Combined effects of benomyl and environmental factors on growth and expression of the fumonisin biosynthetic genes FUM1 and FUM19 by Fusarium verticillioides.

Fusarium verticillioides is predominantly responsible of fumonisin contamination of maize and other cereals in Mediterranean climatic regions. This study examined the interaction of the fungicide benomyl, at ED50 and ED90 concentrations (effective doses of benomyl to reduce growth by 50% and 90%, respectively), with a range of temperatures (20-35 °C) and water potentials (-0.7, -2.8 and -7.0 MPa) compatible with current and foreseen climate change scenarios for these regions on growth and fumonisin biosynthesis in in vitro assays. The expression of fumonisin biosynthetic genes (FUM1 and FUM19) was quantified by real time RT-PCR. FUM1 encodes a polyketide synthase and FUM19 an ABC-type transporter, located both in the fumonisin biosynthetic cluster. The ED50 and ED90 concentrations obtained at 25 °C were 0.93 mg/L and 3.30 mg/L, respectively. Benomyl affected growth and fumonisin gene expression differently but it generally reduced fungal growth and fumonisin biosynthesis and both were significantly affected by temperature and water potential. This indicated that efficacy of benomyl might be compromised at certain conditions, although at similar or lower levels than other fungicides tested. Both fumonisin biosynthetic genes had similar expression patterns in all treatments and their correlation was positive and significant. The results suggested that Mediterranean climatic scenarios might suffer an additional negative impact of climate change by reducing the efficacy of antifungals used to control pathogens and toxigenic fungi.

Contamination of barley seeds with Fusarium species and their toxins in Spain: an integrated approach.

Fusarium is a globally distributed fungal genus that includes different species pathogenic to cereals among others crops. Some of these Fusarium species can also produce toxic compounds towards animals and humans. In this work, the presence of the most important Fusarium toxins was determined in barley seeds from Spain, sampled according to European Union requirements. The results obtained were compared with the presence of mycotoxigenic species considered responsible for their synthesis by using species-specific polymerase chain reaction protocols. Fumonisins B(1) and B(2), zearalenone, trichothecenes type A (T-2 and HT-2) and trichothecenes type B (deoxynivalenol and nivalenol) were analysed by using high-performance liquid chromatography. Deoxynivalenol and zearalenone were detected in 72% and 38% of the barley samples, respectively, at levels below European Union limits in all cases. However, the co-occurrence of both toxins in 34% of the samples suggested that synergistic activity of these two mycotoxins should be evaluated. Nivalenol and HT-2/T-2 were detected at low levels in 17% and 10% of the samples, respectively. Fumonisins occurred in 34% of the samples at levels up to 300 µg/kg. This suggested that they might represent a risk in Spanish barley, and to our knowledge, this is the first report on the presence of fumonisins in barley in this country. The species-specific polymerase chain reaction assays to detect mycotoxin-producing Fusarium species showed a very consistent correlation between F. verticillioides detection and fumonisin contamination as well as F. graminearum presence and zearalenone, deoxynivalenol and nivalenol contamination in barley samples. The approach used in this study provided information of mycotoxin contamination of barley together with the identification of the fungal species responsible for their production. Detection of the species with the current polymerase chain reaction assay strategy may be considered predictive of the potential mycotoxin risk in this matrix.

A molecular based strategy for rapid diagnosis of toxigenic Fusarium species associated to cereal grains from Argentina.

