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PubMed2005

Water, temperature and gas composition interactions affect growth and ochratoxin A production by isolates of Penicillium verrucosum on wheat grain.

AIMS: To examine the effect of interactions between water, temperature and gas composition on growth and ochratoxin A (OTA) production by isolates of Penicillium verrucosum in vitro and in situ on grain-based media and wheat grain. METHODS AND RESULTS: Three isolates of P. verrucosum were examined in relation to radial growth rate and OTA production, and to interacting conditions of water activity (a(w)), temperature and gas composition on a milled wheat medium. Subsequently, detailed temporal studies were carried out on gamma irradiated wheat grain over the range 0.75-0.995 a(w), 10-25 degrees C and air, 25 or 50% CO(2). This showed that optimum growth of P. verrucosum was at 0.98 a(w) in vitro at 25 degrees C, but at 0.95 a(w) and 25 degrees C on wheat grain. The a(w) minimum for growth was about 0.80 a(w), although no OTA was produced under this condition even after 56 days. Significant inhibition of growth and OTA production occurred with 50% CO(2), and 0.90-0.995 a(w) at 25 degrees C. CONCLUSIONS: The optimum and marginal conditions for growth and OTA production on wheat grain have been identified. At least 50% CO(2) is needed to inhibit growth and OTA production by >75% in moist grain (0.90-0.995 a(w)). SIGNIFICANCE AND IMPACT OF THE STUDY: First detailed identification of optimal and marginal interacting conditions of water/temperature and gas composition on growth and OTA production by P. verrucosum on wheat grain. This is a critical component of the postharvest management strategy for minimizing contamination by this important mycotoxin and predicting risk, based on environmental conditions, during drying and storage.

Carbon Dioxide↗
PubMed2006

Advanced resources for plant genomics: a BAC library specific for the short arm of wheat chromosome 1B.

Common wheat (Triticum aestivum L., 2n = 6x = 42) is a polyploid species possessing one of the largest genomes among the cultivated crops (1C is approximately 17 000 Mb). The presence of three homoeologous genomes (A, B and D), and the prevalence of repetitive DNA make sequencing the wheat genome a daunting task. We have developed a novel 'chromosome arm-based' strategy for wheat genome sequencing to simplify this task; this relies on sub-genomic libraries of large DNA inserts. In this paper, we used a di-telosomic line of wheat to isolate six million copies of the short arm of chromosome 1B (1BS) by flow sorting. Chromosomal DNA was partially digested with HindIII and used to construct an arm-specific BAC library. The library consists of 65 280 clones with an average insert size of 82 kb. Almost half of the library (45%) has inserts larger than 100 kb, while 18% of the inserts range in size between 75 and 100 kb, and 37% are shorter than 75 kb. We estimated the chromosome arm coverage to be 14.5-fold, giving a 99.9% probability of identifying a clone corresponding to any sequence on the short arm of 1B. Each chromosome arm in wheat can be flow sorted from an appropriate cytogenetic stock, and we envisage that the availability of chromosome arm-specific BAC resources in wheat will greatly facilitate the development of ready-to-sequence physical maps and map-based gene cloning.

Chromosomes, Artificial, Bacterial↗
PubMed1976

Chemical modification of the tryptophan residues of wheat-germ agglutinin. Effect on fluorescence and saccharide-binding properties.

