Genetic relatedness of mycoplasmalike organisms affecting elm, alder, and ash in Europe and North America

DNA from strain ULW of the European elm witches'-broom mycoplasmalike organism (MLO) maintained in periwinkle was enriched by repeated bisbenzimide-CsCl density gradient centrifugation and cloned in Escherichia coli. Three cloned DNA fragments of the ULW MLO were used as probes to hybridize Southern blots of HindIII-digested DNA prepared from MLO-infected elm, alder, and ash trees and from periwinkle plants infected by various MLOs [...]