Search

Milk thistle, Silybum marianum (L.) Gaertn. (Asteraceae), is an economically important medicinal plant utilized for silymarin production. Moreover, the species has been positively evaluated for vegetable oil and biomass production. Despite these positive characteristics, milk thistle is still marked by traits that are typical of undomesticated species (most importantly natural fruit dispersal at maturity) and requires further genetic improvement for its complete exploitation. This manuscript summarizes all the information collected through time about a collection of nine milk thistle wild and mutant lines and it discusses the possible further utilization of these genotypes. The accessions are characterized by interesting traits related to: fruit silymarin composition (S. marianum chemotype A and B), fruit fatty acid composition (high oleic and high stearic acid lines), fruit condensed tannins content, vegetative biomass composition (modification of xylans or lignin content), vegetative biomass structure (dwarf and tall lines), modifications of leaf variegation (hypervareigated line) and different types of fruit shatter resistance at maturity. All the lines underwent subsequent generations of selfing and are stable for all the described traits. The accessions will be made available at the Genebank of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK, Gatersleben) and may prove to be a useful genetic material for the improvement of qualitative fruit traits (silymarin quality, fatty acid composition) and for the further development of shatter-resistant S. marianum genotypes towards the complete domestication of this promising species.

The genetic diversity among an international collection of 40 maize accessions has been evaluated using DNA ISSR fingerprinting. Among the 180 ISSR markers scored by 15 primers, 161 markers (89.59%) were polymorphic and 19 were unique in 16 accessions. A cluster tree based on the average distance coefficients and the Dice similarity indices divided the accessions into three major groups, each including clusters of accessions assigned to their subspecies. However, a low level of genetic differentiation among the accessions was demonstrated by the STRUCTURE analysis of ISSR data in agreement with the low gene flow (Nm) value among the accessions. A scatter diagram of the principal component analysis (PCA) based on ISSR data analysis revealed that the accessions were differentiated into three groups comparable to those produced by the cluster analysis, in which some accessions of the same subspecies showed a close similarity to each other. A scatter diagram of the principal coordinate analysis (PCoA) based on the drought tolerance indices (DTIs) showed that nine genetically similar accessions share drought tolerance characteristics; these include four of subsp. indurata, three of subsp. everata, and two of subsp. indentata. An abundance of unique ISSR alleles found in the 16 accessions, including the nine drought-tolerant accessions, represents rich untapped genetic resources and these accessions may be exploited in the future breeding of maize commercial lines.

One hundred years ago N.I. Vavilov formulated the Law of homologous series in hereditary variability. Among the broad range of examples that encouraged N.I. Vavilov to make this important generalization, homologous series in plant height variability were mentioned. In the current review, we compare data collected over the century on genetic basis and molecular mechanisms behind the series in plant height variability with the stress on “Green revolution” genes. Application of fertilizers boosted redirection of artificial selection from tall-growing varieties to those with reduced height. The sources of GA-sensitive and GA-insensitive reduced height (Rht) genes in wheat and rice first were involved in crosses in Japan and China. The commercially valuable alleles of the Rht genes were spread broadly in varieties released in 1960s all over the world. Results of genetic studies into inheritance of the Rht genes are summarized for rice and wheat (together with further Triticeae crops–barley and rye). Three orthologous series of reduced plant height genes have been found within Triticeae tribe species and rice: (1) wheat Rht12 and rye Ddw1; (2) wheat Rht-B1/D1 and barley Dwf2; (3) barley denso/sdw1 and rice sd1. Molecular and cell mechanisms underlying plant reduced height are considered with focus on metabolic pathways regulated by commercially valuable alleles of Rht genes: GA-insensitive Rht-B1/D1 and GA-sensitive sd1, denso/sdw1, Rht8, Rht12, Rht18, Ddw1. Overall, in spite of similar metabolic pathways, the certain genes conferring variability for plant height are often distinct, resulting in existence of several “short” orthologous series of genes rather than one series through different cereal taxa.

