The TATA box is one of the best characterized transcription factor binding sites. However, it is not a ubiquitous element of core promoters, and other sequence motifs such as Y Patches seem to play a major role in plants. Here, we present a first genome-wide computational analysis of the TATA box and Y Patch distribution in rice (Oryza sativa L. subsp. japonica) promoter sequences. Utilizing a probabilistic sequence model, we ascertain that only approximately 19% of rice genes possess the TATA box, but approximately 50% contain one or more Y Patches in their core promoters. By computational processing of identified elements, we generated extended TATA box and Y Patch nucleotide frequency matrices capable of predicting these motifs in plants with a high degree of confidence.
Powdery mildew is one of the most consistently damaging diseases of the wheat in Europe.It is caused by the obligate biotrophic fungus Blumeria graminis DC. f. sp.tritici Speer.Consequently, much effort is devoted to the exploitation of genetic plant resistance for disease control.Most of the catalogued powdery mildew resistance genes (M�I����� et al. 2003) confer race-specific hypersensitive responses that remain effective for a short period of time, but may then become ineffective as races with virulence to the resistance genes develop in the pathogen population.In view of the frequent erosion of race-specific genes, race-nonspecific resistance can bring a more satisfactory answer to disease control problems.This type of resistance is characterized as partial, more or less effective against all races of pathogen and result in varying levels of resistance against them (S���� & R������ 2002).In numerous studies of cereals attacked by powdery mildew, resistance has often been intimately associated with the occurrence of cell-wall appositions directly subtending the appressorium and penetration peg of the fungus (e.g.B������� et al. 2002; P���� et al. 2005; F��� & T���� 1993).Although the chemical composition of these appositions, termed papillae, shows considerable variability (A��� 1976), they commonly contain callose, lignin and phenolic substances (N�������� & H������������ 1992).
Phylogenetic relationships among twenty two tetraploid wheats of Triticum dicoccon coming from various European countries and from Near East region were estimated by means of RAPD polymorphism. Based on neighbour-joining clustering method we find out, that all tested accessions were clustered with taxonomic classification in line. Samples from Yugoslavia, Turkey, India, Ethiopia and an American variety Vernal created one cluster and all belong to the supraconvariety asiaticum. Our analyse proved that Slovak relic dicoccon wheats are related to the Yugoslavian emmer and belong to the convar. serbicum. All the rest European accessions together with accessions from Morocco and Israel were included in the second very clearly separated cluster of genotypes which can be classified in supraconvar. dicoccon. Iranian accession is phylogenetic intermediate stage between these two supraconvarieties.
It has been supposed that, wheat powdery mildew populations (Blumeria graminis f. sp. tritici) in Dobra Voda and Turiec Valley may be isolated from other mildew populations by geographical barriers surrounding them. Mildew isolates were obtained from exposed trap plants in mobile and static nurseries (Dobra Voda). The single colony isolates were subsequently tested on detached leaves of seedlings of sets of differential wheat cultivars/lines with known specific resistance genes. Virulence frequencies in the mildew populations from Dobra Voda and Turiec Valley were compared to virulence frequencies from their neighbouring regions. Euclidian distances agreed with geographical distances in populations from Dobra Voda and its neighbouring populations. Cluster analysis has repeatedly proved that mildew population from Turiec Valley belongs to a separate cluster. Differences in virulence. frequencies between these clusters were not significant, however, mildew population from Turiec Valley is considered to be different. Geographical barriers, mountains surrounding Dobra Voda and Turiec Valley, do not maintain any significant isolation for the migration of the pathogen spores on prevailing winds, even though the spread of the similar host genotypes within Slovakia and Europe makes the study of geographical isolation more difficult.
A polymerase chain reaction-based method for the detection of gluten-containing cereals in flours and “gluten-free” bakery products was optimized and its intralaboratory validation was carried out. The optimized method involved DNA isolation by chaotropic solid-phase extraction and PCR with primers of Dahinden et al. [Dahinden I., von Büren M., Lüthy J., 2001. A quantitative competitive PCR system to detect contamination of wheat, barley and rye in gluten-free food for coeliac patients. European Food Research and Technology 212, 228–233]. Using purified DNA, intrinsic detection limit of 42±12pg was determined, which corresponds to 10° genome copies. By the analysis of a panel of 26 European wheat cultivars and flours from six non-gluten-containing plants, which are commonly used for the production of gluten-free bakery products, inclusivity of 100% and exclusivity of 100% were determined. By the analysis of model samples of soya flour and cakes, detection limit of 0.1% (w/w) of fine wheat flour was determined, which is suitable for the analysis of “gluten-free” food products, as it is approximately equivalent to the limit of 10mg per 100g for gluten stated by Codex Alimentarius. The method was successfully applied to four samples of flours and 13 brands of biscuits designated “gluten-free”, out of which two flours and one brand of biscuits were found positive for gluten-containing cereals. The method proved to be suitable for routine use, it was relatively straightforward and could be completed in one working day.
