Composition of guttation fluid from rye, wheat, and barley seedlings

This work was undertaken to determine the kinds and amount of substances that would account for the previously demonstrated differential growth of Claviceps purpurea on guttation fluids from Rosen rye, Genesee wheat, and Traill barley seedlings. Chromatographic methods were used for determining amino acids and sugars, spot tests and spectrometric methods for inorganic materials, and microbiological methods for vitamins.

Total sugar content is about equal in rye and barley fluids, but lower in wheat. Glucose is the principal sugar component of the rye and barley fluids and galactose highest in wheat. Most of the amino acid in all 3 fluids is aspartic acid or asparagine. Barley fluid is far higher than the other 2 in total amino acids, with wheat the lowest. Most inorganic elements are found to be highest in barley and lowest in wheat, with the exception of iron where rye is highest and barley lowest. Barley fluid is highest in choline, p-aminobenzoic acid, thiamine, and uracil, while rye is highest in inositol and pyridoxine. Wheat is much lower than the other 2 in choline and inositol.

     

Pathogenicity of Fusarium graminearum Schwabe isolates from Poland towards seedlings of cereal species

Ten isolates ofFusarium graminearum Schwabe originating from diseased cereal plants and kernels were tested for pathogenicity to various cultivars of wheat, rye, triticale and oats. The isolates varied greatly in their pathogenicity to the seedlings of the species, and were most pathogenic to rye and triticale, less pathogenic to barley and wheat and least pathogenic to oats.     

Occurrence and synthesis of lectin in coleoptiles of germinating wheat,rye and rice seedlings

Occurrence, synthesis and localization of lectins in coleoptiles of 3-day old seedlings of wheat, rye, barley and rice were studied by a combination of high resolution ion-exchange chromatography, in vivo labelling with ³⁵S-cysteine and immunocytochemistry. Whereas no lectin can be isolated or localized in barley coleoptile, 1.9 and 40 ng of lectin per coleoptile was obtained from wheat and rye respectively. Wheat germ agglutinin was localized in the outer layer of the wheat coleoptile and both inner and outer layers of rye coleoptile displayed a specific reaction. In rice, 250 ng of lectin is present in the coleoptile and is distributed throughout this organ. Wheat coleoptiles synthesize no lectin and rye coleoptiles synthesize minute amounts while those from developing rice seedlings incorporate reasonable amounts of ³⁵S-cysteine into lectin.Abbreviations FPLC Fast Protein Liquid Chromatography - GlcNAc N-acetylglucosamine - PBS phosphate buffered saline - SDS-PAGE sodium dodecyl sulphate polyacrylamide gel electrophoresis     

Effects of Seselin and Coumarin on Growth, Indoleacetic Acid Oxidase, and Peroxidase, with Special Reference to Cucumber (Cucumis sativa L.) Radicles

Seselin, a natural coumarin derivative isolated from citrus roots, inhibited radicle growth in seedlings of cucumber (Cucumis sativa), lettuce (Lactuca sativum), radish (Raphanus sativus), and wheat (Triticum aestivum) grown in the dark. Coumarin similarly inhibited radicle growth of cucumber seedlings. Growth retardation of the cucumber radicles was accompanied by an increased activity of peroxidase and indole-3-acetic acid oxidase. Both compounds antagonized indole-3-acetic acid-induced growth of wheat coleoptiles, whereas coumarin was much less effective than seselin in antagonizing gibberellic acid-induced release of reducing sugars from barley endosperm. It is suggested that seselin plays an important role in the regulation of root growth, and that it is the indole-3-acetic acid oxidase cofactor previously detected in citrus roots.     

Constitutive and cold-induced resistance of rye and wheat seedlings to oxidative stress

The influence of cold hardening of rye (Secale cereale L.) and wheat (Triticum aestivum L.) seedlings on their resistance to the oxidative stress (OS) agents, namely, 50 mM hydrogen peroxide or 5 mM iron (II) sulfate was studied. Unhardened rye seedlings were more resistant to hydrogen peroxide than those of wheat, since their growth was less inhibited, and they accumulated lesser amounts of lipid peroxidation products after a treatment with H₂O₂. The interspecific differences in responses to FeSO₄ were less significant. The unhardened seedlings of rye, in comparison with those of wheat, possessed more active guaiacol peroxidase (GPO) and more levels of anthocyanins and proline. In response to the OS agents, the unhardened rye seedlings enhanced activities of superoxide dismutase and catalase, whereas the wheat seedlings enhanced GPO activity and proline content. The cold hardening (6 days at 2°C) increased activities of antioxidant (AO) enzymes, contents of proline, sugars, and anthocyanins in seedlings of both species, and made the seedlings more resistant to the OS agents. After the cold hardening, rye seedlings were more resistant to OS than wheat seedlings. The hardened seedlings of both species activated the AO enzymes in response to H₂O₂ or FeSO₄ greater than the unhardened ones. However, the hardened wheat seedlings, in contrast to the unhardened ones, did not augment the proline content in contact with the OS agents. The conclusion was drawn on different contributions of AO enzymes and low-molecular weight compounds to the basal and induced by the cold—hardening resistances of rye and wheat seedlings to OS.     

