http://hdl.handle.net/2067/1295 Collezione della produzione scientifica del Dipartimento di Produzione Vegetale Wed, 22 May 2013 07:27:17 GMT 2013-05-22T07:27:17Z http://hdl.handle.net/2067/2182 Title: Increased susceptibility to Pseudomonas syringae pv. syringae and Pseudomonas viridiflava of kiwi plants having transgenic rolABC genes and its inheritance in the T1 offspring Authors: Balestra, Giorgio Maria; Rugini, Eddo; Varvaro, Leonardo Abstract: The staminate kiwi (Actinidia deliciosa A. Chev) cv. GTH (Late Yellow Hayward) showed high resistance to the pathogens Pseudomonas syringae pv. syringae and Pseudomonas viridiflava, contrary to the pistillate cv. Hayward which was highly susceptible to both bacteria. The resistant staminate GTH acquired susceptibility when transformed with rolABC of Agrobacterium rhizogenes. This susceptibility was inherited by the T1 offspring containing rolABC genes, derived by crossing pollen of transgenic rolABC GTH with the pistillate cv. Hayward. The susceptibility was probably correlated to high nitrogen content in the leaves of the rolABC plants. The higher susceptibility to P. s. pv. syringae than to P. viridiflava could be correlated with the high degree of auxin production by first bacterium. The high resistance to both bacteria of the staminate GTH was inherited by all the offspring lacking rolABC genes. The possibility of reducing susceptibility of rolABC plants to the pathogens by applying fewer fertilizers in the orchards, which would reduce both costs and environmental impact, is discussed. Description: L'articolo è disponibile sul sito del nuovo editore http://onlinelibrary.wiley.com Sun, 31 Dec 2000 23:00:00 GMT http://hdl.handle.net/2067/2182 2000-12-31T23:00:00Z http://hdl.handle.net/2067/2181 Title: Olea Authors: Rugini, Eddo; De Pace, Ciro; Gutierréz-Pesce, Patricia; Muleo, Rosario Abstract: The genus Olea contains about 30 species were grouped into three subgenera, Tetrapilus, Paniculatae, and Olea (cultivated olive and wild relatives), found in Asia, Australia and Asia, Africa and Europe, respectively. The species O. europaea L. includes six subspecies: Olea europaea L. ssp. europaea (the Mediterranean olives); O. e. laperrinei (distributed in Saharan massifs of Hoggar, Aïr, Jebel Marra in Algeria); O. e. cuspidata (which moved from South Africa to Egypt, East Australian areas and Hawaii, and from Arabia to northern India and Southwest China); O. e. guanchica (Canary Islands); O. e. maroccana (southwestern Morocco); and O. e. cerasiformis (Madeira). Using molecular markers, it has been ascertained that the Mediterranean olives include the cultivated types (O. europaea L. ssp. europaea var. sativa), the true wild oleaster (O. e. e. var. sylvestris), and the feral form olevaster from seedlings raised from seeds of the cultivated types. The oleaster has a narrow range of distribution and it is often mistaken for olevaster. Recolonization of the Mediterranean basin by Oleaster occurred after the last glacial event, from refuges located in both eastern and western Mediterranean basin areas toward southern Europe. Oleaster is a source of rootstock for propagating new improved cultivated varieties. Cultivated and wild forms have the same diploid chromosome number (2n = 46) and are fully interfertile. Triploid and tetraploid genotypes have been isolated from cultivated O.e.e., but polyploid forms have been found in endangered natural populations of O. e. guancica (tetraploid) and O. e. maroccana (hexaploid). Individual oleaster trees showing superior performance for size and/or oil content of fruit were selected empirically during olive domestication and propagated vegetatively as clones using cuttings that were planted directly or, more recently, grafted onto indigenous oleasters. Genetic markers linked for most important agronomic traits, such as size of the tree, content of secondary products of fruit, flowering induction, oil quality, and biotic and abiotic resistance, will help introgression by conventional breeding of oleaster trait-enhancing genes into cultivated olive. Successful results were difficult to achieve due to both the complex genetic basis of the traits to be improved and the long juvenile period of the progenies that delays the expression of the target traits. In vitro techniques to regenerate doubled haploids from hybrids or somaclonal variation induction may complement classical breeding procedures. Genetic transformation could