The oxidation of the tryptophan residues of wheat germ agglutinin by N-bromosuccinimide was investigated under non-denaturing and denaturing conditions. All three tryptophan residues present in wheat germ agglutinin subunit (molecular weight 18 000) could be modified in 0.1 M acetic acid/8 M urea, pH 3.9. One of the residues failed, however, to react with N-bromosuccinimide when the modification was in 0.1 M citrate buffer, pH 6.0. Tryptophan fluorescence of the protein was quenched concomitantly with the oxidation of two tryptophan residues even when the modification was carried out in acetic acid urea. After oxidation of two tryptophan residues per subunit of wheat germ agglutinin, only 15% of the original tryptophan fluorescence remained; upon excitation at 280 nm, tyrosine fluorescence centered at 305 nm could be resolved. The results suggest that there are only two emitters in the protein and that the third tryptophan residue is buried in the native protein and can be modified only in acetic acid urea. This tryptophan residue is quenched in the native protein. Saturation of wheat germ agglutinin with tri-N-acetylchitotriose did not protect the tryptophan residues from oxidation by N-bromosuccinimide. Under these conditions, however, the reactivity of the tryptophan residues towards N-bromosuccinimide was reduced and a higher concentration of the reagent was required to achieve the same extent of oxidation as in the absence of the saccharide. Oxidation of one tryptophan residue per subunit in acetic acid urea led to almost complete loss (97%) of hemagglutinating activity, a 3.5-fold decrease in the affinity constant for tri-N-acetylchitotriose and loss of ability of the subunits (SO20,w = 2.0 S) to reassociate to the native dimer (So20,w = 3.5 S) after dialysis against a non-denaturing buffer. No significant changes in the circular dichroism spectrum of wheat germ agglutinin were observed after oxidation of the three tryptophan residues, suggesting that no gross conformational changes occurred. The steric relationships between the fluorescent tryptophan residues of wheat germ agglutinin and saccharides are discussed.

Binding Sites↗
PubMed1982

Purification and properties of protein methylase II from wheat germ.

Protein methylase II (S-adenosylmethionine: protein-carboxyl O-methyltransferase, EC 2.1.1.24) was purified from wheat germ approximately 1200-fold with a yield of 4.6% by employing gel filtration. The enzyme, using S-adenosyl-L-methionine, methyl-esterifies the free carboxyl group of protein. Since the enzymatic product was unstable and hydrolyzed non-enzymatically to yield methanol, methanol was identified from the hydrolysate by the formation of the methyl ester of 3.5-dinitrobenzoate. The pH optimum for the wheat germ enzyme was 7.0 in contrast to the 6.0 for the methylase II of calf brain. The wheat germ enzyme had a molecular weight of 41 000 compared to 25 000 for the corresponding rat erythrocyte enzyme [S. Kim (1975) Arch. Biochem. Biophys. 161, 652-657]. The enzyme also differed with the mammalian enzyme in protein substrate preference: the mammalian enzyme showed equal preference to histone and immunoglobulin G while the wheat germ enzyme transferred a methyl group 4.5 times more to histone than to immunoglobulin G. The Km values for histone and S-adenosyl-L-methionine were 0.2 mM and 5 microM. S-Adenosyl-L-homocysteine and its analogues, sinefungin and A9145C, were competitive inhibitors with Ki values 1.5 microM, 0.4 microM and 0.1 microM, respectively. To investigate the identity of endogenous substrate(s) for protein methylase II, the crude wheat germ extract was incubated with S-adenosyl-L-[methyl-3H]methionine and the methylated proteins were analyzed by acid/urea and sodium dodecyl sulfate/polyacrylamide gel electrophoresis. Among other methyl acceptors in the wheat germ, histone polypeptides were the major endogenous substrates.

Kinetics↗
PubMed1984

Plant biochemistry of xenobiotics. Purification and properties of a wheat esterase hydrolyzing the plasticizer chemical, bis(2-ethylhexyl)phthalate.

A soluble wheat esterase, catalyzing a cleavage of the mass-produced plasticizer chemical, bis(2-ethylhexyl)phthalate (DEHP), has been discovered. Although wheat plants and seeds as well as cultured wheat cells contained more than 12 non-specific esterase activities, only a single protein with a marked preference for a substrate chain-length of 6-8 carbon atoms was active with DEHP. This enzyme is shown to differ from all previously characterized plant lipases and esterases. The enzyme was purified 10-fold from wheat plants and 280-fold, to electrophoretic homogeneity, from cultured wheat cells. An apparent functional molecular mass of 38 000 Da and an apparent subunit molecular mass of 22 000 Da were determined. Inhibitor experiments pointed to the catalytic involvement of a serine residue. Cleavage of DEHP by the purified enzyme was about 10(4) times slower than cleavage of 4-nitrophenyl octanoate. This was consistent with previous evidence for a rate-limiting role of the esterase reaction in DEHP metabolism by intact wheat cells.