Cytoplasmic DNA variation and relationships in cereal genomes

Summary Chloroplast (cp) and mitochondrial (mt) DNAs were isolated from four cereal genomes (cultivated wheat, rye, barley and oats) and compared by restriction nuclease analysis. Cleavage of cp and mt DNAs by Sal I, Kpn I, Xho I and EcoR I enzymes indicated that each cereal group contains specific cytoplasmic DNAs. A phylogenetic tree of cereal evolution has been obtained on the basis of cp DNA homologies. It is suggested that wheat and rye diverged after their common ancestor had diverged from the ancestor of barley. This was preceded by the divergence of the common ancestor of wheat, rye and barley and the ancestor of oats.The molecular weight of the different cp DNAs was determined from the Sal I and Kpn I patterns. cp DNAs from wheat, rye, barley and oats appeared to be characterized by a very similar molecular weight of about 80–82.10⁶ d.In the case of the mt DNAs, the great number of restriction fragments obtained with the restriction enzymes used prevented precise comparisons and determination of molecular weights.     

Production of trigeneric (barley × wheat) × rye hybrids

Summary Rye (Secale cereale cv. Prolific 2n=14 and 2n =14 + 2B was crossed onto hybrids between barley (Hordeum vulgare 2n = 14) and wheat (Triticum aestivum 2n= 42). Pollinated florets were injected with GA₃ to promote fertilization and hybrid embryo development. At 16 days after pollination the watery caryopses were removed, embryos dissected and cultured on a modified B₅ medium. Approximately 20% of the cultured embryos produced both roots and coleoptile and developed into viable seedlings. Viable seeds were also obtained at a low frequency from the same cross combinations. The hybrids were wheat-like except for the hairy neck characteristic of rye. There were 35 chromosomes in somatic tissue; 21 wheat, 7 barley and 7 rye. The rye chromosomes were distinguishable by their larger size and terminal C-bands. A lower seed set was obtained using pollen from rye plants with 2n=14 + 2B chromosomes than from plants without B chromosomes.Contribution No. 577, Ottawa Research Station     

The Chemical Induction of Supernumerary Shoots in the Developing Embryos of Wheat

The induction of seedlings with multiple shoots by the in vivo treatment of embryos of wheat by herbicides such as 2,4-D, 2,4,5-T, MCPA and TBA as well as mixtures of these substances was studied. Treatment during the first week of embryo development was necessary for the production of additional shoots in the seedling; later treatment gave rise to callused seedlings. Other seedlings such as oats, barley and rye, and other species of wheat were treated, but seedlings with extra shoots were not produced, though callused seedlings were recovered.     

Study of the effect of volatile substances from cereal roots

We traced the liberation and biological effect of volatile substances released from the roots of cereals,i. e. barley, wheat, rye and oats, on seedlings of the same and other plant species. Experiments were carried out in a closed glass apparatus with a static or circulating atmosphere in which the CO₂ and O₂ were permanently absorbed and supplemented, respectively. In some experiments the air was bubbled through water or through solutions of boric acid, barium hydroxide and potassium permanganate. The roots of all four cereals tested released volatile substances with a biological activity which appeared to be non-specific with respect to plant species. The effect of volatile substances was partially decreased by bubbling through water, barium hydroxide and boric acid and was completely removed after passing through the solution of potassium permanganate. Volatile substances liberated from roots of barley inhibited elongation of roots and coleoptile, decreased SH-group content and caused excessive formation of root hairs as well as inhibition of both dry matter production and respiration of roots of rye seedlings. Ethylene was found in the atmosphere of experimental vessels.     

