Molecular identification and mycotoxins analysis of some fungal isolates from postharvest decayed apple in Qena, Egypt

Abstract Background Apples are important for human nutrition because these provide vital nutrients, including vitamins and minerals, that are needed for a balanced diet. A suitable environment for the growth and survival of various microorganisms is also provided by multiple nutrients, such as carbohydrates, minerals, vitamins, and amino acids. Penicillium spp. are the cause of blue mold, one of the most common postharvest apple fruit diseases. Using morphological description and ITS gene sequencing, the current study aimed to identify Penicillium isolates associated with infected apple. High-performance liquid chromatography (HPLC) was used to demonstrate these isolates' capability for producing mycotoxins. Results The initial identification of fungi was based on micromorphological characteristics, growth texture, and colony patterns. Penicillium (35.01%) and Talaromyces (15.62%) were the most prevalent fungal genera. These isolates' morphological identity was validated by ITS gene amplification and sequencing. The generated fragments' ITS gene sequencing values were 477, 480, 510, 478, and 478 bps for Penicillium expansum strain AP1, Penicillium crustosum strain AP2, Talaromyces atroroseus strain AP3, Penicillium expansum strain AP4, and Penicillium expansum strain AP5, respectively. It was examined whether the five isolates could produce citrinin and patulin. The highest value of toxins was recorded for patulin (24180 ppb), that produced by P. expansum AP5, followed by P. crustosum AP2 (19360 ppb). However, the highest value for citrinin was 24890 ppb detected for P. expansum AP4, followed by P. expansum AP5 (19320 ppb). Conclusion Blue mold caused by Penicillium expansum, Penicillium crustosum, and Talaromyces atroroseus. These isolates have the ability to produce citrinin and patulin with different degrees. So blue mold is one of the most harmful diseases in post-harvest apple fruits.