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The availability of genetic maps and phenotypic data of segregating populations allows to localize and map agronomically important genes, and to identify closely associated molecular markers to be used in marker-assisted selection and positional cloning. The objective of the present work was to develop a durum wheat intervarietal genetic and physical map based on genomic microsatellite or genomic simple sequence repeats (gSSR) markers and expressed sequence tag (EST)-derived microsatellite (EST-SSR) markers. A set of 122 new EST-SSR loci amplified by 100 primer pairs was genetically mapped on the wheat A and B genome chromosomes. The whole map also comprises 149 gSSR markers amplified by 120 primer pairs used as anchor chromosome loci, two morphological markers (Black colour, Bla1, and spike glaucousness, Ws) and two seed storage protein loci (Gli-A2 and Gli-B2). The majority of SSR markers tested (182) was chromosome-specific. Out of 275 loci 241 loci assembled in 25 linkage groups assigned to the chromosomes of the A and B genome and 34 remained unlinked. A higher percentage of markers (54.4%), localized on the B genome chromosomes, in comparison to 45.6% distributed on the A genome. The whole map covered 1,605 cM. The B genome accounted for 852.2 cM of genetic distance; the A genome basic map spanned 753.1 cM with a minimum length of 46.6 cM for chromosome 5A and a maximum of 156.2 cM for chromosome 3A and an average value of 114.5 cM. The primer sets that amplified two or more loci mapped to homoeologous as well as to non-homoeologous sites. Out of 241 genetically mapped loci 213 (88.4%) were physically mapped by using the nulli-tetrasomic, ditelosomic and a stock of 58 deletion lines dividing the A and B genome chromosomes in 94 bins. No discrepancies concerning marker order were observed but the cytogenetic maps revealed in some cases small genetic distance covered large physical regions. Putative function for mapped SSRs were assigned by searching against GenBank nonredundant database using TBLASTX algorithms.

Grain protein content (GPC) is one of the most important quality traits in wheat, defining the nutritional and end-use properties and rheological characteristics. Over the years, a number of breeding programs have been developed aimed to improving GPC, most of them having been prevented by the negative correlation with grain yield. To overcome this issue, a collection of durum wheat germplasm was evaluated for both GPC and grain protein deviation (GPD) in seven field trials. Fourteen candidate genes involved in several processes related to nitrogen metabolism were precisely located on two high-density consensus maps of common and durum wheat, and six of them were found to be highly associated with both traits. The wheat collection was genotyped using the 90 K iSelect array, and 11 stable quantitative trait loci (QTL) for GPC were detected in at least three environments and the mean across environments by the genome-wide association mapping. Interestingly, seven QTL were co-migrating with N-related candidate genes. Four QTL were found to be significantly associated to increases of GPD, indicating that selecting for GPC could not affect final grain yield per spike. The combined approaches of candidate genes and genome-wide association mapping led to a better understanding of the genetic relationships between grain storage proteins and grain yield per spike, and provided useful information for marker-assisted selection programs.

In the present study, a detailed deletion map for wheat chromosomes 5A and 5B is reported, as well as an integrated genetic linkage map of chromosome 5A enriched with single nucleotide polymorphism (SNP) markers, useful both for comparison studies with other existing maps and for mapping major genes and quantitative trait loci (QTLs). Physical mapping of 5,011 SNP markers was obtained using Chinese Spring bin deletion lines for the homoeologous chromosomes of group 5; 509 SNPs were also genetically mapped in a recombinant inbred line population segregating for chromosome 5A only, obtained by crossing the cultivar Chinese Spring and the disomic substitution line Chinese Spring-5A dicoccoides. The whole 5A genetic map, containing 572 markers, covered a total length of 248.7 cM distributed among three linkage groups of 83.5, 117.8 and 47.4, respectively. The majority of SNP markers physically mapped on 5A were mapped to a unique bin, while a small percentage was assigned a double location, suggesting the presence of a segment of 5A short arm which may have undergone a duplication followed by an insertion into the long arm of the same chromosome. A QTL analysis for yield components was performed, identifying a major QTL in the sub-telomeric region of chromosome 5A, corresponding to the 5AL15-0.67-0.78 bin; the chromosome segment was 23.5 cM long and included 111 markers. Candidate genes for yield components on chromosome 5A were identified through a syntenic genomic approach by comparison with genomes of model species. Putative function analysis revealed genes involved in basic metabolism and in stress condition responses, including heat shock proteins, chaperones, serine/threonine protein kinases and membrane transporters, located in the region of the QTL. This information represents an important step for map-based and candidate gene-based cloning of yield QTLs.