Seed storage is important to farmers, breeders and for germplasm preservation. During storage, seeds accumulate damage at the structural and metabolic level, which disrupt their function and reduce resistance to adverse external conditions. In this regard, issues related to seed aging prove to be relevant for maintaining the viability of genetic collections. We analyzed morphological characteristics of grains and their coat color for 44 recombinant inbred lines (RILs) of bread wheat grown in four different seasons, 2003, 2004, 2009 and 2014. Our investigations were performed in 2020. For 19 RILs from the same seasons germination was evaluated. Our results demonstrate that genotype significantly affects the variability of all seed traits, and the year of harvesting affects about 80% of them (including all the traits of shape and size). To identify the trend between changes in grain characteristics and harvesting year, we estimated correlation coefficients between them. No significant trend was detected for the grain shape/size traits, while 90% of the color traits demonstrated such a trend. The most significant negative correlations were found between the harvesting year and the traits of grain redness: the greater the storage time, the more intensive is red color component for the grains. At the same time, it was shown that grains of longer storage time (earlier harvesting year) have lighter coat. Analysis of linear correlations between germination of wheat seeds of different genotypes and harvesting years and their seed traits revealed a negative linear relationship between the red component of coat color and germination: the redder the grains, the lower their germination rate. The results obtained demonstrate manifestations of metabolic changes in the coat of grains associated with storage time and their relationship with a decrease of seed viability.

Winter wheat growing areas in the Northern hemisphere are regularly exposed to heavy frost. Due to the negative impact on yield, the identification of genetic factors controlling frost tolerance (FroT) and development of tools for breeding is of prime importance. Here, we detected QTL associated with FroT by genome wide association studies (GWAS) using a diverse panel of 276 winter wheat genotypes that was phenotyped at five locations in Germany and Russia in three years. The panel was genotyped using the 90K iSelect array and SNPs in FroT candidate genes. In total, 17,566 SNPs were used for GWAS resulting in the identification of 53 markers significantly associated (LOD ≥4) to FroT, corresponding to 23 QTL regions located on 11 chromosomes (1A, 1B, 2A, 2B, 2D, 3A, 3D, 4A, 5A, 5B and 7D). The strongest QTL effect confirmed the importance of chromosome 5A for FroT. In addition, to our best knowledge, seven FroT QTLs were discovered for the first time in this study comprising QTLs on chromosomes 3A, 4A, 1B, and two on chromosomes 2D, 3D, and 7D. Identification of novel FroT candidate genes will help to better understand the FroT mechanism in wheat and to develop more effective combating strategies.

Combating hidden hunger through molecular breeding of nutritionally enriched crops requires a better understanding of micronutrient accumulation. We studied natural variation in grain micronutrient accumulation in barley (Hordeum vulgare L.) and searched for candidate genes by assessing marker-trait associations (MTAs) and by analyzing transcriptional differences between low and high zinc (Zn) accumulating cultivars during grain filling. A collection of 180 barley lines was grown in three different environments. Our results show a pronounced variation in Zn accumulation, which was under strong genotype influence across different environments. Genome-wide association mapping revealed 13 shared MTAs. Across three environments, the most significantly associated marker was on chromosome 2H at 82.8 cM and in close vicinity to two yellow stripe like (YSL) genes. A subset of two pairs of lines with contrasting Zn accumulation was chosen for detailed analysis. Whole ears and flag leaves were analyzed 15 days after pollination to detect transcriptional differences associated with elevated Zn concentrations in the grain. A putative α-amylase/trypsin inhibitor CMb precursor was decidedly higher expressed in high Zn cultivars in whole ears in all comparisons. Additionally, a gene similar to barley metal tolerance protein 5 (MTP5) was found to be a potential candidate gene.

The future productivity of wheat (T. aestivum L.) as the most grown crop worldwide is of utmost importance for global food security. Thousand kernel weight (TKW) in wheat is closely associated with grain architecture-related traits, e.g. kernel length (KL), kernel width (KW), kernel area (KA), kernel diameter ratio (KDR), and factor form density (FFD). Discovering the genetic architecture of natural variation in these traits, identifying QTL and candidate genes are the main aims of this study. Therefore, grain architecture-related traits in 261 worldwide winter accessions over three field-year experiments were evaluated.Genome-wide association analysis using 90K SNP array in FarmCPU model revealed several interesting genomic regions including 17 significant SNPs passing false discovery rate threshold and strongly associated with the studied traits. Four of associated SNPs were physically located inside candidate genes within LD interval e.g. BobWhite_c5872_589 (602,710,399 bp) found to be inside TraesCS6A01G383800 (602,699,767-602,711,726 bp). Further analysis reveals the four novel candidate genes potentially involved in more than one grain architecture-related traits with a pleiotropic effects e.g. TraesCS6A01G383800 gene on 6A encoding oxidoreductase activity was associated with TKW and KA. The allelic variation at the associated SNPs showed significant differences betweeen the accessions carying the wild and mutated alleles e.g. accessions carying C allele of BobWhite_c5872_589, TraesCS6A01G383800 had significantly higher TKW than the accessions carying T allele. Interestingly, these genes were highly expressed in the grain-tissues, demonstrating their pivotal role in controlling the grain architecture.These results are valuable for identifying regions associated with kernel weight and dimensions and potentially help breeders in improving kernel weight and architecture-related traits in order to increase wheat yield potential and end-use quality.

