The model pathosystem more studied is Pseudomonas avellanae/Hazelnut. Within this framework, from the initial identification and characterization of the pathogen causing the hazelnut decline in central Italy, were undertaken investigations to reveal the population structure, the origin of the different lineages, the taxonomic position within the Pseudomonas syringae complex as well as control measures and selection of tolerant germplasm. This model is providing interesting results also in term of evolution and adaptation of plant pathogenic bacteria.
The population structure of some plant pathogenic bacteria has been investigated by using repetitive-sequence based PCR (rep-PCR) and ERIC, BOX and REP primer sets jointly with appropriate statistical methods. Apart Pseudomonas avellanae, the following pathogens were studied: Pseudomonas syringae pv. syringae, Pseudomonas savastanoi pv. savastanoi, Xanthomonas arboricola pv. corylina, Xanthomonas arboricola pv. juglandis, Xanthomonas arboricola pv. fragariae, Erwinia amylovora.
For some pathogens, genes involved in the pathogenic mechanisms and some mobile genetic traits are studied. In particular, the dspA/E and hrpN genes and the plasmid pEA29 of Erwinia amylovora and the integrons of several xanthomonads, namely Xanthomonas fragariae, Xanthomonas arboricola pv. pruni, Xanthomonas arboricola pv. juglandis, Xanthomonas arboricola pv. fragariae were analysed.
official diagnostic protocols have been developed for the European Plant Protection
They concern: Xylella fastidiosa (A1 List), Xanthomonas arboricola pv. corylina (A2 List), Xanthomonas vesicatoria and Xanthomonas axonopodis pv. vesicatoria (A2 List), Xilophylus ampelinus (A2 List).
In addition, a protocol for detecting Pseudomonas avellanae in apparently healthy hazelnut trees has been also developed.
Records of new, emerging and re-emerging bacterial diseases
Several cases of new, emerging or re-emerging bacterial diseases of fruit trees species as well as vegetable and ornamental crops were recorded and studied during these years. In all cases, photographic records of field symptoms, isolation and identification by following the Koch’s postulates jointly to the confirmation by phenotypical and molecular techniques have been carried out. This continuous work allowed to establish the pictorial atlas. In some occasions, diseases specimens were supplied by colleagues involved in regional phytosanitary activities.
A project is devoted to the improvement of organic hazelnut production in Italy. In this framework, a national Congress was held on the occurrence and severity of pests and diseases in the different areas of hazelnut production in Italy.
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