Carboxylic Ester Hydrolases↗
PubMed1994

Cloning of a wheat 15-kDa grain softness protein (GSP). GSP is a mixture of puroindoline-like polypeptides.

The wheat starch 15-kDa protein (called grain softness protein or GSP) consists of a major polypeptide and several minor polypeptides. An antiserum raised against GSP was used to screen a wheat cDNA library. A cDNA family encoding approximately 15-kDa proteins that included a heptapeptide sequence previously isolated from protease digests of GSP was identified. A partial cDNA was used in a prokaryotic expression system to produce a fusion protein which reacted strongly against the original anti-GSP serum. A new antiserum raised against the fusion protein produced a weak reaction against a 15-kDa polypeptide extracted from wheat seeds. The results suggest that the proteins encoded by the cDNA family form a minor component of the mixture of 15-kDa polypeptides defined as GSP. RNA complementary to the cDNAs could be extracted from both soft and hard wheat grains from about half-way through grain filling. The encoded proteins are novel members of the 2S superfamily of seed proteins, a diverse family of proteins which maintain a characteristic framework of cysteine residues. The deduced proteins show the highest similarity to the oat 16-kDa avenin and to wheat puroindoline (a lipid-binding 15-kDa protein from wheat). Review of previously published data shows that puroindoline is also closely related to the major polypeptide of GSP, suggesting that the lipid-binding properties of GSP polypeptides may influence grain softness.

Amino Acid Sequence↗
PubMed1991

Wheat dust-associated respiratory disease in a farming community.

Sixty-six volunteers who considered themselves to have wheat dust-related respiratory disease, were reviewed from a farming community. A spectrum of disease was described ranging from a mild allergic rhinitis limited to periods of wheat dust exposure through to perennial asthma in which wheat dust was but one of several precipitating factors. Approximately half of those with asthma had symptoms limited to times of wheat dust exposure. Results of a limited survey of farmers showed patterns of symptoms similar to those in the volunteer group. Most subjects were atopic with elevated IgE levels, and had positive skin prick tests to environmental allergens. All but one of 65 subjects tested had a positive RAST test to wheat dust antigen. It is concluded that wheat dust associated respiratory tract disease is a significant problem in Australian farming communities, that a particular pattern of asthma can be described, and that IgE mediated reactions contribute to this disease pattern.

Adolescent↗
PubMed2005

Towards a generic architectural model of tillering in Gramineae, as exemplified by spring wheat (Triticum aestivum).

This paper presents an architectural model of wheat (Triticum aestivum), designed to explain effects of light conditions at the individual leaf level on tillering kinetics. Various model variables, including blade length and curvature, were parameterized for spring wheat, and compared with winter wheat and other Gramineae species. The architectural model enables simulation of plant properties at the level of individual organs. Parameterization was based on data derived from an outdoor experiment with spring wheat cv. Minaret. Final organ dimensions of tillers could be modelled using the concept of relative phytomer numbers. Various variables in spring wheat showed marked similarities to winter wheat and other species, suggesting possibilities for a general Gramineae architectural model. Our descriptive model is suitable for our objective: investigating light effects on tiller behaviour. However, we plan to replace the descriptive modelling solutions by physiological, mechanistic solutions, starting with the localized production and partitioning of assimilates as affected by abiotic growth factors.

Models, Structural↗
PubMed2006

Physical map of the wheat high-grain protein content gene Gpc-B1 and development of a high-throughput molecular marker.

