Search

Fire blight is a devastating bacterial disease of rosaceous plants. Its damage to apple production is a major concern, since no existing control option has proven to be completely effective. Some commercial apple varieties, such as 'Florina' and 'Nova Easygro', exhibit a consistent level of resistance to fire blight. In this study, we used an F1 progeny of 'Florina' × 'Nova Easygro' to build parental genetic maps and identify quantitative trait loci (QTLs) related to fire blight resistance. Linkage maps were constructed using a set of microsatellites and enriched with amplified fragment length polymorphism (AFLP) markers. In parallel, progeny plants were artificially inoculated with Erwinia amylovora strain CFBP 1430 in a quarantine glasshouse. Shoot length measured 7 days after inoculation (DAI) and lesion length measured 7 and 14 DAI were used to calculate the lesion length as a percentage of the shoot length (PLL1 and PLL2, respectively). Percent lesion length data were log10-transformed (log10(PLL)) and used to perform the Kruskal-Wallis test, interval mapping (IM), and multiple QTL mapping (MQM). Two significant fire blight resistance QTLs were detected in 'Florina'. One QTL was mapped on linkage group 10 by IM and MQM; it explained 17.9% and 15.3% of the phenotypic variation by MQM with log10(PLL1) and log10(PLL2) data, respectively. A second QTL was identified on linkage group 5 by MQM with log10(PLL2) data; it explained 10.1% of the phenotypic variation. Genotyping the plants of 'Florina' pedigree with the microsatellites flanking the QTLs showed that the QTLs on linkage groups 5 and 10 were inherited from 'Jonathan' and 'Starking' (a 'Red Delicious' sport mutation), respectively. Other putative QTLs (defined as QTLs with LOD scores above the chromosomal threshold and below the genome-wide threshold) were detected by IM on linkage groups 5 and 9 of 'Nova Easygro'. Le feu bactérien est une maladie dévastatrice chez les rosacées. Les dommages qu'il cause en pomiculture sont d'autant plus graves qu'aucune méthode de lutte existante n'est complètement efficace. Quelques variétés commerciales, comme 'Florina' et 'Nova Easygro', affichent un niveau stable de résistance au feu bactérien. Dans ce travail, les auteurs ont utilisé la progéniture F1 issue d'un croisement 'Florina' × 'Nova Easygro' pour produire des cartes génétiques parentales et identifier des locus de caractère quantitatif (QTL) contribuant à la résistance au feu bactérien. Des cartes génétiques ont été produites avec des microsatellites et enrichies de marqueurs AFLP (polymorphisme de longueur des produits d'amplification). En parallèle, les plantes des progénitures ont été inoculées avec l'Erwinia amylovora souche CFBP 1430 dans une serre de quarantaine. La longueur des pousses a été mesurée 7 jours après inoculation et la longueur des lésions a été mesurée 7 et 14 jours après inoculation. Ces mesures ont été employées pour calculer la longueur des lésions en pourcentage de la longueur de la pousse (PLL1 et PLL2, respectivement). Ces données sur la longueur de lésion en pourcentage ont fait l'objet d'une transformation log10 (log10(PLL)) et ont été utilisées pour faire un test de Kruskal-Wallis, une cartographie des intervalles (IM) et une cartographie de QTL multiples (MQM). Deux QTL significatifs pour la résistance au feu bactérien ont été détectés chez 'Florina'. Un QTL a été situé sur le groupe de liaison 10 par IM et MQM ; celui-ci expliquait respectivement 17,9 et 15,3 % de la variance phénotypique lors d'analyses MQM avec les données log10(PLL1) et log10(PLL2). Un second QTL a été identifié sur le groupe de liaison 5 par MQM à l'aide des données log10(PLL2) ; il expliquait 10,1 % de la variation phénotypique. Une analyse génotypique des plantes figurant dans le pedigree de 'Florina' à l'aide des marqueurs SSR bordant ces QTL a permis de montrer que le QTL sur le groupe de liaison 10 et le QTL sur le groupe de liaison 5 avaient été hérités respectivement de 'Jonathan' et de 'Starking' (un mutant spontané dérivé de 'Red Delicious'). D'autres QTL putatifs (définis comme des QTL dont les valeurs LOD étaient au-dessus du seuil pour le LOD chromosomique, mais inférieures au LOD pour l'ensemble du génome) ont été détectés par analyse IM sur les groupes de liaison 5 et 9 chez 'Nova Easygro'. [ABSTRACT FROM AUTHOR]

Copyright of Genome is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An abstract of the article "Genetic Variability of the Italian Populations of Guignardia bidwellii, the Agent of "Black Rot" of Grapevine" by P. A. Rinaldi and colleagues is presented.

A new straightforward approach to 1-aryl-2-aminopropanes using easily accessible substrates has been developed. Simple allyl alcohol is shown to be an ideal synthetic equivalent of the C3 propane-1,2-diylium bis-cation synthon in three-component cascade reactions with arenes and sulfonamide nucleophiles to regioselectively afford 1-aryl-2-aminopropanes. The reaction is catalyzed by Cu(OTf) 2 and is expected to involve a Friedel-Crafts-type allylation of the arene, followed by hydroamination.

A new Ru 3 (CO) 12 -catalyzed directed alkenylation of 2-carboxaldimine-heterocyclopentadienes has been accomplished. This process allows coupling of furan, pyrrole, indole, and thiophene 2-carboxaldimines with electron-poor alkenes such as acrylates, vinylsulfones, and styrenes. This regio- and chemoselective oxidative C-H coupling does not require the presence of an additional sacrificial oxidant. Density functional theory calculations allowed us to propose a mechanism and unveiled the nature of the H 2 acceptor.

