Polyphasic classification of Alternaria isolated from hazelnut and walnut fruit in Europe

Soon Gyu Hong, Michela Maccaroni, Patricia J. Figuli, Barry M. Pryor, Alessandra Belisario

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Brown apical necrosis of English walnut and grey necrosis of hazelnut are destructive fruit diseases caused by a complex of opportunistic fungi including several small-spored catenulate Alternaria taxa. Thirty Alternaria isolates recovered from walnut and hazelnut fruit that were pathogenic on their respective host were compared along with type or representative isolates of A. alternata, A. tenuissima, A. arborescens, and A. infectoria using morphological and molecular criteria. Morphological examination using standardized procedures separated the walnut and hazelnut isolates into three morphological groups: the A. alternata group, the A. tenuissima group, and the A. arborescens group based upon common characteristics of the conidium and the sporulation apparatus. To evaluate genetic relationships among these groups, AFLP markers, inter simple sequence repeat (ISSR) markers, and histone gene sequence data were compared. Based upon AFLP data, the A. alternata and A. tenuissima groups comprised a single lineage, and the A. arborescens group comprised a separate lineage. ISSR data supported the grouping by AFLP data except for three isolates of the A. alternata group that clustered with the A. arborescens group. Base substitution of the H4 gene supported the discrimination of the A. arborescens group from the A. alternata and A. tenuissima groups. Tests of hypotheses based upon groupings derived from the various data sets supported the discrimination of the A. arborescens group but did not support the discrimination of the A. alternata group from the A. tenuissima group.

Original languageEnglish (US)
Pages (from-to)1290-1300
Number of pages11
JournalMycological Research
Issue number11
StatePublished - Nov 2006


  • Brown apical necrosis
  • Grey necrosis
  • Molecular phylogeny
  • Plant pathology
  • Species concepts

ASJC Scopus subject areas

  • Biotechnology
  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Plant Science


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