Grain protein content (GPC) is important for human nutrition and has a strong influence on pasta and bread quality. A quantitative trait locus, derived from a Triticum turgidum ssp. dicoccoides accession (DIC), with an average increase in GPC of 14 g kg(-1) was mapped on chromosome 6BS. Using the wheat-rice colinearity, a high-density map of the wheat region was developed and the quantitative trait locus was mapped as a simple Mendelian locus designated Gpc-B1. A physical map of approx. 250 kb of the Gpc-B1 region was developed using a tetraploid wheat bacterial artificial chromosome library. The constructed physical map included the two Gpc-B1 flanking markers and one potential candidate gene from the colinear rice region completely linked to Gpc-B1. The relationship between physical and genetic distances and the feasibility of isolating genes by positional cloning in wheat are discussed. A high-throughput codominant marker, Xuhw89, was developed. A 4-bp deletion present in the DIC allele was absent in a collection of 117 cultivated tetraploid and hexaploid wheat germplasm, suggesting that this marker will be useful to incorporate the high GPC allele from the DIC accession studied here into commercial wheat varieties.

Chromosomes, Plant↗
PubMed2000

Effects of wheat bran and Olestra on objective measures of stool and subjective reports of GI symptoms.

OBJECTIVE: The aim of this study was to compare the effects of two nondigested, nonabsorbed dietary components on objective and subjective measures of gastrointestinal (GI) function. METHODS: A placebo-controlled parallel study compared the effects of wheat bran (20 g/day or 40 g/day in cereal), a well-known dietary fiber, with those of olestra (20 g or 40 g/day in potato chips), a nonabsorbed fat, on stool output, stool apparent viscosity (log peak force for extrusion [PF]), stool water content, and GI symptoms. Sixty subjects resided on a metabolic ward for 9 days: 3 days baseline and 6 days treatment. RESULTS: Compared with placebo, consumption of 20 g/day wheat bran for 6 days resulted in a rapid (within 38 h) increase in mean (+/-SE) stool output (placebo, 150 +/- 29 g/day; bran, 246 +/- 35 g/day, p < 0.05), a directional increase in mean stool water content (placebo, 81.2 +/- 0.8%; bran, 83.9 +/- 0.8%), stool water output (placebo, 159 +/- 54 g/day; bran, 238 +/- 30 g/day), and bowel movement frequency (BM/day) (placebo, 2.2 +/- 0.4; bran, 2.6 +/- 0.4), and no stool-softening effect (placebo log PF, 2.9 +/- 0.1 g; bran log PF, 2.9 +/- 0.1 g). Wheat bran 40 g/day results were not significantly different from wheat bran 20 g/day. Compared with placebo, consumption of olestra 20 g/day and 40 g/day for 6 days showed no significant difference in mean stool output (151 +/- 18 g/day and 204 +/- 28 g/day, respectively), mean BM frequency (1.8 +/- 0.2 BM/day and 2.1 +/- 0.3 BM/day, respectively), and stool water output (138 +/- 13 g/day and 184 +/- 31 g/day, respectively), a significant (p < 0.05) decrease in stool water content (75.5 +/- 1.7% and 72.6 +/- 2.2%, respectively), and either no effect on stool apparent viscosity (olestra 20 g/day, mean log PF, 3.0 +/- 0.1 g) or a gradual stool-softening effect beginning study day 6 (olestra 40 g/day, log PF, 2.7 +/- 0.1 g). None of the treatment groups showed a significant increase in GI symptoms compared with placebo. CONCLUSIONS: Consumption of wheat bran in excess of levels in a typical Western diet significantly increased stool output, but did not soften normal-viscosity stool nor result in an increase in common GI symptoms. The observed plateau effect for wheat bran at 40 g/day suggests a maximal mechanical stimulatory effect. Consumption of olestra in excess of usual snacking conditions did not result in a significant increase in stool output or common GI symptoms. At the highest level tested, olestra resulted in a gradual stool-softening effect after several days of consumption.

Adolescent↗
PubMed2006

Characterization of wheat puroindoline proteins.

