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Helianthus tuberosus L., known as the Jerusalem artichoke, is a hexaploid plant species, adapted to low-nutrient soils, that accumulates high levels of inulin in its tubers. Inulin is a fructose-based polysaccharide used either as dietary fiber or for the production of bioethanol. Key enzymes involved in inulin biosynthesis are well known. However, the gene networks underpinning tuber development and inulin accumulation in H. tuberous remain elusive. To fill this gap, we selected 6,365 expressed sequence tags (ESTs) from an H. tuberosus library to set up a microarray platform and record their expression across three tuber developmental stages, when rhizomes start enlarging (T0), at maximum tuber elongation rate (T3), and at tuber physiological maturity (Tm), in "VR" and "K8-HS142"clones. The former was selected as an early tuberizing and the latter as a late-tuberizing clone. We quantified inulin and starch levels, and qRT-PCR confirmed the expression of critical genes accounting for inulin biosynthesis. The microarray analysis revealed that the differences in morphological and physiological traits between tubers of the two clones are genetically determined since T0 and that is relatively low the number of differentially expressed ESTs across the stages shared between the clones (93). The expression of ESTs for sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructosyltransferase (1-FFT), the two critical genes for fructans polymerization, resulted to be temporarily synchronized and mirror the progress of inulin accumulation and stretching. The expression of ESTs for starch biosynthesis was insignificant throughout the developmental stages of the clones in line with the negligible level of starch into their mature tubers, where inulin was the dominant polysaccharide. Overall, our study disclosed candidate genes underpinning the development and storage of carbohydrates in the tubers of two H. tuberosus clones. A model according to which the steady-state levels of 1-SST and 1-FFT transcripts are developmentally controlled and might represent a limiting factor for inulin accumulation has been provided. Our finding may have significant repercussions for breeding clones with improved levels of inulin for food and chemical industry.

International audience; AbstractTobacco, Nicotiana tabacum, is an industrial crop traditionally used for manufacturing cigarettes. However, due to restriction of European subsidies, an alternative use of tobacco is needed, such as biofuel or biomass. Tobacco is indeed an oilseed crop with an oil yield ranging from 30 to 40 % of seed dry weight. Yet, there is still little information on the cultivation of tobacco for seed oil production. Here, we tested tobacco cultivation as an oilseed crop in Central Italy, where flue-cured tobacco is traditionally cultivated, with an additional trial in Northest Italy. We used the cultivar Solaris, selected for its reduced size and elevated number of flowers, and tested its adaptability to different field management practices in 2013–2014. Results show that in Central Italy fields, at the beginning of ripening, tobacco plants showed on the average a 94–105 cm height and a stem diameter between 1.3–1.6 cm; they had 123–151 capsules and each plant produced on average from 31 to 34 g of seeds. Seed production was evaluated to be 1.1–1.8 t/ha, with an oil yield up to 0.59 t/ha. In Northest Italy, two seed harvests determined a total seed yield of 4.5 t/ha, from which 1.48 t oil/ha could be obtained. The cultivar Solaris was extremely adaptable in terms of morphological parameters and seed yield to different management practices as well as climatic conditions. This study shows for the first time the cultivation feasibility in Italy of a small-size tobacco variety selected for high seed production. With a further optimization of the cultivation protocol to increase the oil yield and to use the by-products, tobacco can really become a novel industrial crop providing renewable sources for both biofuel and biomass as well.

NGC 2516 has been observed by Chandra several times in order to correct the plate scale of the spacecraft's focal plane instruments. Because of this, Chandra has observed NGC 2516 with all four imaging arrangements available. In addition, NGC 2516 has been observed as part of the High Resolution Camera (HRC) guaranteed time program and is scheduled for return plate scale calibration visits. This makes it the best cluster to study for long-term variability. NGC 2516 is about 140 Myr old and less than 400 pc away. In our first paper, we discussed the detection of 150 X-ray sources (42% of which are identified as cluster members) in the calibration data taken during the orbital activation phase of the Chandra mission. In our second paper, we combined all the extant data sets and detected 284 sources, more than half of which are considered likely cluster members. In this our third paper, we further explore techniques of combining Advanced CCD Imaging Spectrometer (ACIS) and HRC Chandra data for timing analysis. We have been able to combine almost 70 ks of observation time, spread over five epochs, to study variability in this cluster on multiple timescales. We find that while stochastic variability rates are about the same for all objects in the sample, the timescale for detecting variability is shorter for late-type stars. Both stochastic and flare variability rates seen in NGC 2516 are similar to those seen in younger clusters IC 348, NGC 1333, and M42.

