Molecular characterization of natural Erwinia amylovora strains deficient in levan synthesis

apples bacteriose bacterioses bacteriosis culture media enfermedades de las plantas enzimas enzyme enzymes enzymic activity erwinia amylovora fructans frutas de pepita glicosiltransferasas glycosyltransferase glycosyltransferases levan maladie des plantes manzana medio de cultivo milieu de culture molecular genetics mutant mutantes mutants pathogenicity pathogens patogenicidad pears pera plant diseases poire polyholoside polysaccharides pome fruits pomme temperatura temperature virulence