Puroindoline proteins were purified from selected UK-grown hexaploid wheats. Their identities were confirmed on the basis of capillary electrophoresis mobilities, relative molecular mass and N-terminal amino acid sequencing. Only one form of puroindoline-a protein was found in those varieties, regardless of endosperm texture. Three allelic forms of puroindoline-b protein were identified. Nucleotide sequencing of cDNA produced by RT-PCR of isolated mRNA indicated that these were the 'wild-type', found in soft wheats, puroindoline-b containing a Gly-->Ser amino acid substitution (position 46) and puroindoline-b containing a Trp-->Arg substitution (position 44). The latter two were found in hard wheats. Microheterogeneity, due to short extensions and/or truncations at the N-terminus and C-terminus, was detected for both puroindoline-a and puroindoline-b. The type of microheterogeneity observed was more consistent for puroindoline-a than for puroindoline-b, and may arise through slightly different post-translational processing pathways. A puroindoline-b allele corresponding to a Leu-->Pro substitution (position 60) was identified from the cDNA sequence of the hard variety Chablis, but no mature puroindoline-b protein was found in this or two other European varieties known to possess this puroindoline-b allele. Wheats possessing the puroindoline-b proteins with point mutations appeared to contain lower amounts of puroindoline protein. Such wheats have a hard endosperm texture, as do wheats from which puroindoline-a or puroindoline-b are absent. Our results suggest that point mutations in puroindoline-b genes may confer hard endosperm texture through accumulation of allelic forms of puroindoline-b proteins with altered functional properties and/or through lower amounts of puroindoline proteins.

Alleles↗
PubMed1995

Biocontrol of mold growth in high-moisture wheat stored under airtight conditions by Pichia anomala, Pichia guilliermondii, and Saccharomyces cerevisiae.

Pichia anomala inhibits the growth of Penicillium roqueforti and Aspergillus candidus on agar. In this investigation, antagonistic activity on agar against 17 mold species was determined. The abilities of Pichia anomala, Pichia guilliermondii, and Saccharomyces cerevisiae to inhibit the growth of the mold Penicillium roqueforti in nonsterile high-moisture wheat were compared by adding 10(3) Penicillium roqueforti spores and different amounts of yeast cells per gram of wheat. Inoculated grain was packed in glass tubes, incubated at 25 degrees C with a restricted air supply, and the numbers of yeast and mold CFU were determined on selective media after 7 and 14 days. Pichia anomala reduced growth on agar plates for all of the mold species tested in a dose-dependent manner. Aspergillus fumigatus and Eurotium amstelodami were the most sensitive, while Penicillium italicum and Penicillium digitatum were the most resistant. Pichia anomala had the strongest antagonistic activity in wheat, with 10(5) and 10(6) CFU/g completely inhibiting the growth of Penicillium roqueforti. Inhibition was least pronounced at the optimum temperature (21 degrees C) and water activity (0.95) for the growth of Penicillium roqueforti. Pichia guilliermondii slightly reduced the growth of Penicillium roqueforti in wheat inoculated with 10(5) and 10(6) yeast CFU/g. S. cerevisiae inhibited mold growth only weakly at the highest inoculum level. Pichia anomala grew from 10(3) to 10(7) CFU/g of wheat in 1 week. To reach the same level, Pichia guilliermondii had to be inoculated at 10(4) CFU while S. cerevisiae required an inoculum of 10(5) CFU to reach 10(7) CFU/g of wheat.

Fungi↗
PubMed1971

Transmission of Salmonella montevideo in wheat by stored-product insects.

Sitophilus oryzae (L.), S. granarius (L.), Tribolium castaneum (Hbst.), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.), Tenebroides mauritanicus (L.), and Cryptolestes pusillus (Schon.) transmitted Salmonella montevideo from wheat contaminated with 10(6) organisms/g to clean wheat. The insects were fed on the contaminated grain for 21 days and were then transferred to clean grain and allowed to feed for 21 days. They were subsequently transferred to two more samples of clean wheat. All species carried S. montevideo into the initial sample of clean wheat but not into a second or third sample. Progeny of the original insects that developed in the contaminated wheat exhibited less ability than the original adults to contaminate clean wheat. Data indicated that few S. montevideo could be carried by the stored-product insects in large masses of grain.