Fusarium species are worldwide causal agents of ear rot in cereals. Their toxigenic potential is a health risk for both humans and animals. In Argentina, most identification of these fungi has been based on morphological and cross-fertility criteria which are time consuming and require considerable expertise in Fusarium taxonomy and physiology. DNA based approaches have been reported as rapid, sensitive and specific alternatives to identify the main fumonisin and trichothecene-producing Fusarium species. In this work, we used PCR assays and the partial sequence of TEF1-alpha gene (Translation Elongation Factor-1 alpha) to identify the fumonisin and trichothecene-producing species in Fusarium isolates from diverse regions of Argentina. The relative efficiency and reliability of those methods to improve mycotoxin risk prediction in this country were also assessed. Species-specific PCR assays were targeted toward multicopy IGS (Intergenic Spacer of rDNA units) and on the toxin biosynthetic genes FUM1 (fumonisins) and TRI13 and TRI7 genes (trichothecenes). PCR assays based on FUM1 gene and IGS sequences allowed detection and discrimination of the fumonisin producers Fusarium proliferatum and Fusarium verticillioides. Molecular identification of nonfumonisin producers from Gibberella fujikuroi species complex was possible after determination of TEF1-alplha gene sequences, which indicated the presence of Fusarium subglutinans, Fusarium andiyazi and Fusarium thapsinum. TEF-1 alpha gene sequences also allowed discrimination of the different species of the Fusarium graminearum complex (F. graminearum sensu lato) as F. graminearum sensu stricto, Fusarium meridionale and Fusarium boothii. The last two species belonged to NIV chemotype and were detected for the first time in the subtropical region of Argentina while F. graminearum sensu stricto was DON producer only, which was also confirmed by specific PCR assays based on TRI137/TRI7 genes. Our results indicated that the PCR assays evaluated in this work are reliable diagnostic tools to detect the main toxigenic Fusarium species associated to cereal grains in Argentina. An extensive epidemiological survey based on the approach presented in this work is currently in progress to know the mycotoxigenic hazard of Fusarium species in cereal grains from the subtropical region of Argentina.

Polymerase chain reaction (PCR) identification of Penicillium brevicompactum, a grape contaminant and mycophenolic acid producer.

Penicillium brevicompactum is a ubiquitous fungal species that contaminates diverse substrates and commodities and produces an array of metabolites toxic to human and animals. The present work has obtained evidence, by liquid chromatography (LC)-ion-trap mass spectrometry, of the ability of P. brevicompactum strains isolated from grapes to produce mycophenolic acid, a potent immunosuppressor. In order to facilitate early diagnosis of this species on commodities for human and animal consumption, a rapid, sensitive and specific polymerase chain reaction (PCR) assay for P. brevicompactum was developed. The specific primers were designed based on the ITS1-5.8S-ITS2ITS (Internal Transcribed Spacers of rRNA genes) multicopy region. This method provides a useful aid to detect the presence of this fungal species in grapes and other commodities in order to prevent the toxins produced entering the food chain.

Variability and characterization of mycotoxin-producing Fusarium spp isolates by PCR-RFLP analysis of the IGS-rDNA region.

In the present report, a total of 75 Fusarium spp isolates (35 of the Gibberella fujikuroi species complex, 26 of F. oxysporum, 7 of F. graminearum, 5 of F. culmorum, 1 of F. cerealis, and 1 of F. poae) from different hosts were characterized morphologically, physiologically and genetically. Morphological characterization was performed according to macroscopic and microscopic aspects. Physiological characterization was based on their ability to produce fumonisin B1 (FB1), fumonisin B2 (FB2), zearalenone (ZEA) and type B trichothecenes (deoxynivalenol, nivalenol and 3-acetyldeoxynivalenol). FB1, FB2, and ZEA were determined by liquid chromatography and trichothecenes by gas chromatography. Molecular characterization of isolates was carried out using an optimized and simple method for isolation of DNA from filamentous fungi and polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) of the intergenic spacer region (IGS) of the rDNA. The results indicated that G. fujikuroi complex isolates can be divided into low and high fumonisin producers. The haplotypes obtained with HhaI, EcoRI, AluI, PstI and XhoI enzymes provided very characteristic groupings of G. fujikuroi isolates as a function of host type and fumonisin producing capacity. F. graminearum, F. culmorum and F. cerealis isolates were high ZEA and type B trichothecene producers, while F. oxysporum and the G. fujikuroi complex isolates did not show this ability. The haplotypes obtained with CfoI, AluI, HapII, XhoI, EcoRI and PstI enzymes permitted to discern these five Fusarium species and G. fujikuroi complex isolates but the restriction patterns of the IGS region did not show any relationship with the geographic origin of isolates.

Characterization of Fusarium spp. isolates by PCR-RFLP analysis of the intergenic spacer region of the rRNA gene (rDNA).