Genetic diversity and population structure are key resources for breeding purposes and genetic studies of important agronomic traits in crops. In this study, we described SNP-based genetic diversity, linkage disequilibrium and population structure in a panel of 179 bread wheat advanced cultivars and old accessions from Bulgaria, using an optimized wheat 25K Infinium iSelect array. Out of 19,019 polymorphic SNPs, 17,968 had а known chromosome position on the A (41%), B (42%) and D (11%) genome, and 6% were not assigned to any chromosome. Homoeologous group 4, in particular chromosome 4D, was the least polymorphic. In the total population, the Nei’s gene diversity was within the range 0.1-0.5, and the polymorphism information content ranged from 0.1 to 0.4. Significant differences between the old and modern collections were revealed with respect to the linkage disequilibrium (LD): the average values for LD (r2), the percentage of the locus pairs in LD and the LD decay were 0.64, 16% and 3.3 for the old germplasm, and 0.43, 30% and 4.1 for the modern releases, respectively. Structure and k-means clustering algorithm divided the panel into three groups. The old accessions formed a distinct subpopulation. The cluster analysis further distinguished the modern releases according to the geographic region and genealogy. Gene exchange was evidenced mainly between the subpopulations of contemporary cultivars. The achieved understanding of the genetic diversity and structure of the Bulgarian wheat population and distinctiveness of the old germplasm could be of interest for breeders developing cultivars with improved characteristics. The obtained knowledge about SNP informativeness and the LD estimation are worthwhile for selecting markers and for considering the composition of a population in association mapping studies of traits of interest.

Salinity increases in the world’s land area and significantly affects the rate of photosynthesis and corresponding plant growth. In this study, the impact of salt stress (200 mM NaCl equivalent to an electrical conductivity of 18.6 mS cm−1) on the photosynthetic apparatus and some growth parameters were investigated in wheat DELLA mutant (Rht-B1c) and wild-type (Rht-B1a) seedlings grown on a half-strength Hoagland solution. Results revealed that salt toxicity was alleviated in the Rht-B1c mutant compared to the Rht-B1a wild type, as manifested by less-reduced leaf pigment content, relative water content, and photochemical activity of photosystem II (PSII) and photosystem I (PSI) after a 9-day salt exposure of plants. Compared to the wild-type wheat, a higher capacity for PSI-dependent cyclic electron flow, preventing the photosynthetic apparatus from oxidative damage, was observed in the mutant plants before and after salt treatment. In addition, an increase of PsaB proteins was detected in the mutant plants after long-term salt stress unlike the wild type. The observed higher oxidation level of P700 (P700+) in the mutant was consistent with higher abundance of PSI-related protein complexes. The data demonstrated that alterations in thylakoid membrane proteins and/or their structural reorganization in wheat DELLA mutant (Rht-B1c) significantly contribute to the alleviation of salt-induced damage of the photosynthetic apparatus. Molecular mechanisms involved in the photosynthetic responses of wheat DELLA mutants to salt stress are discussed.

Low molecular weight carbohydrates of seeds of 10 species of Vicia, namely: V. angustifolia, V. articulata, V. cordata, V. ervilia, V. johannis, V. macrocarpa, V. monantha, V. narbonensis, V. pannonica and V. sativa were analyzed by the high resolution gas chromatography method. Seeds of the investigated species contain common (glucose, fructose, myo-inositol, sucrose, galactinol, di-galactosyl myo-inositol and raffinose family oligosaccharides—RFOs) and species-specific carbohydrates (d-pinitol and its α-d-galactosides—in V. articulata, V. monantha and V. pannonica or d-ononitol and its galactoside—in V. ervilia). Among the species containing in seeds RFOs as the main α-d-galactosides (V. angustifolia, V. cordata, V. johanensis, V. macrocarpa, V. narbonensis and V. sativa), an additional subgroup can be separated, which contains a set of unknown compounds (found in V. angustifolia, V. cordata and V. macrocarpa). Moreover, several other unidentified carbohydrate-containing compounds were detected exclusively in seeds of V. ervilia. The concentrations of total soluble carbohydrates (TSCs), including sugars, RFOs, cyclitols and galactosyl cyclitols and unknown compounds, in seeds differ significantly (P

