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In a previous work, deduced amino acid sequences from twenty wheat peroxidase genes were assigned to seven groups designated as TaPrx108 to TaPrx114. Some of these apoplastic peroxidases have previously shown to play different roles in the plant defense responses to infection by the cereal cyst nematode Heterodera avenae. In the present study, PCR marker analysis using Sears’s aneuploid wheat lines cv. ‘Chinese Spring’ was used to locate four genes encoding peroxidase isozymes. The TaPrx111-A, TaPrx112-D and TaPrx113-F genes were located on the short arm of chromosome 2B and the TaPrx109-C on the long arm of chromosome 1B. These results would agree with the synteny between wheat and rice chromosomes previously established in other studies.

Los resultados obtenidos en un ensayo de campo de una colección de líneas avanzadas de trigo con introgresión de los genes H27 y H30, que confieren resistencia frente al Mosquito del trigo (Mayetiola destructor), evidenciaron que alguna de estas líneas mejoraban significativamente la producción (142%) respecto al testigo susceptible, indicando su posible utilidad como variedades capaces de dar buen rendimiento en ausencia de tratamientos químicos (insecticidas) contra la plaga del mosquito

Changes in ascorbate peroxidase (APX) enzyme activity in response to nematode (Heterodera avenae) attack were studied in roots of three hexaploid wheat lines carrying Cre2, Cre5, or Cre7 nematode resistance genes and the susceptible Triticum aestivum cv. Anza. A spectrophotometric analysis was carried out with root extracts of infected plants 4, 7, 11, and 14 days after nematode inoculation using uninfected plant as control. APX induction in infected resistant genotypes was similar and higher than in the susceptible control. The introgression wheat/Aegilops ventricosa H-93-8 line, carrying the Cre2 gene, and its parental line H-10-15 as susceptible control were used to analyze whether this increase of activity was correlated with the induction of APX gene expression. Genes encoding cytosolic forms of APX were induced in roots of both lines in response to nematode infection. This induction took place both earlier and with greater intensity in the resistant line than in the susceptible one, and it was also higher in the root area at the site of nematode attachment.

En un estudio previo se caracterizaron, alinearon y relacionaron 20 genes que codifican para peroxidasas de trigo. Las secuencias deducidas de estos genes se agruparon en siete grupos, TaPrx108 a TaPrx114, de acuerdo a la similitud entre ellas y con peroxidasas de la Clase III de otras especies. Los genes correspondientes a tres de estos grupos (TaPrx111, TaPrx112 y TaPrx113) mostraron inducción en respuesta a la infección por Heterodera avenae en una línea de trigo resistente. Tres de los genes, TaPrx111-A, TaPrx112-D y TaPrx113-F, fueron localizados en el cromosoma 2BS y posiblemente estén ligados entre si. En el presente estudio, el gen de la peroxidasa TaPrx109-C, fue asignado al brazo largo del cromosoma 1B.

We have used in situ hybridization combining genomic and repeated DNA fluorescent probes to determine the karyotype composition of two bread wheat introgression lines: H-93-33, which carries the gene H27 for resistance to the Hessian fly M. destructor (Delibes et al. 1997); and H-93-8, carrying the gene Cre2 which confers resistance to the cereal cyst nematode H. avenae (Delibes et al. 1993). Both introgression lines had been derived from an earlier cross between T. aestivum subsp. aestivum (2n=42; genome composition AABBDD) and a semi-fertile hybrid between T. turgidum subsp. turgidum (2n=28; genome composition AABB) and the wild grass Ae. ventricosa (2n=28; genome constitution DvDvN¬vNv). We also have examined several resistant advanced lines that were obtained from H-93-33 (lines ID-2151, ID-2193, Ma-1612-a and Ma-1612-b) or H-93-8 (line ID-2150) after 3 to 5 backcrosses with commercial wheats.