In the present study, 44 Fusarium spp. isolates (5 Fusarium culmorum, 7 Fusarium graminearum, 1 Fusarium cerealis, 1 Fusarium poae, 26 Fusarium oxysporum, and 4 Gibberella fujikuroi species complex) were characterized morphologically, physiologically and genetically. All except one (Dutch Collection: CBS 620.72) were isolated from different hosts grown in various Spanish localizations. Morphological characterization was made according to macroscopic and microscopic aspects. Physiological characterization was based on their ability to produce zearalenone (ZEA) and type B trichothecenes (deoxynivalenol, nivalenol and 3-acetyldeoxynivalenol). ZEA was determined by liquid chromatography and trichothecenes by gas chromatography. Confirmation was carried out by liquid chromatography-ion trap-mass spectrometry (ZEA) or gas chromatography-mass spectrometry (trichothecenes). Molecular characterization of isolates was performed using an optimized, simple and low-cost method for isolation of DNA from filamentous fungi and polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) of the intergenic spacer region (IGS) of the rRNA gene (rDNA). The results indicate that F. graminearum, F. culmorum and F. cerealis isolates were high ZEA and type B trichothecene producers, the F. poae isolate produced very low level of nivalenol while F. oxysporum and the G. fujikuroi complex isolates did not show this ability. Restriction patterns of the IGS region did not show any relationship with the host, geographic origin of the isolate and mycotoxin-producing capacity. However, the haplotypes obtained with six restriction enzymes (CfoI, AluI, HapII, XhoI, EcoRI and PstI) permitted to discern the six assayed Fusarium species. Therefore, this is a rapid and suitable methodology that allows closely related strains to group and to estimate the genetic relationships between the groups.

Occurrence and variability of mycotoxigenicFusarium species associated to wheat and maize in the South West of Spain.

The contamination of cereals with mycotoxins produced by species ofFusarium is an important risk to human and animal health. The toxigenic profile is different depending on theFusarium species considered and, in some species, differences can also be observed at intraspecific level. Information about the distribution and variability of the mycotoxigenicFusarium species allow prediction of the toxins that may occur and to devise control strategies. In this work, the occurrence of mycotoxigenicFusarium species associated to cereals was analysed in a wide sample of durum wheat fields (Triticum durum Desf.) and maize from the South West of Spain (Andalucía).F. equiseti, F. graminearum andF. culmorum were the most frequentFusarium species detected in wheat fields followed byF. sambucinum andF. avenaceum, whereas in the case of maize,F. verticillioides andF. proliferatum were the onlyFusarium species present. The relationships of the Spanish isolates from theF. equiseti, F. avenaceum andF. sambucinum species were analysed by nucleotide sequence comparison of a partial region of the Elongation Factor 1 alpha (EF-1α) with other sequences available in data bases. The results indicated thatF. avenaceum andF. equiseti showed high variability and that the SpanishF. equiseti isolates seemed to belong toF. equiseti type II.

Advances in molecular diagnosis of toxigenic Fusarium species: a review.

The development of advanced molecular diagnosis for the critical toxigenic Fusarium species is considered in this review. The specific topics discussed are (1) isolation of mating type genes of Gibberella complex, (2) molecular detection of Fusarium-producing fumonisins, (3) molecular detection of Fusarium-producing trichothecenes and enniatins. Particular attention is given to the development of PCR assays for genes involved in the toxin biosynthesis that would permit the early detection of Fusarium species-producing toxins and potentially even reveal which particular toxin may be present within a food or feed product. Most of these data have been obtained within the 'De-Tox Fungi' project supported by the European Commission (QLK1-CT-1998-01380).

Fumonisin production by Gibberella fujikuroi strains from Pinus species.

Fumonisins are important mycotoxins basically produced by strains from the Gibberella fujikuroi species complex (with anamorphs in Fusarium genus) which contaminate food and feed products representing a risk to human and animal health. In this work, we report for the first time the fumonisin production of Fusarium moniliforme Sheldon strains associated to edible pine nuts of Pinus pinea. P. pinea is an important and widely distributed Pinus species in the Mediterranean area where their pine nuts are consumed raw or slightly processed in diverse food products. In this work, characterization and further identification of those strains were performed by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLPs) of the intergenic spacer region of the rDNA (IGS) with the aid of the eight mating populations (A-H) described for G. fujikuroi species complex. The method was powerful to detect polymorphism, allowing discrimination between individuals and could be used to study the genetic relationships among them and within the G. fujikuroi species complex. Fusarium strains associated to Pinus radiata were also included in the present study. These strains did not produce fumonisins and showed no close relation with the strains isolated from P. pinea. The approach used in this work was rapid and proved to be efficient to assist identification and to characterize and analyse relatedness of new isolates within the G. fujikuroi species complex.