The paper assess the variability of fat content and fatty acids profiles in seeds of a white lupin (Lupinus albus L.) domestic collection. The initial material comprised 371 accessions originated from 30 countries of Europe, Asia, Africa, North- and South America and Australia. According to data given by accession donors the material is divided into four classes of origin: wild lines, landraces, lines created by man and cultivars. Variability of fat content and fatty acids composition were estimated in seeds of each accession. The average fat content for analyzed collection is 9.81%. The broadest range of fat content was noticed for landraces and cultivars as compared to narrowest represented by lines created by man. Fat content ranged from 6.9% (induced mutant Wt 95497) to 14.1% (Polish cultivar Wt 95420 and the landrace Wt 95212 from Jordan). From a dietetic point of view, oil quality is more important than oil quantity in lupin seeds. On average the fatty acid (FA) in examined accessions ranked in following order of abundance: oleic acid (C18:1) > linoleic acid (C18:2) > linolenic acid (C18:3) > palmitic acid (C16:0) > eicosenoic acid (C20:1) > stearic acid (C18:0) ≈ erucic acid (C22:1). In respect to unsaturated fatty acid (UFA), monounsaturated oleic acid in each of estimated classes of accessions was predominant and most abundant (55.7%) in broad range of minimum–maximum values from 41.2 to 66.2%. The second examined monounsaturated fatty acid was erucic acid (1.74%) found in seeds of almost all studied accessions. An exception were four accessions defined similarly to rapeseeds as “zero erucic” forms. In seeds of few accessions a content of erucic acid exceeded 3%. Among polyunsaturated fatty acids linoleic FA (ω−6) dominated followed by linolenic FA (ω−3). Both FA were in the range 13.7–33.2% and 5.6–12.8% with mean values on the level 19.6 and 10.1%, respectively. As a consequence, the examined white lupin seeds showed a very favourable ω−3/ω−6 FA ratio (0.51), ranging from 0.21 to 0.87, much higher than that of most vegetable oils. Fat content was positively correlated with stearic and oleic fatty acids and negatively with palmitic, linoleic, linolenic and erucic acid.

Melanins are a class of darkly pigmented biopolymers which are widely distributed among living organisms. The molecular and cellular mechanisms adopted by bacteria, fungi and animals to synthesize melanin, have been well described, but less is known regarding their production in plants. Here, a pair of barley near isogenic lines, bred to differ with respect to the pigmentation of the spike, was compared in order to understand the tissue and cellular location of melanin deposition. The melanic nature of the pigments purified from black spikes was confirmed by a series of solubility tests and Fourier transform infrared spectroscopy. An analysis of grains harvested at various stages of their development revealed that intracellular pigmented structures first appeared in the pericarp and the husk of black spike plants at early dough stage. The co-localization of these structures with red autofluorescence suggested that they form in chloroplast-derived plastids, here designated “melanoplasts”. Differences in dynamics of plastid internal structure during grain ripening were detected between the lines by transmission electron microscopy. Both lines accumulated plastoglobuli inside plastids, which persisted in black grain pericarp tissue up to the hard dough stage, while neither plastoglobuli nor any plastids were observed in grain of the control line at this stage. The role of plastoglobuli in melanin synthesis is discussed.

Interspecific hybridization and polyploidization are the characteristic processes of evolution in the world of plants. The allopolyploid genomes undergo numerous structural rearrangements associated with the adaptation of separate genomes to each other. An important issue is to establish which part of the total diversity of genes characteristic of the ancestral forms have been preserved and manifested in the complex genomes. The aim of this work was to compare the diversity of the adaptive morphological trait-leaf pubescence among the relatives and the ancestors of hexaploid wheats to establish the variability of its phenotypic manifestation as a result of evolution and domestication. This was achieved through the study of quantitative characteristics of leaf pubescence among 47 representatives of di-, tetra- and hexaploid species of genera Triticum and Aegilops, the donors of the individual genomes of the allopolyploid Triticum species. Quantification of leaf pubescence was based on automated counting of the trichome number (N) and trichome length (L) estimation on a leaf fold and calculation of the pubescence index H (L/N). The species with different sets of elementary genomes differed for the type of pubescence. The ploidy level affected only the trichome length and the index of pubescence H L/N . The density of the hairs was affected by the individual genomes A and B, whereas genome D significantly influenced all of the studied pubescence parameters. The diploid species showed the largest variability while the cultivated durum wheats lacked pubescence. Bread wheat demonstrated pubescence characterized by a close correlation between N and L.

