Populations of doubled haploids for genetic mapping in hexaploid winter triticale.

To create a framework for genetic dissection of hexaploid triticale, six populations of doubled haploid (DH) lines were developed from pairwise hybrids of high-yielding winter triticale cultivars. The six populations comprise between 97 and 231 genotyped DH lines each, totaling 957 DH lines. A consensus genetic map spans 4593.9 cM is composed of 1576 unique DArT markers. The maps reveal several structural rearrangements in triticale genomes. In preliminary tests of the populations and maps, markers specific to wheat segments of the engineered rye chromosome 1R (RM1B) were identified. Example QTL mapping of days to heading in cv. Krakowiak revealed loci on chromosomes 2BL and 2R responsible for extended vernalization requirement, and candidate genes were identified. The material is available to all parties interested in triticale genetics.

The effect of multigenerational diet containing genetically modified triticale on immune system in mice.

The safety assessment of genetically modified (GM) food and feed is performed to identify the possible effects upon animal and human health, also the long-term, multigenerational influence upon functioning of different organs and systems, such as the immune system. In this study C57BL/6J mice were fed for five consecutive generations with pellets containing 20% of conventional triticale grain (control) vs. pellets containing 20% of the transgenic triticale grain resistant to BASTA herbicide (experimental). The F5 experimental animals showed enlarged inguinal and axillary lymph nodes, but not spleens, and increased WBC counts in blood (but within the norm for Mus musculus). Immunophenotyped cell suspensions derived from spleens, inguinal and axillaris lymph nodes and PBMCs from blood showed the significant decrease in the percentage of T cells in spleen and lymph nodes and the B cells in lymph nodes and blood of the F5 experimental mice in comparison to the control F5 mice. Immunoblotting analysis of IL-2, IL-4, IL-10, IL-12, IL- 6, IFN-gamma levels in serum showed significantly increased IL-2 levels and decreased IL-6 levels in the F5-experimental mice sera. No significant changes in the levels of IgE in sera in both mice groups were observed. The obtained results indicate that multigenerational use of feeds for rodents containing the GM-triticale leads to expansion of the B cell compartment in the secondary lymphoid organs, but it is not caused by malignant processes or the allergic response.

Wheat (Triticum aestivum) seedlings secrete proteases from the roots and, after protein addition, grow well on medium without inorganic nitrogen.

This paper reports on the role of proteases secreted by roots in nitrogen capture by plants. The study was conducted on aseptically cultivated wheat seedlings (Triticum aestivum cv. Tacher) obtained from embryos isolated from grains. Seedlings were cultivated for 21 days on deionised water, Murashige Skoog medium (MS), MS without inorganic nitrogen (IN), and MS without IN, in which IN was replaced by casein (0.01%, 0.1% or 1%). Comparison of seedlings grown on these media showed that casein entirely compensated for the lack of inorganic nitrogen in the medium. Shoots and roots of seedlings cultivated on MS medium with this protein had higher fresh weight than those cultivated on MS medium without casein. The increase in fresh weight of seedlings was correlated with casein concentration and proteolytic activity in the medium. In conclusion, wheat that uses proteases secreted by the roots can directly utilise proteins in the medium as a source of nitrogen without prior digestion by microbial proteases and without protein mineralisation. These results suggest the important role of organic nitrogen fertilisers in increasing wheat yield.

Androgenic response to preculture stress in microspore cultures of barley.

Various stresses such as starvation and cold or heat shocks have been identified as triggers in the induction of the microspore embryogenesis. This study attempts to quantify the effects of different pretreatment conditions for successful microspore culture of malting barley (cv. Scarlett). While the sporophytic microspore development could be induced from treated and nontreated microspores, abiotic stress was essential for embryo formation and plant regeneration. The type of stress treatment applied affected the numbers and the ratios of albino and green plants regenerated, as well as their fertility. The highest number of green plants was obtained after the treatment of anthers in 0.3 M mannitol at 32 degrees C for 24 h before microspore culture.

Direct embryogenesis and green plant regeneration from isolated microspores of hexaploid triticale (x Triticosecale Wittmack) cv. Bogo.

The use of doubled haploids improves the efficiency of cultivar development in many crops and can be helpful in genetic and molecular studies. The major problem with this approach is the low efficiency of green plant regeneration. We describe here an efficient method for inducing embryos and regenerating green plants directly from isolated microspores of hexaploid triticale (x Triticosecale Wittmack) cv. Bogo. The absence of growth regulators in the induction medium was the most effective condition for the formation of embryo-like structures. The highest induction rates were observed at microspore densities of 1.5x10(5) microspores and 2x10(5) microspores per milliliter. Such cultures produced an average of 54.9 green plants per single donor spike. The frequency of albino plants ranged from 9.3% to 22.9%. Among the green progeny tested, 30.8% were spontaneously doubled haploids.

Phytotoxicity of deoxynivalenol to wheat calli.

The main objective of this study was to determine the toxicity of DON (deoxynivalenol) in wheat tissue culture after two weeks of contact. It was observed that increase of toxin concentration in medium caused decrease of regeneration ability of the calli. Three tested genotypes showed different sensitivity to 25 ppm of DON.

Transient expression of chimaeric genes in dividing and non-dividing cereal protoplasts after PEG-induced DNA uptake.

Transient expression of chimaeric genes (neomycin phosphotransferase fused to four different promoters) was detected in suspension culture derived protoplasts of maize, barley and rice, in mesophyll protoplasts of maize, rice, rye, and root protoplasts of maize. The introduction and expression of foreign genes could be performed with both dividing and non-dividing protoplasts by applying the PEG transformation method. The significance of this method for the functional analysis of genes was demonstrated by the differential expression of a regulated gene in protoplasts of different tissues in agreement with its expression in the donor tissue.

Plant regeneration and initiation of cell suspensions from root-tip derived callus of Oryza sativa L. (rice).

Root-tip derived suspended callus of Oryza sativa cv. Thaipei showed the capacity for plant regeneration via organogenesis. Cell cultures were induced in liquid Murashige-Skoog medium containing 2 mg/l 2.4-dichlorophenoxyacetic acid. Dicamba or Picloram were effective for induction of organogenesis. Shoots and roots differentiated following subculture on medium lacking auxins but containing kinetin. At 1 and 4 mg/l Dicamba and 1 mg/l Picloram normal green plants were regenerated whereas with 7 mg/l Dicamba in the medium only albino plantlets were obtained. Regenerated plantlets were grown to maturity and set seed. Cell suspension cultures, initiated from the root-tip derived calli, provided suitable material for protoplast isolation.