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A doubled haploid (DH) population derived from a cross between the Japanese cultivar 'Fukuho-kumogi' and the Israeli wheat line 'Oligoculm' was used to map genome regions involved in the expression of grain yield, yield components, and spike features in wheat (Triticum aestivum L). A total of 371 markers (RAPD, SSR, RFLP, AFLP, and two morphological traits) were used to construct the linkage map that covered 4190 cM of wheat genome including 28 linkage groups. The results of composite interval mapping for all studied traits showed that some of the quantitative trait loci (QTL) were stable over experiments conducted in 2004 and 2005. The major QTL located in the Hair-Xpsp2999 interval on chromosome 1A controlled the expression of grains/spike ([R.sup.2] = 12.9% in 2004 and 22.4% in 2005), grain weight/spike ([R.sup.2] = 21.4% in 2004 and 15.8% in 2005), and spike number ([R.sup.2] = 15.6% in 2004 and 5.4% in 2005). The QTL for grain yield located on chromosomes 6A, 6B, and 6D totally accounted for 27.2% and 31.7% of total variation in this trait in 2004 and 2005, respectively. Alleles inherited from 'Oligoculm' increased the length of spikes and had decreasing effects on spike number. According to the data obtained in 2005, locus Xgwm261 was associated with a highly significant spike length QTL ([R.sup.2] = 42.33%) and also the major QTL for spikelet compactness ([R.sup.2] = 26.1%). Key words: doubled haploid, grain yield, QTL, spike features, wheat. Une population de lignees haploides doublees (DH) derivees d'un croisement entre le cultivar japonais 'Fukuhokumogi' et la lignee israelienne 'Oligoculm' a ete employee pour identifier des regions du genome qui sont impliquees dans l'expression du rendement en grains, des composantes du rendement ainsi que des caracteristiques de l'epi chez le ble (Triticum aestivum L.). Au total, 371 marqueurs (RAPD, SSR, RFLP, AFLP et deux caracteres morphologiques) ont ete utilises pour produire une carte genetique s'etendant sur 4190 cM repartis sur 28 groupes de liaison. Les resultats d'une analyse de cartographie d'intervalles composite pour tous les caracteres a l'etude a montre que certains des locus de caracteres quantitatifs (QTL) etaient stables pour les experiences realisees en 2004 et 2005. Le QTL majeur situe dans l'intervalle Hair- Xpsp2999 sur le chromosome 1A controlait le nombre de grains/epi ([R.sup.2] = 12,9 % en 2004 et 22,4 % en 2005), le poids en grains/epi ([R.sup.2] = 21,4 % en 2004 et 15,8 % en 2005), ainsi que le nombre d'epis ([R.sup.2] = 15,6 % en 2004 et 5,4 % en 2005). Les QTL pour le rendement en grains qui sont situes sur les chromosomes 6A, 6B et 6D expliquaient conjointement 27,2 % et 31,7 % de la variation pour ce caractere en 2004 et en 2005 respectivement. Les alleles du parent 'Oligoculm' contribuaient a augmenter la longueur des epis et a decroitre le nombre d'epis. Sur la base des resultats obtenus en 2005, le locus Xgwm261 a ete associe avec un QTL tres hautement significatif ([R.sup.2] = 42,33 %) pour la longueur des epis et avec un QTL majeur pour la densite des epillets ([R.sup.2] = 26,1 %) Mots-cles : haploides doubles, rendement en grains, QTL, caracteristiques de l'epi, ble. [Traduit par la Redaction], Introduction The progress in genetic improvement over the last century was based mainly on the use of single genes with relatively clear-cut effects on the phenotype (Newbury 2003). As agronomic [...]