A dimerization/cyclization reaction of 2-benzylamino-phenols for the direct synthesis of the oxazolo-phenoxazine skeleton is reported. The reaction occurs under copper catalysis in the presence of hypervalent iodine(III), giving selectively the 5 H -oxazolo[4,5- b ]phenoxazine compounds. The cascade process, which allows the conversion of the substrates into the tetracyclic products, involves three C-H functionalization steps. Initial oxidation of electron-rich arenes by the hypervalent iodine is essential for the dimerization of substrates, whereas the formation of the five-membered rings is promoted by the copper species. 1-Benzyl-2-phenyl-6-(aryl-benzyl)amino-benzimidazoles are regioselectively obtained using N , N '-dibenzyl-phenylenediamines as starting substrates. The fluorescence emission properties of these classes of products have been evaluated.

Pyrimidine-1,3-oxazolidin-2-arylimino hybrids have been synthesized as a new class of antibacterial agents. The synthetic approach exploits a Cu(II)-catalyzed intramolecular halkoxyhalogenation of alkynyl ureas, followed by a Suzuki coupling reaction with 2,4-dimethoxypyrimidin-5-boronic acid. Biological screenings revealed that most of the compounds showed moderate to good activity against two Gram-positive ( B. subtilis , S. aureus ) and three Gram-negative ( P. aeruginosa , S. typhi , K. pneumonia ) pathogenic strains. A molecular docking study, performed in the crystal structure of 50S ribosomal unit of Haloarcula marismortui, indicated that pyrimidine-oxazolidin-2-arylimino hybrids 8c and 8h exhibited a high binding affinity (-9.65 and -10.74 kcal/mol), which was in agreement with their good antibacterial activity. The obtained results suggest that the combination of pyrimidine and oxazolidone moieties can be considered as a valid basis to develop new further modifications towards more efficacious antibacterial compounds.

A highly effective synthesis of haloalkylidene-substituted heterocycles by copper(II)-catalyzed cyclization of alkynyl ureas and secondary amides has been developed. The reaction, which involves a catalytic amount of CuCl2 and a stoichiometric amount of N-halosuccinimide, occurs selectively through an alkoxyhalogenation process. Alternatively, alkoxychlorination and alkoxybromination reactions can be performed working solely with stoichiometric CuCl2 and CuBr2, respectively.

This review highlights the development of palladium-catalyzed C-H and N-H functionalization reactions involving indole derivatives. These procedures require unactivated starting materials and are respectful of the basic principle of sustainable chemistry tied to atom economy.

In a simple procedure, the intramolecular hydroarylation of N-propargyl-pyrrole-2-carboxamides was accomplished with the aid of gold(III) catalysis. The reaction led to differently substituted pyrrolo[2,3-c]pyridine and pyrrolo[3,2-c]pyridine derivatives arising either from direct cyclization or from a formal rearrangement of the carboxamide group. Terminal alkynes are essential to achieve bicyclic pyrrolo-fused pyridinones by a 6-exo-dig process, while the presence of a phenyl group at the C-C triple bond promotes the 7-endo-dig cyclization giving pyrrolo-azepines.

A variety of 3-vinyl-substituted imidazo[1,5-a]indole derivatives were synthesized by intramolecular Pd-catalyzed cyclization of the title allenamides through either a domino carbopalladation/exo-cyclization process or a novel hydroamination reaction that proceeds smoothly under microwave irradiation. Both the observed pathways involve a π-allyl-palladium(II) complex arising from insertion of the allene group into a palladium(II) species, the latter being formed in situ by the intervention of an aryl iodide or of the N-H group. In both cases, the role of nucleophile is covered by the indole nitrogen.

Direct synthesis of 2-substituted 5-oxazolecarbaldehydes was performed by intramolecular reaction of propargylamides through treatment with a catalytic amount of Pd(II) salts in the presence of a stoichiometric amount of reoxidant agent. The heterocyclization process was well-tolerated by a wide range of aryl, heteroaryl, and alkyl propargylamides. This protocol constitutes a valuable synthetic pathway to 5-oxazolecarbaldehydes, alternative to the formylation on oxazole rings, often unsatisfactory in term of regioselectivity and yields.

[reaction: see text] N-Methoxyindoles are produced in moderate to excellent yields from the reaction between nitrosoarenes and alkynes in the presence of K2CO3/(CH3)2SO4. Terminal alkynes with conjugating substituents afford 3-substituted N-methoxyindoles exclusively. The analogous reactions with methyl propiolate provide a one-step preparation of phytoalexin analogues from Wasabi.

A divergent synthesis of quinazolin-4-ones and 1,4-benzodiazepin-5-ones by Pd(II)-catalyzed intramolecular amination of tosylated N-allyl-anthranilamides is described. Both kinds of products were available in high yields depending on the different reaction conditions., (Copyright 2004 American Chemical Society)

Indole 2-carboxamide derivatives 4 underwent palladium-catalyzed intramolecular cyclization reactions to afford beta-carbolinones or pyrazino[1,2-a]indoles according to different reaction pathways. The complete regioselectivity of the reactions was obtained in different reaction conditions.

On starting from N-allyl-substituted 2-indolecarbaldehydes and exploiting the intramolecular nitrone cycloaddition methodology, we synthesized a number of the title fused-ring indole derivatives in racemic as well as enantiopure form.