Important microevolutional processes have taken place in the wheat powdery mildew population over the last thirty years. There has been a considerable change in the race composition of the pathogen population and in the prevalent races. Of the 78 races identified, only eleven have “lived” for more than 15 years. Many races were only isolated in one or two years. The number of virulence genes rose from 2.03 in 1973 to 5.63 in 1993. On the basis of race composition and virulence the wheat powdery mildew population between 1971 and 1999 can be divided into four distinct groups. A large proportion of the powdery mildew isolates are virulent to most resistance genes. Complete resistance is provided by resistance genes Pm4a (Khapli) and partial resistance by Pm2+Mld (Halle st. 13471), Pm4b+ (TP 315/2) and Pm1+2+9 (Normandie). The majority of cultivated varieties carry the resistance gene Pm8 due to the presence of the 1B/1R translocation.
In 1993 the frequency of virulence genes and fungicide - sensitivity in regional populations of barley powdery mildew was found in Hungary. Samples of pathogen spores were trapped by jet spore sampler mounted on a car roof.In all observed regions we found high virulence frequencies against resistance genes M1-g, M1-k, M1-a6, M1-a12 and M1-La. We found the lowest virulence frequency against fesistance genes M1-a7, +AB and M1(W) with considerable regional differences. No isolate of pathogen virulene against recessive resistance gene m1-o throughout Hungary was found.Population of powdery mildew from Hungary has a decreased sensitivity against fungicides of the triazole group. The lowest sensitiviti against triadimenol (Bayfidan) and flutriafol (Impact) was found. The most resistant pathogen population from western Hungary was found against propiconazole (Tilt). At triazole fungicides the highest sensitivity of pathogen population against tebuconazol (Folicur) was observed. Population of pathogen is sensitive against morpholine compound - fenpropimorph (Corbel) on the level of standard control isolates.
In the year 1992 a total of 163 isolates of wheat powdery mildew were tested. The samples of mildew isolates were obtained by means of a mobile spore catching apparatus. The populations from 4 regions of Slovakia and 3 regions of Hungary were analyzed. The resistance due to Pm5, Pm8 and Ml-i genes at the observed locations has already been overcome. The resistance genes Pm1, Pm2 and a gene combination Pm2 + Pm6 ensure the protection only against a part of the pathotypes of powdery mildew population. Virulence corresponding to the Pm4b gene has been low so far. The regional patterns of pathogen virulence are in good agreement with the gene resistance spectrum by the cultivars grown regionally. Little differences in virulence among the populations from the regions of Slovakia and Hungary indicate that this part of Eastern Europe should be considered as an epidemiologic unit.
The virulence of barley and wheat powdery mildew against the known resistance genes was examined in Slovakia and Hungary. Along the route the conidia were collected from the air, they were cultivated in the laboratory and the frequency of virulence genes of the pathogen population was determined.The authors claim that the barley powdery mildew population is the least virulent against the gene-combination M1-a7+M1-Ab and the gene M1-a1. The rate of races virulent to M1-a3 resistance gene is essentially lower in Slovakia (7,9%) than in Hungary (34,2%), while its contrary was observed as regards the gene M1-a13. On the territory of both countries barley mildew pustules virulent against varieties with resistance genes M1-a6, M1-a7, M1-a9, M1-a12, M1-La M1-g and M1-k were often isolated by the authors.The wheat powdery mildew population is virulent in both countries to resistance genes and combinations Pm2, Pm2+6, and especially to Pm5, Pm8 and M1i. Some deviation was found in the case of resistance genes Pm1, Pm4a, Pm4b+Pm8 and Pm4b+M1i. The powdery mildew population seemed to be avirulent to Pm4a gene along the Nitra-BratisIava route, and to gene-combination Pm4b+Pm8 along the Papa-Szekesfe-hervar route.As the barley varieties bred in Slovakia are also produced in Hungary, and a considerable part of the wheat varieties are developed in both countries by using the same resistance sources, the outbreak of a powdery mildew epidemic may therefore be influenced in a similar way by the genetic background.
Without Abstract
Normal threshold approximation to analyticity of two-body scattering amplitude formulated in the spaceC3 of independent complex variables\(\hat s,\hat t,\hat u\) and restricted by the assumption of polynomial boundedness in all three variables leads to a three-dimensional integral representation which is shown to reproduce Mandelstam representation on the complex plane\(\hat s + \hat t + \hat u = \sum\limits_{i = 1}^4 {m_i^2 } \).