Effects of introgressed 4Nv Aegilops ventricosa chromosome on yield and yield components in bread wheat

The incompatible interaction between plant and pathogen is often determined by the hypersensitive reaction (HR). This response is associated with accumulation of reactive oxygen species (ROS), which results in adverse growth conditions for pathogens. Two major mechanisms involving either NADPH oxidases or peroxidases have been proposed for generation of ROS. Peroxidases (PER, EC 1.11.1.7), present in all land plants, are members of a large multigenic family with high number of isoforms involved in a broad range of physiological processes. PER genes, which are expressed in nematode feeding sites, have been identified in several plant species (Zacheo et al. 1997). A strong correlation between HR and PER activities at four and seven days post nematode infection, was detected in roots of wheat lines carrying Cre2, Cre5 (from Ae. ventricosa) or Cre7 (from Ae. triuncialis) Heterodera avenae resistance genes (Andrés et al. 2001; Montes et al. 2003, 2004). We have studied changes in root of peroxidase mRNAs levels after infection by H. avenae of a wheat/Ae. ven¬tricosa introgression line (H-93-8) carrying Cre2 (Delibes et al. 1993). We also report and classify the predicted protein sequences derived from complete peroxidase transcripts.

Stable wheat-Aegilops introgression lines with 42 chromosomes (H-93), derived by repeated selfing from a cross (Triticum turgidum x Aegilops ventricosa) x T. aestivum, have been characterized using the following DNA probes and isozyme markers: (1) single or low-copy DNA fragments from Ae. ventricosa; (2) known cDNA probes corresponding to 1-thionin, monomeric -amylase inhibitor, the CM3 subunit of tetrameric -amylase inhibitor, and sucrose synthase from wheat; (3) anonymous cDNA probes from wheat that have been mapped by Sharp et al. (1989); (4) isozyme markers corresponding to aconitase, shikimate dehydrogenase, adenylate kinase, and endopeptidase. Meiotic metaphases of appropriate hybrids involving selected H-93 lines have been investigated by the Giemsa C-banding technique. The substitution of whole chromosomes [(5A) 5Mv; (4D) 4Mv; (5D) 5Mv; (7D) 7Mv] and chromosomal segments (1Mv; 3Mv; 5Mv; 7Mv) from the Mv genome of Aegilops ventricosa has been demonstrated. The distribution of selected markers among putative wheat-Ae. ventricosa addition lines has also been investigated. The 7Mv addition has been characterized for the first time, while the identity of the previously reported 5Mv and 6Mv additions has been confirmed.

Gene Pch1, which confers resistance to eyespot disease (Pseudocercosporella herpotrichoides Fron), has been located on chromosome 7D in the H-93 wheat-Aegilops ventricosa transfer lines using isozyme markers and DNA probes corresponding to group 7 chromosomes. Previous experiments had failed to ascertain this location. The lack of segregation of the resistance trait in progeny from reciprocal crosses between lines H-93-70 and VPM1 indicates that their respective resistance factors are allelic. Line H-93-51 carries the endopeptidase allele Ep-D1b but is susceptible to eyespot, which indicates that resistance to eyespot is not a product of the Ep-D locus, as had been proposed in a previous hypohesis

El presente articulo revisa sucintamente un conjunto de investigaciones sobre la biología molecular de un tejido vegetal, el endospermo de los cereales, que puede considerarse el producto comestible mas importante a escala mundial. en dichas investigaciones se han utilizado técnicas bioquímicas, citogeneticas y de ingeniería genética para el conocimiento básico y la manipulación practica del conjunto de especies cultivadas denominadas cereales. los estudios realizados han abarcado los siguientes aspectos principales: purificación y caracterización de proteínas, caracterización y localizacion cromosomica de genes estructurales y reguladores involucrados en el control genético de la composición bioquímica del tejido, clonaje de genes de plantas en bacterias, y transferencia genica entre especies vegetales. las aplicaciones practicas derivadas hasta ahora incluyen desde métodos para la identificación de especies, variedades, y materias primas, a la transferencia de genes de interés agronómico desde especies silvestres a cultivadas. a medio plazo, los avances realizados en la manipulación in vitro de genes vegetales serán de utilidad practica en la aplicación de la ingeniería genética a la mejora vegetal.