Background: Proanthocyanidins (PAs) are secondary metabolites that strongly affect plant quality traits. The concentration and the structure of these metabolites influence the palatability and nutritional value of forage legumes. Hence, modulating PAs in the leaves of forage legumes is of paramount relevance for forage breeders worldwide. The lack of genetic variation in the leaf PA trait within the most important forage species and the difficulties in engineering this pathway via the ectopic expression of regulatory genes, prompted us to pursue alternative strategies to enhance this trait in forage legumes of agronomic interest. The Lotus genus includes forage species which accumulate PAs in edible organs and can thus be used as potential donor parents in breeding programs. Results: We recovered a wild, diploid and PA-rich population of L. corniculatus and crossed with L. tenuis. The former grows in an alkaline-salty area in Spain while the latter is a diploid species, grown extensively in South American pastures, which does not accumulate PAs in the herbage. The resulting interspecific hybrids displayed several traits of outstanding agronomic relevance such as rhizome production, PA levels in edible tissues sufficient to prevent ruminal bloating (around 5 mg of PAs/g DW), biomass production similar to the cultivated parent and potential for adaptability to marginal lands. We show that PA levels correlate with expression levels of the R2R3MYB transcription factor TT2 and, in turn, with those of the key structural genes of the epicatechin and catechin biosynthetic pathways leading to PA biosynthesis. Conclusions: The L. tenuis x L. corniculatus hybrids, reported herein, represent the first example of the introgression of the PA trait in forage legumes to levels known to provide nutritional and health benefits to ruminants. Apart from PAs, the hybrids have additional traits which may prove useful to breed forage legumes with increased persistence and adaptability to marginal conditions. Finally, our study suggests the hybrids and their progeny are an invaluable tool to gain a leap forward in our understanding of the genetic control of PA biosynthesis and tolerance to stresses in legumes. Fil: Escaray, Francisco José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: Passeri, Valentina. Institute of Biosciences and BioResources; Italia. Consiglio Nazionale delle Ricerche; Italia Fil: Babuin, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: Marco, Francisco. Universidad de Valencia; España Fil: Carrasco, Pedro. Universidad de Valencia; España Fil: Damiani, Francesco. Consiglio Nazionale delle Ricerche; Italia. Institute of Biosciences and BioResources; Italia Fil: Pieckenstain, Fernando Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina Fil: Paolocci, Francesco. Consiglio Nazionale delle Ricerche; Italia. Institute of Biosciences and BioResources; Italia Fil: Ruiz, Oscar Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús). Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas. Instituto de Investigaciones Biotecnológicas "Dr. Raúl Alfonsín" (sede Chascomús); Argentina

Lotus corniculatus plants transformed with a maize cDNA (G1L) encoding a sulphur-rich γ-zein were obtained by using two fusion genes: one with the CaMV 35S promoter, the other with the ribulose bisphosphate carboxylase small subunit (rbcS) promoter. The highest expression of G1L mRNA was found in plants transformed with G1L under the rbcS promoter. The steady state level of G1L mRNA in the leaves was generally directly correlated with the G1L copy number. However, due to a transcriptional block, no G1L mRNA was detected in some of the 35S-G1L multi-copy transformants. Analyses with methylation-sensitive restriction enzymes revealed that the T-DNA of the silenced 35S-G1L transformants was methylated. T-DNA copy number, G1L silencing activity, and the state of methylation were strictly correlated in primary transformants. A cross between two 35S-G1L transformed plants, one (S) with the T-DNA methylated and the other (NS) without, showed that: (1) the methylated state of T-DNA passed through meiosis; and (2) when T-DNA copies from the two parents were combined in the progeny, the unmethylated T-DNA copies of parent NS became methylated at different levels and G1L mRNA production was dependent on the degree of methylation.