Abstract: The infection of the model legume Medicago truncatula with Ralstonia solanacearum GMI1000 gives rise to bacterial wilt disease via colonisation of roots. The root and leaf responses to early infection (1 and 3 days post infection) were characterised to investigate the molecular mechanisms of plant resistance or susceptibility. A proteomics approach based on pools of susceptible and resistant recombinant inbred lines was used to specifically target the mechanisms for tolerance. Differential abundances were evidenced for proteins involved in defence (e.g., PR5, PR10, or Kunitz protease inhibitors) and signalling pathways (such as cyclophilin). R. solanacearum inoculation modifies expression levels of those genes, either in both genotypes (AOS1, LOX4, and proteinase inhibitors) or specifically in the resistant line (PR proteins). Exogenous application of salicylic acid (SA) enhanced tolerance to the bacteria, whereas methyl jasmonate (MeJA) enhanced short‐term tolerance then promoted disease in the susceptible ecotype, suggesting that they may mediate defence responses. Conversely, proteomics‐identified genes were also shown to be SA or MeJA responsive. This is the first description of differential response to R. solanacearum in M. truncatula. Our results suggest that root basal defence is activated at 1 dpi, together with the JA pathway. Specific resistance is then evidenced at three dpi, with the up‐regulation of SA‐dependent PR proteins. [ABSTRACT FROM AUTHOR]

Chloroplast DNA has been used extensively to analyze plant phylogenies at different taxonomic levels because of its size, organization and sequence conservation. In the present research, two chloroplastic regions, petA– psaJ, trnC– trnD and four DNA barcodes ( trnH– psbA, ITS , rbcL, matK), were used to introduce suitable regions for the assessment of genetic diversity among P.granatum L. genotypes. Analysis of psbE– petL in petA– psaJ region revealed 1,300 nucleotides with 4.29 % genetic diversity among genotypes, while trnC– petN in trnC– trnD region showed 1.8 % genetic diversity. Therefore, despite the results obtained from the study of other plants, the trnC– trnD region had a low potential for the evaluation of diversity among pomegranate genotypes. Analysis of DNA barcodes in pomegranate showed that trnH– psbA (genetic diversity 2.91 %) provides the highest intra-species variation, followed by ITS (genetic diversity 0.44 %). Eighteen genotypes from different geographical origins of Iran were used to investigate psbE– petL and trnH– psbA potential as novel barcodes to determine genetic polymorphism and characterize pomegranate genotypes. The results suggested that two regions, psbE– petL and trnH– psbA, were more suitable for determining intra-species relationships of pomegranate. [ABSTRACT FROM AUTHOR]

Bermudagrass (Cynodon spp.) is a major turfgrass for home lawns, public parks, golf courses and sport fields and is known to have originated in the Middle East. Morphological and physiological characteristics are not sufficient to differentiate some bermudagrass genotypes because the differences between them are often subtle and subjected to environmental influences. In this study, twenty seven bermudagrass accessions and introductions, mostly from different parts of Iran, were assayed by inter-simple sequence repeat (ISSR) markers to differentiate and explore their genetic relationships. Fourteen ISSR primers amplified 389 fragments of which 313 (80.5%) were polymorphic. The average polymorphism information content (PIC) was 0.328, which shows that the majority of primers are informative. Cluster analysis using the un-weighted paired group method with arithmetic average (UPGMA) method and Jaccard's similarity coefficient (r = 0.828) grouped the accessions into six main clusters according to some degree to geographical origin, their chromosome number and some morphological characteristics. It can be concluded that there exists a wide genetic base of bermudograss in Iran and that ISSR markers are effective in determining genetic diversity and relationships among them. [ABSTRACT FROM AUTHOR]

The relationships among 55 wheat accessions (47 accessions collected from Iran and eight accessions provided by the Institute of Plant Biology of the University of Zurich, Switzerland) belonging to eight species carrying A genome (Triticum monococcum L., T. boeoticum Boiss., T. urartu Tumanian ex Gandilyan, T. durum Desf., T. turgidum L., T. dicoccum Schrank ex Schübler, T. dicoccoides (Körn. ex Asch. & Graebner) Schweinf. and T. aestivum L.) were evaluated using 31 A genome specific microsatellite markers. A high level of polymorphism was observed among the accessions studied (PIC = 0.77). The highest gene diversity was revealed among T. durum genotypes, while the lowest genetic variation was found in T. dicoccoides accessions. The analysis of molecular variance (AMOVA) showed a significant genetic variance (75.56%) among these accessions, representing a high intra-specific genetic diversity within Triticum taxa in Iran. However, such a variance was not observed among their ploidy levels. Based on the genetic similarity analysis, the accessions collected from Iran were divided into two main groups: diploids and polyploids. The genetic similarity among the diploid and polyploid species was 0.85 and 0.89 respectively. There were no significant differences in A genome diversity from different geographic regions. Based on the genetic diversity analyses, we consider there is value in a greater sampling of each species in Iran to discover useful genes for breeding purposes. [ABSTRACT FROM AUTHOR]