A double interspecific oross {Triticum turgidum (AB) var. rubroatrum H-l-1 x Ae. ventvicosa (DM°) AP-l} x T.aestivum (ABD) cv. Almatense H-10-1S was carried out in 1950 by M. Alonso Peña (Cuenca, Spain) and 70 Unes were devived from it by vepeated selfing (Unes H-93-1 thvough 70). Pveliminavy biochemical evidence indicated genetic tvansfev fvom the M° genome of Ae.ventvicosa into some of these Unes. A more detailed biochemical and cytological characteriza tion of the H-93- Unes was undertaken. A progress report of these studies is presented here. Fourten biochemical systems, each representing a set of up to 4 homoeologous loci, weve investigated in the vavental material, in the H-93- Unes, and in Ae. squavrosa (DD), Ae. comosa (MM) and Ae. uniaristata (M^-M11). Biochemical markers controlled by the A or B genomes of one or both wheat parents weve distributed in the H-93- Unes as expected if the egcells fvom the self-stevile ABDM0 hybvid, rescued by the ABD polen, cavvied the complete A and B genomes from T. tuvgidum. The distvibution of biochemical mavkevs contvolled by the D genomes of one ov both D genome parents indicated that most of the eggcells from the ABDM0 hybrid carvied most of the D genome, i.e. 3 out of 8 markers of the former tupe were absent in a few Unes each, ind.icating incomplete homology between the two D genomes, non-homologous transfer or deletion. Biochemical characters present in Ae. ventricosa (DM°), Ae. comosa (M), Ae. uniaristata (M11) and absent in T. aestivum (ABD), Ae. squarrosa (D) and T. tuvgidum (AB) were selected as M° genome markers. Two of these markers were not transmited to the H-93- Unes, three were tvansmitted with low fvequency and one with a high fvequency. Resistance to Erisiphe graminis was determined by Dosba and Doussinault at Rennes and was found to be transmitted with low fvequency. Somatic chromosome numbers of the H-93- Unes were counted and all weve found to be hexaploid. Meiosis was studied in Unes cavvying M° genome mavkevs and in their hybrids with the T. aestivum parent, to determine the máximum numbev of alien chvornosornespvesent in each Une. The joint considevation of the biochemical and the cytological evidence se^me to indícate that the genetic tvansfev has taken place by chvomosome substitution and by vecombination.

There are not good intraspecific sources of resistance to the eyespot disea se of wheat, aaused by Cercosporella herpotrichoides Fvon . The -ínterspecifia transfer of genes for resistanoe from Aegitops ventricosa into hexaploid wheat has been only partially achieved, because the degree of resistanoe attained is not as high as that of the donor. We report here on the transfer of resistanoe in a double oross (Triticum turgidum var. rubroatrwv H-1-1 x Ae.ventricosa AP-D x T.aestivum cv. Almatense H-10-15. The high level of resistanoe in a high proportion of the lines strongly suggests a simple genetic control for this oharacter (possibly by one major gene). The gene(s) responsible for resistanoe in the selected lines must be associa ted with the D genome of Aegilops ventricosa on the basis of a detailed study of the distribution of biochemioal markers in the H-93 lines. These results do not exelude that genes with similar effeets might be looated in the M° genome.

In the laboratory of M. Metzlaff, genome specific DNA probes from Hordeum vulgare were cloned and characterized by H. Junghans. Regarding repeated DNA sequences our further investigations will concéntrate on the proofof alien chromatin in the wheat -Ae. markgrafii crossing material and on the enlargement of the investigation to their distribution in Poaceae species.

