Morphological and chemical characterization of Alternaria populations from apple fruit

PAVICICH, MARÍA AGUSTINA; NIELSEN, KRISTIAN FOG; PATRIARCA, ANDREA

INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2022

0168-1605

Alternaria is a frequent contaminant of apple fruit,causing severe economic losses. It can produce external lesions and mouldycore, characterised by a rotten area in the apple core.In the present study, morphological and chemical characterization of Alternariafrom apples was performed, evaluating differences related to agriculturalpractices and type of disease.A low morphological diversity was observed; most of the isolates wereidentified as A. tenuissima sp.-grp. (95 %). A. arborescenssp.-grp. and A. gaisen sp.-grp. were present in a proportion of1 %, and 3 % of the isolates showed intermediate characteristics betweenthese sp.-grps. and were identified as Alternaria sp. The chemicaldiversity was greater; 27 secondary metabolites were produced by the appleisolates. The most frequents were altertoxin-I (85 %), altechromone A(76 %), tentoxin (69 %), and tenuazonic acid (68 %). Thealternariols were produced in a lower frequency when comparing with isolatesfrom other crops; alternariol, 58 % and alternariol monomethyl ether,57 %. The predominant secondary metabolite profile included compounds fromdifferent chemical families, such as dibenzopyrones, tetramic acids, perylenequinones, and cyclic tetrapeptides.A wider metabolomic capacity was observed in isolates from conventionalapples when compared to those from organic fruit, with the predominance of strongproducers of altertoxins and alternariols. The isolates from mouldy core showedhigher ability to produce metabolites from different chemical families thanthose from external lesions. The wide chemical diversity of the Alternariaapple population should be considered to assess the health risk associated withapple by-products.