A quick and reproducible tool for cultivar identification is useful to assess in certified seed production programs and to resolve legal conflicts. Simple Sequence Repeats (SSRs) have been the elected markers to carry out cultivar identification studies. The main aim of this research was to define the minimum number of SSR markers to distinguish 80 durum wheat cultivars. Preliminary, an analysis of 11 SSRs informativeness was carried out on a subset of 28 durum wheat cultivars. The discriminating ability of each primer was estimated both with Polymorphism Information Content (PIC) and with Resolving power (Rp). Rp resulted the best parameter for assessing the discriminatory power of SSR primers (r=0.94***; P≤0.001). The marker Xwmc597 was able to discriminate all the 28 cultivars. Successively, 80 genotypes were analysed using three SSR markers with the higher Rp value. Two SSRs were able to distinguish all the 80 genotypes. Particularly, Xwmc597 was able to distinguish 69/80 genotypes while Xwmc415 identified the other cultivars. An identification key was obtained combining the data of these two markers.

Wheat is one of the most important crop grown worldwide, and especially in the Mediterranean basin, durum wheat is the most used for typical food industry. Due to the variable climate conditions, one of the most important targets for breeders in these areas is the identification of high yielding genotypes. The objective of the present study was to evaluate phenotypic variability in a set of Tunisian and Algerian durum wheat germplasm based on adaptive and yield related traits. Analysis of variance showed significant variation among genotypes, and high heritability for the analyzed agronomic traits. Tiller number per spike and spiked tiller per spike, which are an indication of the crop’s ability to maximize crop yield, ranged from 2.31 to 6.24 and 0.99 to 3.98 respectively. Heading date, one of the most important adaptive trait in cereal, also showed variability, ranging from 127 to 146 days after emergence. The 74 analyzed genotypes showed a high heritability value of thousand kernel weight (53.2%). Interestingly, genetic advance evaluated for thousand kernel weight was 13.77 g. The lowest but definitely moderate heritability value was recorded for tiller number per plant (42%), with a genetic advance of 0.51 tillers per plant. These data are an important starting point for the identification and future breeding of genotypes with higher genetic potential, important requirement for the production of high yielding wheat varieties.

Phellinus torulosus (Pers.) Bourd. et Galz. is the causal agent of white rot that infects especially the roots and the collar of old trees and shrubs of many species. The random amplified polymorphic DNA (RAPD) technique using polymerase chain reaction (PCR) was used to explore the genetic variability in 138 P. torulosus isolates from 139 oak woods of Apulia and Basilicata. The use of 16 random primers yielded 150 polymorphic fragments. The dendrograms generated by analysing RAPD data did not show correlations between the clusters and other characters such as morphotypes, host species and geographic origin [Phellinus torulosus (Pers.) Bourd et Galz. è l'agente causale della carie bianca che infetta specialmente le radici e il colletto degli alberi e degli arbusti adulti di numerose specie. E' stata utilizzata la tecnica del DNA polimorfico amplificato a caso (Random Amplified Polymorphic DNA, RAPD) impiegando la reazione a catena della polimerasi (Polymerase Chain Reaction, PCR) per studiare la variabilità genetica in 138 isolati di P. torulosus raccolti da 139 querceti della Puglia e della Basilicata. L'impiego di 16 random primer ha consentito di produrre 150 frammenti polimorfici. I dendrogrammi generati dall'analisi dei dati RAPD non evidenziano correlazioni fra i cluster e altri caratteri come morfotipi, specie ospiti e origine geografica]

Endophytic fungi are commonly detected in the crown of plants of genus Quercus, especially in declining trees, and their pathogenicity is often a point of discussion among scientists. Preliminary results on the variability and incidence of endophytes collected in 20 oak woods of four regions in southern Italy are reported. In each wood, samples were collected in spring and autumn 2002, from four healthy and/or declining Q. pubescens Willd. and Q. cerris L. adult trees. Isolations were obtained in vitro in agar media in Petri dishes from 30 buds, bark, and wood of 15 one-year-old and 15 three-year-old twigs per species and oak wood. The colonisation frequency of each endophyte was based on the formula CF = (N sub(i)/N sub(t)) x 100 (N sub(i) = number of isolations yielding the same endophyte and N sub(t) = number of all isolations done). The data from the spring survey showed that Discula quercina (West.) v. Arx (CF = 17.3%), Biscogniauxia mediterranea (De Not.) O: Kuntze (CF = 12.0%) and Aureobasidium pullulans (De Bary) Arn. (CF = 5.5%) were the most frequent fungi regardless the Quercus species. Isolations from samples collected in autumn proved that D. quercina was still the most frequent (CF = 13.9%), followed by Trichoderma sp. (CF = 12.6%), Botryosphaeria stevensii Shoemaker (CF = 6.4%) and A. pullulans (CF = 5.5%), while B. mediterranea was considered as \"occasional\" (CF<5.0%). Other \"occasional\" endophytes belonged to the genera Alternaria, Cytospora, Phoma and Phomopsis. In general, D. quercina and A. pullulans occurred mainly in both buds and one-year-old twigs, B. mediterranea was mostly isolated from three-year-old twigs, while 18% of samples did not originate any colonies. This percentage arose to 41% if only wood samples were considered. Since some of the recorded endophytes are well-known weak pathogens, this investigation points out the additional role that endophytes from buds and bark tissues can play in oak decline, especially when trees are weakened by environmental stress factors.