Se resumen las investigaciones realizadas sobre genética bioquímica de la especie aloploide de Triticum aestivum L. (trigo común). Dichas investigaciones abarcan los siguientes aspectos: a) localización cromosómica de genes que controlan sistemas moleculares; b) formas de interacción entre los genomios integrados en dicha especie; c) transferencia genética extraespecífica y extragenérica desde Aegilops ventricosa, Sécale cereale y Agropyron elongatum a trigo. Se especula sobre las implicaciones evolutivas de los resultados obtenidos y se enumeran las aplicaciones prácticas.

La introducción de caracteres extragenéricos o extraespecíficos en plan tas cultivadas tiene interés teórico y una reconocida importancia práctica (ver p.ej. ref.1). En el caso de los trigos cultivados, pueden actuar como donadores de genes que controlan caracteres de calidad, de resistencia a agentes patógenos, etc., especies afines de los géneros Sécale, Agropyron y Aegilops. Los métodos empleados para la introducción de estos caracteres son variados y dependen de la afinidad existente entre la especie donadora y la receptora. El proceso de transferencia requiere, en primer lugar, salvar los impe_ dimentos que se presentan para el acceso del material genético extraño al núcleo receptor y, posteriormente, lograr la integración estable de dicho material.

The extraspecific transfer of genes into cultivated plants is of considerable interest both in basic and applied terms (Sears, 1956; Riley and Kimber 1966). The wild grass Aegilops ventricosa has been recognised for almost 30 years as an important potential donor of genes that determine characters of agronomic interest. More specifically, Sprague (1936) discovered in this species a high level of resistance to the fungus Pseudocercosporella herpotrichoides, which causes eyespot disease. This disease is responsible for considerable lodging and reductions of yield in extensive áreas of wheat cultivation. The level of resistance of wheat cultivars is too low, even among the less susceptible ones (Capelle Desprez and Cerco) and no single genes for resistance had been described in any species. Attemps to transfer resistance from Ae.ventricosa to wheat had been only partially successful. The purpose of this paper is to review work carried out in our laboratory for the past 12 years on the transfer of genes between these two species. This work has led to the recent demonstre^ tion of a major dominant gene for resistance, which confers a high level of resistance to cultivated wheat.

Endosperm protein and isozyme patterns of Unes derived from the ovoss [Tritioum turgidum (AABB) x Aegilops ventrioosa (DDMVMV)] x T_. aes tivum (AABBDD) were studied. Five bioohemioal oharaoters pvesent in Ae_. ventrioosa (DDM°M°), Ae_. oomosa (MU) and Ae_. uniaris tata (MUMU) , but absent from Ae. squarrosa (DD)t T_. aes tivum (AABBDD) and T_. turgidum (AABB) were investigated. Three of these were identified in several Unes3 indioating gene transfer from the M° genome of Ae. ventrioosa into hexaploid wheat. The wide distribution of one of the markers (CM-4) suggests its previous transfer to the D genome of Ae. ventrioosa.

Advanced wheat lines carrying the Hessian fly resistance gene H27 were obtained by backcrossing the wheat/Aegilops ventricosa introgression line, H-93-33, to commercial wheat cultivars as recurrent parents. The Acph-N v 1 marker linked to the gene H27 on the 4Nv chromosome of this line was used for marker assisted selection. Advanced lines were evaluated for Hessian fly resistance in field and growth chamber tests, and for other agronomic traits during several crop seasons at different localities of Spain. The hessian fly resistance levels of lines carrying the 4Nv chromosome introgression (4D/4Nv substitution and recombination lines that previously were classified by in situ hybridisation) were high, but always lower than that of their Ae. ventricosa progenitor. Introgression lines had higher grain yields in infested field trials than those without the 4Nv chromosome and their susceptible parents, but lower grain yields under high yield potential conditions. The 4Nv introgression was also associated with later heading, and lower tiller and grain numbers/m2 . In addition, it was associated with longer and more lax spikes, and higher values of grain weight and grain protein content. However, the glutenin and gliadin expression, as well as the bread-making performance, were similar to those of their recurrent parents