A collection of twenty-six Diaporthe helianthi isolates deriving from different geographic origin was analysed in order to determine the presence of extra-chromosomal genetic determinants and their molecular diversity. Extra-chromosomal bands in total genomic DNAs were identified in all the French and the Yugoslavian isolates and in only one Italian isolate, while no Romanian and Argentinean isolates resulted to host any plasmids. When tested for their chemical-physical nature by Rnase A and DNA exonucleases (III-exo and λ-exo) digestions, they were recognised as linear plasmids sized about 2.3 Kb. More detailed analysis was then performed on a plasmid purified from a French isolate (plasmid F). Its intracellular localisation resulted to be mitochondrial. Plasmid F was also exploited as a probe in Southern hybridisation experiments and it recognised only plasmids present in genomes of French and Yugoslavian isolates (countries were the disease has a heavy incidence) suggesting some specificity in relation to the geographic origin. An RFLP hybridisation analysis performed on genomic DNAs revealed a homogeneous restriction pattern in all French and Yugoslavian isolates, strongly supporting the hypothesis of a molecular relationship among plasmids present in those isolates.
Plasmid distribution in European Diaporthe helianthi isolates
VERGARA, Mariarosaria;
2005
Abstract
A collection of twenty-six Diaporthe helianthi isolates deriving from different geographic origin was analysed in order to determine the presence of extra-chromosomal genetic determinants and their molecular diversity. Extra-chromosomal bands in total genomic DNAs were identified in all the French and the Yugoslavian isolates and in only one Italian isolate, while no Romanian and Argentinean isolates resulted to host any plasmids. When tested for their chemical-physical nature by Rnase A and DNA exonucleases (III-exo and λ-exo) digestions, they were recognised as linear plasmids sized about 2.3 Kb. More detailed analysis was then performed on a plasmid purified from a French isolate (plasmid F). Its intracellular localisation resulted to be mitochondrial. Plasmid F was also exploited as a probe in Southern hybridisation experiments and it recognised only plasmids present in genomes of French and Yugoslavian isolates (countries were the disease has a heavy incidence) suggesting some specificity in relation to the geographic origin. An RFLP hybridisation analysis performed on genomic DNAs revealed a homogeneous restriction pattern in all French and Yugoslavian isolates, strongly supporting the hypothesis of a molecular relationship among plasmids present in those isolates.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