The lateral spikelets of two-rowed barley are reduced in size and sterile, but in six-rowed barley all three spikelets are fully fertile. The trait is largely controlled by alleles at the vrsl locus on chromosome arm 2HL, as modified by the allele present at the / locus on chromosome arm 4HS. Molecular markers were developed to saturate the 4HS region by exploiting expressed sequence-tags, either previously mapped in barley to this region, or present in the syntenic region of rice chromosome 3. Collinearity between rice and barley was strong in the 4.8cM interval BJ468164-AV933435 and the 10cM interval AV942364-BJ455560. A major QTL for lateral spikelet fertility (the I locus) explained 44% of phenotypic variance, and was located in the interval CB873567-BJ4739I6. The genotyping of near-isogenic lines for I placed the locus in a region be-tween CB873567 and EBmac635, and therefore the most likely position of the I locus was proximal to CB873567 in a 5.3 cM interval between CB873567-BJ473916. [ABSTRACT FROM AUTHOR]

Spike morphology is a key characteristic in the study of barley domestication, yield, and use. Multiple alleles at the vrs1 locus control the development and fertility of the lateral spikelets of barley. We developed five amplified fragment length polymorphism (AFLP) markers tightly linked to the vrs1 locus using well-characterized near-isogenic lines as plant materials. The AFLP markers were integrated into three different maps, in which 'Azumamugi' was used as the maternal parent. Of the three maps, Hordeum vulgare L. 'Azumamugi' × H. vulgare 'Golden Promise' showed recombination of the AFLP markers and the vrs1 locus (closest, 0.05 cM), providing the best mapping population for positional cloning of alleles at the vrs1 locus. Conversion of AFLP bands into polymorphic sequence-tagged sites (STSs) is necessary for further high-throughput genotype scoring and for bacterial artificial chromosome (BAC) library screening. We cloned and sequenced the five AFLP bands and synthesized primer pairs. PCR amplification generated DNAs of the same size from all four parental lines for each marker. Restriction endonuclease treatment of e40m36-1110/AccIII, e34m13-260/Psp1406I, e52m32-270/FokI, and e31m26-520/MnlI revealed fragment length polymorphisms between 'Azumamugi' and all the two-rowed parents. Allelism between the AFLPs and corresponding STS markers was confirmed genetically, indicating the usefulness of the STSs as genetic markers. [ABSTRACT FROM AUTHOR]

Aegilops cylindrica , a salt-tolerant gene pool of wheat, is a useful plant model for understanding mechanism of salt tolerance. A salt-tolerant USL26 and a salt-sensitive K44 genotypes of A. cylindrica , originating from Uremia Salt Lake shores in Northwest Iran and a non-saline Kurdestan province in West Iran, respectively, were identified based on screening evaluation and used for this work. The objective of the current study was to investigate the expression patterns of four genes related to ion homeostasis in this species. Under treatment of 400 mM NaCl, USL26 showed significantly higher root and shoot dry matter levels and K + concentrations, together with lower Na + concentrations than K44 genotype. A. cylindrica HKT1;5 ( AecHKT1;5 ), SOS1 ( AecSOS1 ), NHX1 ( AecNHX1 ) and VP1 ( AecVP1 ) were partially sequenced to design each gene specific primer. Quantitative real-time PCR showed a differential expression pattern of these genes between the two genotypes and between the root and shoot tissues. Expressions of AecHKT1;5 and AecSOS1 was greater in the roots than in the shoots of USL26 while AecNHX1 and AecVP1 were equally expressed in both tissues of USL26 and K44. The higher transcripts of AecHKT1;5 in the roots versus the shoots could explain both the lower Na + in the shoots and the much lower Na + and higher K + concentrations in the roots/shoots of USL26 compared to K44. Therefore, the involvement of AecHKT1;5 in shoot-to-root handover of Na + in possible combination with the exclusion of excessive Na + from the root in the salt-tolerant genotype are suggested.