Development of conserved ortholog set markers linked to the restorer gene Rfp1 in rye

Restoration of male fertility is a prerequisite for hybrid rye breeding and currently the most straightforward approach to minimize ergot infection in hybrid rye varieties. Molecular markers are important tools for the efficient introgression and management of restorer genes like Rfp1 originating from unadapted genetic resources. Furthermore, closely linked markers flanking Rfp1 are indispensible for identifying and selecting individuals with haplotypes showing recombination between Rfp1 and other gene(s) that reside in close proximity and have a negative influence on yield. We identified orthologous gene sets in rice, Brachypodium, and Sorghum and used these gene models as templates to establish conserved ortholog set (COS) markers for the restorer gene Rfp1 on the long arm of rye chromosome 4R. The novel co-dominant markers delimit Rfp1 within a 0.7-cM interval and allow prediction of Rfp1 genotypes with a precision not feasible before. The COS markers enabled an alignment of the improved genetic map of rye chromosome 4R with wheat and barley maps and allowed identification of regions orthologous to Rfp1 in wheat and barley on the short arms of chromosomes 6D and 6H, respectively. Results obtained in this study revealed that micro-collinearity around the Rfp1 locus in rye is affected by rearrangements relative to other grass genomes. The impact of the novel COS markers for practical hybrid rye breeding is discussed.     

Distribution of the hordatines in barley

Concentrations of agmatine, coumarylagmatine and the antifungal hordatines in the shoots of barley seedlings have been determined at various stages of growth. Coumarylagmatine declined with age on a fresh weight basis, both in diurnal illumination and in continuous darkness. Hordatines A and B (estimated together) declined in the light to the 30th day after germination but their concentrations were stable in the dark to the 12th day. Hordatine M declined in the light to the 30th day and in the dark to the 12th day from germination. Agmatine declined in both light and dark to the 12th day. On the 30th day from germination potassium deficiency caused an increase in hordatines A + B ( × 6), hordatine M ( × 2) and agmatine ( × 13). Infection of the 11-day-old seedlings with mildew (Erysiphe graminis) caused an increase in the content of hordatine A + B ( × 6), hordatine M ( × 2) and agmatine ( × 2) 13 days later. Hordatines occurred in seedlings of H. bulbosum, H. distichon, H. murinum and H. spontaneum, though not in seedlings of H. jubatum, maize, millet, oats, rice, rye or wheat. Arginine decarboxylase activity declined with age in barley seedlings grown in the light or dark from the 3rd to the 12th day.     

Orientation of wheat seedling organs in relation to gravity

Seedlings of wheat (Triticum aestivum L.) were grown in special holders that permitted the coleoptile and early roots to develop in moist air. The orientation of the organs of seedlings erect to gravity was compared with that of organs produced on a horizontal clinostat. Orientation was described by the angular position of each organ tip with reference to the axis of the embryo. Comparative tests were also made with barley, rye, and oat seedlings.

The coleoptile of all species developed curvatures in 3 dimensions when geotropic responses were eliminated. The primary root was not precise in its positive geotropism. Seedlings grew on clinostats with much greater variations in the lateral orientation of the central root and with a tendency for it to curve away from the endosperm to a greater degree than in erect seedlings.

The symmetry of root system in wheat was found to depend on a specific mechanism. Under the influence of gravity the earliest lateral roots were oriented in a plane at characteristic angles of about 57.5° with the ideal primary root. The corresponding angles for lateral roots growing on clinostats were greater by about 47.5° as a result of epinasty not previously reported in roots. This force also appeared to be active in the seminal roots of barley and rye but not of oats.

The curvatures in coleoptiles grown without the directional effects of gravity correspond to the results of growth imbalance in Coleus stems in the absence of lateral transport of their auxin by gravity. Root epinasty appears to be based on auxin imbalance. Curvatures in the primary root are also interpreted as results of asymmetrical distribution of growth hormone.

     

Characterization of the caleosin gene family in the Triticeae

Background

The caleosin genes encode proteins with a single conserved EF hand calcium-binding domain and comprise small gene families found in a wide range of plant species. Some members of the gene family have been shown to be upregulated by environmental stresses including low water availability and high salinity. Caleosin 3 from wheat has been shown to interact with the α-subunit of the heterotrimeric G proteins, and to act as a GTPase activating protein (GAP). This study characterizes the size and diversity of the gene family in wheat and related species and characterizes the differential tissue-specific expression of members of the gene family.