Agglutination Tests↗
PubMed1997

N-acyl-homoserine lactone-mediated regulation of phenazine gene expression by Pseudomonas aureofaciens 30-84 in the wheat rhizosphere.

Pseudomonas aureofaciens 30-84 is a soilborne bacterium that colonizes the wheat rhizosphere. This strain produces three phenazine antibiotics which suppress take-all disease of wheat by inhibition of the causative agent Gaeumannomyces graminis var. tritici. Phenazines also enhance survival of 30-84 within the wheat rhizosphere in competition with other organisms. Expression of the phenazine biosynthetic operon is controlled by the phzR/phzI N-acyl-homoserine lactone (AHL) response system (L. S. Pierson III et al., J. Bacterial 176:3966-3974, 1994; D. W. Wood and L. S. Pierson III, Gene 168:49-53, 1996). By using high-pressure liquid chromatography coupled with high-resolution mass spectrometry, the AHL produced by PhzI has now been identified as N-hexanoyl-homoserine lactone (HHL). In addition, the ability of HHL to serve as an interpopulation signal molecule in the wheat rhizosphere has been examined by using isogenic reporter strains. Disruption of phzI reduced expression of the phenazine biosynthetic operon 1,000-fold in the wheat rhizosphere. Coinoculation of an isogenic strain which produced the endogenous HHL signal restored phenazine gene expression in the phzI mutant to wild-type levels in situ. These results demonstrate that HHL is required for phenazine expression in situ and is an effective interpopulation signal molecule in the wheat rhizosphere.

4-Butyrolactone↗
PubMed1984

Wheat flour sensitisation and airways disease in urban bakers.

A total of 176 bakers and 24 subjects employed as bread slicers and wrappers were studied to examine the effect of occupational category on respiratory symptoms, ventilatory capacity, non-specific bronchial reactivity, and prick skin test responses to wheat and common allergens. Bakers had a greater prevalence of attacks of wheeze and dyspnoea and more frequently considered that work affected their chests than did slicers and wrappers. Bakers with a history of asthma with onset since starting work in a bakery had a greater prevalence of chronic cough and sputum, increased bronchial reactivity, and positive prick skin test responses to wheat and common allergens than other bakers. There was a significant association between the frequency of positive prick skin tests to wheat and common allergens, suggesting that prior atopy facilitates sensitisation to cereal antigens. The frequency of positive prick skin responses to common allergens, however, declined with increasing baking duration whereas the frequency of positive skin responses to wheat increased with increasing baking duration, suggesting that subjects who were sensitised to common allergens were leaving the industry whereas subjects who stayed in the industry increased their risk of developing sensitisation to wheat. Oven handlers had a greater prevalence of attacks of wheeze and dyspnoea and more frequently considered that work affected their chests than either dough makers or general bakers. They also had a greater prevalence of positive prick skin test responses to wheat than dough makers or general bakers. Oven handlers also had a lower mean standardised casual FEV1 than either general bakers or dough makers. Thus oven handlers appear to have a greater risk of developing respiratory allergy and airflow obstruction than bakers in other occupational categories.

Adult↗
PubMed2002

Vernalization-induced changes of the DNA methylation pattern in winter wheat.