The aim of this study was to produce somatic hybrids between tetraploid (2n=4x=32) M. sativa and diploid (2n=2x=16) M. falcata and analyse their genomic structure. Protoplasts from genotypes selected for regeneration ability from the cultivar Rangelander of M. sativa and Wisfal-1 of M. falcata were electrofused. Seven somatic hybrid calli were produced and one of them regenerated plants. The hybrid nature of these plants and their genetic composition were assessed with morphological, cytological, and molecular analyses. The resulting plants were hyper-aneuploid (2n=33) and contained one extra long chromosome, indicating that a translocation had taken place. The presence of both types of parental sequences in the RAPDs analysis confirmed the true hybrid nature of the plants. Rearrangements within the parental genomes and the presence of somaclonal variation among hybrid plants were observed through an RFLP analysis of the nucleolar organizing region (NOR). The possible causes for the gross genomic alterations, and the suitability of this method for transferring useful agronomic traits from wild species to cultivated alfalfa, are discussed.

Interspecific somatic hybrid plants were obtained by symmetrical electrofusion of mesophyll protoplasts of Medicago sativa with callus protoplasts of Medicago arborea. Somatic hybrid calli were picked manually from semi-solid culture medium after they were identified by their dual color in fluorescent light. Twelve putative hybrid calli were selected and one of them regenerated plants. The morphogenesis of the somatic hybrid calli was induced by the synthetic growth regulator 1,2 benzisoxazole-3-acetic acid. Somatic hybrid plants showed intensive genome rearrangements, as evidenced by isozyme and RFLP analysis. The morphology of somatic hybrid plants was in general intermediate between the parents. The production of hybrids by protoplast fusion between sexually incompatible Medicago species is related to the in vitro respon siveness of the parental protoplasts. The possibility of using somatic hybrid plants in alfalfa breeding is discussed.

Culture conditions have been established for callus induction and growth from different explants in L. angustissimus L. Calli were obtained from hypocotyls, leaves, stems, cotyledons and roots cultured on media containing 2,4-dichlorophenoxyacetic acid or α-naphthaleneacetic acid with kinetin, N6 − Δ2 or benzyladenine in different combinations and concentrations. Only those calli induced in presence of α-naphthaleneacetic acid with benzyladenine or kinetin produced shoots. Calli induced from hypocotyl explants were the most efficient in regeneration of shoots. Transformation with an Agrobacterium rhizogenes binary vector carrying the plasmid pBI 121.1 is reported. The percentage of cotransformation was estimated by testing GUS activity in hairy roots. The integration of Ri T-DNA and the NPTII gene in transformed plants was confirmed by molecular analyses and in vitro culture of transgenic tissues in the presence of kanamycin.

Plant regeneration from explant and protoplast derived callus has been achieved in Medicago littoralis cv. Harbinger 1886, an annual legume resistant to the fungus Pseudopeziza medicaginis. Callus was induced from different tissue explants and the fastest growth rate was observed for hypocotyls in B5 medium with 2 mg l−1 2,4-dichlorophenoxyacetic acid and 0.5 mg l−1 N6-benzyladenine. Protoplasts were isolated from cotyledons and leaves of sterile plants and from callus; the first two kinds of protoplasts showed a plating efficiency of 5.6% and 5%, respectively, when embedded in agarose. Plant regeneration occurred on media containing % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9qq-f0-yqaqVeLsFr0-vr% 0-vr0db8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaqGobWaaW% baaSqabeaacaqG2aaaaOGaaeOVfiaabs5adaahaaWcbeqaaiaaikda% aaGccaqG+waaaa!3F97!\[{\text{N}}^{\text{6}} {\text{\Delta }}^2 {\text{}}\]isopentenyl-adenine combined with indole-3-acetic acid or 1,2-benzisoxazole-3-acetic acid, and on media with N6-benzyladenine plus α-naphtaleneacetic acid; a cytokinin/auxin ratio higher than 1 induced embryos while a ratio around 1 stimulated shoot formation. Embryo development and rooting of shoots were performed in RL medium without growth regulators.

Somatic hybrid plants produced by protoplast fusion between tetraploid Medicago sativa (2n= 4x=32) and the diploid species Medicago coerulea (2n= 2x=16) have been RFLP fingerprinted to establish their nuclear composition. Although all of the chromosomes were present, molecular analysis revealed an incomplete incorporation of the alleles of the diploid parent in the fusion products. In the polycross progeny the alleles of both parents segregated in a Mendelian mode. Cytological observations indicated that in the somatic hybrid population minor abnormalities are present; these are restricted mainly to the formation of univalents and lagging chromosomes. Meiosis appeared to be more stable than has been previously reported in the hexaploids of alfalfa. The somatic hybrids grown in the field had a rather vigorous aspect, particularly with respect to the vegetative organs. Forage yield was comparable to that of thmore productive parent. The results are discussed with a view to utilizing the somatic hybrids as starting material for breeding alfalfa at the hexaploid level.