Results

A total of 34 gene family members that belong to eleven paralogous groups of caleosins were identified in the hexaploid bread wheat, T. aestivum. Each group was represented by three homeologous copies of the gene located on corresponding homeologous chromosomes, except the caleosin 10, which has four gene copies. Ten gene family members were identified in diploid barley, Hordeum vulgare, and in rye, Secale cereale, seven in Brachypodium distachyon, and six in rice, Oryza sativa. The analysis of gene expression was assayed in triticale and rye by RNA-Seq analysis of 454 sequence sets and members of the gene family were found to have diverse patterns of gene expression in the different tissues that were sampled in rye and in triticale, the hybrid hexaploid species derived from wheat and rye. Expression of the gene family in wheat and barley was also previously determined by microarray analysis, and changes in expression during development and in response to environmental stresses are presented.

Conclusions

The caleosin gene family had a greater degree of expansion in the Triticeae than in the other monocot species, Brachypodium and rice. The prior implication of one member of the gene family in the stress response and heterotrimeric G protein signaling, points to the potential importance of the caleosin gene family. The complexity of the family and differential expression in various tissues and under conditions of abiotic stress suggests the possibility that caleosin family members may play diverse roles in signaling and development that warrants further investigation.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-239) contains supplementary material, which is available to authorized users.     

In situ and in vitro ruminal starch degradation of grains from different rye,triticale and barley genotypes

In recent years, advances in plant breeding were achieved, which potentially led to modified nutritional values of cereal grains. The present study was conducted in order to obtain a broad overview of ruminal digestion kinetics of rye, triticale and barley grains, and to highlight differences between the grain species. In total, 20 genotypes of each grain species were investigated using in situ and in vitro methods. Samples were ground (2 mm), weighed into polyester bags, and incubated in situ 1 to 48 h in three ruminally cannulated lactating dairy cows. The in vitro gas production of ground samples (1 mm) was measured according to the ‘Hohenheim Gas Test’, and cumulative gas production was recorded over different time spans for up to 72 h. There were significant differences (P<0.05) between the species for most parameters used to describe the in situ degradation of starch (ST) and dry matter (DM). The in situ degradation rate (c) and effective degradability (assuming a passage rate of 8%/h; ED8) of ST differed significantly between all grains and was highest for rye (rye: 116.5%/h and 96.2%; triticale: 85.1%/h and 95.0%; barley: 36.2%/h and 90.0% for c and ED₈, respectively). With respect to DM degradation, the ranking of the species was similar, and predicted c values exhibited the highest variation within species. The in vitro gas production rate was significantly higher (P<0.05) for rye than for triticale and barley (rye: 12.5%/h; triticale: 11.5%/h; barley: 11.1%/h). A positive relationship between the potential gas production in vitro and the maximal degradable DM fraction in situ was found using all samples (r=0.84; P<0.001) as well as rye (P=0.002) and barley (P<0.001) alone, but not for triticale. Variation in ruminal in situ degradation parameters within the grain species resulted from the high c values, but was not reflected in the ED estimates. Therefore, the usage of mean values for the ED of DM and ST for each species appears reasonable. Estimated metabolisable energy concentrations (ME, MJ/kg DM) and the estimated digestibility of organic matter (dOM, %) were significantly lower (P<0.05) for barley than for rye and triticale. Rye and triticale dOM and ME values were not significantly different (P=0.386 and 0.485).     

The invasion of root tips of cereals by the cereal cyst nematode Heterodera avenue

Newly germinated seedlings of susceptible cultivars of oats, wheat, barley and rye were inoculated with second-stage juveniles of Heterodera avenae in pots of sand. Subsequent examination showed oat root tips to be more commonly invaded, and by a greater range of nematode numbers than the other cereals. A comparison of oats and barley showed that lower nematode numbers in barley were not due to a higher emigration from barley; invasion, establishment and emigration by nematodes all being greater in oats. Second-stage juveniles were more likely to migrate prior to establishment in barley than in oats.     

Use of Polymerase Chain Reaction To Detect the Take-All Fungus, Gaeumannomyces graminis, in Infected Wheat Plants

Gaeumannomyces graminis, the causative agent of take-all disease of wheat, barley, and oats, was detected in infected wheat seedlings by using the polymerase chain reaction to amplify Gaeumannomyces-specific DNA fragments. Nested primers and two rounds of amplification were used to amplify two fragments, approximately 287 and 188 bp in size, from G. graminis-infected wheat seedlings. The use of nested primers greatly decreased the number of nonspecific amplification products. Polymerase chain reaction products were not obtained with DNA from seedlings infected with several other phytopathogenic fungi or with DNA from uninfected seedlings. Amplified products were visualized on agarose gels, and their identities were confirmed by DNA hybridization. This method did not require culturing the fungus and has potential for detecting G. graminis in infested wheat, barley, or oat fields.     