Anthocyanins contribute to plants’ defence against a number of abiotic and biotic stress agents. The anthocyanin pigmentation of the barley leaf sheath is genetically determined by Ant1, a gene which maps to a region of chromosome 7HS delimited by the microsatellite loci Xgbms0226 and Xgbms0240. The sequence of the maize gene C1 (encoding an R2R3 MYB factor regulating anthocyanin synthesis) was used for the PCR-based cloning of Ant1. In ant1 genotypes, no transcript is generated in the leaf sheath, whereas the gene is active in the presence of the dominant allele. A comparison of the coding and promoter sequences of Ant1 (which induces purple pigmentation in the leaf sheath) and ant1 (which does not) showed that the key polymorphisms lay in the promoter sequence. The transcription of four anthocyanin synthesis structural genes (Chi, F3h, Dfr, Ans) was dependent on the allelic status of Ant1.

Seed longevity is a crucial issue for germplasm conservation and seed marketing. This trait is determined not only by environmental conditions, but also by genetic factors. Molecular mapping of responsible loci has been performed with several crops, but not with tobacco (Nicotianatabacum L.). In the present study, we investigate 122 recombinant inbred lines derived from a cross between the cultivars Florida 301 and Hicks. Four germination-related traits were studied by examining seeds either untreated or after controlled deterioration (CD): total germination (TG, %), normal germination (%), time to reach 50 % of TG (h), and the area under the curve after 200 h of germination. Whereas Hicks exhibited high germination percentage and speed in untreated (fresh) seeds, Florida 301 seems to withstand the CD treatment better, having increased seed longevity. In total, four genomic regions located on four different linkage groups (LGs) were identified to be associated with the selected traits. Positive alleles for the individual traits were contributed by both parents. A major quantitative trait locus (QTL) for high percentage TG located on LG 8/18 appeared in both control and deteriorated seeds and was contributed by Hicks. In contrast, Florida 301 donated a favorable allele for germination speed on LG seven after CD only. The position of this locus compared well with a QTL detected in the same population, in a former study examining resistance against the black shank disease caused by Phytophthora nicotianae). The effects of environmental growing conditions of the mother plants on seed longevity are discussed.

Background Among natural populations, there are different colours of barley (Hordeum vulgare L.). The colour of barley grains is directly related to the accumulation of different pigments in the aleurone layer, pericarp and lemma. Blue grain colour is due to the accumulation of anthocyanins in the aleurone layer, which is dependent on the presence of five Blx genes that are not sequenced yet (Blx1, Blx3 and Blx4 genes clustering on chromosome 4HL and Blx2 and Blx5 on 7HL). Due to the health benefits of anthocyanins, blue-grained barley can be considered as a source of dietary food. The goal of the current study was to identify and characterize components of the anthocyanin synthesis regulatory network for the aleurone layer in barley. Results The candidate genes for components of the regulatory complex MBW (consisting of transcription factors MYB, bHLH/MYC and WD40) for anthocyanin synthesis in barley aleurone were identified. These genes were designated HvMyc2 (4HL), HvMpc2 (4HL), and HvWD40 (6HL). HvMyc2 was expressed in aleurone cells only. A loss-of-function (frame shift) mutation in HvMyc2 of non-coloured compared to blue-grained barley was revealed. Unlike aleurone-specific HvMyc2, the HvMpc2 gene was expressed in different tissues; however, its activity was not detected in non-coloured aleurone in contrast to a coloured aleurone, and allele-specific mutations in its promoter region were found. The single-copy gene HvWD40, which encodes the required component of the regulatory MBW complex, was expressed constantly in coloured and non-coloured tissues and had no allelic differences. HvMyc2 and HvMpc2 were genetically mapped using allele-specific developed CAPS markers developed. HvMyc2 was mapped in position between SSR loci XGBS0875-4H (3.4 cM distal) and XGBM1048-4H (3.4 cM proximal) matching the region chromosome 4HL where the Blx-cluster was found. In this position, one of the anthocyanin biosynthesis structural genes (HvF3’5’H) was also mapped using an allele-specific CAPS-marker developed in the current study. Conclusions The genes involved in anthocyanin synthesis in the barley aleurone layer were identified and characterized, including components of the regulatory complex MBW, from which the MYC-encoding gene (HvMyc2) appeared to be the main factor underlying variation of barley by aleurone colour. Electronic supplementary material The online version of this article (10.1186/s12870-017-1122-3) contains supplementary material, which is available to authorized users.