Characterization and in vitro expression patterns of an exopolygalacturonase encoding gene from Fusarium oxysporum f.sp. radicis lycopersici.

AIMS: In this work, we report the isolation, characterization and expression pattern in in vitro cultures of an EXOPG encoding gene (pgx2), a novel EXOPG encoding gene of Fusarium oxysporum f.sp. radicis lycopersici, responsible for foot crown and root rot disease in tomato plants. The gene was compared with other fungal polygalacturonases (PGs) previously reported. METHODS AND RESULTS: Partial sequences of the purified EXOPG native protein were used to design primers that amplified a genomic fragment by PCR. The amplified genomic fragment was used as a probe to screen a genomic library. One isolated clone was analysed. The complete genomic, cDNA and the deduced amino acid sequences were compared with other fungal EXOPGs and ENDOPGs. Regulation of pgx2 expression was analysed by Northern blot in in vitro cultures supplemented with different carbon sources. CONCLUSIONS: Pgx2 was present as single copy in the haploid genome of several Fusarium species. PGX2 showed the conserved amino acid motifs typical of PGs and those reported for fungal EXOPGs. Pgx2 was regulated at transcriptional level showing similar expression pattern to other EXOPG encoding gene (pgx1) when the fungus was cultured on different carbon sources suggesting a coordinate expression of both genes. This similarity would be supported by the presence of common putative regulatory motifs in the upstream regions of both genes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study reports the analysis of a novel EXOPG gene of the tomato pathogen F. oxysporum f.sp. radicis lycopersici, a contribution to the understanding of the role of cell-wall-degrading enzymes produced by fungi during pathogenesis.

The course of pectin degradation by polygalacturonases from Fusarium oxysporum f. sp. radicis lycopersici.

The production of polygalacturonases from Fusarium oxysporum f. sp. radicis lycopersici (FORL) occurred sequentially, and endo- and exo-polygalacturonases (PG) predominated at different times during growth. At first FORL produced a PG which did not release monomers from pectins and was unable to hydrolyse dimers and trimers. Later a complex was produced in which exo-PG seemed to be the predominant activity; the monomer was released rapidly and this activity was able to degrade dimers and trimers.

Control of polygalacturonase synthesis in Fusarium oxysporum f.sp. radicis lycopersici.

Genetic control of polygalacturonase (PG) activity from Fusarium oxysporum f.sp. radicis lycopersici was analyzed on pectin and glucose cultures. One exopolygalacturonase from F. oxysporum f.sp. radicis lycopersici was strongly induced, in stationary culture, when the fungus was grown on apple pectin, while on glucose no extracellular PG activity could be detected. Although SDS-PAGE detected the presence of a putative PG band (66 kDa) in both conditions, specific antibodies obtained against the purified PG only detected it in PG-inducing conditions, that is to say, when apple pectin was used as the carbon source. Northern blot analysis of RNA of two isolates of F. oxysporum f.sp. radicis lycopersici (r6 and r2) confirmed that this regulation of PG synthesis was exerted at the transcriptional level. Only one single mRNA species of around 1400 nucleotides was detected on the cultures containing pectin and was absent in glucose-grown cultures. Southern blot analysis of genomic DNA indicated that pg gene seems to be present in a single copy in the genomes of F. oxysporum f.sp. radicis lycopersici r6 and r2 and Fusarium oxysporum f.sp. lycopersici, showing similar hybridization patterns in all species. The partial sequence of this pg gene from F. oxysporum f.sp. radicis lycopersici r6, which is also reported, showed high similarity to diverse PGs already reported. Exopolygalacturonase of F. oxysporum f.sp. radicis lycopersici r6 is heavily glycosylated; its deglycosylated form had a molecular mass of 50 kDa.

Analysis of regulatory elements involved in the induction of two tobacco genes by salicylate treatment and virus infection.