ObjectiveTo assess the contribution of regional grey matter (GM) atrophy and functional disconnection in determining the level of cognitive decline in patients with Alzheimer's disease (AD) at different clinical stages.MethodsTen patients with amnesic mild cognitive impairment (a-MCI), 11 patients with probable AD and 10 healthy controls were recruited. T1 volumes were obtained from each subject and postprocessed according to an optimised voxel based morphometry protocol. Resting state functional MRI data were also collected from the same individuals and analysed to produce connectivity maps after identification of the default mode network (DMN) by independent component analysis.ResultsCompared with healthy controls, both AD and a-MCI patients showed a similar regional pattern of brain disconnection between the posterior cingulate cortex (PCC) and the medial prefrontal cortex and the rest of the brain. Conversely, the distribution of GM atrophy was significantly more restricted in a-MCI than in AD patients. Interestingly, the PCC showed reduced connectivity in a-MCI patients in the absence of GM atrophy, which was, in contrast, detectable at the stage of fully developed AD.ConclusionsThis study indicates that disconnection precedes GM atrophy in the PCC, which is a critical area of the DMN, and supports the hypothesis that GM atrophy in specific regions of AD brains likely reflects a long term effect of brain disconnection. In this context, our study indicates that GM atrophy in PCC accompanies the conversion from MCI to AD.

head blight (scab) is one of the most widespread and damaging diseases of wheat, causing grain yield and quality losses and production of harmful mycotoxins. Development of resistant varieties is hampered by lack of effective resistance sources in the tetraploid wheat primary gene pool. Here we dissected the genetic basis of resistance in a new durum wheat ( ssp. ) Recombinant inbred lines (RILs) population obtained by crossing an hexaploid resistant line and a durum susceptible cultivar. A total of 135 RILs were used for constituting a genetic linkage map and mapping loci for head blight incidence, severity, and disease-related plant morphological traits (plant height, spike compactness, and awn length). The new genetic map accounted for 4,366 single nucleotide polymorphism markers assembled in 52 linkage groups covering a total length of 4,227.37 cM. Major quantitative trait loci (QTL) for scab incidence and severity were mapped on chromosomes 2AS, 3AL, and 2AS, 2BS, 4BL, respectively. Plant height loci were identified on 3A, 3B, and 4B, while major QTL for ear compactness were found on 4A, 5A, 5B, 6A, and 7A. In this work, resistance to was transferred from hexaploid to durum wheat, and correlations between the disease and morphological traits were assessed.

Wheat grain protein content (GPC) and yield components are complex quantitative traits influenced by a multi-factorial system consisting of both genetic and environmental factors. Although seed storage proteins represent less than 15% of mature kernels, they are crucial in determining end-use properties of wheat, as well as the nutritional value of derived products. Yield and GPC are negatively correlated, and this hampers breeding programs of commercially valuable wheat varieties. The goal of this work was the evaluation of genetic variability for quantity and composition of seed storage proteins, together with yield components [grain yield per spike (GYS) and thousand-kernel weight (TKW)] in a durum wheat population obtained by an inter-specific cross between a common wheat accession and the durum cv. Saragolla. Quantitative trait loci (QTL) analysis was conducted and closely associated markers identified on a genetic map composed of 4,366 SNP markers previously obtained in the same durum population genotyped with the 90K iSelect SNP assay. A total of 22 QTL were detected for traits related to durum wheat quality. Six genomic regions responsible for GPC control were mapped on chromosomes 2B, 3A, 4A, 4B, 5B, and 7B, with major QTL on chromosomes 2B, 4A, and 5B. Nine loci were detected for GYS: two on chromosome 5B and 7A and one on chromosomes 2A, 2B, 4A, 4B, 7B, with the strongest QTL on 2B. Eight QTL were identified for TKW, three of which located on chromosome 3A, two on 1B and one on 4B, 5A, and 5B. Only small overlapping was found among QTL for GYS, TKW, and GPC, and increasing alleles coming from both parents on different chromosomes. Good candidate genes were identified in the QTL confidence intervals for GYS and TKW.