Diversity of mycotoxins and other secondary metabolites recovered from blood oranges infected byColletotrichum,Alternaria, andPenicilliumspecies

Abstract

AbstractThis study identified secondary metabolites produced byAlternaria alternata,Colletotrichum gloeosporioidesandPenicillium digitatumin fruits of two blood orange cultivars before harvest. Analysis was performed by UHPLC–Q-TOF-MS. Three types of fruits were selected, asymptomatic, symptomatic showing necrotic lesions caused by hail, and mummified. Extracts from peel and juice were analyzed separately.Penicillium digitatumwas the prevalent species recovered from mummified and hail-injured fruits. Among 47 secondary metabolites identified, 16, 18 and 13 were ofA. alternata,C. gloeosporioidesandP. digitatum, respectively. Consistently with isolations, indicating the presence of these fungi also in asymptomatic fruits, the metabolic profiles of the peel of hail-injured and asymptomatic fruits did not differ substantially. Major differences were found in the profiles of juice from hail injured and mummified fruits, such as a significant higher presence of 5,4-dihydroxy-3,7,8-trimethoxy-6C-methylflavone and Atrovenetins, particularly in the juice of mummified fruits of Tarocco Lempso cultivar. Moreover, the mycotoxins Patulin and Rubratoxin B were detected exclusively in mummified fruits. Patulin was detected in both the juice and peel, with a higher relative abundance in the juice, while Rubratoxin B was detected only in the juice. These findings provide basic information for evaluating and preventing the risk of contamination by mycotoxins in the citrus fresh fruit supply chain and juice industry.