Vernalization is a cold treatment that induces or accelerates flowering and insures that temperate-zone plants will not flower until after winter. There is evidence that vernalization results in DNA demethylation that induces flowering. Differences in DNA methylation can be determined using methylation-sensitive amplified fragment length polymorphisms (AFLPs). Methylation-sensitive AFLPs utilize restriction enzyme isoschizomers that are differentially sensitive to methylation, producing polymorphisms related to methylation differences as opposed to sequence differences. Near-isogenic lines (NILs) have been developed for spring vs. winter habit in wheat (Triticum aestivum) and allow for the study of a single vernalization locus. In this study, differences in the methylation pattern were determined for spring and winter NILs, as well as for unvernalized and vernalized individuals. Winter wheat was more highly methylated than spring wheat and methylation-related AFLPs were produced between winter and spring wheat. Changes in the methylation pattern were observed at the end of vernalization, one week after the end of vernalization, and four weeks after the end of vernalization of winter wheat. However, the most methylation differences were observed one week after removal of winter wheat from cold treatment. Our data suggest that there is not only a vernalization-induced demethylation related to flower induction, but there is also a more general and non-specific demethylation of sequences unrelated to flowering. Two methylation-related AFLPs induced by vernalization were shared among all of the winter NILs.

Cold Temperature↗
PubMed2003

Characterization of six wheat x Thinopyrum intermedium derivatives by GISH, RFLP, and multicolor GISH.

Restriction fragment length polymorphism (RFLP) analysis and multicolor genomic in situ hybridization (GISH) are useful tools to precisely characterize genetic stocks derived from crosses of wheat (Triticum aestivum) with Thinopyrum intermedium and Thinopyrum elongatum. The wheat x Th. intermedium derived stocks designated Z1, Z2, Z3, Z4, Z5, and Z6 were initially screened by multicolor GISH using Aegilops speltoides genomic DNA for blocking and various combinations of genomic DNA from Th. intermedium, Triticum urartu, and Aegilops tauschii for probes. The probing (GISH) results indicated that lines Z1 and Z3 were alien disomic addition lines with chromosome numbers of 2n = 44. Z2 was a substitution line in which chromosome 2D was substituted by a pair of Th. intermedium chromosomes; this was confirmed by RFLP and muticolour GISH. Z4 (2n = 44) contained two pairs of wheat--Th. intermedium translocated chromosomes; one pair involved A-genome chromosomes, the other involved D- and A- genome chromosomes. Z5 (2n = 44) contained one pair of wheat--Th. intermedium translocated chromosomes involving the D- and A-genome chromosomes of wheat. Z6 (2n = 44) contained one pair of chromosomes derived from Th. intermedium plus another pair of translocated chromosomes involving B-genome chromosomes of wheat Line Z2 was of special interest because it has some resistance to infection by Fusarium graminearum.

Blotting, Southern↗
PubMed2004

The transfer and characterization of resistance to common root rot from Thinopyrum ponticum to wheat.

Common root rot, caused by Cochliobolus sativus (Ito and Kurib) Drechs. ex Dastur, is a major soil-borne disease of spring and winter wheat (Triticum aestivum L. em Thell.) on the Canadian prairies. Resistance to common root rot from Thinopyrum ponticum (Podp.) Liu and Wang was transferred into wheat via crossing with Agrotana, a resistant wheat - Th. ponticum partial amphiploid line. Evaluation of common root rot reactions showed that selected advanced lines with blue kernel color derived from a wheat x Agrotana cross expressed more resistance than the susceptible T. aestivum 'Chinese Spring' parent and other susceptible wheat check cultivars. Cytological examination revealed 41 to 44 chromosomes in the advanced lines. Genomic in situ hybridization, using total genomic DNA from Pseudoroegneria strigosa (M. Bieb) A. Löve (St genome) as a probe, demonstrated that the blue kernel plants had two pairs of spontaneously translocated J-Js and Js-J chromosomes derived from the J and Js genome of Th. ponticum. The presence of these translocated chromosomes was associated with increased resistance of wheat to common root rot. The lines with blue aleurone color always had a subcentromeric Js-J translocated chromosome. The subtelocentric J-Js translocated chromosome was not responsible for the blue kernel color. The genomic in situ hybridization analysis on meiosis revealed that the two spontaneous translocations were not reciprocal translocations.

Ascomycota↗