Seventeen ecotypes of the wild species Medicago polymorpha adapted to a Sardinian (Italy) environment have been evaluated for their response to tissue culture. The accession Samughero-Albi was the more respondent for callus induction and, together with Usassai, showed the highest regeneration capacity on media containing 1 mg l-1 2iP and 0.1 mg l-1 IAA. The morphogenetic response was also affected by the explant source. The hypocotyl-derived-calli were the best regenerating tissues. Regenerated plantlets were difficult to root and it was possible to obtain plants with a well developed root system only after 5–7 weeks of culture on media containing 2iP and IAA both at 0.2 mg l-1. Mesophyll cells were the best protoplast yielding source but only those isolated from roots were able to divide and to regenerate plants. Results are discussed in relation to the genotype specificity for the morphogenetic response and the feasibility of using M. polymorpha in the somatic hybridization with M. sativa.

Proanthocyanidins (PAs) are agronomically important biopolymers in higher plants composed primarily of catechin and epicatechin units. The biosynthesis of these natural products is regulated by transcription factors including proteins of the R2R3MYB class. To gain insight into the genetic control of the catechin and epicatechin branches of the PA pathway in forage legumes, here the effects of the expression of FaMYB1, a flavonoid R2R3MYB repressor from strawberry, in Lotus corniculatus (birdsfoot trefoil), were tested. It was found that in leaves of T(0) transgenic lines the degree of PA inhibition correlated with the level of FaMYB1 expression. These effects were heritable in the transgene-positive plant T(1) generation and were tissue specific as the suppression of proanthocyanidin biosynthesis was most pronounced in mesophyll cells within the leaf, whereas other flavonoid and phenolic compounds were substantially unaltered. The data suggest that FaMYB1 may counter-balance the activity of the endogenous transcriptional MYB-bHLH-WD40 (MBW) complex promoting proanthocyanidin biosynthesis via the catechin and epicatechin branches and that FaMYB1 does not interfere with the expression levels of a resident R2R3MYB activator of PAs. It is proposed that in forage legumes leaf cell commitment to synthesize proanthocyanidins relies on the balance between the activity of activator and repressor MYBs operating within the MBW complex.

Symmetric somatic hybrid plants have been produced by electrofusion of leaf protoplasts of Medicago sativa and callus protoplasts of Medicago coerulea. The selection of hybrid individuals has been performed at the cellular level by recording the positions of single heterocaryons immobilized in a semisolid culture medium. The hybrid nature of the heterokaryons was assessed in fluorescent light on the basis of their color. Hybrid minicalli were picked up manually and grown first on propagating, and then on regenerating, media. Six putative hybrid calli were selected and two of them regenerated several plants. The hybrid nature of the regenerants was confirmed by cytological and isozyme analysis. Among the several morphological traits taken into account for the characterization of somatic hybrid plants, some were intermediate, some lower, and some higher, with respect to the parents. The somatic hybrid plants were fertile and set seed. The production of somatic hybrid plants in the genus Medicago is discussed in relation to the regenerating capability of parental protoplasts.

Leaf mesophyll protoplasts of Medicago arborea (2n = 32) were electrofused with cell suspension and/or callus protoplasts of Medicago sativa. Heterokaryons were identified in agarose beds by their dual fluorescein isothiocianate—chlorophyll fluorescence and their coordinates were recorded. Hybrid minicalli were manually picked up and grown first in nurse culture and then in callus induction medium. Hybrid nature of the selected calli was confirmed by isoenzyme analyses. In order to verify whether morphogenesis of somatic hybrid calli was affected by cell incompatibility, mesophyll and cell suspension protoplasts, derived from the same plant of M. sativa with high embryogenic capacity, were fused. Only callus tissues derived from mesophyll protoplasts retained the highly embryogenic character of the M. sativa genotype, while hybrid cell lines were non-morphogenic and showed isoenzyme patterns similar to tissues derived from cell suspension protoplasts. The achievement of somatic hybrid plants in the genus Medicago is discussed.

