Diversity and Symbiotic Associations of Endophytic Fungi in Calotropis procera (Aiton) W.T. Aiton (Asclepiadaceae) Across Three Egyptian Regions: Phenotypic Characterization and Mitotic Activity

Endophytic fungi are essential contributors to fungal biodiversity, playing key roles in plant defense against pathogens, alleviation of abiotic stress, and promotion of growth. This study conducted a comprehensive survey of the phenotypic characterization of Calotropis procera and its associated endophytic fungi across three regions in Egypt: Qena-Safaga, Qena, and Qena-Kosseir. Positive and significant Pearson correlations among plant morphological traits suggest intrinsic connections. Fungal species diversity exhibited significant variation across the three regions examined. Particularly, the Qena-Kosseir region demonstrated the highest fungal species richness both in soil samples and endophytic fungi. Unique to this region, Allocanariomyces tritici, Aspergillus terreus, Chaetomium globosum, C. murorum, Cladosporium cladosporioides, C. sphaerospermum, Fusarium proliferatum, Penicillium crustosum, P. granulatum, P. spinuloseum, and Roussoella intermedia were identified as endophytes. Additionally, compared to other regions, the Qena-Kosseir area exhibited the presence of Aspergillus fumigatus, A. ochraceus, A. ornatus, A. sclerotiocabonarus, Drechslera halodes, Emericella echinulata, Fusarium oxysporum, and Macrophomina phaseolina in soil samples, underscoring its distinct fungal community composition. Furthermore, antimitotic assays using the Allium cepa test revealed distinct effects of endophytic extracts on various mitotic stages. Of the 33 treatments, 11 showed an increase in the mitotic index (MI), indicating a potential positive effect on plant growth and cell division. This study offers valuable insights into the diversity and functional roles of endophytic fungi associated with C. procera, highlighting their promising applications in sustainable agriculture and plant health management.