Tobacco genes encoding the PR-1a protein and a glycine-rich protein are expressed after treatment of plants with salicylate or infection with tobacco mosaic virus. Upstream sequences of these genes were fused to reporter genes, and these constructs were used to transform tobacco. Upstream sequences of the PR-1a gene of 689 base pairs or longer were sufficient for induction of the reporter gene in tobacco mosaic virus-inoculated leaves, systemically induced leaves from infected plants, and leaves treated with salicylate. No such induction was found with upstream sequences of 643 base pairs or shorter of the PR-1a gene. When the PR-1a upstream sequence from nucleotides -625 to -902 was fused to the cauliflower mosaic virus 35S core promoter, a construct was obtained that conferred tobacco mosaic virus and salicylate inducibility to the reporter gene in transgenic plants. This confirmed the localization of tobacco mosaic virus- and salicylate-responsive elements between positions -643 and -689 in the PR-1a promoter. With the glycine-rich protein gene, an upstream sequence of 645 base pairs was sufficient for tobacco mosaic virus and salicylate inducibility of the reporter gene, whereas constructs containing 400 base pairs or fewer of the glycine-rich protein promoter were largely inactive.

Chromosomal identification and meiotic behavior of reciprocal translocations in a rye polymorphic population. Evolutionary implications.

The spontaneous interchange polymorphism of rye cultivar "Ailés" is composed, as can be deduced from the chromosomal identification of the interchanges analyzed, of several different reciprocal translocations in which the chromosomes of its haploid complement are involved with a similar frequency, except for chromosomes 4R and 6R. Several features of chromosome behavior at metaphase I, such as configuration and orientation of quadrivalents and frequency of chiasmata, were analyzed in structural heterozygotes for different interchanges. The two main factors affecting the orientation of quadrivalents at metaphase I proved to be the morphology of these chromosome associations at metaphase I and, in particular, the frequency of bound chromosome arms that they showed. A genotypic control of alternate orientation of quadrivalents independent of chiasmata frequency was not detected. In addition, the frequency of alternate orientation shows no relation to the fitness. Possible evolutionary implications of the results obtained are discussed.

Location of genes coding isozyme markers on Aegilops umbellulata chromosomes adds data on homoeology among Triticeae chromosomes.

Zymogram analysis was used to identify the Aegilops umbellulata chromosomes that carry the structural genes for particular isozymes. Wheat, Aegilops and wheat-Aegilops hybrid derivative lines (which contained identified Aegilops chromosomes) were tested by gel electrophoresis for isozymes of particular enzymes. It was found that Aegilops chromosome A (nomenclature according to G. Kimber 1967) carries a structural gene for 6-phosphogluconate dehydrogenase, Aegilops chromosome B carries structural genes for glucose phosphate isomerase and phosphoglucose mutase, Aegilops chromosome D carries genes for leaf peroxidases, Aegilops chromosome E carries structural genes for endosperm peroxidases, acid phosphatases and leaf esterases, Aegilops chromosome F carries a gene for embryo plus scutellum peroxidases and Aegilops chromosome G carries structural genes for endosperm alkaline phosphatases, leaf alkaline phosphatases and leaf esterases. The results obtained indicate that chromosome B is partially homoeologous of the wheat chromosomes of group 1 and 4, and chromosome E is partially homoeologous of wheat chromosomes of groups 7 and 4. Circumstantial evidence is also provided about the possible association between chromosomes C, D and A of A. umbellulata respectively with chromosomes 5, 2 and 1 of wheat.

Genetics of rye phosphatases: evidence of a duplication.

Genetic analyses were conducted on alkaline phosphatases of the endosperm of dry kernels and leaf acid phosphatases in four open pollinated and one inbred line of cultivated rye (Secale cereale L.). A total of seven alkaline phosphatase isozymes were observed occurring at variable frequencies in the different cultivars analyzed. We propose that at least five loci control the alkaline phosphatases of rye endosperm - Alph-1, Alph-2, Alph-3, Alph-4 and Alph-5 - all of which have monomeric behaviour. The leaf acid phosphatases are controlled by one locus and have a dimeric quaternary structure. All loci coding for alkaline phosphatase isozymes showed one active, dominant allele and one null, recessive allele, except for the locus Alph-3 which showed two active, dominant alleles and one null, recessive one. The linkage analyses suggest the existence of two linkage groups for alkaline phosphatases: one of them would contain Alph-2, Alph-4, Alph-5 and the locus/loci coding isozymes 6 and 7. This linkage group is located in the 7RS chromosome arm. The other group would include Alph-1 and Alph-3 loci, being located in the 1RL chromosome arm. Leaf acid phosphatases have been previously located in the 7RL chromosome arm. Our data also support an independent relationship between loci controlling the endosperm alkaline phosphatases and leaf acid phosphatases.

