Forest@ - Rivista di Selvicoltura ed Ecologia Forestale Ultimi lavori pubblicati Copyright (c) 2004-2015, Italian Society of Silviculture an Forest Ecology. All rights reserved it PHP 5.3.1 (Gabriele Bucci) (Gabriele Bucci) 60 Forest@ Web Site Articoli Scientifici: Necrosi corticali da Brenneria nigrifluens e altri batteri su noce in impianti piemontesi: studio dell’evoluzione della malattia in campo e caratterizzazione di isolati con rep-PCR <p><b>Giorcelli A, Gennaro M</b></p><p><b>NECROSI CORTICALI DA BRENNERIA NIGRIFLUENS E ALTRI BATTERI SU NOCE IN IMPIANTI PIEMONTESI: STUDIO DELL’EVOLUZIONE DELLA MALATTIA IN CAMPO E CARATTERIZZAZIONE DI ISOLATI CON REP-PCR</b></p><p><b>Abstract</b>: Owing to its increasing incidence, a study was performed on walnut bacterial bark canker by Brenneria nigrifluens, a disease native to California but spreading over Europe since about twenty years. B. nigrifluens may compromise wood quality and, in some cases, impair plant survival due to extensive cankers and bark necroses. Bacterial isolates obtained from bark tissue fragments, typed by rep-PCR analysis after multiplication on proper selective growing media, confirmed the diagnosis of the causal agent, despite the presence of other bacterial species. B. nigrifluens was detected in 28% of common walnut arboricultural stands located in Piedmont plains and hills, especially those located in the Vercelli province and in some areas of the Alessandria province. Based on the results of the cluster analysis carried out on PCR amplicons, none of the other bacterial isolates showed any genotypic similarity with the related B. rubrifaciens, the agent of the deep bark canker of walnut, which has not been detected in Europe yet. The application of the three rep-PCR variants, including BOX-PCR applied for the first time to B. nigrifluens, gave similar results, but with different cluster structures. In two pilot plantations, trees already presenting necroses did not necessarily develop new necroses or enlarge the pre-existing cankers in the following years. The disease apparently does not spread according to a climate factor, whereas it may be affected by plant genotype that possibly promotes the transition of B. nigrifluens, probably already present in tissues in an asymptomatic endophytic phase, to the pathogenic phase.</p><p><b>Keywords</b>: English Walnut, Brenneria nigrifluens, Shallow Bark Canker, Rep-PCR, Wood Arboriculture</p><p><i>Forest@ 11 (4): 180-188 (2014)</i> - doi: 10.3832/efor1335-011<br/><a href="" target="_blank"></a></p><hr size="1"/> Giorcelli A, Gennaro M Articoli Scientifici 2014-11-20 Copyright (c) 2015, Italian Society of Silviculture an Forest Ecology. All rights reserved