The tomato is one of the most consumed agri-food products in Lebanon. Several fungal pathogens, including Alternaria species, can infect tomato plants during the whole growing cycle. Alternaria infections cause severe production and economic losses in field and during storage. In addition, Alternaria species represent a serious toxicological risk since they are able to produce a wide range of mycotoxins, associated with different toxic activities on human and animal health. Several Alternaria species were detected on tomatoes, among which the most important are A. solani, A. alternata, and A. arborescens. A set of 49 Alternaria strains isolated from leaves and stems of diseased tomato plants were characterised by using a polyphasic approach. All strains were included in the recently defined phylogenetic Alternaria section and grouped in three well-separated sub-clades, namely A. alternata (24 out of 49), A. arborescens (12 out of 49), and A. mali morpho-species (12 out of 49). One strain showed high genetic similarity with an A.limoniasperae reference strain. Chemical analyses showed that most of the Alternaria strains, cultured on rice, were able to produce alternariol (AOH), alternariol methyl ether (AME), altenuene (ALT) and tenuazonic acid (TA), with values up to 5634, 16,006, 5156, and 4507 mg kg⁻¹, respectively. In addition, 66% of the strains were able to co-produce simultaneously the four mycotoxins investigated. The pathogenicity test carried out on 10 Alternaria strains, representative of phylogenetic sub-clades, revealed that they were all pathogenic on tomato fruits. No significant difference among strains was observed, although A. alternata and A. arborescens strains were slightly more aggressive than A. mali morpho-species strains. This paper reports new insights on mycotoxin profiles, genetic variability, and pathogenicity of Alternaria species on tomatoes.

The apple is one of the most important fruit tree crops in the Mediterranean region. Lebanon, in particular, is among the top apple producer countries in the Middle East; however, recently, several types of damage, particularly rot symptoms, have been detected on fruits in cold storage. This study aims to identify the causal agents of apple decay in Lebanese post-harvest facilities and characterize a set of 39 representative strains of the toxigenic fungus Penicillium. The results demonstrated that blue mould was the most frequent fungal disease associated with apples showing symptoms of decay after 3–4 months of storage at 0 °C, with an average frequency of 76.5% and 80.6% on cv. Red and cv. Golden Delicious apples, respectively. The morphological identification and phylogenetic analysis of benA gene showed that most Penicillium strains (87.2%) belong to P. expansum species whereas the remaining strains (12.8%) belong to P. solitum. Furthermore, 67.7% of P. expansum strains produced patulin when grown on apple puree for 14 days at 25 °C with values ranging from 10.7 mg kg⁻¹ to 125.9 mg kg⁻¹, whereas all P. solitum did not produce the mycotoxin. This study highlights the presence of Penicillium spp. and their related mycotoxin risk during apple storage and calls for the implementation of proper measures to decrease the risk of mycotoxin contamination of apple fruit products.

Verticillium dahliae Kleb. is a soilborne pathogen causing Verticillium wilt disease on several hosts. The pathogen survival structure (i.e., microsclerotia) can be efficiently spread by different dispersal methods. In the present study, the medium to long dispersal spread of the pathogen through rivers and irrigation canals was investigated. Samples of sediments (n = 29) were gathered from eight Lebanese rivers and three regional irrigation canals, in addition to samples of soil particles and plant residues (n = 14) from irrigation filters in commercial orchards. Specific conventional and real-time nested polymerase chain reaction assays detected the pathogen in six rivers—Al Kabir, Al Bared, Litani, Al Awali, Ostwan, and Litani South—and in all sampled canals—Ostwan, Al Bared, and Litani Canal 900. Starting DNA quantities ranged from 0.2 pg to 21.318 ng and an inoculum density, determined by a traditional plating method, varied between nondetectable and 0.2 microsclerotia/g. Viable V. dahliae microsclerotia were also found in residues collected from mesh-type irrigation filters of five commercial orchards. This study confirms that water is an important inoculum source of V. dahliae, being involved in the efficient spread of microsclerotia in Lebanese agricultural areas.

Common fig (Ficus carica L.) in is one of the most important crops in the Mediterranean area. In Italy, it is grown on a total area of 2118 ha. In Apulia (South-eastern Italy), the annual productio...

Alternaria is a ubiquitous genus that may infect wheat in many countries, causing the disease black point. The present study aimed to assess contamination by fungi, of durum wheat kernels from Lebanon, and identify the main Alternaria species contaminants. Alternaria was detected in the majority (97%) of the inspected fields. Contamination by Alternaria differed among the samples according to their geographical origins. The greatest contamination was detected in the West Bekaa area (average 59%), followed by Akkar (55%), and lowest was observed in Baalbeck (2%). HPLC-DAD analyses performed on grain samples showed that altenuene, alternariol, alternariol monomethyl ether, and tenuazonic acid were not detected in any sample. Phylogenetic analyses, based on DNA sequences of β-tubulin, glyceraldehyde-3-phosphate dehydrogenase and calmodulin gene fragments, showed that Alternaria field strains belonged to two major sections: Alternaria (51%) and Infectoriae (40%). The remaining strains were in separate clades in sections Ulocladioides (3%), Chalastospora (3%) and Pseudoalternaria (3%). Although this study revealed no contamination of wheat kernels by Alternaria mycotoxins, the potential risk of mycotoxin accumulation remains high due to the widespread occurrence of toxigenic Alternaria species on kernels.