speed up the development of new genotypes, and transgenic olive plants with modified growth habit and putative induced disease resistance are being tested under filed conditions. However, the development of an efficient regeneration method from mature tissue is the limiting factor for the routine application of this technology to olive genetic improvement. Description: L'articolo è disponibile sul sito dell'editore http://www.springerlink.com Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2067/2181 2010-12-31T23:00:00Z http://hdl.handle.net/2067/2176 Title: Optimisation of regeneration and maintenance of morphogenic callus in pear (Pyrus communis L.) by simple and double regeneration techniques Authors: Abdollahi, Hamid; Muleo, Rosario; Rugini, Eddo Abstract: The purpose of our work was to improve the regeneration capacity of leaf explants and the maintenance of shoot morphogenesis in callus of six pear cultivars: Abate Fetel, Conference, Dar Gazi, Harrow Sweet, Kaiser and Williams, by altering the composition of both regeneration and proliferation media of explant donor shoots, and choosing the right type of explant. Regeneration capacity of leaf explants collected from in vitro shoots has been improved in the majority of cultivars also due to shoot preconditioning. For the first time, long term morphogenic callus production and maintenance have been established in some cultivars by a “double regeneration”. Using this technique, morphogenic callus of two cultivars, ‘Dar Gazi’ and ‘Conference’, was maintained for several subcultures but only when they were initiated from small leaflets – less than 2–3 mm long – which had been collected from the neoformed adventitious buds. MS medium [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassay with tobacco tissue culture. Physiol. Plant. 15, 473–497] proved to be an efficient regeneration medium by stimulating adventitious buds, while the explants of all cultivars, except for Kaiser, showed a high regeneration capacity when they were collected from shoots proliferated on modified QL medium [Quoirin, M, Lepoivre, P., Boxus, P., 1977. Un premier bilan de dix annees de recherche sur les cultures de meristemes et la multiplication in vitro de fruitiers ligneux. Compte rendu des recherches, Station des Cultures Fruitieres et Maraicheres de Gembloux (1976–1977), 93–117]. This medium conferred leaf expansion, overcoming 90% of regeneration in explants of cv Dar Gazi and Williams. Well expanded leaves were obtained and collected by rooting the shoots, while regeneration percentage was not improved and the number of adventitious shoots was increased in most cultivars, reaching up to 10 shoots per explant. When cefotaxime at 200 mg/l, which is normally effective in controlling Agrobacterium, was used for genetic transformation, regeneration percentage and number of shoots per explant (in leaf explants collected from rooted shoots) were increased and a uniform bud regeneration on all the leaf surface was promoted. Description: L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com Sat, 31 Dec 2005 23:00:00 GMT http://hdl.handle.net/2067/2176 2005-12-31T23:00:00Z http://hdl.handle.net/2067/2175 Title: Micropropagation of Teucrium fruticans L., an ornamental and medicinal plant Authors: Frabetti, Marco; Gutiérrez-Pesce, Patricia; Mendoza-de Gyves, Emilio; Rugini, Eddo Abstract: An efficient protocol for in vitro propagation of the valuable ornamental and medicinal plant Bush germander (Teucrium fruticans L.) was developed through axillary shoot proliferation. A Murashige and Skoog agar medium supplemented with benzylaminopurine (6.6 μM), α-naphthaleneacetic acid (0.053 μM), and sucrose (3%) significantly improved the production of multiple shoots directly from nodal segment explants, resulting in an average of 2.8 shoots per segment with an average of 6.8 nodes per shoot that would be potential newly formed explants. The new shoots were developed without a marked decrease in the average height of the shoots. Shoots treated with 2.5 μM indole-3-butyric acid showed the highest average root number (7.9) and the highest percentage of rooting (94%). Plantlets were hardened off and transferred to jiffy pots for acclimatization under greenhouse conditions, resulting in a 100% survival rate. Description: L'articolo è disponibile sul sito dell'editore http://www.springerlink.com Wed, 31 Dec 2008 23:00:00 GMT http://hdl.handle.net/2067/2175 2008-12-31T23:00:00Z