A cultivar of Medicago sativa was transformed with Agrobacterium tumefaciens strain At81 binary-vector carrying the plasmid pKan3A, with the neomycin phosphotransferase gene under the control of the mannopine biosynthesis promoter. Stem segments were infected with the bacterium and kanamycin resistant calli were obtained; plant regeneration via somatic embryogenesis and polyembryogenesis was achieved only in media devoid of the antibiotic. Genetic transformation was confirmed by the presence of the structural gene through DNA-DNA hybridization and the enzymatic assay showed its functional expression. Mesophyll protoplasts, leaf calli and S1 progeny of transformed plants grew in the presence of kanamycin (100 μgml-1). Results are discussed in relation to the use of kanamycin-resistant plants in somatic hybridization in the genus Medicago.

Plant regeneration from leaf- and cotyledon-derived calli and from protoplast-derived tissue has been obtained in Lotus pedunculatus. Callus induction was achieved with 2,4-D and plant regeneration required the following two media sequences: bud formation was stimulated by IAA and BA and shoot growth by kinetin. Root formation occurred in the presence of IAA. Cotyledon protoplasts showed a low plating efficiency and plant regeneration was achieved via an intervening callus phase.

Evidence from numerous feeding studies with cows indicates that excessive ruminal protein degradation may be the most limiting nutritional factor in higher-quality temperature legume forages such as alfalfa and clover (Barry and McNabb, 1999). Condensed tannins (CT), found in some minor forage legumes, are known to decrease protein degradation. However, genes involved in CT biosynthesis are still largely unidentified. Since Lotus corniculatus is an in vitro highly responsive species and it does accumulate CT in edible tissues, it represents an invaluable legume model species to gain information on regulatory mechanisms leading to CT biosynthesis.

Although the necessity of interpreting the different behaviours of supposedly stable structures (the genes) and the visible differentiation of cells was outlined long ago (1934) by TH Morgan (reviewed in Jorgensen, 1994), little attention was paid to the reversible changes in the genes till the pioneering works of McClintock in the early 60s. More recently, even for the evidences coming out from the application of recombinant genetics, considerable attention has been devoted to epigenetics. Epigenetics is defined as “the study of mitotically and/or meiotically heritable changes in the function of a gene that cannot be explained by changes in its DNA sequence, and methylation is a DNA modification which has been postulated to play a central role in epigenetic regulation by modulating access to genetic information (Riggs, 1975; Holliday and Pugh, 1975).

According to the more recent classification of the Medicago genus (Quiros and Bauchan 1988), alfalfa is a unique large species named Medicago sativafalcata complex, reassembling many subspecies, sativa, falcata, coerulea, glutinosa, and glomerata, that were previously considered as separate species.

Download : Download full-size image The paper shorty describes the importance of modulating the presence of condensed tannins (CT) in the forage of legume species for improving their nutritive value. The different strategies adopted to modify CT levels in forage legumes are summarised. The paper is focused on the experiments aimed at the modification of CT levels utilising sense and antisense transformation. This strategy is adopted to produce mutants useful for isolating through cDNA comparative analyses the still unidentified genes of the CT pathway.

The genus Medicago belongs to the family Leguminosae, and includes diploid (2n = 16), polyploid (2n = 32; 2n = 48; 2n = 64), wild, and cultivated species. The most important cultivated species are tetraploid and belong to the Medicago sativa complex, derived from intermating among M. sativa subsp. saliva, M. falcata, and M. glutinosa.

The structure and maturation of the male gonad of the Mediterranean vermetid gastropod Dendropoma petraeum are described. Histological sections of the gonads were made throughout development and gonad activity was monitored at regular monthly intervals. During the autumn months the gonad is very small and is surrounded by a large quantity of connective tissue; it becomes more voluminous from December to August, with the highest growth peak in springtime. The stages of spermatogenesis were also observed and described.

Lotus corniculatus L. plants were transformed with Agrobacterium rhizogenes binary vector carrying the maize Sn regulatory gene driven by the 35S promoter. These plants showed modifications in the pattern of accumulation of proanthocyanidin (PA). All the transformed plants but one showed an increase in PA content in the root relative to control untransformed and control gus gene transformed plants (C). With respect to the PAaccumulation in leaves, Sn transgenic plants were grouped in two classes: suppressed (S), that showed a consistent reduction of foliar PAcontent, and unsuppressed (U) that did not differ significantly from controls. Dihydroflavanol reductase (DFR) and leucocyanidin reductase (LAR) enzyme activities in S and U plant leaves mirrored the changes seen with foliar PA accumulation. LAR activity in the roots was consistent with the root PA levels. Mature Sn mRNA accumulated in the leaves of U plants, but not in leaves of S plants; however, leaves of both S and U plants were able to initiate Sn transcription. All Sn-transformed plants accumulated Sn message in root tissue. A possible negative interaction of Sn and an unidentified homologous endogene is proposed for explaining the behaviour of S plants.