Globally, over 7.4 million accessions of crop seeds are stored in gene banks, and conservation of genotypic variation is pivotal for breeding. We combined genetic and biochemical approaches to obtain a broad overview of factors that influence seed storability and ageing in barley (Hordeum vulgare). Seeds from a germplasm collection of 175 genotypes from four continents grown in field plots with different nutrient supply were subjected to two artificial ageing regimes. Genome-wide association mapping revealed 107 marker trait associations, and hence, genotypic effects on seed ageing. Abiotic and biotic stresses were found to affect seed longevity. To address aspects of abiotic, including oxidative, stress, two major antioxidant groups were analysed. No correlation was found between seed deterioration and the lipid-soluble tocochromanols, nor with oil, starch and protein contents. Conversely, the water-soluble glutathione and related thiols were converted to disulphides, indicating a strong shift towards more oxidizing intracellular conditions, in seeds subjected to long-term dry storage at two temperatures or to two artificial ageing treatments. The data suggest that intracellular pH and (bio)chemical processes leading to seed deterioration were influenced by the type of ageing or storage. Moreover, seed response to ageing or storage treatment appears to be significantly influenced by both maternal environment and genetic background.

The existence of hybrid dwarfs from intraspecific crosses in wheat (Triticum aestivum) was described 100 years ago, and the genetics underlying hybrid dwarfness are well understood. In this study, we report a dwarf phenotype in interspecific hybrids between wheat and rye (Secale cereale). We identified two rye lines that produce hybrid dwarfs with wheat and have none of the hitherto known hybrid dwarfing genes. Genetic analyses revealed that both rye lines carry a single allelic gene responsible for the dwarf phenotype. This gene was designated Hdw-R1 (Hybrid dwarf-R1). Application of gibberellic acid (GA3 ) to both intraspecific (wheat-wheat) and interspecific (wheat-rye) hybrids showed that hybrid dwarfness cannot be overcome by treatment with this phytohormone. Histological analysis of shoot apices showed that wheat-rye hybrids with the dwarf phenotype at 21 and 45 days after germination failed to develop further. Shoot apices of dwarf plants did not elongate, did not form new primordia and had a dome-shaped appearance in the seed. The possible relationship between hybrid dwarfness and the genes responsible for the transition from vegetative to generative growth stage is discussed.

Phytohormones, a group of structurally unrelated small molecules are plant-signalling compounds that trigger induced resistance against certain pathogens and herbivores. The hormones jasmonic acid (JA), ABA, salicilic acid (SA) and ethylene (ET) are known to play major roles in regulating plant defence responses. In order to determine the changes in growth and in the chlorophyll content induced by the exogenous application of these elicitors, a set of DH lines of the Oregon-Wolfe Barley mapping population, previously screened to locate aphid resistant genes, was investigated. The aim of the current research was to map the induced defence genes and to reveal the relationship with aphid resistance. There were highly significant differences between controls and hormone treated plants in the aerial fresh and dry weights (AFW, ADW), the foliar area (FA) and the root dry weight (RDW). More than 15 JA and ET-induced lines exceeded the chlorophyll (Ch) values of their controls. Most of the plant traits were associated with the same genetic windows on chromosomes 3H, 5H and 7H in the controls and hormone treated plants. QTL(s) identified on chromosome 3H and 5H explained most of the variation of AFW, ADW, FA and RDW of controls and treated plants. QTL(s) located on chromosome 5H were associated with the variation of chlorophyll contents on JA-treated plants. The Ch in ET and ABA-treated plants was associated with two different regions on chromosome 7H. One of the latter genetic windows also explained the variation of RDW of ET- and ABA-treated plants. A sequence homology search was performed to derive the putative function of the genes linked to the QTLs. Several QTLs were identified located close to aphid resistance genes previously mapped. This is the first report of genes associated with hormone response in barley that could be involved with insect resistance. Those recombinant lines carrying the appropriate alleles could be useful for breeding barley to enlarge the genetic base of defence against stress., Facultad de Ciencias Agrarias y Forestales

Understanding of the genetic basis of physiological properties, which are most relevant to water-deficit tolerance would be helpful for genomic-assisted improvement of bread wheat. A set of bread wheat inter-varietal single chromosome substitution lines (ISCSLs) of variety ‘Janetzkis Probat’ (JP) in the genetic background of ‘Saratovskaya’ 29 (S29) were used to reveal the critical chromosomes in wheat genome controlling tolerance to water deficit. The same lines were involved in the identification of chromosomes associated with the activity of antioxidant enzymes that are closely related to the detoxification of H2O2 [catalase (CAT), ascorbate peroxidase, dehydroascorbate reductase and glutathione reductase (GR)]. The recipient cultivar S29 was highly drought tolerant while the donor JP was sensitive. Using non-metric multidimensional scaling of yield components and indices of drought tolerance/susceptibility chromosomes 2A and 4D, substitution in the genetic background of S29 was found to lead to a critical decrease of water-deficit tolerance. The drop of tolerance correlated with a sharp decline of cumulative activity of the catalase and the enzymes of ascorbate–glutathione cycle in wheat leaves. Clear evidence was obtained for the involvement of genes present on the homoeologous group 2 chromosomes in the control of GR and CAT activity. Substitution of the chromosome 4D had a significant reducing impact on the CAT activity level.

