Accumulation of Mutated Maize Zeins in Transgenic Forage Legumes

Accumulation of zeins, the endosperm storage proteins of maize, in a heterologous plant expression system was attempted. Plants of birdsfoot trefoil (Lotus corniculatus) and alfalfa (Medicago sativa) were transformed by Agrobacterium with binary vectors harboring genes that code for γ-zein and β-zein, two proteins rich in sulphur amino acids. Adding the ER retention signal KDEL to the C-terminal domain modified zein polypeptides. Our long-term goal was to improve birdsfoot trefoil and alfalfa forage quality. Significant levels of γ- zein:KDEL and β-zein:KDEL were detected in primary transformants of birdsfoot trefoil. Moreover, alfalfa plants expressing γ-zein:KDEL in the leaves were obtained. γ-zein:KDEL accumulated in spherical or elliptical electron-dense bodies of birdsfoot trefoil leaves. The protein bodies were present in the cytoplasm of either mesophyll cells or epidermis cells

Light Intensity Is Positively Correlated with the Synthesis of Condensed Tannins in \u3ci\u3eLotus corniculatus\u3c/i\u3e

The importance of Condensed Tannins (CT) in forage legumes has been well documented in several studies. The role of plant genetics in this field is the acquisition of competences in order to be able to modulate CT synthesis in leaves of these species. The role of light has been investigated in this work on the increase of condensed tannin levels in leaves of two contrasting genotypes of birdsfoot trefoil (Lotus corniculatus)

High Polymorphism for Forage Production of \u3ci\u3eLotus corniculatus Sn\u3c/i\u3e Transformants

Transgenic plants obtained from transformation of one individual of Lotus corniculatus with the maize gene Sn, a transactivator of anthocyanin pathway, were analysed for the expression of the transgene and for the accumulation of condensed tannins. A great variability was observed for these two traits. Some extreme individuals were clonally propagated and analysed for rooting ability and plant growth. Unexpectedly, a strong correlation between condensed tannin level, rooting ability and plant growth was observed. These results are discussed in order to explore new strategies to increase plant productivity in forage legumes

Role of the BANYULS(BAN) Gene from Arabidopsis Thaliana in Transgenic Alfalfa Expression of Anthocyanins and Proanthocyanidins

Condensed tannins (CTs) are flavonoid oligomers, many of which have beneficial effects on animal (bloat safe) and human health. The BAN gene encodes anthocyanidin reductase (ANR), an enzyme proposed to convert anthocyanidins to their corresponding 2,3-cis-flavan-3-ols (Xie et al., 2003). Ectopic expression of BAN in Alfalfa transgenic foliage results in accumulation of CTs. Thus, it has been assumed that the BAN gene also acts in starter units for the condensation of tannins in Alfalfa

Diagnostic du cancer du poumon: développement d’une méthode pour la détection de la mutation EGFR T790M

Le but de ce travail est de comparer le rendement de 4 kits d’extraction de ctDNA dans le plasma dans le cadre du cancer du poumon NSCLC-EGFR positif. Une bonne qualité d’ADN permettrait de rechercher la mutation de résistance EGFR p.T790M

An Italian functional genomic resource for Medicago truncatula

Background: Medicago truncatula is a model species for legumes. Its functional genomics have been considerably boosted in recent years due to initiatives based both in Europe and US. Collections of mutants are becoming increasingly available and this will help unravel the genetic control of important traits for many species of legumes. Findings: Our report is on the production of three complementary mutant collections of the model species Medicago truncatula produced in Italy in the frame of a national genomic initiative. Well established strategies were used: Tnt1 mutagenesis, TILLING and activation tagging. Both forward and reverse genetics screenings proved the efficiency of the mutagenesis approaches adopted, enabling the isolation of interesting mutants which are in course of characterization. We anticipate that the reported collections will be complementary to the recently established functional genomics tools developed for Medicago truncatula both in Europe and in the United States

Périgord black truffle genome uncovers evolutionary origins and mechanisms of symbiosis