Selection for high and low dry matter yield within an ecotype of Lolium perenne L. was effective in producing two highly differentiated populations. The evaluation of the materials obtained after three cycles of selection snowed a realized heritability of 0.13 and a symmetrical response in the two directions of selection. The difference between populations selected in opposite directions was 448.9 mg/plant and was significant from early stages of development. After four cycles of selection, realized heritability was 0.10. The low heritability estimate suggested that more efficient selection criteria for the improvement of forage yield are needed.

The correlated responses to divergent selection for dry matter yield within an ecotype of Lolium perenne L. were evaluated in two experiments under different cutting regimes. Both experiments showed that selection for dry matter yield did not affect leaf size and caused asymmetrical correlated responses on the rate of tiller production and the rate of leaf appearance. Selection for high dry matter yield resulted in an increased rate of tiller production without change in the rate of leaf appearance. Selection for low dry matter yield did reduce both the rate of leaf appearance and the rate of tiller production.

In alfalfa (Medicago sativa) regeneration is genotype-specific. In order to study the genetic control of somatic embryogenesis and to constitute a synthetic cultivar characterized by its high regeneration ability, 2 embryogenic plants selected from the cv. Adriana were selfed, intercrossed and also crossed in both directions with 5 non-embryogenic genotypes of the same cultivar.

We have characterized the genetic consequences of somatic hybridization within the ribosomal DNA (rDNA) of three interspecific hybrids, each involving M. sativa as one of the parents. Restriction-fragment-length-polymorphisms (RFLPs) of rDNA spacers and fluorescent-in-situ-hybridization (FISH) of an 18S-gene probe to mitotic chromosomes were used to compare parental and hybrid species. The M. sativa-coerulea hybrid retained all six parental nucleolar-organizing regions (NORs) and all parental RFLPs representing a complete integration of rDNA. The M. sativa-arborea hybrid retained five of six parental NORs while losing half of the arborea-specific RFLPs, indicating that simple chromosome loss of one arborea NOR accounted for the RFLP losses. Dramatic alterations occurred within the M. sativa-falcata hybrid where five of six parental NORs were retained and new rDNA RFLPs were created and amplified differentially among somaclonal-variant plants. The molecular basis of the new RFLPs involved increased numbers of a 340-bp subrepeating element within the rDNA intergenic spacer (IGS), suggesting that recurrent cycles of unequal recombination occurred at high frequency within the rDNA in somatic lineages.

Arbuscular mycorrhiza (AM) is the most wide-spread plant-fungus symbiosis on earth. Investigating this kind of symbiosis is considered one of the most promising ways to develop methods to nurture plants in more natural manners, avoiding the complex chemical productions used nowadays to produce artificial fertilizers. In previous work we used the Calculus of Wrapped Compartments (CWC) to investigate different phases of the AM symbiosis. In this paper, we continue this line of research by modelling the colonisation of the plant root cells by the fungal hyphae spreading in the soil. This study requires the description of some spatial interaction. Although CWC has no explicit feature modelling a spatial geometry, the compartment labelling feature can be effectively exploited to define a discrete surface topology outlining the relevant sectors which determine the spatial properties of the system under consideration. Different situations and interesting spatial properties can be modelled and analysed in such a lightweight framework (which has not an explicit notion of geometry with coordinates and spatial metrics), thus exploiting the existing CWC simulation tool., Comment: In Proceedings CompMod 2011, arXiv:1109.1044

The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra} program that has imaged the central 0.5 sq.deg of the COSMOS field (centered at 10h, +02deg) with an effective exposure of ~160ksec, and an outer 0.4sq.deg. area with an effective exposure of ~80ksec. The limiting source detection depths are 1.9e-16 erg cm(-2) s(-1) in the Soft (0.5-2 keV) band, 7.3e(-16) erg cm^-2 s^-1 in the Hard (2-10 keV) band, and 5.7e(-16) erg cm(-2) s(-1) in the Full (0.5-10 keV) band. Here we describe the strategy, design and execution of the C-COSMOS survey, and present the catalog of 1761 point sources detected at a probability of being spurious of, Revised to omit egregious bold facing and fix missing ',' in author list