The changes in the reproductive barrier between hexaploid wheat ( Triticum aestivum L.) and rye ( Secale cereale L.) can be induced using in situ embryo rescue of abnormal embryos, yielding stable fertile amphidiploid plants. In intergeneric crosses between hexaploid wheat (Triticum aestivum L.) and rye (Secale cereale L.), postzygotic barriers may occur at different stages of hybrid development. One such mechanism is embryo lethality, which is genetically determined by the interaction and expression of two incompatible genes in wheat (Eml-A1) and rye (Eml-R1). Using in vitro culture methods as stressors, we overcame this hybrid lethality. Normal and abnormal embryos were observed to build embryogenic calli and produce regenerated plantlets in a similar manner. The high regenerative capacity of the abnormal embryos led us to conclude that the reproductive barrier in these intergeneric hybrids may have an epigenetic origin that can be easily overcome by culturing immature embryos via callus induction. After colchicine treatment during callus culture, amphidiploid plants were obtained. However, most of these plants did not produce seeds, due mainly to sterility of the pollen but also of the embryo sacs. These findings demonstrate that hybrid sterility affects both male and female gametophytes in plants obtained from abnormal embryos. The key roles of double fertilization and stress factors in the implementation of the apical meristem formation program in embryos from incompatible intergeneric crosses between hexaploid wheat and rye during in vitro culture are discussed. We also propose a hypothetical model for a wheat–rye lethality system involving differential expression of incompatible wheat Eml-A1 and rye Eml-R1b alleles in an identical genetic background.

About 10% of the world's vegetable production is generated from Brassicaceae, wherein Brassica rapa is a dominating species. There is growing evidence that glucosinolates (GLSs), main plant secondary metabolites in Brassicales, play an important role in promoting human health. Natural genetic diversity of B. rapa can be explored for vegetable improvement. We analyzed leaves and tubers of 16 B. rapa turnips for their GLS composition by UHPLC-DAD and the corresponding hydrolysis products by GC–MS. Thirteen GLSs were identified, 8 aliphatic, 4 indolic and one aromatic. 3-Butenyl GLS was prevailing in both plant organs while in tubers 2-hydroxy-3-butenyl GLS and 2-phenylethyl GLS occurred in high amounts. A total of 24 GLS breakdown products were detected in tubers and 16 in leaves. Epithionitriles were the main hydrolysis products in both plant organs with 4,5-epithiopentanenitrile and 3-hydroxy-4,5-epithiopentanenitrile being the main compounds. When comparing leaves and tubers, an accumulation of GLSs and their breakdown products was observed in tubers compared to leaves. Our analysis achieved the comprehensive profiling of all GLS metabolites in a collection of B. rapa turnips, underlining the natural variation not only of intact GLS, but also of their breakdown products.

While often thought of as a smoking drug, tobacco (Nicotiana spp.) is now considered as a plant of choice for molecular farming and biofuel production. Here, we describe a noninvasive means of deriving both the distribution of lipid and the microtopology of the submillimeter tobacco seed, founded on nuclear magnetic resonance (NMR) technology. Our platform enables counting of seeds inside the intact tobacco capsule to measure seed sizes, to model the seed interior in three dimensions, to quantify the lipid content, and to visualize lipid gradients. Hundreds of seeds can be simultaneously imaged at an isotropic resolution of 25 µm, sufficient to assess each individual seed. The relative contributions of the embryo and the endosperm to both seed size and total lipid content could be assessed. The extension of the platform to a range of wild and cultivated Nicotiana species demonstrated certain evolutionary trends in both seed topology and pattern of lipid storage. The NMR analysis of transgenic tobacco plants with seed-specific ectopic expression of the plastidial phosphoenolpyruvate/phosphate translocator, displayed a trade off between seed size and oil concentration. The NMR-based assay of seed lipid content and topology has a number of potential applications, in particular providing a means to test and optimize transgenic strategies aimed at the manipulation of seed size, seed number, and lipid content in tobacco and other species with submillimeter seeds.