Biochemical evidence of homoeology between Triticum aestivum and Agropyron intermedium chromosomes.

The alcohol dehydrogenase (ADH), phosphoglucose mutase (PGM), glucosephosphate isomerase (GPI), glutamic oxaloacetic transaminase (GOT), malate dehydrogenase (MDH), leaf esterases (ESTL), leaf acid (ACPH) and endosperm alkaline (PHE) phosphatases, leaf peroxidases (PERL) zymogram phenotypes of Triticum aestivum, Agropyron intermedium, Triticum aestivum - Agropyron intermedium octoploids and six Agropyron intermedium chromosome additions to Triticum aestivum and two ditelocentric addition lines were determined. It was found that the six disomic chromosome addition lines and one ditelocentric chromosome addition line could be distinguished from one another and from the other possible lines on the basis of the zymogram phenotypes of these isozymes. The structural gene Acph-X1 was located on Agropyron chromosome L1, the genes Got-X3 and Mdh-X2 on chromosome L2, the gene Gpi-X1 on chromosome L3, the genes Adh-X1, Pgm-X1 and Phe-3 on chromosome L4, gene Perl-1 on chromosome L5 and the gene Estl-2 on chromosome L7 and chromosome arm L7d2. These gene locations provide evidence of homoeology between Agropyron chromosomes L1, L2, L3, L4, L5 and L7 and the Triticum aestivum chromosomes of homoeologous groups 7, 3, 1, 4, 2 and 6, respectively.

Association of Isozymes with a Reciprocal Translocation in Cultivated Rye (SECALE CEREALE L.).

In rye (Secale cereale L. cv. "Ailés") the progeny of a cross between a structural heterozygote for a reciprocal translocation (involving the 1R chromosome) and a homozygote for the standard chromosome arrangement were analyzed for the electrophoretic patterns of eight different leaf isozymes and also for their meiotic configuration at metaphase I.--The Got-3 and Mdh-2b loci are linked to each other and also to the reciprocal translocation. The Mdh-2b locus is located in the interstitial segment of the 3Rq chromosome arm, with an estimated distance of 8 cM to the breakpoint. Therefore, the reciprocal translocation involves the 1R and 3R chromosomes.--Also, the Mdh-1 and 6-Pgd-2 loci are linked (16 +/- 3 cM) and have been located on the 2Rq arm. Finally, the Per-3 and Per-4 loci are located on the 2Rp chromosome arm at an estimated distance of 26 +/- 4 cM.

Chromosomal location of isozyme markers in wheat-barley addition lines.

The peroxidase (CPX, PER), α-amylase (α-AMY), acid and alkaline phosphatase (PHE, PHS) and esterase (EST) zymogram phenotypes of 'Chinese Spring' wheat, 'Betzes' barley and a number of presumptive 'Betzes' chromosome additions to 'Chinese Spring' were determined. It was found that five disomic chromosome addition lines could be distinguished from one another and from the other two possible lines on the basis of the zymogram phenotypes of these isozymes. The structural genes Cpxe-H1 and Cpxe-H2 were located in 'Betzes' chromosome 1, the Perl-H5 and Perl-H6 in chromosome 2, the α-Amy-H2 and α-Amy-H3 in chromosome 7, the Phs-H5 and Phs-H4 in chromosomes 1 and 3 respectively, the Phe-H2, Phe-H3 and Phe-H4 in chromosome 1, the Phe-H1 in chromosome 3, the Ests-H4, Este-H2 and Ests-H6, Este-H8 in chromosomes 1 and 3 respectively and the Estl-H10 and Estl-H2 structural genes were related to chromosomes 3 and 6 respectively. These gene locations provide evidence of homoeology between 'Betzes' chromosomes 1, 2, 3, 6 and 7 and the rye chromosomes 7, 2, 3, 6 and 5, respectively, and also between 'Betzes' chromosomes 1, 2, 3, 6 and 7 and the 'Chinese Spring' homoeologous groups 7, 2, 3, 6 and 5, respectively.

Phosphogluco mutase - a biochemical marker for group 4 chromosomes in the Triticinae.

Structural genes for the isozymes of phosphogluco mutase (PGM) (EC 2.7.5.1) have been located on chromosome arms 4Aα, 4BL and 4DS of hexaploid wheat. These results support the homoeologies observed among these chromosome arms and also support the notion of conservation of gene synteny groups within the Triticinae.