Molecular identification and genetic variation of Alternaria species isolated from tomatoes using ITS1 sequencing and inter simple sequence repeat methods

Profile and in silico analysis of metabolite compounds of the endophytic fungus Alternaria alternata K-10 from Drymoglossum piloselloides as antioxidants and antibacterials

Endophytic fungi are known for producing secondary metabolites with valuable biological activities, including antiviral, anticancer, antibacterial, and antioxidant properties. This study aims to evaluate an endophytic fungus from Dragon Scales leaves (Drymoglossum piloselloides) and analyze its metabolites as antioxidants and antibacterials. In this study, an endophytic fungus was isolated from the leaves of Dragon Scales (D. piloselloides) and identified using molecular analysis of the Internal Transcribed Spacer (ITS) ribosomal RNA locus. The fungus was authenticated as Alternaria alternata strain K-10. Crude extracts were obtained using n-hexane and ethyl acetate and analyzed via GC-MS Shimadzu-QP 2010 Ultra with NIST spectral library. Antibacterial activity was observed against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using the paper disc method, showing inhibition zones of 8.7-9.3 mm and 8.8-9.4 mm for ethyl acetate and n-hexane extracts, respectively. Ethyl acetate and n-hexane extracts exhibited strong antioxidant potential against 2,2-diphenyl-1-picrylhydrazil (DPPH) radical (IC50 values of 50.99 μg mL-1 and 74.44 μg mL-1, respectively). GC-MS analysis revealed 40 compounds in both extracts, some of which, including 2-ethylhexyl ester benzoic acid, benzo-b-dihydropyran-6-hydroxy-4-4-5-7-8-pentamethyl, diethyl phthalate, and octadecanoic acid, were identified through in silico analysis and found to possess antioxidant properties. These findings hold implications for potential applications of the plant and its biological constituent to be developed as lead compounds in the medical sector.

Morphological and Molecular Characterization of Some Alternaria Species Isolated from Tomato Fruits Concerning Mycotoxin Production and Polyketide Synthase Genes

Tomatoes (Lycopersicon esculentum) are one of the main crops grown in Egypt. The fungal black spot illness of fruits is usually associated with the secretion of mycotoxin by Alternaria toxigenic species. Twenty Alternaria isolates were isolated from infected tomatoes fruits by baiting technique, morphologically identified to species level, and confirmed using Internal Transcribed Spacer (ITS) gene sequencing. ITS gene sequencing of fragments obtained 547, 547, 542, 554, and 547 bp for A. alternata, A. brassicicola, A. citri, A. radicina, and A. tenuissima, respectively. Alternaria species were investigated for mycotoxin production using the high-performance liquid chromatography (HPLC) technique. The data from the HPLC analysis showed that the mycotoxins were determined in four out of five Alternaria species, with the incidence ranging from 0.89–9.85 µg/mL of fungal extract at different retention times. Alternaria alternata was the most active species and produced three types of toxins. Polyketide synthase genes (pksH and pksJ) which are involved in the Alternaria toxin’s biosynthesis were also amplified from the DNA of Alternaria species.

The first case report of thorn-induced Alternaria alternata infection of the hand in an immunocompetent host

BACKGROUND

Fungal infection secondary to a penetrating plant thorn injury in upper extremities is infrequently reported especially in immunocompetent hosts. Alternaria is a dematicaceous hyphomycete, commonly found in decay and plant pathogens, and Alternaria alternata has been regarded as the most frequent species among more than 400 s of its species. This case is the first report of thorn-induced Alternaria alternata infection of the hand in an immunocompetent host.

CASE PRESENTATION

A 47-year-old male patient was admitted to our institution with persistent pain and swelling of the right hand even after a prior surgical removal of a previous thorn injury. Upon impression of abscess, chronic extensor tenosynovitis, and septic arthritis at the 3rd metacarpophalangeal joint based on advanced imaging, the patient underwent surgical incision and drainage. Intraoperative culture, biopsy, and gene molecular sequencing results revealed fungal infection with Alternaria alternata. Postoperatively, the patient was treated with oral itraconazole (200 mg q 12 h) for nine consecutive months.

CONCLUSIONS

We report the first case of chronic extensor tenosynovitis and septic arthritis of the hand with Alternaria alternata after a thorn injury in an immunocompetent host. Despite rare incidences of fungal extensor tenosynovitis and septic arthritis, the current case strongly suggests a careful examination of social history and surgical debridement along with a prolonged use of appropriate anti-fungal agents in thorn injuries.