and pale-yellow petals or between petals and leaves, indicating that these enzymes may play a key role in the carotenoid biosynthesis in E. grandiflorum. The expression levels of CCD4 were high in both pale-yellow and white petals during development, suggesting that carotenoid degradation activity is high in the petals. We then conclude that the total carotenoid accumulation level could be determined by the balance between carotenoid biosynthesis and degradation activities. [ABSTRACT FROM AUTHOR]

All publicly available opium poppy expressed sequence tag ( EST) sequences, totalling 20 885, were assembled into unigenes and examined for simple sequence repeats ( SSRs). Nearly 19% of the 14 957 unigenes contained SSRs with 4% harbouring more than one SSR. Average density of the SSRs was 1 SSR per 3.6 kb of non-redundant EST sequence. Trinucleotide SSRs were most frequently identified (39%), and many of the most prevalent motifs were AT-rich. Flanking primers were designed for 86% of the SSRs and 67 primer pairs were tested on 37 opium poppy accessions and seven related species. All markers were transferable to the related species. Polymorphism information content ( PIC) values for the markers were intermediate for comparisons within opium poppy (average of 0.27) and slightly higher for comparisons across species (average of 0.29). The markers were found to be useful for diversity analysis as they successfully distinguished among Turkish opium poppy accessions and land races. [ABSTRACT FROM AUTHOR]

With 3 figures and 1 table A 600 bp fragment of the ethylene-receptor gene 2 ( ETR2) was sequenced in Petunia and Calibrachoa genotypes and in putative intergeneric somatic hybrids. In total, 16 genus-specific single base pair polymorphisms (SNPs) were detected. These were used to construct, genus specific restriction maps and a Cleaved Amplified Polymorphic Sequence marker with specific 400 bp fragments for Petunia and 550 bp for Calibrachoa. This diagnostic and robust marker is suitable to distinguish Petunia and Calibrachoa and is a valuable tool for the identification of intergeneric somatic hybrids which are currently developed in model breeding programmes. Based on sequence data for the ETR2 fragment, phylogenetic analyses were conducted. Neighbour-Joining trees reveal distinct subgroups of ETR2 of each genus, therefore supporting recent results of molecular phylogenetic studies on Petunia and Calibrachoa. Sequences of putative hybrids are represented in both subgroups, confirming their hybrid status. [ABSTRACT FROM AUTHOR]

Blackspot, caused byDiplocarpon rosae, is the most severe and ubiquitous disease of garden roses, but information is lacking about genotype-specific forms of resistance and susceptibility of the host. Macro- and microscopic analyses of 34 rose genotypes with a defined monoconidial culture black spot inoculum identified susceptible and resistant rose genotypes and further genotype-specific subdivisions, indicating the presence of partial forms of resistance and different resistance mechanisms. In total, eight interaction types were characterized, five representing compatible (types 1–5) and three representing incompatible interactions (types 6–8). The incompatible interactions were characterized by the lack of any visible fungal structures beneath the cuticle (type 8), single-cell necroses (type 7) or necroses of larger cell clusters (type 6), the latter two types with penetration hyphae and haustoria in epidermal cells. [ABSTRACT FROM AUTHOR]

Differentiation into physiological races of Diplocarpon rosae, which causes blackspot on wild and cultivated roses, was investigated with single conidial isolates of the pathogen. Infection experiments with a simple excised leaf assay demonstrated differential interactions between single isolates and a set of 10 test rose genotypes. Differential reactions could be observed among rose varieties as well as between and within a wild rose species. Accordingly, five different physiological races can be identified among the 15 isolates tested. A breeding line and one genotype of the wild species Rosa wichuraiana were found to be resistant against all isolates tested. These data will be employed in further investigations on the genetics of blackspot resistance in roses and for resistance breeding programmes. [ABSTRACT FROM AUTHOR]