Previously, it was suggested that purple grain colour was transferred to bread wheat from purple-grained tetraploid T. durum. In the current study, we demonstrated that the D genome of bread wheat ‘Purple’ carries one of two complementary genes determining purple grain colour. This gene was mapped on the short arm of chromosome 7D 2.5 cM distal to the locus Rc-D1 determining red coleoptile colour. This position is highly comparable with that of the Pp1 gene mapped earlier on the short arm of chromosome 7B in tetraploid T. durum.We suggest the Pp genes on T. durum chromosome 7B and T. aestivum chromosome 7D are orthologous. We designated them Pp-B1 and Pp-D1, respectively. Microsatellite-based genotyping of near-isogenic lines ‘i:S29Pp1Pp2PF’ and ‘i:S29Pp1Pp3P’, their recurrent (T. aestivum ‘Saratovskaya 29’) and donor (T. aestivum ‘Purple Feed’ and ‘Purple’, respectively) parents showed the presence of donor introgressions on chromosomes 2A and 7D in both near-isogenic lines. In addition to previously des...

A collection of 220 accessions of parsley (Petroselinum crispum [Mill.] Nyman) was evaluated at two experimental stations (Gatersleben and Quedlinburg, Germany) under natural infection. Widespread origins of tested accessions provide the opportunity for first-time characterization of existence, spreading and level of resistance/susceptibility to the economically important pathogens Septoria petroselini Desm., Plasmopara petroselini Savul. et O. Savul. and Erysiphe heraclei DC. ex Saint-Aman causing Septoria blight, downy mildew and powdery mildew respectively throughout the species P. crispum. For each pathogen, accessions free or nearly free of symptoms were found: S. petroselini: free 1, nearly free 25, P. petroselini: free 51, nearly free 22 and E. heraclei: free 166. Eight accessions are free or nearly free of symptoms for all three pathogens: PET36, PET169, PET172, PET177, PET178, PET192, PET212 and PET214. The accession PET16 is free of symptoms for both S. petroselini and P. petroselini. Most of the resistant material comes from Southern and Eastern Europe. There could be a centre for resistances of parsley.

The pattern of inheritance of powdery mildew resistance expressed by two bread wheat (cultivar ‘Alcedo’)/Aegilops markgrafiiintrogression lines was explored using F2populations bred from crosses made with the powdery mildew-susceptible cultivar ‘Kanzler’. Disease reaction was tested at both seedling and adult plant stages. Two resistance loci, designatedQPm.ipk-1AandQPm.ipk-7A, were identified as mapping to the distal ends of chromosome arms 1AS and 7AL, respectively. WhereasQPm.ipk-1Awas expressed throughout the plant's life,QPm.ipk-7Awas only effective at the seedling stage. The map location of both resistance loci indicated that resistances originated fromA. markgrafii.The possible genetic relationship of these disease-resistant genes to knownPmgenes is discussed in the context of synteny.

A collection of introgression lines was obtained from crosses of common wheat ( Triticum aestivum L.) cultivars with tetraploid wheat Triticum timopheevii (Zhuk.). Evaluation of resistance to fungal diseases re - vealed the lines with resistance to leaf and stem rusts, powdery mildew, spot blotch, and loose smut, the most widespread in Siberian region of Russia. Localization of the T. timopheevii genome fragments by means of microsatellite markers determined higher frequency of substitutions and translocations on chromosomes 1А, 2A, 2B, 5A, 5B and 6B. Molecular mapping of the loci determining leaf rust resistance revealed two independ - ent loci on chromosomes 5B and 2A. The major locus on 5BS.5BL-5GL translocated chromosome accounting 64% of the phenotypic variance of the trait was found to be closely linked to microsatellite markers Xgwm814 and Xgwm1257. The other, minor locus, controlling 11% of the trait was mapped next to Xgwm312 on chromo- some 2A. Microsatellite markers located near these genes may be used for controlling the transfer of valuable traits in new wheat cultivars.

Anthocyanin accumulation in vegetative organs has a relationship to stress resistance in plants. In wheat, ability to accumulate anthocyanins in the coleoptile is inherited and controlled by the Rc (red coleoptile) genes. The aim of the current study was to find potential sources of ‘strong’ Rc alleles conferring very high levels of anthocyanin production and to study the effect of genetic background on Rc expression. We measured the relative anthocyanin content (OD530) in the coleoptile of different wheat and wheat-alien genetic stocks and accessions to find potential sources of ‘strong’ Rc alleles conferring very high levels of anthocyanin production. The OD530 values varied from 0.514 to 3.311 in genotypes having red coleoptiles. The highest anthocyanin content was detected in coleoptiles of four Triticum dicoccoides accessions originating from Israel and the Russian T. aestivum cultivar ‘Novosibirskaya 67’, suggesting that their Rc alleles can be used to increase anthocyanin content in the coleoptile of wheat cultivars. It is also suggested that rye Rc alleles, such as that of Russian cultivar ‘Selenga’, can be used to increase anthocyanin content in triticale seedlings.