LetterInternational audienceThe Périgord black truffle ($Tuber\ melanosporum$ Vittad.) and the Piedmont white truffle dominate today's truffle market. The hypogeous fruiting body of $T.\ melanosporum$ is a gastronomic delicacy produced by an ectomycorrhizal symbiont endemic to calcareous soils in southern Europe. The worldwide demand for this truffle has fuelled intense efforts at cultivation. Identification of processes that condition and trigger fruit body and symbiosis formation, ultimately leading to efficient crop production, will be facilitated by a thorough analysis of truffle genomic traits. In the ectomycorrhizal $Laccaria\ bicolor$, the expansion of gene families may have acted as a 'symbiosis toolbox'. This feature may however reflect evolution of this particular taxon and not a general trait shared by all ectomycorrhizal species. To get a better understanding of the biology and evolution of the ectomycorrhizal symbiosis, we report here the sequence of the haploid genome of $T.\ melanosporum$, which at $\sim$125 megabases is the largest and most complex fungal genome sequenced so far. This expansion results from a proliferation of transposable elements accounting for $\sim$58% of the genome. In contrast, this genome only contains $\sim$7,500 protein-coding genes with very rare multigene families. It lacks large sets of carbohydrate cleaving enzymes, but a few of them involved in degradation of plant cell walls are induced in symbiotic tissues. The latter feature and the upregulation of genes encoding for lipases and multicopper oxidases suggest that $T.\ melanosporum$ degrades its host cell walls during colonization. Symbiosis induces an increased expression of carbohydrate and amino acid transporters in both $L.\ bicolor$ and $T.\ melanosporum$, but the comparison of genomic traits in the two ectomycorrhizal fungi showed that genetic predispositions for symbiosis $-$'the symbiosis toolbox'$-$ evolved along different ways in ascomycetes and basidiomycete

Optimal population size for RFLP-assisted cultivar identification in alfalfa (Medicago sativa L.)

The ability of RFLP markers to distinguish between 2 heterogeneous alfalfa ecotypes, "Vogherese" and "Maremmana", was correlated with the number of plants sampled in either single-plant or bulk analyses. Independent subsample populations of 20 and 50 plants were compared for variance component partitioning and band frequencies in 20-, 50- and 100-plant subpopulations of Maremmana. Homogeneity within 3 independent bulks of the same size as given above was taken as a measure of bulk optimal size. A minimum of 50 plants is required for both single-plant and bulk analyses; however, for a large majority of bands analysed, no significant differences were detected for their frequency among populations of 20, 50 and 100 plants, with the exception of 6 bands out of 48. One ecotype-specific marker was found through bulk analysis. Results are discussed in relation to the improvement of RFLP methodology for cultivar identification in alfalfa.Taille de population optimale pour l'identification des cultivars par RFLP chez la luzerne (Medicago sativa L.). La capacité des marqueurs RFLP de distinguer entre deux écotypes hétérogènes de luzerne, "Vogherese " et "Maremmana ", a été comparée avec le nombre de plantes composant un échantillon utilisé aussi bien pour l'analyse sur des plantes individuelles que sur des plantes en mélange ("bulk "). La partition des composantes de la variance a été comparée dans des sous-échantillons de populations indépendantes de 20 et 50 plantes, et les fréquences de bandes ont été aussi comparées dans des sous-populations de Maremmana constituées par 20, 50 et 100 plantes. Le degré d'homogénéité révelé à l'intérieur de 3 "bulks " indépendants, de tailles identiques à celles qui viennent d'être mentionnées, a été pris comme mesure de la taille optimale du "bulk ". Un minimum de 50 plantes est nécessaire aussi bien pour l'analyse sur plantes individuelles qu'en "bulk ", alors que pour la grande majorité des bandes analysée, aucune différence significative de leur fréquence n'a été relevée entre les populations de 20, 50 et 100 plantes, à l'exception de 6 bandes sur 48. Un marqueur spécifique d'un écotype a été trouvé au moyen de l'analyse "bulk ". Les résultats sont discutés dans l'optique d'une amélioration de la méthodologie RFLP servant à l'identification des cultivars chez la luzerne

Variation for polyphenol oxidase activity in stems of Medicago species

Polyphenol oxidase (PPO) activity was detected in stems of both glandular-haired and glabrous wild Medicago species. Two PPO isoforms appeared in each Medicago species, the heavier isoform ranged from 120 to 180 kDa and the lighter one from 65 to 75 kDa. The substrate affinity for 4-methyl catechol was quite low (Km around 0.5 mM) in all the species examined. The PPO specific activity present in the stem epidermis of insect-resistant Medicago spp. was remarkably higher than that measured in the same tissue of susceptible alfalfa, thus suggesting a possible role of PPO in resistance against biotic stresses. (© Inra/Elsevier, Paris.)L'activité de la polyphénoloxydase (PPO) dans des tiges d'espèces de Medicago. L'activité de la polyphénoloxydase a été détectée dans des tiges d'espèces spontanées de Medicago, aussi bien du type à poils glandulaires que du type glabre. Deux isoformes de PPO sont apparues dans chacune des espèces de Medicago, la plus lourde allant de 120 à 180 kDa et la plus légère de 65 à 75 kDa. L'affinité du substrat pour le 4-méthylcatéchol est restée sur des valeurs plutôt basses (Km aux alentours de 0,5 mM) chez toutes les espèces examinées. L'activité spécifique de la PPO relevée dans l'épiderme de la tige des espèces résistantes aux insectes est apparue comme nettement plus forte que celle mesurée dans le même tissu chez la luzerne sensible, ce qui suggère que la PPO pourrait jouer un rôle dans la résistance aux stress biotiques. (© Inra/Elsevier, Paris.