Host range,mating type and population structure of Magnaporthe sp. of a single barley field in São Paulo state,Brazil

Brazil is blast disease hot spot because severe epidemics have occurred among wheat, triticale, rye, barley and oat crops. Although the first outbreak of barley blast appeared in 1998, little information is available. Therefore, this study aimed to examine host range, mating type composition and population structure of Magnaporthe sp. from a single barley field in São Paulo, Brazil. To examine pathogenicity, 25 Magnaporthe isolates were inoculated on five, three, two and two cultivars of barley, wheat, oat and rice, respectively, and one cultivar each of rye, corn, sorghum, triticale and certain weeds (Cenchrus echinatus, Setaria geniculata, Brachiaria plantaginea and Eleusine indica). Mating type distribution of 33 isolates was investigated by molecular tools. The genotypic divergence of 41 barley and five wheat isolates was investigated by 15 random amplified polymorphic DNA primers and unweighted pair group method with arithmetic mean. The host range of the barley blast pathogen included wheat, oat, rye and triticale but not rice and weeds. Sexual reproduction appeared to not be involved in the high genotypic diversity because only a single isolate, MAT1‐2, was identified. The majority of barley isolates clustered together with wheat blast, except for four, suggesting a different origin.     

DNA condensation with polyamines. II. Electron microscopic studies

Approximately 75% of the wheat and rye genomes consist of repeated sequence DNA. Three-quarters of the non-repeated or few copy sequences in wheat are less than 1000 base-pairs long, whilst in rye approximately half of the non-repeated or few copy sequences are in this size class. Most of the remaining non-repeated or few copy sequences appear to be a few thousand base-pairs long.In this paper a somewhat novel approach has been used to quantitatively analyse the linear organisation of the large proportion of repeated sequence DNA as well as the non-repeated DNA in the wheat and rye genomes. Repeated sequences in the genomes of oats, barley, wheat and rye have been used as probes to distinguish and isolate four different groups of repeated sequences and their neighbouring sequences from the wheat and rye genomes. Radioactively labelled wheat or rye DNA fragments ranging from 200 to over 9000 nucleotides long were incubated separately with large excesses of denatured unlabelled oats, barley, wheat and rye DNAs to C_ot values which enable all the repeated sequences of the unlabelled DNA to renature. The following parameters were then determined from the proportions of total labelled DNA in fragments which had at least partially renatured. (1) The proportions of the repeated sequences in the labelled DNAs that were able to hybridise to each unlabelled DNA; (2) the mean distance apart of the hybridising sequences on the longer labelled fragments; and (3) the proportion of the genome in which the hybridising sequences were concentrated. Analysis of these results, together with those of separate experiments designed to quantitatively estimate the nature of sequences unable to reanneal with the repeated sequences of each of the probe DNAs, have enabled schematic maps to be drawn which show how the repeated and non-repeated sequences are arranged in the wheat and rye genomes.Both genomes are constructed from millions of relatively short sequences, most of them considerably shorter than 3000 base-pairs. This structure was recognised because adjacent sequences can be distinguished by their frequency of repetition (i.e. repeated or non-repeated) or by their evolutionary origin. Approximately 40 to 45% of the wheat genome and 30 to 35% of the rye genome consists of short non-repeated sequences interspersed between short repeated sequences. Approximately 50% of the wheat genome and 60% of the rye genome consists of tandemly arranged repeated sequences of different evolutionary origins. It is postulated that much of this complex repeated sequence DNA could have arisen from amplification of compound sequences, each containing repeated and non-repeated sequence DNA.Short repeated sequences with a number average length of around 200 base-pairs and which occupy about 20% of the wheat and rye genomes are related to repeated sequences also found in oats and barley. They are concentrated in 60 to 70% of the wheat and rye genomes, being interspersed with different short repeated sequences and a significant proportion of the short non-repeated sequences.Rye chromosomes contain more DNA than wheat chromosomes. This is principally, but not entirely, due to additional repeated sequence DNA. Many quantitative changes appear to have occurred in both genomes, possibly affecting most families of repeated sequences, since wheat and rye diverged from a common ancestor. Both species contain species-specific repeated sequences (24% of rye genome; 16% of wheat genome) but a large proportion of these are closely interspersed with repeated sequences found in both genomes.